47 results on '"Feiner JR"'
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2. High oxygen partial pressure decreases anemia-induced heart rate increase equivalent to transfusion.
- Author
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Feiner JR, Finlay-Morreale HE, Toy P, Lieberman JA, Viele MK, Hopf HW, Weiskopf RB, Feiner, John R, Finlay-Morreale, Heather E, Toy, Pearl, Lieberman, Jeremy A, Viele, Maurene K, Hopf, Harriet W, and Weiskopf, Richard B
- Abstract
Background: Anemia is associated with morbidity and mortality and frequently leads to transfusion of erythrocytes. The authors sought to directly compare the effect of high inspired oxygen fraction versus transfusion of erythrocytes on the anemia-induced increased heart rate (HR) in humans undergoing experimental acute isovolemic anemia.Methods: The authors combined HR data from healthy subjects undergoing experimental isovolemic anemia in seven studies performed by the group. HR changes associated with breathing 100% oxygen by nonrebreathing facemask versus transfusion of erythrocytes at their nadir hemoglobin concentration of 5 g/dl were examined. Data were analyzed using a mixed-effects model.Results: HR had an inverse linear relationship to hemoglobin concentration with a mean increase of 3.9 beats per min per gram of hemoglobin (beats/min/g hemoglobin) decrease (95% CI, 3.7-4.1 beats/min/g hemoglobin), P < 0.0001. Return of autologous erythrocytes significantly decreased HR by 5.3 beats/min/g hemoglobin (95% CI, 3.8-6.8 beats/min/g hemoglobin) increase, P < 0.0001. HR at nadir hemoglobin of 5.6 g/dl (95% CI, 5.5-5.7 g/dl) when breathing air (91.4 beats/min; 95% CI, 87.6-95.2 beats/min) was reduced by breathing 100% oxygen (83.0 beats/min; 95% CI, 79.0-87.0 beats/min), P < 0.0001. The HR at hemoglobin 5.6 g/dl when breathing oxygen was equivalent to the HR at hemoglobin 8.9 g/dl when breathing air.Conclusions: High arterial oxygen partial pressure reverses the heart rate response to anemia, probably because of its usability rather than its effect on total oxygen content. The benefit of high arterial oxygen partial pressure has significant potential clinical implications for the acute treatment of anemia and results of transfusion trials. [ABSTRACT FROM AUTHOR]- Published
- 2011
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3. Effects of skin pigmentation on pulse oximeter accuracy at low saturation.
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Bickler PE, Feiner JR, Severinghaus JW, Bickler, Philip E, Feiner, John R, and Severinghaus, John W
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- 2005
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4. In Response.
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Bickler PE, Feiner JR, and Lipnick M
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- 2024
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5. Low Perfusion and Missed Diagnosis of Hypoxemia by Pulse Oximetry in Darkly Pigmented Skin: A Prospective Study.
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Gudelunas MK, Lipnick M, Hendrickson C, Vanderburg S, Okunlola B, Auchus I, Feiner JR, and Bickler PE
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- Humans, Prospective Studies, Retrospective Studies, Hypoxia diagnosis, Oxygen, Perfusion, Missed Diagnosis, Oximetry
- Abstract
Background: Retrospective clinical trials of pulse oximeter accuracy report more frequent missed diagnoses of hypoxemia in hospitalized Black patients than White patients, differences that may contribute to racial disparities in health and health care. Retrospective studies have limitations including mistiming of blood samples and oximeter readings, inconsistent use of functional versus fractional saturation, and self-reported race used as a surrogate for skin color. Our objective was to prospectively measure the contributions of skin pigmentation, perfusion index (PI), sex, and age on pulse oximeter errors in a laboratory setting., Methods: We enrolled 146 healthy subjects, including 25 with light skin (Fitzpatrick class I and II), 78 with medium (class III and IV), and 43 with dark (class V and VI) skin. We studied 2 pulse oximeters (Nellcor N-595 and Masimo Radical 7) in prevalent clinical use. We analyzed 9763 matched pulse oximeter readings (pulse oximeter measured functional saturation [Sp o2 ]) and arterial oxygen saturation (hemoximetry arterial functional oxygen saturation [Sa o2 ]) during stable hypoxemia (Sa o2 68%-100%). PI was measured as percent infrared light modulation by the pulse detected by the pulse oximeter probe, with low perfusion categorized as PI < 1%. The primary analysis was to assess the relationship between pulse oximeter bias (difference between Sa o2 and Sp o2 ) by skin pigment category in a multivariable mixed-effects model incorporating repeated-measures and different levels of Sa o2 and perfusion., Results: Skin pigment, PI, and degree of hypoxemia significantly contributed to errors (bias) in both pulse oximeters. For PI values of 1.0% to 1.5%, 0.5% to 1.0%, and <0.5%, the P value of the relationship to mean bias or median absolute bias was <.00001. In lightly pigmented subjects, only PI was associated with positive bias, whereas in medium and dark subjects bias increased with both low perfusion and degree of hypoxemia. Sex and age was not related to pulse oximeter bias. The combined frequency of missed diagnosis of hypoxemia (pulse oximeter readings 92%-96% when arterial oxygen saturation was <88%) in low perfusion conditions was 1.1% for light, 8.2% for medium, and 21.1% for dark skin., Conclusions: Low peripheral perfusion combined with darker skin pigmentation leads to clinically significant high-reading pulse oximeter errors and missed diagnoses of hypoxemia. Darkly pigmented skin and low perfusion states are likely the cause of racial differences in pulse oximeter performance in retrospective studies., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 International Anesthesia Research Society.)
- Published
- 2024
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6. Reducing Volatile Anesthetic Waste Using a Commercial Electronic Health Record Clinical Decision Support Tool to Lower Fresh Gas Flows.
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Olmos AV, Robinowitz D, Feiner JR, Chen CL, and Gandhi S
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- Sevoflurane, Desflurane, Electronic Health Records, Anesthesia, Inhalation, Anesthetics, Inhalation, Isoflurane, Methyl Ethers, Decision Support Systems, Clinical
- Abstract
Background: Volatile anesthetic consumption can be reduced by minimizing excessive fresh gas flows (FGFs). Currently, it is unknown whether decision support tools embedded within commercial electronic health record systems can be successfully adopted to achieve long-term reductions in FGF rates. The authors describe the implementation of an electronic health record-based clinical decision support tool aimed at reducing FGF and evaluate the effectiveness of this intervention in achieving sustained reductions in FGF rates and volatile anesthetic consumption., Methods: On August 29, 2018, we implemented a decision support tool within the Epic Anesthesia Information Management System (AIMS) to alert providers of high FGF (>0.7 L/min for desflurane and >1 L/min for sevoflurane) during maintenance of anesthesia. July 22, 2015, to July 10, 2018, served as our baseline period before the intervention. The intervention period spanned from August 29, 2018, to December 31, 2019. Our primary outcomes were mean FGF (L/min) and volatile agent consumption (mL/MAC-h). Because a simple comparison of 2 time periods may result in false conclusions due to underlying trends independent of the intervention, we performed segmented regression of the interrupted time series to assess the change in level at the start of the intervention and the differences in slopes before and after the intervention. The analysis was also adjusted for potential confounding variables. Data included 44,899 cases using sevoflurane preintervention with 26,911 cases postintervention, and 17,472 cases using desflurane with 1185 cases postintervention., Results: Segmented regression of the interrupted times series demonstrated a decrease in mean FGF by 0.6 L/min (95% CI, 0.6-0.6 L/min; P < .0001) for sevoflurane and 0.2 L/min (95% CI, 0.2-0.3 L/min; P < .0001) for desflurane immediately after implementation of the intervention. For sevoflurane, mL/MAC-h decreased by 3.8 mL/MAC-h (95% CI, 3.6-4.1 mL/MAC-h; P < .0001) after implementation of the intervention and decreased by 4.1 mL/MAC-h (95% CI, 2.6-5.6 mL/MAC-h; P < .0001) for desflurane. Slopes for both FGF and mL/MAC-h in the postintervention period were statistically less negative than the preintervention slopes (P < .0001 for sevoflurane and P < .01 for desflurane)., Conclusions: A commercial AIMS-based decision support tool can be adopted to change provider FGF management patterns and reduce volatile anesthetic consumption in a sustainable fashion., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 International Anesthesia Research Society.)
- Published
- 2023
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7. Frequency, Method, Intensity, and Health Sequelae of Sexual Choking Among U.S. Undergraduate and Graduate Students.
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Herbenick D, Fu TC, Eastman-Mueller H, Thomas S, Svetina Valdivia D, Rosenberg M, Guerra-Reyes L, Wright PJ, Kawata K, and Feiner JR
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- Adolescent, Female, Humans, Male, Sexual Partners, Students, Surveys and Questionnaires, Airway Obstruction epidemiology, Sexual Behavior
- Abstract
Although sexual choking is now prevalent, little is known about how people engage in choking in terms of frequency, intensity, method, or potential health sequelae. In a campus-representative survey of undergraduate and graduate students, we aimed to: (1) describe the prevalence of ever having choked/been choked as part of sex; (2) examine the characteristics of choking one's sexual partners (e.g., age at first experience, number of partners, frequency, intensity, method); (3) examine the characteristics of having been choked during sex; and (4) assess immediate responses of having been choked including the extent to which frequency and method (e.g., hand, ligature, limb) of having been choked predicts the range of responses endorsed by participants. A total of 4254 randomly sampled students (2668 undergraduate, 1576 graduate) completed a confidential online survey during Spring 2021. The mean age of first choking/being choked was about 19, with more undergraduates than graduate students reporting first choking/being choked in adolescence. Women and transgender/gender non-binary participants were significantly more likely to have been choked than men. Participants more often reported the use of hands compared to limbs or ligature. Common responses to being choked were pleasurable sensations/euphoria (81.7%), a head rush (43.8%), feeling like they could not breathe (43.0%), difficulty swallowing (38.9%), unable to speak (37.6%), and watery eyes (37.2%). About 15% had noticed neck bruising and 3% had lost consciousness from being choked. Greater frequency and intensity of being choked was associated with reports of more physical responses as was use of limb (arm, leg) or ligature., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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8. Pulse Oximeter Performance, Racial Inequity, and the Work Ahead.
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Okunlola OE, Lipnick MS, Batchelder PB, Bernstein M, Feiner JR, and Bickler PE
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- Humans, Hypoxia diagnosis, Hypoxia etiology, Skin Pigmentation, Oximetry, Oxygen
- Abstract
It has long been known that many pulse oximeters function less accurately in patients with darker skin. Reasons for this observation are incompletely characterized and potentially enabled by limitations in existing regulatory oversight. Based on decades of experience and unpublished data, we believe it is feasible to fully characterize, in the public domain, the factors that contribute to missing clinically important hypoxemia in patients with darkly pigmented skin. Here we propose 5 priority areas of inquiry for the research community and actionable changes to current regulations that will help improve oximeter accuracy. We propose that leading regulatory agencies should immediately modify standards for measuring accuracy and precision of oximeter performance, analyzing and reporting performance outliers, diversifying study subject pools, thoughtfully defining skin pigmentation, reporting data transparently, and accounting for performance during low-perfusion states. These changes will help reduce bias in pulse oximeter performance and improve access to safe oximeters., Competing Interests: The UCSF Hypoxia Research Laboratory, Clinimark, and Physio Monitor, LLC charge pulse oximeter manufacturers for performing validation studies, but no companies were involved with the writing or data analysis presented in this paper., (Copyright © 2022 by Daedalus Enterprises.)
- Published
- 2022
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9. Perioperative Normal Saline Administration and Delayed Graft Function in Patients Undergoing Kidney Transplantation: A Retrospective Cohort Study.
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Kolodzie K, Cakmakkaya OS, Boparai ES, Tavakol M, Feiner JR, Kim MO, Newman TB, and Niemann CU
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- Adult, Aged, Cohort Studies, Delayed Graft Function diagnosis, Female, Humans, Kidney Transplantation trends, Male, Middle Aged, Perioperative Care methods, Retrospective Studies, Delayed Graft Function chemically induced, Delayed Graft Function epidemiology, Kidney Transplantation adverse effects, Perioperative Care adverse effects, Saline Solution administration & dosage, Saline Solution adverse effects
- Abstract
Background: Perioperative normal saline administration remains common practice during kidney transplantation. The authors hypothesized that the proportion of balanced crystalloids versus normal saline administered during the perioperative period would be associated with the likelihood of delayed graft function., Methods: The authors linked outcome data from a national transplant registry with institutional anesthesia records from 2005 to 2015. The cohort included adult living and deceased donor transplants, and recipients with or without need for dialysis before transplant. The primary exposure was the percent normal saline of the total amount of crystalloids administered perioperatively, categorized into a low (less than or equal to 30%), intermediate (greater than 30% but less than 80%), and high normal saline group (greater than or equal to 80%). The primary outcome was the incidence of delayed graft function, defined as the need for dialysis within 1 week of transplant. The authors adjusted for the following potential confounders and covariates: transplant year, total crystalloid volume, surgical duration, vasopressor infusions, and erythrocyte transfusions; recipient sex, age, body mass index, race, number of human leukocyte antigen mismatches, and dialysis vintage; and donor type, age, and sex., Results: The authors analyzed 2,515 records. The incidence of delayed graft function in the low, intermediate, and high normal saline group was 15.8% (61/385), 17.5% (113/646), and 21% (311/1,484), respectively. The adjusted odds ratio (95% CI) for delayed graft function was 1.24 (0.85 to 1.81) for the intermediate and 1.55 (1.09 to 2.19) for the high normal saline group compared with the low normal saline group. For deceased donor transplants, delayed graft function in the low, intermediate, and high normal saline group was 24% (54/225 [reference]), 28.6% (99/346; adjusted odds ratio, 1.28 [0.85 to 1.93]), and 30.8% (277/901; adjusted odds ratio, 1.52 [1.05 to 2.21]); and for living donor transplants, 4.4% (7/160 [reference]), 4.7% (14/300; adjusted odds ratio, 1.15 [0.42 to 3.10]), and 5.8% (34/583; adjusted odds ratio, 1.66 [0.65 to 4.25]), respectively., Conclusions: High percent normal saline administration is associated with delayed graft function in kidney transplant recipients., (Copyright © 2021, the American Society of Anesthesiologists. All Rights Reserved.)
- Published
- 2021
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10. Pediatric Distraction on Induction of Anesthesia With Virtual Reality and Perioperative Anxiolysis: A Randomized Controlled Trial.
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Jung MJ, Libaw JS, Ma K, Whitlock EL, Feiner JR, and Sinskey JL
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- Age Factors, Anxiety diagnosis, Anxiety etiology, Anxiety psychology, Child, Child, Preschool, Female, Humans, Male, Prospective Studies, San Francisco, Time Factors, Treatment Outcome, Anesthesia, General adverse effects, Anxiety prevention & control, Child Behavior, Preoperative Care, Virtual Reality
- Abstract
Background: Perioperative pediatric anxiety is common and can have a negative psychological impact on children undergoing surgery and anesthesia. Studies have shown an incidence of anxiety at induction of up to 50%. Audiovisual distraction, including virtual reality (VR), is a noninvasive, nonpharmacological modality that may reduce perioperative anxiety. The goal of this study was to determine whether immersive audiovisual distraction with a VR headset during induction of general anesthesia (GA) in pediatric patients reduced preoperative anxiety., Methods: In this randomized-controlled, parallel-group study, 71 children 5-12 years of age scheduled for elective surgery with GA were randomly allocated to a VR group or a non-VR (No VR) control group. VR group patients underwent audiovisual distraction with a VR headset during induction in the operating room, whereas the control group received no audiovisual distraction. The primary outcome was the Modified Yale Preoperative Anxiety Scale (mYPAS), which was measured at 3 time points to assess patient anxiety: in the preoperative holding area before randomization, on entering the operating room, and during induction of GA. The primary outcome was analyzed using univariate analysis and a linear mixed-effects model. Secondary outcomes included postinduction parental anxiety measured by the State-Trait Anxiety Inventory, pediatric induction compliance, and parental satisfaction., Results: Average patient age was 8.0 ± 2.3 years (mean ± standard deviation [SD]), and 51.4% of patients were female. Baseline variables were not substantially different between the VR group (33 patients) and the No VR group (37 patients). No patients received preoperative anxiolytic medication. Baseline mYPAS scores were not different between the groups, with scores of 28.3 (23.3-28.3) (median [interquartile range {IQR}]) in both. The change in mYPAS scores from baseline to time of induction was significantly lower in the VR group versus control group (0.0 [0.0-5.0] vs 13.3 [5.0-26.7]; P < .0001). In the mixed-effects model, the VR group had an estimated 6.0-point lower mYPAS score (95% confidence interval [CI], 0.7-11.3; P = .03) at room entry than the No VR group, and 14.5-point lower score (95% CI, 9.3-19.8; P < .0001) at induction versus control. Randomization to VR did not alter parental anxiety (0 [-2 to 2]), pediatric induction compliance (0 [0-0]), or parental satisfaction (-3 [-8 to 2]) (difference in medians [95% CI])., Conclusions: This study demonstrates a reduction in pediatric preoperative anxiety with the use of VR. Preoperative VR may be an effective noninvasive modality for anxiolysis during induction of anesthesia in children., Competing Interests: Conflicts of Interest: See Disclosures at the end of the article., (Copyright © 2020 International Anesthesia Research Society.)
- Published
- 2021
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11. "Silent" Presentation of Hypoxemia and Cardiorespiratory Compensation in COVID-19.
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Bickler PE, Feiner JR, Lipnick MS, and McKleroy W
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- Humans, SARS-CoV-2, COVID-19 complications, COVID-19 physiopathology, Heart physiopathology, Hypoxia etiology, Hypoxia physiopathology, Respiratory System physiopathology
- Published
- 2021
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12. Anesthesia for Maternal-Fetal Interventions: A Survey of Fetal Therapy Centers in the North American Fetal Therapy Network.
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Wood CL, Zuk J, Rollins MD, Silveira LJ, Feiner JR, Zaretsky M, and Chatterjee D
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- Adult, Child, Female, Humans, North America, Pregnancy, Anesthesia, Anesthesiology, Fetal Diseases surgery, Fetal Therapies
- Abstract
Introduction: A wide range of fetal interventions are performed across fetal therapy centers (FTCs). We hypothesized that there is significant variability in anesthesia staffing and anesthetic techniques., Methods: We conducted an online survey of anesthesiology directors at every FTC within the North American Fetal Therapy Network (NAFTNet). The survey included details of fetal interventions performed in 2018, anesthesia staffing models, anesthetic techniques, fetal monitoring, and postoperative management., Results: There was a 92% response rate. Most FTCs are located within an adult hospital and employ a small team of anesthesiologists. There is heterogeneity when evaluating anesthesiology fellowship training and staffing, indicating there is a multidisciplinary specialty team-based approach even within anesthesiology. Minimally invasive fetal interventions were the most commonly performed. The majority of FTCs also performed ex utero intrapartum treatment (EXIT) and open mid-gestation procedures under general anesthesia (GA). Compared to FTCs only performing minimally invasive procedures, FTCs performing open fetal procedures were more likely to have a pediatric surgeon as director and performed more minimally invasive procedures., Conclusions: There is considerable variability in anesthesia staffing, caseload, and anesthetic techniques among FTCs in NAFTNet. Most FTCs used maternal sedation for minimally invasive procedures and GA for EXIT and open fetal surgeries., (© 2021 S. Karger AG, Basel.)
- Published
- 2021
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13. The Association Between Vena Cava Implantation Technique and Acute Kidney Injury After Liver Transplantation.
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Hannon V, Kothari RP, Zhang L, Bokoch MP, Hill R, Roll GR, Mello A, Feiner JR, Liu KD, Niemann CU, and Adelmann D
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- Acute Kidney Injury diagnosis, Acute Kidney Injury mortality, Female, Glomerular Filtration Rate, Graft Survival, Humans, Incidence, Liver Transplantation mortality, Male, Middle Aged, Retrospective Studies, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, Vascular Surgical Procedures mortality, Warm Ischemia adverse effects, Acute Kidney Injury prevention & control, Liver Transplantation adverse effects, Vascular Surgical Procedures adverse effects, Vena Cava, Inferior surgery
- Abstract
Background: Acute kidney injury (AKI) after liver transplantation is associated with increased morbidity and mortality. It remains controversial whether the choice of vena cava reconstruction technique impacts AKI., Methods: This is a single-center retrospective cohort of 897 liver transplants performed between June 2009 and September 2018 using either the vena cava preserving piggyback technique or caval replacement technique without veno-venous bypass or shunts. The association between vena cava reconstruction technique and stage of postoperative AKI was assessed using multivariable ordinal logistic regression. Causal mediation analysis was used to evaluate warm ischemia time as a potential mediator of this association., Results: The incidence of AKI (AKI stage ≥2) within 48 h after transplant was lower in the piggyback group (40.3%) compared to the caval replacement group (51.8%, P < 0.001). Piggyback technique was associated with a reduced risk of developing a higher stage of postoperative AKI (odds ratio, 0.49; 95% confidence interval, 0.37-0.65, P < 0.001). Warm ischemia time was shorter in the piggyback group and identified as potential mediator of this effect. There was no difference in renal function (estimated glomerular filtration rate and the number of patients alive without dialysis) 1 y after transplant., Conclusions: Piggyback technique, compared with caval replacement, was associated with a reduced incidence of AKI after liver transplantation. There was no difference in long-term renal outcomes between the 2 groups.
- Published
- 2020
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14. New Method of Destroying Waste Anesthetic Gases Using Gas-Phase Photochemistry.
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Rauchenwald V, Rollins MD, Ryan SM, Voronov A, Feiner JR, Šarka K, and Johnson MS
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- Anesthesia, Inhalation adverse effects, Anesthetics, Inhalation analysis, Greenhouse Gases analysis, Hazardous Waste analysis, Humans, Anesthetics, Inhalation adverse effects, Anesthetics, Inhalation chemistry, Greenhouse Gases adverse effects, Greenhouse Gases chemistry, Hazardous Waste adverse effects, Photochemistry methods
- Abstract
Background: The inhalation anesthetics are potent greenhouse gases. To reduce the global environmental impact of the health care sector, technologies are sought to limit the release of waste anesthetic gas into the atmosphere., Methods: Using a photochemical exhaust gas destruction system, removal efficiencies for nitrous oxide, desflurane, and sevoflurane were measured at various inlet concentrations (25% and 50%; 1.5%, 3.0%, and 6.0%; and 0.5%, 1.0%, and 2.0%, respectively) with flow rates ranging from 0.25 to 2.0 L/min. To evaluate the economic competitiveness of the anesthetic waste gas destruction system, its price per ton of carbon dioxide equivalent was calculated and compared to other greenhouse gas abatement technologies and current market prices., Results: All inhaled anesthetics evaluated demonstrate enhanced removal efficiencies with decreasing flow rates (P < .0001). Depending on the anesthetic and its concentration, the photochemical exhaust gas destruction system exhibits a constant first-order removal rate, k. However, there was not a simple relation between the removal rate k and the species concentration. The costs for removing a ton of carbon dioxide equivalents are <$0.005 for desflurane, <$0.114 for sevoflurane, and <$49 for nitrous oxide., Conclusions: Based on this prototype study, destroying sevoflurane and desflurane with this photochemical anesthetic waste gas destruction system design is efficient and cost-effective. This is likely also true for other halogenated inhalational anesthetics such as isoflurane. Due to differing chemistry of nitrous oxide, modifications of this prototype photochemical reactor system are necessary to improve its removal efficiency for this gas.
- Published
- 2020
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15. Response to Burtscher re: "Increased Cytokines at High Altitude: Lack of Effect of Ibuprofen on Acute Mountain Sickness, Physiological Variables, or Cytokine Levels".
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Bickler P, Feiner JR, and Lundeberg J
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- Acute Disease, Altitude, Cytokines, Humans, Altitude Sickness, Ibuprofen
- Published
- 2018
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16. Increased Cytokines at High Altitude: Lack of Effect of Ibuprofen on Acute Mountain Sickness, Physiological Variables, or Cytokine Levels.
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Lundeberg J, Feiner JR, Schober A, Sall JW, Eilers H, and Bickler PE
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- Acclimatization drug effects, Adult, Altitude Sickness blood, Altitude Sickness drug therapy, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Brain metabolism, Cytokines genetics, Double-Blind Method, Female, Gene Expression drug effects, Granulocyte-Macrophage Colony-Stimulating Factor blood, Granulocyte-Macrophage Colony-Stimulating Factor genetics, Heart Rate drug effects, Humans, Ibuprofen therapeutic use, Interleukin-10 blood, Interleukin-10 genetics, Interleukin-1beta blood, Interleukin-1beta genetics, Interleukin-6 blood, Interleukin-6 genetics, Interleukin-8 blood, Interleukin-8 genetics, Male, Middle Aged, Muscle, Skeletal metabolism, Oximetry, Oxygen metabolism, RNA, Messenger blood, Treatment Failure, Tumor Necrosis Factor-alpha blood, Tumor Necrosis Factor-alpha genetics, Young Adult, Altitude Sickness physiopathology, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Cytokines blood, Ibuprofen pharmacology, Oxygen blood
- Abstract
Lundeberg, Jenny, John R. Feiner, Andrew Schober, Jeffrey W. Sall, Helge Eilers, and Philip E. Bickler. Increased cytokines at high altitude: lack of effect of ibuprofen on acute mountain sickness, physiological variables or cytokine levels. High Alt Med Biol. 19:249-258, 2018., Introduction: There is no consensus on the role of inflammation in high-altitude acclimatization., Aims: To determine the effects of a nonsteroidal anti-inflammatory drug (ibuprofen 400 mg every 8 hours) on blood cytokines, acclimatization, acute mountain sickness (AMS, Lake Louise Score), and noninvasive oxygenation in brain and muscle in healthy volunteers., Materials and Methods: In this double-blind study, 20 volunteers were randomized to receive ibuprofen or placebo at sea level and for 48 hours at 3800 m altitude. Arterial, brain, and leg muscle saturation with near infrared spectroscopy, pulse oximetry, and heart rate were measured. Blood samples were collected for cytokine levels and cytokine gene expression., Results: All of the placebo subjects and 8 of 11 ibuprofen subjects developed AMS at altitude (p = 0.22, comparing placebo and ibuprofen). On arrival at altitude, the oxygen saturation as measured by pulse oximetry (S
p O2 ) was 84.5% ± 5.4% (mean ± standard deviation). Increase in blood interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) levels occurred comparably in the placebo and ibuprofen groups (all not significant, univariate test by Wilcoxon rank sum). Increased IL-6 was associated with higher AMS scores (p = 0.002 by Spearman rank correlation). However, we found no difference or association in AMS score and blood or tissue oxygenation between the ibuprofen and placebo groups., Conclusions: We found that ibuprofen, at the package-recommended adult dose, did not have a significant effect on altitude-related increases in cytokines, AMS scores, blood, or tissue oxygenation in a population of healthy subjects with a high incidence of AMS.- Published
- 2018
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17. Intraoperative Management of Liver Transplant Patients Without the Routine Use of Renal Replacement Therapy.
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Adelmann D, Olmos A, Liu LL, Feiner JR, Roll GR, Burdine L, Tavakol M, Syed S, Orandi BJ, and Niemann CU
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- Acidosis etiology, End Stage Liver Disease complications, End Stage Liver Disease diagnosis, End Stage Liver Disease physiopathology, Female, Humans, Hyperkalemia etiology, Intraoperative Care adverse effects, Kidney Transplantation adverse effects, Liver Transplantation adverse effects, Male, Middle Aged, Renal Insufficiency complications, Renal Insufficiency diagnosis, Renal Insufficiency physiopathology, Retrospective Studies, Risk Factors, Treatment Outcome, End Stage Liver Disease surgery, Intraoperative Care methods, Kidney Transplantation methods, Liver Transplantation methods, Renal Dialysis adverse effects, Renal Insufficiency therapy
- Abstract
Background: Renal failure is common among patients undergoing liver transplantation. Liver allocation based on the model for end-stage liver disease score has increased the number of recipients who require perioperative renal replacement therapy (RRT). Although RRT can be continued intraoperatively, the risks and benefits of intraoperative RRT are not well defined. The aim of this study is to report the intraoperative management of patients with pretransplant renal failure at a transplant center with extremely infrequent utilization of intraoperative RRT., Materials and Methods: We performed a retrospective analysis of all adult patients undergoing orthotopic liver or simultaneous liver-kidney (SLK) transplantation between June 2009 and December 2015. Patients were divided into 2 groups based on their need for pretransplant RRT., Results: A total of 785 patients underwent liver or SLK transplant during the study period. One hundred and seventy-four patients (22.2%) required preoperative dialysis. Only 2 patients required intraoperative RRT. There was no difference in the incidence of acidosis or hyperkalemia between patients who required preoperative dialysis and those who did not., Conclusions: We describe the successful management of patients undergoing liver or SLK transplantation almost entirely without the need for intraoperative RRT.
- Published
- 2018
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18. Four Types of Pulse Oximeters Accurately Detect Hypoxia during Low Perfusion and Motion.
- Author
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Louie A, Feiner JR, Bickler PE, Rhodes L, Bernstein M, and Lucero J
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- Adult, Algorithms, Artifacts, Female, Humans, Male, Motion, Oxygen, Reference Values, Reproducibility of Results, Young Adult, Hypoxia diagnosis, Oximetry instrumentation
- Abstract
Background: Pulse oximeter performance is degraded by motion artifacts and low perfusion. Manufacturers developed algorithms to improve instrument performance during these challenges. There have been no independent comparisons of these devices., Methods: We evaluated the performance of four pulse oximeters (Masimo Radical-7, USA; Nihon Kohden OxyPal Neo, Japan; Nellcor N-600, USA; and Philips Intellivue MP5, USA) in 10 healthy adult volunteers. Three motions were evaluated: tapping, pseudorandom, and volunteer-generated rubbing, adjusted to produce photoplethsmogram disturbance similar to arterial pulsation amplitude. During motion, inspired gases were adjusted to achieve stable target plateaus of arterial oxygen saturation (SaO2) at 75%, 88%, and 100%. Pulse oximeter readings were compared with simultaneous arterial blood samples to calculate bias (oxygen saturation measured by pulse oximetry [SpO2] - SaO2), mean, SD, 95% limits of agreement, and root mean square error. Receiver operating characteristic curves were determined to detect mild (SaO2 < 90%) and severe (SaO2 < 80%) hypoxemia., Results: Pulse oximeter readings corresponding to 190 blood samples were analyzed. All oximeters detected hypoxia but motion and low perfusion degraded performance. Three of four oximeters (Masimo, Nellcor, and Philips) had root mean square error greater than 3% for SaO2 70 to 100% during any motion, compared to a root mean square error of 1.8% for the stationary control. A low perfusion index increased error., Conclusions: All oximeters detected hypoxemia during motion and low-perfusion conditions, but motion impaired performance at all ranges, with less accuracy at lower SaO2. Lower perfusion degraded performance in all but the Nihon Kohden instrument. We conclude that different types of pulse oximeters can be similarly effective in preserving sensitivity to clinically relevant hypoxia.
- Published
- 2018
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19. Comparison of Transcranial Doppler and Ultrasound-Tagged Near Infrared Spectroscopy for Measuring Relative Changes in Cerebral Blood Flow in Human Subjects.
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Lipnick MS, Cahill EA, Feiner JR, and Bickler PE
- Subjects
- Adult, Female, Humans, Male, Monitoring, Intraoperative methods, Monitoring, Intraoperative standards, Spectroscopy, Near-Infrared standards, Ultrasonography, Doppler, Transcranial standards, Blood Flow Velocity physiology, Cerebrovascular Circulation physiology, Spectroscopy, Near-Infrared methods, Ultrasonography, Doppler, Transcranial methods
- Abstract
Background: Currently, no reliable method exists for continuous, noninvasive measurements of absolute cerebral blood flow (CBF). We sought to determine how changes measured by ultrasound-tagged near-infrared spectroscopy (UT-NIRS) compare with changes in CBF as measured by transcranial Doppler (TCD) in healthy volunteers during profound hypocapnia and hypercapnia., Methods: Ten healthy volunteers were monitored with a combination of TCD, UT-NIRS (c-FLOW, Ornim Medical), as well as heart rate, blood pressure, end-tidal PCO2 (PEtCO2), end-tidal O2, and inspired O2. Inspired CO2 and minute ventilation were controlled to achieve 5 stable plateau goals of EtCO2 at 15-20, 25-30, 35-40, 45-50, and 55-60 mm Hg, for a total of 7 measurements per subject. CBF was assessed at a steady state, with the TCD designated as the reference standard. The primary analysis was a linear mixed-effect model of TCD and UT-NIRS flow with PEtCO2, which accounts for repeated measures. Receiver operating characteristic curves were determined for detection of changes in CBF., Results: Hyperventilation (nadir PEtCO2 17.1 ± 2.4) resulted in significantly decreased mean flow velocity of the middle cerebral artery from baseline (to 79% ± 22%), but not a consistent decrease in UT-NIRS cerebral flow velocity index (n = 10; 101% ± 6% of baseline). Hypercapnia (peak PEtCO2 59.3 ± 3.3) resulted in a significant increase from baseline in both mean flow velocity of the middle cerebral artery (153% ± 25%) and UT-NIRS (119% ± 11%). Comparing slopes versus PEtCO2 as a percent of baseline for the TCD (1.7% [1.5%-2%]) and UT-NIRS (0.4% [0.3%-0.5%]) shows that the UT-NIRS slope is significantly flatter, P < .0001. Area under the receiver operating characteristic curve was significantly higher for the TCD than for UT-NIRS, 0.97 (95% confidence interval, 0.92-0.99) versus 0.75 (95% confidence interval, 0.66-0.82)., Conclusions: Our data indicate that UT-NIRS cerebral flow velocity index detects changes in CBF only during hypercarbia but not hypocarbia in healthy subjects and with much less sensitivity than TCD. Additional refinement and validation are needed before widespread clinical utilization of UT-NIRS.
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- 2018
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20. Effects of Changes in Arterial Carbon Dioxide and Oxygen Partial Pressures on Cerebral Oximeter Performance.
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Schober A, Feiner JR, Bickler PE, and Rollins MD
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- Adult, Female, Humans, Male, Partial Pressure, Radial Artery metabolism, Young Adult, Brain blood supply, Brain metabolism, Carbon Dioxide blood, Cerebrovascular Circulation physiology, Oximetry methods, Oxygen blood
- Abstract
Background: Cerebral oximetry (cerebral oxygen saturation; ScO2) is used to noninvasively monitor cerebral oxygenation. ScO2 readings are based on the fraction of reduced and oxidized hemoglobin as an indirect estimate of brain tissue oxygenation and assume a static ratio of arterial to venous intracranial blood. Conditions that alter cerebral blood flow, such as acute changes in PaCO2, may decrease accuracy. We assessed the performance of two commercial cerebral oximeters across a range of oxygen concentrations during normocapnia and hypocapnia., Methods: Casmed FORE-SIGHT Elite (CAS Medical Systems, Inc., USA) and Covidien INVOS 5100C (Covidien, USA) oximeter sensors were placed on 12 healthy volunteers. The fractional inspired oxygen tension was varied to achieve seven steady-state levels including hypoxic and hyperoxic PaO2 values. ScO2 and simultaneous arterial and jugular venous blood gas measurements were obtained with both normocapnia and hypocapnia. Oximeter bias was calculated as the difference between the ScO2 and reference saturation using manufacturer-specified weighting ratios from the arterial and venous samples., Results: FORE-SIGHT Elite bias was greater during hypocapnia as compared with normocapnia (4 ± 9% vs. 0 ± 6%; P < 0.001). The INVOS 5100C bias was also lower during normocapnia (5 ± 15% vs. 3 ± 12%; P = 0.01). Hypocapnia resulted in a significant decrease in mixed venous oxygen saturation and mixed venous oxygen tension, as well as increased oxygen extraction across fractional inspired oxygen tension levels (P < 0.0001). Bias increased significantly with increasing oxygen extraction (P < 0.0001)., Conclusions: Changes in PaCO2 affect cerebral oximeter accuracy, and increased bias occurs with hypocapnia. Decreased accuracy may represent an incorrect assumption of a static arterial-venous blood fraction. Understanding cerebral oximetry limitations is especially important in patients at risk for hypoxia-induced brain injury, where PaCO2 may be purposefully altered.
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- 2018
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21. Incidence and Management of Umbilical Artery Flow Abnormalities during Open Fetal Surgery.
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Sinskey JL, Rollins MD, Whitlock E, Moon-Grady AJ, Vu L, Feiner JR, and Ferschl MB
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- Adult, Blood Flow Velocity, Female, Humans, Incidence, Intraoperative Complications diagnostic imaging, Intraoperative Complications epidemiology, Intraoperative Complications therapy, Placental Insufficiency diagnostic imaging, Placental Insufficiency therapy, Pregnancy, Retrospective Studies, Ultrasonography, Doppler, Fetus surgery, Meningomyelocele surgery, Placental Insufficiency epidemiology, Umbilical Arteries diagnostic imaging
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Introduction: Umbilical artery (UA) Doppler ultrasound is used to assess uteroplacental insufficiency. Absent or reversed end diastolic flow (AREDF) in the UA is associated with increased perinatal mortality in fetuses with intrauterine growth restriction. We describe the incidence of UA Doppler abnormalities during open fetal surgery., Methods: We conducted a retrospective review of patients undergoing open in utero myelomeningocele (MMC) repair between 2008 and 2015. Intermittent UA Dopplers were performed during key portions of all cases. Our primary outcome was the rate of any AREDF. Secondary outcomes included analysis of absent versus reversed end diastolic flow (EDF), vasopressor use, and volatile anesthetic and clinical outcomes., Results: Thirty-four of 47 fetuses developed UA Doppler abnormalities intraoperatively. Nineteen had absent EDF and 15 had reversed EDF. No AREDF was present before induction, and all AREDF resolved by postoperative day 1. Ten of 19 (52.6%) patients who received sevoflurane had reversed EDF, versus 5/28 (17.9%) for desflurane, odds ratio (95% CI) 5.11 (1.36-19.16), p = 0.02. One intraoperative fetal death occurred in the AREDF group., Discussion: AREDF is a common phenomenon during open MMC repair. Anesthetic agent choice may influence this risk. Future studies of UA flow during fetal surgery are needed to further evaluate the impact of intraoperative AREDF on fetal well-being., (© 2017 S. Karger AG, Basel.)
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- 2018
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22. Effects of Acute, Profound Hypoxia on Healthy Humans: Implications for Safety of Tests Evaluating Pulse Oximetry or Tissue Oximetry Performance.
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Bickler PE, Feiner JR, Lipnick MS, Batchelder P, MacLeod DB, and Severinghaus JW
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- Acidosis etiology, Acidosis physiopathology, Acute Disease, Adaptation, Physiological, Animals, Attention, Biomarkers blood, Brain physiopathology, Cardiac Output, Cognition, Cognition Disorders etiology, Cognition Disorders physiopathology, Cognition Disorders psychology, Disease Models, Animal, Humans, Hypoxia blood, Hypoxia complications, Hypoxia physiopathology, Predictive Value of Tests, Pulmonary Ventilation, Reproducibility of Results, Risk Assessment, Risk Factors, Severity of Illness Index, Time Factors, Hypoxia diagnosis, Oximetry, Oxygen blood
- Abstract
Extended periods of oxygen deprivation can produce acidosis, inflammation, energy failure, cell stress, or cell death. However, brief profound hypoxia (here defined as SaO2 50%-70% for approximately 10 minutes) is not associated with cardiovascular compromise and is tolerated by healthy humans without apparent ill effects. In contrast, chronic hypoxia induces a suite of adaptations and stresses that can result in either increased tolerance of hypoxia or disease, as in adaptation to altitude or in the syndrome of chronic mountain sickness. In healthy humans, brief profound hypoxia produces increased minute ventilation and increased cardiac output, but little or no alteration in blood chemistry. Central nervous system effects of acute profound hypoxia include transiently decreased cognitive performance, based on alterations in attention brought about by interruptions of frontal/central cerebral connectivity. However, provided there is no decrease in cardiac output or ischemia, brief profound hypoxemia in healthy humans is well tolerated without evidence of acidosis or lasting cognitive impairment.
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- 2017
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23. Evaluating Pulmonary Function: An Assessment of PaO2/FIO2.
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Feiner JR and Weiskopf RB
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- Hemoglobins analysis, Humans, Oxygen blood, Blood Gas Analysis, Models, Statistical, Pulmonary Gas Exchange physiology
- Abstract
Objectives: PaO2/FIO2 is used commonly for diagnosis of lung injury (acute respiratory distress syndrome and transfusion-related acute lung injury), for assessment of pulmonary disease course and therapy, and in pulmonary transplantation for evaluation of donor lungs and clinical outcome. It was developed for convenience, without formal mathematical and graphic assessment to validate its suitability for these purposes., Design: We examined, mathematically and graphically, the relationship of PaO2/FIO2 to FIO2 at constant normal and several degrees of increased intrapulmonary shunting (QS/QT), assessing the impact of intra- and extrapulmonary factors on the relationship and thus the reliability of PaO2/FIO2., Measurements and Main Results: The relationship of PaO2/FIO2 varies at all shunt fractions but most with QS/QT from 0.1 to 0.3 with FIO2 approximately greater than 0.4. At higher QS/QT, the relationship is more constant and changes less with FIO2 more than 0.4. Hemoglobin concentration and arterial-venous oxygen content difference have large effects that can confound interpretation of PaO2/FIO2. Barometric pressure has a substantial effect; PCO2, base excess, and respiratory quotient have small effects., Conclusions: At high QS/QT with FIO2 more than 0.4, the relationship of PaO2/FIO2 to FIO2 is relatively constant. However, with QS/QT of 0.1-0.3, PaO2/FIO2 changes substantially with FIO2. Understanding the important effects of nonpulmonary factors (especially hemoglobin concentration and arterial-venous oxygen content difference) should enhance appropriate clinical use, interpretation of PaO2/FIO2, and interpretation of previous publications and future studies (especially those seeking to assess effects of anemia or transfusion on lung function). The ratio of PaO2/FIO2 is a good tool for some, but not many clinical circumstances, and is insufficiently robust for most research applications.
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- 2017
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24. The Accuracy of 6 Inexpensive Pulse Oximeters Not Cleared by the Food and Drug Administration: The Possible Global Public Health Implications.
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Lipnick MS, Feiner JR, Au P, Bernstein M, and Bickler PE
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- Adult, Biomarkers blood, Equipment Design, Female, Health Care Costs, Healthy Volunteers, Humans, Male, Materials Testing, Oximetry economics, Predictive Value of Tests, Reproducibility of Results, United States, Device Approval, Global Health economics, Oximetry instrumentation, Oxygen blood, United States Food and Drug Administration
- Abstract
Background: Universal access to pulse oximetry worldwide is often limited by cost and has substantial public health consequences. Low-cost pulse oximeters have become increasingly available with limited regulatory agency oversight. The accuracy of these devices often has not been validated, raising questions about performance., Methods: The accuracy of 6 low-cost finger pulse oximeters during stable arterial oxygen saturations (SaO2) between 70% and 100% was evaluated in 22 healthy subjects. Oximeters tested were the Contec CMS50DL, Beijing Choice C20, Beijing Choice MD300C23, Starhealth SH-A3, Jumper FPD-500A, and Atlantean SB100 II. Inspired oxygen, nitrogen, and carbon dioxide partial pressures were monitored and adjusted via a partial rebreathing circuit to achieve 10 to 12 stable target SaO2 plateaus between 70% and 100% and PaCO2 values of 35 to 45 mm Hg. Comparisons of pulse oximeter readings (SpO2) with arterial SaO2 (by Radiometer ABL90 and OSM3) were used to calculate bias (SpO2 - SaO2) mean, precision (SD of the bias), and root mean square error (ARMS)., Results: Pulse oximeter readings corresponding to 536 blood samples were analyzed. Four of the 6 oximeters tested showed large errors (up to -6.30% mean bias, precision 4.30%, 7.53 ARMS) in estimating saturation when SaO2 was reduced <80%, and half of the oximeters demonstrated large errors when estimating saturations between 80% and 90%. Two of the pulse oximeters tested (Contec CMS50DL and Beijing Choice C20) demonstrated ARMS of <3% at SaO2 between 70% and 100%, thereby meeting International Organization for Standardization (ISO) criteria for accuracy., Conclusions: Many low-cost pulse oximeters sold to consumers demonstrate highly inaccurate readings. Unexpectedly, the accuracy of some low-cost pulse oximeters tested here performed similarly to more expensive, ISO-cleared units when measuring hypoxia in healthy subjects. None of those tested here met World Federation of Societies of Anaesthesiologists standards, and the ideal testing conditions do not necessarily translate these findings to the clinical setting. Nonetheless, further development of accurate, low-cost oximeters for use in clinical practice is feasible and, if pursued, could improve access to safe care, especially in low-income countries.
- Published
- 2016
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25. In Reply.
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Whitlock EL, Feiner JR, and Chen LL
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- 2016
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26. Predicting mortality in the intensive care unit: a comparison of the University Health Consortium expected probability of mortality and the Mortality Prediction Model III.
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Lipshutz AK, Feiner JR, Grimes B, and Gropper MA
- Abstract
Background: Quality benchmarks are increasingly being used to compare the delivery of healthcare, and may affect reimbursement in the future. The University Health Consortium (UHC) expected probability of mortality (EPM) is one such quality benchmark. Although the UHC EPM is used to compare quality across UHC members, it has not been prospectively validated in the critically ill. We aimed to define the performance characteristics of the UHC EPM in the critically ill and compare its ability to predict mortality with the Mortality Prediction Model III (MPM-III)., Methods: The first 100 consecutive adult patients discharged from the hospital (including deaths) each quarter from January 1, 2009 until September 30, 2011 that had an intensive care unit (ICU) stay were included. We assessed model discrimination, calibration, and overall performance, and compared the two models using Bland-Altman plots., Results: Eight hundred ninety-one patients were included. Both the UHC EPM and the MPM-III had excellent performance (Brier score 0.05 and 0.06, respectively). The area under the curve was good for both models (UHC 0.90, MPM-III 0.87, p = 0.28). Goodness of fit was statistically significant for both models (UHC p = 0.002, MPM-III p = 0.0003), but improved with logit transformation (UHC p = 0.41; MPM-III p = 0.07). The Bland-Altman plot showed good agreement at extremes of mortality, but agreement diverged as mortality approached 50 %., Conclusions: The UHC EPM exhibited excellent overall performance, calibration, and discrimination, and performed similarly to the MPM-III. Correlation between the two models was poor due to divergence when mortality was maximally uncertain.
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- 2016
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27. Perioperative Mortality, 2010 to 2014: A Retrospective Cohort Study Using the National Anesthesia Clinical Outcomes Registry.
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Whitlock EL, Feiner JR, and Chen LL
- Subjects
- Adult, Cohort Studies, Female, Humans, Male, Middle Aged, Odds Ratio, Retrospective Studies, Time Factors, United States epidemiology, Anesthesia mortality, Anesthesia statistics & numerical data, Anesthesiology statistics & numerical data, Outcome Assessment, Health Care statistics & numerical data, Perioperative Period statistics & numerical data, Registries statistics & numerical data
- Abstract
Background: The National Anesthesia Clinical Outcomes Registry collects demographic and outcome data from anesthesia cases, with the goal of improving safety and quality across the specialty. The authors present a preliminary analysis of the National Anesthesia Clinical Outcomes Registry database focusing on the rates of and associations with perioperative mortality (within 48 h of anesthesia induction)., Methods: The authors retrospectively analyzed 2,948,842 cases performed between January 1, 2010, and May 31, 2014. Cases without procedure information and vaginal deliveries were excluded. Mortality and other outcomes were reported by the anesthesia provider. Hierarchical logistic regression was performed on cases with complete information for patient age group, sex, American Society of Anesthesiologists physical status, emergency case status, time of day, and surgery type, controlling for random effects within anesthesia practices., Results: The final analysis included 2,866,141 cases and 944 deaths (crude mortality rate, 33 per 100,000). Increasing American Society of Anesthesiologists physical status, emergency case status, cases beginning between 4:00 PM and 6:59 AM, and patient age less than 1 yr or greater than or equal to 65 yr were independently associated with higher perioperative mortality. A post hoc subgroup analysis of 279,154 patients limited to 22 elective case types, post hoc models incorporating either more granular estimate of surgical risk or work relative value units, and a post hoc propensity score-matched cohort confirmed the association with time of day., Conclusions: Several factors were associated with increased perioperative mortality. A case start time after 4:00 PM was associated with an adjusted odds ratio of 1.64 (95% CI, 1.22 to 2.21) for perioperative death, which suggests a potentially modifiable target for perioperative risk reduction. Limitations of this study include nonstandardized mortality reporting and limited ability to adjust for missing data.
- Published
- 2015
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28. Alfentanil during rapid sequence induction with thiopental 4 mg/kg and rocuronium 0.6 mg/kg: tracheal intubation conditions.
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Abou-Arab MH, Feiner JR, Spigset O, and Heier T
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- Adult, Alfentanil blood, Female, Humans, Logistic Models, Male, Middle Aged, Rocuronium, Alfentanil administration & dosage, Androstanols administration & dosage, Intubation, Intratracheal, Thiopental administration & dosage
- Abstract
Background: Opioids have become an integral part of anaesthesia induction. We aimed to determine the dose of alfentanil needed to obtain perfect tracheal intubation conditions during rapid sequence induction with standard doses of thiopental and rocuronium, where laryngoscopy was initiated 55 s after commencement of drug administration. The influence of covariates (sex, body weight, age, alfentanil plasma concentration at laryngoscopy) was tested., Methods: Eighty-four healthy individuals were randomly assigned to receive one of the seven assessor-blinded alfentanil doses (0, 10, 20, 30, 40, 50 and 60 μg/kg) in conjunction with thiopental 4 mg/kg and rocuronium 0.6 mg/kg. For drug administration, 15 s was allowed. Laryngoscopy was initiated 40 s after rocuronium and tracheal intubation concluded within 70 s after commencement of drug administration. Alfentanil doses associated with 50%, 90% and 95% probability of perfect intubation conditions were determined with logistic regression. Multiple logistic regressions were used to test the influence of covariates. The relationship between alfentanil dose and concentration at laryngoscopy was analysed with linear regression. The effects of covariates on plasma concentrations of alfentanil were tested with multiple linear regressions., Results: Perfect intubation conditions of 95% probability was obtained with 56 μg/kg (confidence intervals 44-68). None of the covariates were significant predictors of perfect intubation conditions. Alfentanil plasma concentration correlated with dose and increased with increasing body weight (1.7 ng/ml/kg)., Conclusion: Perfect intubation conditions during rapid sequence induction can be obtained with clinically relevant doses of alfentanil in most healthy patients anaesthetized with thiopental 4 mg/kg and rocuronium 0.6 mg/kg., (© 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)
- Published
- 2015
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29. A Clinical Trial to Detect Subclinical Transfusion-induced Lung Injury during Surgery.
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Feiner JR, Gropper MA, Toy P, Lieberman J, Twiford J, and Weiskopf RB
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- Acute Lung Injury etiology, Adolescent, Adult, Aged, Elective Surgical Procedures adverse effects, Erythrocyte Transfusion adverse effects, Female, Humans, Intraoperative Complications etiology, Male, Middle Aged, Pulmonary Gas Exchange physiology, Young Adult, Acute Lung Injury diagnosis, Elective Surgical Procedures trends, Erythrocyte Transfusion trends, Intraoperative Complications diagnosis
- Abstract
Background: Transfusion-related acute lung injury incidence remains the leading cause of posttransfusion mortality. The etiology may be related to leukocyte antibodies or biologically active compounds in transfused plasma, injuring susceptible recipient's lungs. The authors have hypothesized that transfusion could have less severe effects that are not always appreciated clinically and have shown subtly decreased pulmonary oxygen gas transfer in healthy volunteers after transfusion of fresh and 21-day stored erythrocytes. In this study, the authors tested the same hypothesis in surgical patients., Methods: Ninety-one patients undergoing elective major spine surgery with anticipated need for erythrocyte transfusion were randomly allocated to receive their first transfusion of erythrocytes as cell salvage (CS), washed stored, or unwashed stored. Clinicians were not blinded to group assignment. Pulmonary gas transfer and mechanics were measured 5 min before and 30 min after erythrocyte transfusion., Results: The primary outcome variable, gas transfer, as assessed by change of PaO2/FIO2, with erythrocyte transfusion was not significant in any group (mean ± SD; CS: 9 ± 59; washed: 10 ± 26; and unwashed: 15 ± 1) and did not differ among groups (P = 0.92). Pulmonary dead space (VD/VT) decreased with CS transfusion (-0.01 ± 0.04; P = 0.034) but did not change with other erythrocytes; the change from before to after erythrocyte transfusion did not differ among groups (-0.01 to +0.01; P = 0.28)., Conclusions: The authors did not find impaired gas exchange as assessed by PaO2/FIO2 with transfused erythrocytes that did or did not contain nonautologous plasma. This clinical trial did not support the hypothesis of erythrocyte transfusion-induced gas exchange deficit that had been found in healthy volunteers.
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- 2015
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30. Pupillary effects of high-dose opioid quantified with infrared pupillometry.
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Rollins MD, Feiner JR, Lee JM, Shah S, and Larson M
- Subjects
- Adult, Analgesics, Opioid administration & dosage, Autonomic Nervous System drug effects, Blood Pressure drug effects, Carbon Dioxide blood, Dose-Response Relationship, Drug, Female, Heart Rate drug effects, Humans, Infusions, Intravenous, Male, Oxygen blood, Piperidines administration & dosage, Piperidines pharmacology, Remifentanil, Respiratory Insufficiency chemically induced, Respiratory Insufficiency physiopathology, Analgesics, Opioid pharmacology, Pupil drug effects, Reflex, Pupillary drug effects
- Abstract
Background: The pupillary light reflex is a critical component of the neurologic examination, yet whether it is present, depressed, or absent is unknown in patients with significant opioid toxicity. Although opioids produce miosis by activating the pupillary sphincter muscle, these agents may induce significant hypercarbia and hypoxia, causing pupillary constriction to be overcome via sympathetic activation. The presence of either "pinpoint pupils" or sympathetically mediated pupillary dilation might prevent light reflex assessment. This study was designed to determine whether the light reflex remains quantifiable during opioid-induced hypercarbia and hypoxia., Methods: Ten volunteers were administered remifentanil with a gradually increasing infusion rate and intermittent boluses, until the increasing respiratory depression produced an oxyhemoglobin saturation of 85% or less with associated hypercarbia. Subjects' heart rate, blood pressure, respiration, and transcutaneous carbon dioxide level were continuously recorded. Arterial blood gases and pupillary measures were taken before opioid administration, at maximal desaturation, and 15 min after recovery., Results: The opioid-induced oxygen desaturation (≤ 85%) was associated with significant hypercarbia and evidence of sympathetic activation. During maximal hypoxia and hypercarbia, the pupil displayed parasympathetic dominance (2.5 ± 0.2 mm diameter) with a robust quantifiable light reflex. The reflex amplitude was linearly related to pupil diameter., Conclusions: Opioid administration with significant accompanying hypercarbia and hypoxia results in pupil diameters of 2 to 3 mm and a reduced but quantifiable pupillary light reflex. The authors conclude that the pupillary examination and evaluation of the light reflex remain useful for neurologic assessment during opioid toxicity.
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- 2014
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31. Factors affecting the performance of 5 cerebral oximeters during hypoxia in healthy volunteers.
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Bickler PE, Feiner JR, and Rollins MD
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- Adult, Brain metabolism, Female, Humans, Hypoxia diagnosis, Male, Middle Aged, Oximetry standards, Oxygen Consumption, Sex Factors, Skin Pigmentation physiology, Young Adult, Hypoxia blood, Oximetry instrumentation, Oximetry methods
- Abstract
Background: Cerebral oximetry is a noninvasive optical technology that measures frontal cortex blood hemoglobin-oxygen saturation. Commercially available cerebral oximeters have not been evaluated independently. Unlike pulse oximeters, there are currently no Food and Drug Administration standards for performance or accuracy. We tested the hypothesis that cerebral oximeters accurately measure a fixed ratio of the oxygen saturation in cerebral mixed venous and arterial blood., Methods: We evaluated the performance of 5 commercially available cerebral oximeters: the EQUANOX® 7600 in 3- and 4-wavelength versions (Nonin Medical, Plymouth, MN), FORE-SIGHT® (Casmed, Branford, CT), INVOS® 5100C (Covidien, Boulder, CO), and the NIRO-200NX® (Hamamatsu Photonics, Hamamatsu City, Japan) during stable isocapnic hypoxia in volunteers. Twenty-three healthy adults (14 men, 9 women) had sensors placed on each side of the forehead. The subject's inspired oxygen (FIO2) was then changed to produce 6 steady-state arterial oxygen saturation (SaO2) levels between 100% and 70%, while end-tidal CO2 was maintained constant. At each plateau, simultaneous blood samples from the jugular bulb and radial artery were analyzed with a hemoximeter (OSM-3, Radiometer Medical A/S, Copenhagen, Denmark). Each cerebral oximeter's bias was calculated as the difference between the instrument's reading (cerebral saturation, ScO2) with the weighted saturation of venous and arterial blood (Sa/vO2), as specified by each manufacturer (INVOS: 25% arterial/75% venous; FORE-SIGHT, EQUANOX, and NIRO: 30% arterial/70% venous)., Results: Five hundred forty-two comparisons between paired blood samples and oximeter readings were analyzed. The pooled root mean square error was 8.06%, a value higher than for pulse oximeters, which is ±3% by Food and Drug Administration standards. The mean % bias ± SD (precision) and root mean square errors were: FORE-SIGHT 1.76 ± 3.92 and 4.28; INVOS 0.05 ± 9.72 and 9.69; NIRO-200NX -1.13 ± 9.64 and 9.68; EQUANOX-3 λ 2.48 ± 8.12 and 8.47; EQUANOX-4 λ 2.84 ± 6.27 and 6.86. The FORE-SIGHT, NIRO-200NX, and EQUANOX-3 λ had significantly more positive bias at lower SaO2. The amount of bias during hypoxia was reduced when the bias was calculated on the basis of difference between oximeter reading and the arterial and mixed venous saturation difference rather than the weighted average of blood saturation, indicating that differences in the ratio between arterial and venous blood volumes account for some of the positive bias at low saturation. Dark skin pigment tended to produce more negative bias in all instruments but bias was significantly larger than zero only for the FORE-SIGHT oximeter. Bias was significantly more negative in women for INVOS and EQUANOX devices but not for the FORE-SIGHT device., Conclusions: While responsive to desaturation, cerebral oximeters exhibited large variation in reading errors between subjects, with mean bias possibly related to variations in the ratio of arterial and venous blood in the sampling area of the brain. This ratio is probably not fixed, as assumed by the manufacturers, but dynamically changes with hypoxia. Better understanding these factors could improve the performance of cerebral oximeters and help establish saturation or blood flow thresholds for brain well-being.
- Published
- 2013
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32. Accuracy of carboxyhemoglobin detection by pulse CO-oximetry during hypoxemia.
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Feiner JR, Rollins MD, Sall JW, Eilers H, Au P, and Bickler PE
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- Adolescent, Adult, Carbon Monoxide Poisoning diagnosis, Female, Humans, Hypoxia diagnosis, Male, Middle Aged, Young Adult, Carboxyhemoglobin metabolism, Hypoxia blood, Oximetry methods, Oximetry standards
- Abstract
Background: Carbon monoxide poisoning is a significant problem in most countries, and a reliable method of quick diagnosis would greatly improve patient care. Until the recent introduction of a multiwavelength "pulse CO-oximeter" (Masimo Rainbow SET(®) Radical-7), obtaining carboxyhemoglobin (COHb) levels in blood required blood sampling and laboratory analysis. In this study, we sought to determine whether hypoxemia, which can accompany carbon monoxide poisoning, interferes with the accurate detection of COHb., Methods: Twelve healthy, nonsmoking, adult volunteers were fitted with 2 standard pulse-oximeter finger probes and 2 Rainbow probes for COHb detection. A radial arterial catheter was placed for blood sampling during 3 interventions: (1) increasing hypoxemia in incremental steps with arterial oxygen saturations (SaO2) of 100% to 80%; (2) normoxia with incremental increases in %COHb to 12%; and (3) elevated COHb combined with hypoxemia with SaO2 of 100% to 80%. Pulse-oximeter (SpCO) readings were compared with simultaneous arterial blood values at the various increments of hypoxemia and carboxyhemoglobinemia (≈25 samples per subject). Pulse CO-oximeter performance was analyzed by calculating the mean bias (SpCO - %COHb), standard deviation of the bias (precision), and the root-mean-square error (A(rms))., Results: The Radical-7 accurately detected hypoxemia with both normal and elevated levels of COHb (bias mean ± SD: 0.44% ± 1.69% at %COHb <4%, and -0.29% ± 1.64% at %COHb ≥4%, P < 0.0001, and A(rms) 1.74% vs 1.67%). COHb was accurately detected during normoxia and moderate hypoxia (bias mean ± SD: -0.98 ± 2.6 at SaO2 ≥95%, and -0.7 ± 4.0 at SaO2 <95%, P = 0.60, and A(rms) 2.8% vs 4.0%), but when SaO2 decreased below approximately 85%, the pulse CO-oximeter always gave low signal quality errors and did not report SpCO values., Conclusions: In healthy volunteers, the Radical-7 pulse CO-oximeter accurately detects hypoxemia with both low and elevated COHb levels, and accurately detects COHb, but only reads SpCO when SaO2 is more than approximately 85%.
- Published
- 2013
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33. The effect of deep and awake tracheal extubation on turnover times and postoperative respiratory complications post adenoid-tonsillectomy.
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Menda SK, Gregory GA, Feiner JR, Zwass MS, and Ferschl MB
- Subjects
- Humans, Retrospective Studies, Time Factors, Adenoidectomy adverse effects, Airway Extubation methods, Postoperative Complications etiology, Respiration Disorders etiology, Tonsillectomy adverse effects
- Published
- 2012
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34. Sex-related differences in the relationship between acceleromyographic adductor pollicis train-of-four ratio and clinical manifestations of residual neuromuscular block: a study in healthy volunteers during near steady-state infusion of mivacurium.
- Author
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Heier T, Feiner JR, Wright PM, Ward T, and Caldwell JE
- Subjects
- Adult, Deglutition drug effects, Drug Administration Schedule, Electric Stimulation methods, Electromyography methods, Female, Hand Strength, Head Movements drug effects, Humans, Isoquinolines administration & dosage, Jaw drug effects, Jaw physiology, Male, Mivacurium, Muscle, Skeletal drug effects, Muscle, Skeletal physiology, Neuromuscular Junction physiology, Neuromuscular Nondepolarizing Agents administration & dosage, Sex Characteristics, Young Adult, Isoquinolines pharmacology, Neuromuscular Blockade methods, Neuromuscular Junction drug effects, Neuromuscular Nondepolarizing Agents pharmacology
- Abstract
Background: Studies in volunteers suggest that train-of-four (TOF) ratios >0.9 are needed to retain normal function of muscles involved in upper airway patency, swallowing, and vital capacity breathing. We determined if sex-related differences exist in the relationship between adductor pollicis (AP) TOF ratio and measures of neuromuscular function commonly used to assess recovery from neuromuscular block., Methods: In 10 males and 10 females, three steady-state levels of neuromuscular block were achieved with mivacurium infusions. TOF ratio was measured with acceleromyography at the AP. Hand grip strength and the ability to clench the teeth, raise the head >5 s, swallow, protrude the tongue, and open the eyes were tested at each stable block level and reconciled to uncorrected and normalized (pre-paralysis values) TOF measures. These relationships were compared between sexes., Results: The ability to clench teeth and head raise >5 s was lost at a significantly greater TOF ratio in males than females. The percentage decrease in handgrip strength with decreasing TOF ratio was proportionally greater in males than females. Forty per cent of the males were unable to clench the teeth at an uncorrected TOF ratio >0.9. When TOF ratios were normalized, clinical functions showed no decrement at TOF ratio >0.9 in any volunteer., Conclusions: Sex-related differences exist in the relationship between AP TOF ratio and clinical measures of muscle function used to assess recovery from neuromuscular block. Normalization of AP TOF ratios is recommended because a non-normalized TOF ratio of 0.9 does not guarantee adequate reversal of neuromuscular block.
- Published
- 2012
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35. Emergent orthotopic liver transplantation for hemorrhage from a giant cavernous hepatic hemangioma: case report and review.
- Author
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Vagefi PA, Klein I, Gelb B, Hameed B, Moff SL, Simko JP, Fix OK, Eilers H, Feiner JR, Ascher NL, Freise CE, and Bass NM
- Subjects
- Adult, Female, Hemangioma, Cavernous diagnosis, Hemangioma, Cavernous surgery, Hemorrhage etiology, Humans, Liver Neoplasms diagnosis, Tomography, X-Ray Computed, Abdominal Cavity, Emergencies, Hemangioma, Cavernous complications, Hemorrhage surgery, Liver Neoplasms complications, Liver Transplantation methods
- Abstract
Introduction: Cavernous hemangiomas represent the most common benign primary hepatic neoplasm, often being incidentally detected. Although the majority of hepatic hemangiomas remain asymptomatic, symptomatic hepatic hemangiomas can present with abdominal pain, hemorrhage, biliary compression, or a consumptive coagulopathy. The optimal surgical management of symptomatic hepatic hemangiomas remains controversial, with resection, enucleation, and both deceased donor and living donor liver transplantation having been reported., Case Report: We report the case of a patient found to have a unique syndrome of multiorgan cavernous hemangiomatosis involving the liver, lung, omentum, and spleen without cutaneous involvement. Sixteen years following her initial diagnosis, the patient suffered from intra-abdominal hemorrhage due to her giant cavernous hepatic hemangioma. Evidence of continued bleeding, in the setting of Kasabach-Merritt Syndrome and worsening abdominal compartment syndrome, prompted MELD exemption listing. The patient subsequently underwent emergent liver transplantation without complication., Conclusion: Although cavernous hemangiomas represent the most common benign primary hepatic neoplasm, hepatic hemangioma rupture remains a rare presentation in these patients. Management at a center with expertise in liver transplantation is warranted for those patients presenting with worsening DIC or hemorrhage, given the potential for rapid clinical decompensation.
- Published
- 2011
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36. Improved accuracy of methemoglobin detection by pulse CO-oximetry during hypoxia.
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Feiner JR and Bickler PE
- Subjects
- Administration, Inhalation, Biomarkers blood, Female, Humans, Hypoxia blood, Injections, Intravenous, Male, Materials Testing, Oxygen administration & dosage, Predictive Value of Tests, Reproducibility of Results, San Francisco, Sodium Nitrite administration & dosage, Carboxyhemoglobin metabolism, Fingers blood supply, Hemoglobins metabolism, Hypoxia diagnosis, Methemoglobin metabolism, Oximetry
- Abstract
Background: Methemoglobin in the blood cannot be detected by conventional pulse oximetry and may bias the oximeter's estimate (Spo(2)) of the true arterial functional oxygen saturation (Sao(2)). A recently introduced "pulse CO-oximeter" (Masimo Rainbow SET® Radical-7) that measures SpMet, a noninvasive measurement of the percentage of methemoglobin in arterial blood (%MetHb), was shown to read spuriously high values during hypoxia. In this study we sought to determine whether the manufacturer's modifications have improved the device's ability to detect and accurately measure methemoglobin and deoxyhemoglobin simultaneously., Methods: Twelve healthy adult volunteer subjects were fitted with sensors on the middle finger of each hand, and a radial arterial catheter was placed for blood sampling. Intravenous administration of ∼300 mg of sodium nitrite elevated subjects' methemoglobin levels to a 7% to 11% target level, and hypoxia was induced to different levels of Sao(2) (70% to 100%) by varying fractional inspired oxygen. Pulse CO-oximeter readings were compared with arterial blood values measured with a Radiometer ABL800 FLEX multi-wavelength oximeter. Pulse CO-oximeter methemoglobin reading performance was analyzed by the bias (SpMet-%MetHb), and by observing the incidence of meaningful reading errors and predictive value at the various hypoxia levels. Spo(2) bias (Spo(2)--Sao(2)), precision, and root-mean-square error were evaluated during conditions of elevated methemoglobin., Results: Observations spanned 74% to 100% Sao(2) and 0.4% to 14.4% methemoglobin with 307 blood draws and 602 values from the 2 oximeters. Masimo methemoglobin reading bias and precision over the full Sao(2) span was 0.16% and 0.83%, respectively, and was similar across the span. Masimo Spo(2) readings were biased -1.93% across the 70% to 100% Sao(2) range., Conclusions: The Rainbow's methemoglobin readings are acceptably accurate over an oxygen saturation range of 74%-100% and a methemoglobin range of 0%-14%.
- Published
- 2010
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- View/download PDF
37. Relationship between normalized adductor pollicis train-of-four ratio and manifestations of residual neuromuscular block: a study using acceleromyography during near steady-state concentrations of mivacurium.
- Author
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Heier T, Caldwell JE, Feiner JR, Liu L, Ward T, and Wright PM
- Subjects
- Adolescent, Adult, Anesthesia Recovery Period, Deglutition drug effects, Deglutition physiology, Female, Functional Residual Capacity, Hand Strength physiology, Humans, Jaw physiology, Male, Mivacurium, Movement drug effects, Muscle, Skeletal drug effects, Residual Volume, Respiratory Function Tests, Speech drug effects, Tongue physiology, Vision, Ocular drug effects, Young Adult, Electromyography, Isoquinolines, Muscle, Skeletal physiology, Neuromuscular Blockade, Neuromuscular Nondepolarizing Agents
- Abstract
Background: Baseline acceleromyographic adductor pollicis train-of-four (TOF) ratio varies significantly between individuals and is often greater than unity. Thus, normalization of acceleromyography data is necessary. The relationship between normalized acceleromyographic TOF ratio, lung volumes, and clinical signs of residual neuromuscular block was studied., Methods: In 12 healthy volunteers, three steady-state levels of neuromuscular block were achieved with mivacurium infusions. TOF ratio was measured acceleromyographically at the adductor pollicis using a preload. Lung volume measurements and a series of clinical tests were made at each stable block and reconciled to the normalized TOF measures., Results: None experienced airway obstruction or arterial oxygen desaturation, even at normalized TOF ratio less than 0.4. Functional residual capacity remained unchanged whereas vital capacity decreased linearly with decreasing TOF ratio. The ability to protrude the tongue was preserved at all times. The ability to clench the teeth was lost in one volunteer at normalized TOF ratio of 0.84 but retained in four at normalized TOF ratio less than 0.4. Four volunteers lost the ability both to raise the head more than 5 s and to swallow, with the most sensitive individual demonstrating these effects at normalized TOF ratio of 0.60. At mean normalized TOF ratio of 0.42, the mean handgrip strength was approximately 20% of baseline value., Conclusion: Lung vital capacity decreased linearly with decreasing TOF ratio. Responses to clinical tests of muscle function varied to a large extent among individuals at comparable TOF ratios. None of the volunteers had significant clinical effects of neuromuscular block at normalized acceleromyographic TOF ratio greater than 0.90.
- Published
- 2010
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- View/download PDF
38. Accuracy of methemoglobin detection by pulse CO-oximetry during hypoxia.
- Author
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Feiner JR, Bickler PE, and Mannheimer PD
- Subjects
- Adult, Blood Gas Analysis, Carboxyhemoglobin analysis, Data Interpretation, Statistical, Female, Humans, Male, Methemoglobinemia blood, Oximetry instrumentation, Oxygen blood, Predictive Value of Tests, Reproducibility of Results, Sodium Nitrite, Carbon Monoxide blood, Hemoglobinometry methods, Hypoxia blood, Methemoglobin analysis, Methemoglobinemia diagnosis, Oximetry methods
- Abstract
Background: Methemoglobin in the blood cannot be detected by conventional pulse oximetry, although it can bias the oximeter's estimate (Spo2) of the true arterial functional oxygen saturation (Sao2). A recently introduced "Pulse CO-Oximeter" (Masimo Rainbow SET(R) Radical-7 Pulse CO-Oximeter, Masimo Corp., Irvine, CA) is intended to additionally monitor noninvasively the fractional carboxyhemoglobin and methemoglobin content in blood. The purpose of our study was to determine whether hypoxia affects the new device's estimated methemoglobin reading accuracy, and whether the presence of methemoglobin impairs the ability of the Radical-7 and a conventional pulse oximeter (Nonin 9700, Nonin Medical Inc., Plymouth, MN) to detect decreases in Sao2., Methods: Eight and 6 healthy adults were included in 2 study groups, respectively, each fitted with multiple sensors and a radial arterial catheter for blood sampling. In the first group, IV administration of approximately 300 mg sodium nitrite increased subjects' methemoglobin level to a 7% to 8% target and hypoxia was induced to different levels of Sao2 (70%-100%) by varying fractional inspired oxygen. In the second group, 15% methemoglobin at room air and 80% Sao2 were targeted. Pulse CO-oximeter readings were compared with arterial blood values measured using a Radiometer multiwavelength hemoximeter. Pulse CO-oximeter methemoglobin reading performance was analyzed by observing the incidence of meaningful reading errors at the various hypoxia levels. This was used to determine the impact on predictive values for detecting methemoglobinemia. Spo2 reading bias, precision, and root mean square error were evaluated during conditions of elevated methemoglobin., Results: Observations spanned 66.2% to 99% Sao2 and 0.6% to 14.4% methemoglobin over the 2 groups (170 blood draws). Masimo methemoglobin reading bias and precision over the full Sao2 span was 7.7% +/- 13.0%. Best accuracy was found in the 95% to 100% Sao2 range (1.9% +/- 2.5%), progressing to its worst in the 70% to 80% range (24.8% +/- 15.6%). Occurrence of methemoglobin readings in error >5% increased over each 5-point decrease in Sao2 (P < 0.05). Masimo Spo2 readings were biased -6.3% +/- 3.0% in the 95% to 100% Sao2 range with 4% to 8.3% methemoglobin. Both the Radical-7 and Nonin 9700 pulse oximeters accurately detected decreases in Sao(2) <90% with 4% to 15% methemoglobin, despite displaying low Spo2 readings when Sao2 was >95%., Conclusions: The Radical-7's methemoglobin readings become progressively more inaccurate as Sao2 decreases <95%, at times overestimating true values by 10% to 40%. Elevated methemoglobin causes the Spo2 readings to underestimate Sao2 similar to conventional 2-wavelength pulse oximeters at high saturation. Spo2 readings from both types of instruments continue to trend downward during the development of hypoxemia (Sao2 <90%) with methemoglobin levels up to 15%.
- Published
- 2010
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39. Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: the effects of oximeter probe type and gender.
- Author
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Feiner JR, Severinghaus JW, and Bickler PE
- Subjects
- Adult, Black or African American, Asian People, Bias, Equipment Design, Female, Hispanic or Latino, Humans, Male, Multivariate Analysis, Oxyhemoglobins analysis, Reference Values, Reproducibility of Results, Sex Factors, Transducers, White People, Oximetry instrumentation, Oxygen blood, Skin Pigmentation
- Abstract
Introduction: Pulse oximetry may overestimate arterial oxyhemoglobin saturation (Sao2) at low Sao2 levels in individuals with darkly pigmented skin, but other factors, such as gender and oximeter probe type, remain less studied., Methods: We studied the relationship between skin pigment and oximeter accuracy in 36 subjects (19 males, 17 females) of a range of skin tones. Clip-on type sensors and adhesive/disposable finger probes for the Masimo Radical, Nellcor N-595, and Nonin 9700 were studied. Semisupine subjects breathed air-nitrogen-CO2 mixtures via a mouthpiece to rapidly achieve 2- to 3-min stable plateaus of Sao2. Comparisons of Sao2 measured by pulse oximetry (Spo2) with Sao2 (by Radiometer OSM-3) were used in a multivariate model to assess the source of errors., Results: The mean bias (Spo2 - Sao2) for the 70%-80% saturation range was 2.61% for the Masimo Radical with clip-on sensor, -1.58% for the Radical with disposable sensor, 2.59% for the Nellcor clip, 3.6% for the Nellcor disposable, -0.60% for the Nonin clip, and 2.43% for the Nonin disposable. Dark skin increased bias at low Sao2; greater bias was seen with adhesive/disposable sensors than with the clip-on types. Up to 10% differences in saturation estimates were found among different instruments in dark-skinned subjects at low Sao2., Conclusions: Multivariate analysis indicated that Sao2 level, sensor type, skin color, and gender were predictive of errors in Spo2 estimates at low Sao2 levels. The data suggest that clinically important bias should be considered when monitoring patients with saturations below 80%, especially those with darkly pigmented skin; but further study is needed to confirm these observations in the relevant populations.
- Published
- 2007
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40. Mild hypothermia, but not propofol, is neuroprotective in organotypic hippocampal cultures.
- Author
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Feiner JR, Bickler PE, Estrada S, Donohoe PH, Fahlman CS, and Schuyler JA
- Subjects
- Animals, Calcium metabolism, Cell Survival drug effects, Cerebral Cortex cytology, Cerebral Cortex drug effects, GABA Antagonists pharmacology, Neurons drug effects, Organ Culture Techniques, Picrotoxin pharmacology, Pyramidal Cells drug effects, Rats, Rats, Sprague-Dawley, Receptors, GABA-A drug effects, Receptors, Glutamate drug effects, Anesthetics, Intravenous pharmacology, Hippocampus pathology, Hypothermia, Induced, Neuroprotective Agents, Propofol pharmacology
- Abstract
The neuroprotective potency of anesthetics such as propofol compared to mild hypothermia remains undefined. Therefore, we determined whether propofol at two clinically relevant concentrations is as effective as mild hypothermia in preventing delayed neuron death in hippocampal slice cultures (HSC). Survival of neurons was assessed 2 and 3 days after 1 h oxygen and glucose deprivation (OGD) either at 37 degrees C (with or without 10 or 100 microM propofol) or at an average temperature of 35 degrees C during OGD (mild hypothermia). Cell death in CA1, CA3, and dentate neurons in each slice was measured with propidium iodide fluorescence. Mild hypothermia eliminated death in CA1, CA3, and dentate neurons but propofol protected dentate neurons only at a concentration of 10 microM; the more ischemia vulnerable CA1 and CA3 neurons were not protected by either 10 microM or 100 microM propofol. In slice cultures, the toxicity of 100 muM N-methyl-D-aspartate (NMDA), 500 microM glutamate, and 20 microM alpha-amino-5-methyl-4-isoxazole propionic acid (AMPA) was not reduced by 100 microM propofol. Because propofol neuroprotection may involve gamma-aminobutyric acid (GABA)-mediated indirect inhibition of glutamate receptors (GluRs), the effects of propofol on GluR activity (calcium influx induced by GluR agonists) were studied in CA1 neurons in HSC, in isolated CA1 neurons, and in cortical brain slices. Propofol (100 and 200 microM, approximate burst suppression concentrations) decreased glutamate-mediated [Ca2+]i increases (Delta[Ca2+]i) responses by 25%-35% in isolated CA1 neurons and reduced glutamate and NMDA Delta[Ca2+]i in acute and cultured hippocampal slices by 35%-50%. In both CA1 neurons and cortical slices, blocking GABAA receptors with picrotoxin reduced the inhibition of GluRs substantially. We conclude that mild hypothermia, but not propofol, protects CA1 and CA3 neurons in hippocampal slice cultures subjected to oxygen and glucose deprivation. Propofol was not neuroprotective at concentrations that reduce glutamate and NMDA receptor responses in cortical and hippocampal neurons.
- Published
- 2005
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41. Productivity versus availability as a measure of faculty clinical responsibility.
- Author
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Feiner JR, Miller RD, and Hickey RF
- Subjects
- Humans, Anesthesiology, Efficiency
- Abstract
Unlabelled: Faculty clinical time is an extremely valuable commodity. Most departments quantify faculty clinical time on an "availability" basis (e.g., number of days in the operating room or nights on call). We hypothesize that a productivity measure (i.e., determination of actual clinical care delivered rather than availability of such care) would produce different results than the availability system. The "billable hour" was chosen as the measurement device. It was defined as time that anesthesia was actually given, as obtained from the anesthetic record. After collecting data for a year, we found that despite parity using the availability system, the billable hour system detected significant differences between faculty within and between groups. We conclude that "availability" and "productivity" systems produce different conclusions regarding the relative contributions of an individual faculty or subspecialty group., Implications: Accountability of clinical activities by faculty is crucial to the financial status of any department of anesthesia. We hypothesized that methods of availability (e.g., amount of time scheduled for clinical activities) versus productivity measure (actual amount of clinical care delivered) would be quite different between faculty and differing subspecialty groups. Even though the availability system distributed clinical time on an equal basis, there was a wide difference of clinical productivity within and between specialty groups. We conclude that a productivity measure (i.e., billable hours) is a more accurate reflection of faculty productivity than an availability system and is more in line with departmental sources of financial income.
- Published
- 2001
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42. Hemoglobin desaturation after succinylcholine-induced apnea: a study of the recovery of spontaneous ventilation in healthy volunteers.
- Author
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Heier T, Feiner JR, Lin J, Brown R, and Caldwell JE
- Subjects
- Adolescent, Adult, Apnea blood, Female, Humans, Male, Oxygen blood, Apnea chemically induced, Hemoglobins metabolism, Neuromuscular Depolarizing Agents pharmacology, Respiration drug effects, Succinylcholine pharmacology
- Abstract
Background: Because of the rapid recovery of neuromuscular function after succinylcholine administration, there is a belief that patients will start breathing sufficiently rapidly to prevent significant oxygen desaturation. The authors tested whether this belief was valid., Methods: Twelve healthy volunteers aged 18-45 yr participated in the study. After preoxygenation to an end-tidal oxygen concentration greater than 90%, each subject received 5 mg/kg thiopental and 1 mg/kg succinylcholine. Oxygen saturation (SaO2) was measured at both a finger and an ear lobe (beat to beat). During the period of apnea and as they were recovering, the volunteers received continuous verbal reassurance by the investigators. If the SaO2 decreased below 80%, the volunteers received chin lift and, if necessary, assisted ventilation. The length of time the subject was apneic and level of desaturation were related by linear regression analysis. One hour after recovery and again 1 week later, subjects were asked a series of questions regarding their emotional experience., Results: In six volunteers, SaO2 decreased below 95% during apnea; in four, SaO2 decreased below 80%, necessitating chin lift and assisted ventilation in three. Apnea time was significantly longer in volunteers who reached SaO2 less than 80% than in those who did not (7.0+/-0.4 and 4.1+/-0.3 min, respectively), and there was a significant correlation between the length of time the subject was apneic and the magnitude of desaturation., Conclusions: Spontaneous recovery from succinylcholine-induced apnea may not occur sufficiently quickly to prevent hemoglobin desaturation in subjects whose ventilation is not assisted.
- Published
- 2001
- Full Text
- View/download PDF
43. Acute severe isovolemic anemia impairs cognitive function and memory in humans.
- Author
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Weiskopf RB, Kramer JH, Viele M, Neumann M, Feiner JR, Watson JJ, Hopf HW, and Toy P
- Subjects
- Adult, Anemia blood, Blood Volume physiology, Female, Humans, Male, Mental Recall physiology, Psychomotor Performance physiology, Reaction Time physiology, Anemia psychology, Cognition physiology, Hemoglobins metabolism, Memory physiology
- Abstract
Background: Erythrocytes are transfused to prevent or treat inadequate oxygen delivery resulting from insufficient hemoglobin concentration. Previous studies failed to find evidence of inadequate systemic oxygen delivery at a hemoglobin concentration of 5 g/dl. However, in those studies, sensitive, specific measures of critical organ function were not used. This study tested the hypothesis that acute severe decreases of hemoglobin concentration alters human cognitive function., Methods: Nine healthy volunteers, age 29 +/- 5 yr (mean +/- SD), were tested with verbal memory and standard, computerized neuropsychologic tests before and after acute isovolemic reduction of their hemoglobin to 7, 6, and 5 g/dl and again after transfusion of their autologous erythrocytes to return their hemoglobin concentration to 7 g/dl. To control for duration of the experiment, each volunteer also completed the same tests on a separate day, without alteration of hemoglobin, at times of the day approximately equivalent to those on the experimental day., Results: No test showed any change in reaction time or error rate at hemoglobin concentration of 7 g/dl compared with the data at the baseline hemoglobin concentration of 14 g/dl. Reaction time, but not error rate, for horizontal addition and digit-symbol substitution test (DSST) increased at hemoglobin 6 g/dl (mean horizontal addition, 19%; 95% confidence interval [CI], 4-34%; mean DSST, 10%; 95% CI, 4-17%) and further at 5 g/dl (mean horizontal addition, 43%; 95% CI, 6-79%; mean DSST, 18%; 95% CI, 4-31%). Immediate and delayed memory was degraded at hemoglobin 5 g/dl but not at 6 g/dl. Return of hemoglobin to 7 g/dl returned all tests to baseline, except for the DSST, which significantly improved, and returned to baseline the following morning after transfusion of all autologous erythrocytes., Conclusion: Acute reduction of hemoglobin concentration to 7 g/dl does not produce detectable changes in human cognitive function. Further reduction of hemoglobin level to 6 and 5 g/dl produces subtle, reversible increases in reaction time and impaired immediate and delayed memory. These are the first prospective data to demonstrate subtle degraded human function with acute anemia of hemoglobin concentrations of 6 and 5 g/dl. This reversibility of these decrements with erythrocyte transfusion suggests that our model can be used to test the efficacy of erythrocytes, oxygen therapeutics, or other treatments for acute anemia.
- Published
- 2000
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44. Interactive effects of pH and temperature on N-methyl-D-aspartate receptor activity in rat cortical brain slices.
- Author
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Gray AT, Buck LT, Feiner JR, and Bickler PE
- Subjects
- Adenosine Triphosphate metabolism, Animals, Cytosol drug effects, Cytosol metabolism, Hydrogen-Ion Concentration, In Vitro Techniques, Kinetics, Rats, Rats, Sprague-Dawley, Receptors, N-Methyl-D-Aspartate drug effects, Regression Analysis, Temperature, Calcium metabolism, Cerebral Cortex physiology, N-Methylaspartate pharmacology, Receptors, N-Methyl-D-Aspartate physiology
- Abstract
Low extracellular pH decreases the activity of the N-methyl-D-aspartate (NMDA) glutamate receptor, and may thus limit neuronal calcium overload during cerebral ischemia. During induced hypothermia, alkaline pH ("alphastat regulation") is often used to preserve cardiac and enzymatic function. The purpose of this study is to measure the functional activity of cerebral cortex NMDA receptors over the range of temperatures used in profound hypothermic cardiopulmonary bypass (20-37 degrees C). Extracellular pH was varied over a broad range relevant to both alphastat and pH stat acid-base management (7.0-7.8). Change in cytosolic free calcium evoked by 50 microM NMDA in brain slices was used as an index of NMDA receptor activity. Cortical slices (300 microns thick) were loaded with fura-2 Aspartate Methyl for study in a fluorometer. At 37 degrees C, a change in extracellular pH from 7.1 to 7.8 increased the NMDA-evoked change in cytosolic calcium in brain slices by a factor of 4 (p < 0.05). In contrast, at 20 degrees C there was minimal effect of changing extracellular pH from 7.1 to 7.8 (27% increase). We conclude that hypothermia results in decreased pH sensitivity of the NMDA receptor. The results predict that different strategies of pH management during induced hypothermia may have limited impact on NMDA receptor-mediated processes, such as neuronal calcium overload.
- Published
- 1997
- Full Text
- View/download PDF
45. Volatile and intravenous anesthetics decrease glutamate release from cortical brain slices during anoxia.
- Author
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Bickler PE, Buck LT, and Feiner JR
- Subjects
- Animals, Cerebral Cortex drug effects, In Vitro Techniques, Rats, Rats, Sprague-Dawley, Anesthetics, Inhalation pharmacology, Anesthetics, Intravenous pharmacology, Cerebral Cortex metabolism, Enflurane pharmacology, Glutamic Acid metabolism, Halothane pharmacology, Hypoxia metabolism, Propofol pharmacology, Thiopental pharmacology
- Abstract
Background: Extracellular accumulation of the excitatory neurotransmitter L-glutamate during cerebral hypoxia or ischemia contributes to neuronal death. Anesthetics inhibit release of synaptic neurotransmitters but it is unknown if they alter net extrasynaptic glutamate release, which accounts for most of the glutamate released during hypoxia or ischemia. The purpose of this study was to determine if different types of anesthetics decrease hypoxia-induced glutamate release from rat brain slices., Methods: Glutamate released from cortical brain slices was measured fluorometrically with the glutamate dehydrogenase catalyzed formation of the reduced form of nicotinamide adenine dinucleotide phosphate. Glutamate release was measured in oxygenated (PO2 = 400 mmHg), hypoxic ((PO2 = 20 mmHg), and anoxic ((PO2 = 20 mmHg plus 100 microM NaCN) solutions and with clinical concentrations of anesthetics (halothane 325 microM, enflurane 680 microM, propofol 200 microM, sodium thiopental 50 microM). The source of glutamate released during these stresses was defined with toxins inhibiting N and P type voltage-gated calcium channels, and with calcium-free medium., Results: Glutamate released during hypoxia or anoxia was 1.5 and 5.3 times greater, respectively, than that evoked by depolarization with 30 mM KCl. Hypoxia/anoxia-induced glutamate release was not mediated by synaptic voltage-gated calcium channels, but probably by the reversal of normal uptake mechanisms. Halothane, enflurane, and sodium thiopental, but not propofol, decreased hypoxia-evoked glutamate release by 50-70% (P < 0.05). None of the anesthetics alter basal glutamate release., Conclusions: The authors conclude that halothane, enflurane, and sodium thiopental but not propofol, at clinical concentrations, decrease extrasynaptic release of L-glutamate during hypoxic stress.
- Published
- 1995
- Full Text
- View/download PDF
46. Hypoxic ventilatory response predicts the extent of maximal breath-holds in man.
- Author
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Feiner JR, Bickler PE, and Severinghaus JW
- Subjects
- Adult, Carbon Dioxide analysis, Carbon Dioxide physiology, Female, Functional Residual Capacity, Humans, Hypercapnia physiopathology, Male, Maximal Voluntary Ventilation, Oxygen analysis, Oxygen blood, Oxygen physiology, Oxyhemoglobins analysis, Oxyhemoglobins physiology, Tidal Volume, Total Lung Capacity, Hypoxia physiopathology, Respiration
- Abstract
To understand the factors influencing breath-holding performance, we tested whether the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR) were predictors of the extent of maximal breath-holds as measured by breath-hold duration, the lowest oxyhemoglobin saturation (SpO2min), lowest calculated PaO2 (PaO2min) and highest end-tidal PCO2 (PETCO2max) reached. Steady state isocapnic HVR and hyperoxic HCVR were measured in 17 human volunteers. Breath-holds were made at total lung capacity (TLC), at TLC following hyperventilation, at functional residual capacity, and at TLC with FIO2 = 0.15. SpO2 was measured continuously by pulse oximetry, and alveolar gas was measured at the end of breath-holds by mass spectrometry. PaO2min was calculated from SpO2min and PETCO2max. HVR was a significant predictor of both SpO2min and PaO2min. HVR and forced vital capacity were predictors of breath-hold duration by multiple linear regression. HCVR had no significant predictive value. We conclude that HVR, but not HCVR, is a significant predictor of breath-holding performance.
- Published
- 1995
- Full Text
- View/download PDF
47. Hemodynamic effects of intermittent pneumatic compression of the legs.
- Author
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Unger RJ and Feiner JR
- Subjects
- Aged, Blood Pressure, Central Venous Pressure, Humans, Intensive Care Units, Male, Pulmonary Wedge Pressure, Pulse, Surgical Procedures, Operative, Gravity Suits, Hemodynamics
- Published
- 1987
- Full Text
- View/download PDF
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