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BackgroundInfants with hypoxic-ischemic encephalopathy are often treated with therapeutic hypothermia and high-frequency ventilation. Fluctuations in PaCO2 during therapeutic hypothermia are associated with poor neurodevelopmental outcomes. Transcutaneous CO2 monitors offer a noninvasive estimate of PaCO2 represented by transcutaneously measured partial pressure of carbon dioxide (PtcCO2 ). We aimed to assess the precision between PtcCO2 and PaCO2 values in neonates undergoing therapeutic hypothermia.MethodsThis was a retrospective chart review of 10 neonates who underwent therapeutic hypothermia requiring respiratory support over 2 y. A range of 2-27 simultaneous PtcCO2 and PaCO2 pairs of measurements per neonate were analyzed via linear mixed models and a Bland-Altman plot for multiple observations per neonate.ResultsA linear mixed-effect model demonstrated that PtcCO2 and PaCO2 (controlling for sex) were similar. The 95% CI of the mean difference ranged from -2.3 to 5.7 mm Hg (P = .41). However, precision was poor as the PtcCO2 ranged from > 18 mm Hg to < 13 mm Hg than PaCO2 values for 95% of observations.ConclusionsThe neonates' PtcCO2 was as much as 18 mm Hg higher to 13 mm Hg lower than the PaCO2 95% of the time. Transcutaneous CO2 monitoring may not be a good trending tool, nor is it appropriate for estimating PaCO2 in patients undergoing therapeutic hypothermia.

Objective：To compare the accuracy of end - tidal carbon dioxide partial pressure（PETCO2）and transcutaneous carbon dioxide partial pressure（PTCCO2）in predicting arterial carbon dioxide pressure（PaCO2）in patients undergoing retroperitoneoscopic urologic surgery. Methods：Fifty patients undergoing retroperitoneoscopic urologic surgery under general anesthesia were included. Values of PaCO2，PETCO2，and PTCCO2 were measured before and 30，60，90 min after insufflation. The differences between PaCO2-PETCO2 and PaCO2-PTCCO2 were calculated. Correlation and regression analysis were conducted between PaCO2 and PETCO2，as well as between PaCO2 and PTCCO2. Bland-Altman analysis was used to assess the agreement between PaCO2 and the other two variables. Results：The absolute differences of PaCO2-PETCO2 and PaCO2-PTCCO2were（13.20 ± 4.43）mmHg and（4.35 ± 2.56）mmHg，respectively（P ＜ 0.05）. The correlation coefficient between PaCO2 and PETCO2was 0.79（r 2 =0.62，P ＜ 0.001），and between PaCO2 and PTCCO2 was 0.91（r 2 =0.83， P ＜ 0.001）. The 95% limits of agreement between PaCO2 and PETCO2 were 4.53 to 21.88 mmHg and between PaCO2 and PTCCO2 were -3.18 to 10.48 mmHg. Conclusion：PTCCO2 monitoring improves the accuracy of estimating PaCO2 in patients undergoing retroperitoneoscopic urologic surgery. [ABSTRACT FROM AUTHOR]

BACKGROUND: Infants with hypoxic-ischemic encephalopathy are often treated with therapeutic hypothermia and high-frequency ventilation. Fluctuations in PaCO2 during therapeutic hypothermia are associated with poor neurodevelopmental outcomes. Transcutaneous CO2 monitors offer a noninvasive estimate of PaCO2 represented by transcutaneously measured partial pressure of carbon dioxide (PtcCO2). We aimed to assess the precision between PtcCO2 and PaCO2 values in neonates undergoing therapeutic hypothermia. METHODS: This was a retrospective chart review of 10 neonates who underwent therapeutic hypothermia requiring respiratory support over 2 y. A range of 2--27 simultaneous PaCO2 and PaCO2 pairs of measurements per neonate were analyzed via linear mixed models and a Bland-Altman plot for multiple observations per neonate. RESULTS: A linear mixed-effect model demonstrated that PaCO2 and PaCO2 (controlling for sex) were similar. The 95% CI of the mean difference ranged from 22.3 to 5.7 mm Hg (P 5 .41). However, precision was poor as the PaCO2 ranged from > 18 mm Hg to < 13 mm Hg than PaCO2 values for 95% of observations. CONCLUSIONS: The neonates' PaCO2 was as much as 18 mm Hg higher to 13 mm Hg lower than the PaCO295% of the time. Transcutaneous CO2 monitoring may not be a good trending tool, nor is it appropriate for estimating PaCO2 in patients undergoing therapeutic hypothermia. [ABSTRACT FROM AUTHOR]

Background Current methods of intrapartum fetal monitoring based on heart rate, increase the rates of operative delivery but do not prevent or accurately detect fetal hypoxic brain injury. There is a need for more accurate methods of intrapartum fetal surveillance that will decrease the incidence of adverse perinatal and long-term neurodevelopmental outcomes while maintaining the lowest possible rate of obstetric intervention. Fetal pulse oximetry (FPO) is a technology that may contribute to improved intrapartum fetal wellbeing evaluation by providing a non-invasive measurement of fetal oxygenation status. Objective This systematic review and meta-analysis aims to synthesise the evidence examining the association between intrapartum fetal oxygen saturation levels and adverse perinatal and long-term outcomes in the offspring. Methods We will include randomised control trials (RCTs), cohort, cross-sectional and case-control studies which examine the use of FPO during labour as a means of measuring intrapartum fetal oxygen saturation and assess its effectiveness at detecting adverse perinatal and long-term outcomes compared to existing intrapartum surveillance methods. A detailed systematic search of PubMed, EMBASE, CINAHL, The Cochrane Library, Web of Science, ClinicalTrials.Gov and WHO ICTRP will be conducted following a detailed search strategy until February 2024. Three authors will independently review titles, abstracts and full text of articles. Two reviewers will independently extract data using a pre-defined data extraction form and assess the quality of included studies using the Risk of Bias tool for RCTs and Newcastle-Ottawa Scale for observational studies. The grading of recommendations, assessment, development, and evaluation (GRADE) approach will be used to evaluate the certainty of the evidence. We will use random-effects meta-analysis for each exposure-outcome association to calculate pooled estimates using the generic variance method. This systematic review will follow the Preferred Reporting Items for Systematic reviews and Meta-analyses and MOOSE guidelines. PROSPERO registration CRD42023457368 (04/09/2023)

Background There is a need for quick skin blood flow tests that can be performed in the wound healing field. Antera 3D® is a compact scanner using multispectral imaging. It can perform quick assessment of skin conditions. The purpose of the present study was to investigate the ability of the Antera 3D® to assess skin blood flow in comparison with transcutaneous partial pressure of oxygen (TcPO2) measurements. Methods This study was conducted on 13 patients with a history of lower extremity ulcers. Measurements of hemoglobin average level (hereafter, Hb score) measured by Antera 3D® and TcPO2 measured by a transcutaneous blood gas monitor were obtained at the same sites on the dorsal foot and lower leg. Differences in Hb score and TcPO2 were analyzed by t-test for each measurement site and for the presence of peripheral arterial disease (PAD). The correlation between TcPO2 and Hb score was analyzed by Pearson's correlation coefficient. Results Twenty-four limbs were tested. Hb score was higher (P < 0.001) and TcPO2 was lower (P = 0.056) in the dorsal foot compared to the lower leg. In the dorsal foot, Hb score was higher (P = 0.023) and TcPO2 was lower (P = 0.046) in patients with PAD compared to those without PAD. A significant negative correlation (r = -0.68; 95% confidence interval -0.85 to -0.38, P < 0.001) between TcPO2 and Hb score was observed in the dorsal foot. Conclusion The negative correlation between TcPO2 and Hb score may reflect compensatory peripheral vasodilation due to occlusion or stenosis of central arteries. This study showed that Hb score measured by Antera 3D® may be related to skin blood flow. [ABSTRACT FROM AUTHOR]

Background: Methemoglobinemia (MetHb) is a rare and potentially severe dyshemoglobinemia that can be induced by exposure to oxidizing agents, decreasing the functional capacity of the hemoglobin molecule to transport and release oxygen into the tissues. MetHb can originate from gases with oxidizing capacity generated by internal combustion engines, although since the universalization of catalyst converters in automobiles, a tiny proportion of MetHb poisoning is due to exposure to engine gases and fumes. Within this group, only two cases due to suicidal motivations have been reported in the last 30 years. Case presentation: Here, we expose the case of a patient with MetHb levels of 25.2% (normal 0–1.5%) who with suicidal motivations had attached and locked a hose to the exhaust pipe of her vehicle with electrical tape, becoming exposed to a sustained concentration of the vehicle's exhaust. Upon her arrival at the emergency department, the presence of generalized greyish cyanosis with alterations of the sensorium, dissociation between saturation measured by arterial blood gas analysis and pulse oximetry (98% vs. 85%), no response to high-flow oxygen therapy, and an excellent response to intravenous methylene blue treatment were highlighted. Conclusions: This report illustrates an original case of acute toxic acquired MetHb due to inhalation of oxidizing substances originating from the bad ignition of an internal combustion engine. When evaluating a patient with suspected gas intoxication, we usually consider poisoning by the most common toxins, such as carbon monoxide or cyanide. In this context, we propose an algorithm to assist in the suspicion of this entity in patients with cyanosis in the emergency department. MetHb poisoning should be suspected, and urgent co-oximetry should be requested when there is no congruence between cyanosis intensity and oxygen saturation measured by pulse oximetry, if there is discordance between the results of oxygen saturation measured by arterial blood gas and pulse oximeter, and if there is no response to oxygen treatment. This algorithm could be useful to not delay diagnosis, improve prognosis, and limit potential sequelae. [ABSTRACT FROM AUTHOR]

The use of clinical scoring to assess for severity of respiratory distress and respiratory failure is challenging due to subjectivity and interrater variability. Transcutaneous Capnography (TcpCO2) can be used as an objective tool to assess a patient's ventilatory status. This study was designed to assess for any correlation of continuous monitoring of TcpCO2 with the respiratory clinical scores and deterioration in children admitted for acute respiratory distress. A prospective observational study over one year on children aged 2 weeks to 5 years admitted with acute respiratory distress or failure secondary to Bronchiolitis and Reactive airway disease was performed. Continuous TcpCO2 monitoring for upto 48 h was recorded. Investigators, bedside physicians, respiratory therapists, and nurses were blinded from the transcutaneous trends at the time of data collection. Total of 813 TcpCO2 measurements at standard intervals of 30 min were obtained on 38 subjects. Subjects with abnormal TcpCO2 (> 45 mmHg) were younger (6.9 ± 5.2 vs. 23.05 ± 17.7 months,) and were more likely to be on higher oxygen flow rate (0.52 L/min/kg vs 0.46 lier/min/kg, p = 0.004) and higher FiO2 (38.4 vs 33.6, p < 0.001 using heated high flow nasal cannula. No difference was found in bronchiolitis score or PEW score in subjects with normal and abnormal TcpCO2. A small but statistically significant increase in TcpCO2 was observed at the escalation of care. Even though odds of escalation of care are higher with abnormal TcpCO2 (OR 1.92), this difference did not reach statistical significance. pCO2 can provide additive information for non-invasive clinical monitoring of children requiring varying respiratory support; however, it does not provide predictive value for escalation or de-escalation of care. [ABSTRACT FROM AUTHOR]

Background: Methemoglobinemia (MetHb) is a rare and potentially severe dyshemoglobinemia that can be induced by exposure to oxidizing agents, decreasing the functional capacity of the hemoglobin molecule to transport and release oxygen into the tissues. MetHb can originate from gases with oxidizing capacity generated by internal combustion engines, although since the universalization of catalyst converters in automobiles, a tiny proportion of MetHb poisoning is due to exposure to engine gases and fumes. Within this group, only two cases due to suicidal motivations have been reported in the last 30 years. Case presentation: Here, we expose the case of a patient with MetHb levels of 25.2% (normal 0–1.5%) who with suicidal motivations had attached and locked a hose to the exhaust pipe of her vehicle with electrical tape, becoming exposed to a sustained concentration of the vehicle’s exhaust. Upon her arrival at the emergency department, the presence of generalized greyish cyanosis with alterations of the sensorium, dissociation between saturation measured by arterial blood gas analysis and pulse oximetry (98% vs. 85%), no response to high-flow oxygen therapy, and an excellent response to intravenous methylene blue treatment were highlighted. Conclusions: This report illustrates an original case of acute toxic acquired MetHb due to inhalation of oxidizing substances originating from the bad ignition of an internal combustion engine. When evaluating a patient with suspected gas intoxication, we usually consider poisoning by the most common toxins, such as carbon monoxide or cyanide. In this context, we propose an algorithm to assist in the suspicion of this entity in patients with cyanosis in the emergency department. MetHb poisoning should be suspected, and urgent co-oximetry should be requested when there is no congruence between cyanosis intensity and oxygen saturation measured by pulse oximetry, if there is discordance between the results of oxygen saturation measured by arterial blood gas and pulse oximeter, and if there is no response to oxygen treatment. This algorithm could be useful to not delay diagnosis, improve prognosis, and limit potential sequelae.

Skin graft vascularization is investigated mainly by histological evaluation. Immunohistochemical analysis has been conducted only in mice. Transcutaneous oxygen tension (TcPO2), which is an index of blood flow, has not been evaluated in skin grafts and only a few studies have reported biologic monitoring data using color tone evaluation and surface temperature. In humans, these tests can be performed non‐invasively. To evaluate human skin graft vascularization, we analyzed biomonitoring data after skin grafting. We evaluated 14 patients who underwent skin grafting surgery at Nagoya City University Hospital. The TcPO2, color tone, surface temperature, and dermoscopic observations at recipient sites were measured at postoperative day (POD) 4, 6, and 11. Mean TcPO2 levels at POD4, 6, and 11 were 12.7, 15.2, and 33.5 mmHg, respectively, and significantly higher at POD11 than at POD4 (p = 0.003, Steel–Dwass test). Dermoscopic observation revealed gradually increasing redness and yellowness. Color tone evaluation measured by spectrophotometry supported the appearance. The a*(redness) value at POD4, 6, and 11 was 6.19, 9.20, and 11.27, respectively, and significantly higher at POD11 than at POD4 (p < 0.001, Steel–Dwass test). The b*(yellowness) value at POD4, 6, and 11 was 8.83, 9.24, and 13.02, respectively, and significantly higher at POD11 than at POD4 (p = 0.020, Steel–Dwass test). The surface temperature did not significantly differ between graft and control sites. These findings suggest that skin graft vascularization started by POD6 and stabilized by POD11. Because TcPO2 increases after POD4, skin grafts should remain undisturbed until at least POD11. [ABSTRACT FROM AUTHOR]

To evaluate the changes that take place in the perfusion, oxygenation and local temperature of the skin of the sacrum and trochanter when subjected to direct pressure for 2 h. Quasi-experimental study in the preclinical phase with healthy subjects acting as their own controls (intrasubject control). The outcome variables were measured with a laser Doppler system (local temperature and oxygenation) and by near-infrared spectroscopy (perfusion). The pressure exerted was measured with a capacitive pressure sensor. No more than one week elapsed between the sacrum and trochanter measurements. The study sample consisted of 18 persons. The comparative analysis of the fluctuations in the parameters measured on the skin of the trochanters and sacrum, according to the time elapsed, revealed a statistically significant increase in temperature and in the pressure exerted. On the other hand, the changes in capillary blood flow and in SaO2 were not statistically significant. Our study results show that changes found in terms of temperature and pressure should be taking into account when planning personalised repositioning to patients according to biomechanical and biological situations that vary between anatomical areas. In future research, the changes reported could be evaluated in patients with risk factors for the development of pressure ulcers, thus facilitating the introduction of more personalised planning in the care and prevention of these injuries. • Significant changes in sacral and trochanteric skin temperature have been observed over time. • The external validity of our findings needs to be confirmed by further study in clinical settings. • Future research about risk factors of PU may lead to personalised prevention. [ABSTRACT FROM AUTHOR]

Background: Current methods of intrapartum fetal monitoring based on heart rate, increase the rates of operative delivery but do not prevent or accurately detect fetal hypoxic brain injury. There is a need for more accurate methods of intrapartum fetal surveillance that will decrease the incidence of adverse perinatal and long-term neurodevelopmental outcomes while maintaining the lowest possible rate of obstetric intervention. Fetal pulse oximetry (FPO) is a technology that may contribute to improved intrapartum fetal wellbeing evaluation by providing a non-invasive measurement of fetal oxygenation status., Objective: This systematic review and meta-analysis aims to synthesise the evidence examining the association between intrapartum fetal oxygen saturation levels and adverse perinatal and long-term outcomes in the offspring., Methods: We will include randomised control trials (RCTs), cohort, cross-sectional and case-control studies which examine the use of FPO during labour as a means of measuring intrapartum fetal oxygen saturation and assess its effectiveness at detecting adverse perinatal and long-term outcomes compared to existing intrapartum surveillance methods. A detailed systematic search of PubMed, EMBASE, CINAHL, The Cochrane Library, Web of Science, ClinicalTrials.Gov and WHO ICTRP will be conducted following a detailed search strategy until February 2024. Three authors will independently review titles, abstracts and full text of articles. Two reviewers will independently extract data using a pre-defined data extraction form and assess the quality of included studies using the Risk of Bias tool for RCTs and Newcastle-Ottawa Scale for observational studies. The grading of recommendations, assessment, development, and evaluation (GRADE) approach will be used to evaluate the certainty of the evidence. We will use random-effects meta-analysis for each exposure-outcome association to calculate pooled estimates using the generic variance method. This systematic review will follow the Preferred Reporting Items for Systematic reviews and Meta-analyses and MOOSE guidelines., Prospero Registration: CRD42023457368 (04/09/2023)., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Mitchell JM et al.)

Background: Infants with hypoxic-ischemic encephalopathy are often treated with therapeutic hypothermia and high-frequency ventilation. Fluctuations in P aCO 2 during therapeutic hypothermia are associated with poor neurodevelopmental outcomes. Transcutaneous CO 2 monitors offer a noninvasive estimate of P aCO 2 represented by transcutaneously measured partial pressure of carbon dioxide (P tcCO 2 ). We aimed to assess the precision between P tcCO 2 and P aCO 2 values in neonates undergoing therapeutic hypothermia., Methods: This was a retrospective chart review of 10 neonates who underwent therapeutic hypothermia requiring respiratory support over 2 y. A range of 2-27 simultaneous P tcCO 2 and P aCO 2 pairs of measurements per neonate were analyzed via linear mixed models and a Bland-Altman plot for multiple observations per neonate., Results: A linear mixed-effect model demonstrated that P tcCO 2 and P aCO 2 (controlling for sex) were similar. The 95% CI of the mean difference ranged from -2.3 to 5.7 mm Hg ( P = .41). However, precision was poor as the P tcCO 2 ranged from > 18 mm Hg to < 13 mm Hg than P aCO 2 values for 95% of observations., Conclusions: The neonates' P tcCO 2 was as much as 18 mm Hg higher to 13 mm Hg lower than the P aCO 2 95% of the time. Transcutaneous CO 2 monitoring may not be a good trending tool, nor is it appropriate for estimating P aCO 2 in patients undergoing therapeutic hypothermia., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Background and Aims: Not many studies have explored the correlation between arterial carbon dioxide tension (PaCO2) and end-tidal carbon dioxide tension (ETCO2) in surgeries requiring pneumoperitoneum of more than 1 hour duration with the patient in non-supine position. The aim of our study was to evaluate the correlation of ETCO2with PaCO2in patients undergoing laparoscopic nephrectomy under general anaesthesia. Methods: A descriptive study was performed in thirty patients undergoing laparoscopic nephrectomy from September 2014 to August 2015. The haemodynamic parameters, minute ventilation, PaCO2and ETCO2measured at three predetermined points during the procedure were analysed. Correlation was checked using Pearson's Correlation Coefficient Test. P

The myths surrounding women’s participation in sport have been reflected in respiratory physiology. This study aims to demonstrate that continuous monitoring of blood oxygen saturation during a maximal exercise test in female athletes is highly correlated with the determination of the second ventilatory threshold (VT2) or anaerobic threshold (AnT). The measurements were performed using a pulse oximeter during a maximum effort test on a treadmill on a population of 27 healthy female athletes. A common behavior of the oxygen saturation evolution during the incremental exercise test characterized by a decrease in saturation before the aerobic threshold (AeT) followed by a second significant drop was observed. Decreases in peripheral oxygen saturation during physical exertion have been related to the athlete’s physical fitness condition. However, this drop should not be a limiting factor in women’s physical performance. We found statistically significant correlations between the maximum oxygen uptake and the appearance of the ventilatory thresholds (VT1 and VT2), the desaturation time, the total test time, and between the desaturation time and the VT2. We observed a relationship between the desaturation time and the VT2 appearance. Indeed, a linear regression model between the desaturation time and the VT2 appearance can predict 80% of the values in our sample. Besides, we suggest that pulse oximetry is a simple, fairly accurate, and non-invasive technique for studying the physical condition of athletes who perform physical exertion.

Aim: To evaluate the relationship between the pressure exerted on the heel of one foot resting directly on a mattress, versus that exerted on the other heel, protected by a pillow beneath the Achilles tendon area and the changes thus produced in perfusion, oxygenation and temperature in the skin of heels of healthy volunteers lying in a supine position. Design: Experimental study in a pre‐clinical phase, with healthy volunteer participants and intrapeople control. Methods: The study was carried out from November 2017 – May 2018. A pressure measurement surface was placed between the participant and the constant low‐pressure support surface. Doppler laser devices were used to measure local temperature and perfusion. The degree of oxygenation was determined using an infrared beam close to the pressure zone in each heel. Both feet rested immobile on the bed, in a natural position, for 2 hr. To ensure intrapeople control, in every case the left heel was raised slightly, compared with the right. Results: Eighteen participants took part in this study. Analysis of the results obtained showed that capillary blood flow was significantly reduced in the heel subjected to pressure, compared with the other heel, while no significant effects on oxygen saturation or temperature were observed. The variables associated with greater oxygen saturation were capillary blood flow, local temperature and pressure exerted. Fat‐free mass, fat mass and duration of exposure to pressure were all significantly associated with reduced oxygen saturation. Conclusions: In healthy participants, when the heel is subjected to constant pressure against a constant low‐pressure support surface, there is a significant reduction in blood flow, compared with the heel where pressure is relieved. However, there are no significant differences in temperature or tissue oxygenation. Impact: Significant reductions in vascular flow were observed; however, the oxygenation and temperature of the heel tissues remained unchanged. These findings, corroborated in real patients, would advance our understanding and facilitate decision‐making on measures to prevent pressure ulcers, such as repositioning or tissue protection. Trial registration: The protocol is registered in ClinicalTrials.gov (NCT02736838). [ABSTRACT FROM AUTHOR]

Previous research has suggested correlations between the end-tidal partial pressure of carbon dioxide (PETCO2) and the partial pressure of arterial carbon dioxide (PaCO2) in mechanically ventilated patients, but both the relationship between PETCO2 and PaCO2 and whether PETCO2 accurately reflects PaCO2 in neonates and infants are still controversial. This study evaluated remote sampling of PETCO2 via an epidural catheter within an endotracheal tube to determine the procedure's clinical safety and efficacy in the perioperative management of neonates. Methods: Abdominal surgery was performed under general anesthesia in 86 full-term newborns (age 1–30 days, weight 2.55–4.0 kg, American Society of Anesthesiologists class I or II). The infants were divided into 2 groups (n = 43 each), and carbon dioxide (CO2) gas samples were collected either from the conventional position (the proximal end) or a modified position (the distal end) of the epidural catheter. Results: The PETCO2 measured with the new method was significantly higher than that measured with the traditional method, and the difference between PETCO2 and PaCO2 was also reduced. The accuracy of PETCO2 measured increased from 78.7% to 91.5% when the modified sampling method was used. The moderate correlation between PETCO2 and PaCO2 by traditional measurement was 0.596, which significantly increased to 0.960 in the modified sampling group. Thus, the PETCO2 value was closer to that of PaCO2. Conclusion: PETCO2 detected via modified carbon dioxide monitoring had a better accuracy and correlation with PaCO2 in neonates.

Background: Transcutaneous oxygen pressure (TcpO 2 ) is a precise method for determining oxygen perfusion in wounded tissues. The device uses either electrochemical or optical sensors., Aim: To evaluate the usefulness of TcpO 2 measurements on free flaps (FFs) in diabetic foot ulcers (DFUs)., Methods: TcpO 2 was measured in 17 patients with DFUs who underwent anterolateral thigh (ALT)-FF surgery and compared with 30 patients with DFU without FF surgery., Results: Significant differences were observed in the ankle-brachial index; duration of diabetes; and haemoglobin, creatinine, and C-reactive protein levels between the two groups. TcpO 2 values were similar between two groups except on postoperative days 30 and 60 when the values in the ALT-FF group remained < 30 mmHg and did not increase > 50 mmHg., Conclusion: Even if the flap is clinically stable, sympathectomy due to adventitia stripping during anastomosis and arteriovenous shunt progression due to diabetic polyneuropathy could lead to low TcpO 2 values in the ALT-FF owing to its thick fat tissues, which is supported by the slow recovery of the sympathetic tone following FF. Therefore, TcpO 2 measurements in patients with DFU who underwent FF reconstruction may be less accurate than in those who did not., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

BACKGROUND: High electrode temperature during transcutaneous monitoring is associated with skin burns in extremely premature infants. We evaluated the accuracy and precision of CO2 and O2 measurements using lower transcutaneous electrode temperatures below 42°C. METHODS: We enrolled 20 neonates. Two transcutaneous monitors were placed simultaneously on each neonate, with one electrode maintained at 42°C and the other randomized to temperatures of 38, 39, 40, 41, and 42°C. Arterial blood was collected twice at each temperature. RESULTS: At the time of arterial blood sampling, values for transcutaneously measured partial pressure of CO2 (PtcCO2) were not significantly different among test temperatures. There was no evidence of skin burning at any temperature. For PtcCO2, Bland-Altman analyses of all test temperatures versus 42°C showed good precision and low bias. Transcutaneously measured partial pressure of O2 (PtcO2) values trended arterial values but had large negative bias. CONCLUSION: Transcutaneous electrode temperatures as low as 38°C allow an assessment of PtcCO2 as accurate as that with electrodes at 42°C. [ABSTRACT FROM AUTHOR]

Background and Aims: Not many studies have explored the correlation between arterial carbon dioxide tension (PaCO2) and end-tidal carbon dioxide tension (ETCO2) in surgeries requiring pneumoperitoneum of more than 1 hour duration with the patient in non-supine position. The aim of our study was to evaluate the correlation of ETCO2 with PaCO2 in patients undergoing laparoscopic nephrectomy under general anaesthesia. Methods: A descriptive study was performed in thirty patients undergoing laparoscopic nephrectomy from September 2014 to August 2015. The haemodynamic parameters, minute ventilation, PaCO2 and ETCO2 measured at three predetermined points during the procedure were analysed. Correlation was checked using Pearson's Correlation Coefficient Test. P <0.05 was considered statistically significant. Results: Statistical analysis of the values showed a positive correlation between ETCO2 and PaCO2 (P < 0.05). Following carbon dioxide insufflation, both ETCO2 and PaCO2 increased by 5.4 and 6.63 mmHg, respectively, at the end of the 1st hour. The PaCO2-ETCO2 gradient was found to increase during the 1st hour following insufflation (4.07 ± 2.05 mmHg); it returned to the pre-insufflation values in another hour (2.93 ± 1.43 mmHg). Conclusion: Continuous ETCO2 monitoring is a reliable indicator of the trend in arterial CO2 fluctuations in the American Society of Anesthesiologists Grades 1 and 2 patients undergoing laparoscopic nephrectomy under general anaesthesia. [ABSTRACT FROM AUTHOR]

Background Polydeoxyribonucleotide (PDRN) is known to have anti-inflammatory and angiogenic effects and to accelerate wound healing. The aim of this study was to investigate whether PDRN could improve peripheral tissue oxygenation and angiogenesis in diabetic foot ulcers. Methods This was a prospective randomized controlled clinical trial. Twenty patients with a non-healing diabetic foot ulcer were randomly distributed into a control group (n=10) and a PDRN group (n=10). Initial surgical debridement and secondary surgical procedures such as a split-thickness skin graft, primary closure, or local flap were performed. Between the initial surgical debridement and secondary surgical procedures, 0.9% normal saline (3 mL) or PDRN was injected for 2 weeks by the intramuscular (1 ampule, 3 mL, 5.625 mg, 5 days per week) and perilesional routes (1 ampule, 3 mL, 5.625 mg, 2 days per week). Transcutaneous oxygen tension (TcPO2) was evaluated using the Periflux System 5000 with TcPO2/CO2 unit 5040 before the injections and on days 1, 3, 7, 14, and 28 after the start of the injections. A pathologic review (hematoxylin and eosin stain) of the debrided specimens was conducted by a pathologist, and vessel density (average number of vessels per visual field) was calculated. Results Compared with the control group, the PDRN-treated group showed improvements in peripheral tissue oxygenation on day 7 (P<0.01), day 14 (P<0.001), and day 28 (P<0.001). The pathologic review of the specimens from the PDRN group showed increased angiogenesis and improved inflammation compared with the control group. No statistically significant difference was found between the control group and the PDRN group in terms of vessel density (P=0.094). Complete healing was achieved in every patient. Conclusions In this study, PDRN improved peripheral tissue oxygenation. Moreover, PDRN is thought to be effective in improving inflammation and angiogenesis in diabetic foot ulcers. [ABSTRACT FROM AUTHOR]

Background Previous research has suggested correlations between the end-tidal partial pressure of carbon dioxide (P ET CO 2 ) and the partial pressure of arterial carbon dioxide (PaCO 2 ) in mechanically ventilated patients, but both the relationship between P ET CO 2 and PaCO 2 and whether P ET CO 2 accurately reflects PaCO 2 in neonates and infants are still controversial. This study evaluated remote sampling of P ET CO 2 via an epidural catheter within an endotracheal tube to determine the procedure's clinical safety and efficacy in the perioperative management of neonates. Methods Abdominal surgery was performed under general anesthesia in 86 full-term newborns (age 1–30 days, weight 2.55–4.0 kg, American Society of Anesthesiologists class I or II). The infants were divided into 2 groups (n = 43 each), and carbon dioxide (CO 2 ) gas samples were collected either from the conventional position (the proximal end) or a modified position (the distal end) of the epidural catheter. Results The P ET CO 2 measured with the new method was significantly higher than that measured with the traditional method, and the difference between P ET CO 2 and PaCO 2 was also reduced. The accuracy of P ET CO 2 measured increased from 78.7% to 91.5% when the modified sampling method was used. The moderate correlation between P ET CO 2 and PaCO 2 by traditional measurement was 0.596, which significantly increased to 0.960 in the modified sampling group. Thus, the P ET CO 2 value was closer to that of PaCO 2 . Conclusion P ET CO 2 detected via modified carbon dioxide monitoring had a better accuracy and correlation with PaCO 2 in neonates. [ABSTRACT FROM AUTHOR]

Background: There is a need for quick skin blood flow tests that can be performed in the wound healing field. Antera 3D® is a compact scanner using multispectral imaging. It can perform quick assessment of skin conditions. The purpose of the present study was to investigate the ability of the Antera 3D® to assess skin blood flow in comparison with transcutaneous partial pressure of oxygen (TcPO2) measurements., Methods: This study was conducted on 13 patients with a history of lower extremity ulcers. Measurements of hemoglobin average level (hereafter, Hb score) measured by Antera 3D® and TcPO2 measured by a transcutaneous blood gas monitor were obtained at the same sites on the dorsal foot and lower leg. Differences in Hb score and TcPO2 were analyzed by t-test for each measurement site and for the presence of peripheral arterial disease (PAD). The correlation between TcPO2 and Hb score was analyzed by Pearson's correlation coefficient., Results: Twenty-four limbs were tested. Hb score was higher ( P < 0.001) and TcPO2 was lower ( P = 0.056) in the dorsal foot compared to the lower leg. In the dorsal foot, Hb score was higher ( P = 0.023) and TcPO2 was lower ( P = 0.046) in patients with PAD compared to those without PAD. A significant negative correlation ( r = -0.68; 95% confidence interval -0.85 to -0.38, P < 0.001) between TcPO2 and Hb score was observed in the dorsal foot., Conclusion: The negative correlation between TcPO2 and Hb score may reflect compensatory peripheral vasodilation due to occlusion or stenosis of central arteries. This study showed that Hb score measured by Antera 3D® may be related to skin blood flow., Competing Interests: The authors declare no conflict of interest., (©2023 Tottori University Medical Press.)

A camera-based imaging system was previously developed for mapping venous blood oxygenation in human skin. However, several limitations were realized in later applications, which could lead to either significant bias in the estimated oxygen saturation value or poor spatial resolution in the map of the oxygen saturation. To overcome these issues, an upgraded system was developed using improved modeling and image processing algorithms. In the modeling, Monte Carlo (MC) simulation was used to verify the effectiveness of the ratio-to-ratio method for semi-infinite and two-layer skin models, and then the relationship between the venous oxygen saturation and the ratio-to-ratio was determined. The improved image processing algorithms included surface curvature correction and motion compensation. The curvature correction is necessary when the imaged skin surface is uneven. The motion compensation is critical for the imaging system because surface motion is inevitable when the venous volume alteration is induced by cuff inflation. In addition to the modeling and image processing algorithms in the upgraded system, a ring light guide was used to achieve perpendicular and uniform incidence of light. Cross-polarization detection was also adopted to suppress surface specular reflection. The upgraded system was applied to mapping of venous oxygen saturation in the palm, opisthenar and forearm of human subjects. The spatial resolution of the oxygenation map achieved is much better than that of the original system. In addition, the mean values of the venous oxygen saturation for the three locations were verified with a commercial near-infrared spectroscopy system and were consistent with previously published data. [ABSTRACT FROM AUTHOR]

Objective: In bariatric surgery, arterial carbon dioxide (PaCO2) and oxygen (PaO2) pressures are important but sometimes difficult to measure. The purpose of the present study was to investigate whether transcutaneous carbon dioxide (tcPCO2) and oxygen (tcPO2) pressures can be used to monitor PaCO2 and PaO2, respectively, in laparoscopic bariatric surgery. Methodology: This non-blind, comparadive study was conducted at operating room in the city hospital. Ten adult obese (Body Mass Index (BMI) > 35) patients for laparoscopic bariatric surgery (Bariatric group), and 10 normal weight (BMI < 30) adult patients for open gastric surgery (Control group) were studied. After an epidural catheter insertion at T6-7 or T 7-8, anesthesia was induced with midazolam, propofol, fentanyl, and vecuronium, and was maintained with continuous propofol and remifentanil, intermittent vecuronium and epidural lidocaine. After anesthesia induction, a radial artery catheter was inserted. The electrode of transcutaneous monitor was put on the chest ipsilateral to a radial artery catheter. Pressure controlled ventilation was used in both groups. During surgery at four random points in each patient samples were drawn for arterial blood gas analysis, and measurements of end-tidal carbon dioxide (EtCO2), tcPO2 and tcPCO2 were performed. Results: TcPCO2 and PaCO2 in the control group had good correlation, while no correlation was found in the bariatric group. TcPO2 and PaO2, tcPCO2 and EtCO2, and PaCO2 and EtCO2 had no correlation in both groups. The bias and limits of agreement of tcPCO2 - PaCO2, tcPO2 - PaO2, EtCO2 - tcPCO2, and PaCO2 - EtCO2 were larger in the bariatric group than the control group. Conclusion: Our study concludes that TcPO2 and tcPCO2 cannot be surrogate measurements of PaO2 and PaCO2, respectively in laparoscopic bariatric surgery. [ABSTRACT FROM AUTHOR]

Abstract Introduction Skills to aid in the management of trauma patients and critically ill surgical patients in the intensive care setting are important topics that are not uniformly covered in medical schools. Significant recent attention has been directed toward developing preparatory courses to bridge this gap and heighten the readiness of senior medical students as they transition to surgical residency. This resource includes comprehensive materials intended to prepare senior medical students for management of trauma patients and critically ill surgical patients in the intensive care setting. Methods The materials provided were designed for use as part of a preparatory course for fourth-year medical students entering surgical specialties, and include all instructor's blueprints, PowerPoint slides, and handouts for four separate sessions. A multiple-choice knowledge test is also included. This resource may be used by course directors for surgery PGY-1 preparatory classes/bootcamps, for independent study by individuals planning to matriculate into surgical residencies, or as a review source for those already in surgical training. While these materials were designed to meet the needs of new surgical house staff, the contents are easily generalizable to other medical specialties, and would prove useful for any trainee managing hospital inpatients. Results The outcomes from this course have been extensively studied. Through pre- and postcourse surveys, knowledge tests, and technical examinations, we measured confidence and skill acquisition in specific, job-related tasks. In 2010, 62 individuals were studied (22 course graduates, 16 PGY-1 nonparticipant controls at our home institution, and 24 nonparticipant peer controls at outside institutions). We found that course participants demonstrated marked improvement in task-specific confidence in all tasks from course beginning to end as indicated by improved scores on written and technical skill examinations. Further, course participants outperformed peers in all tasks one month into internship, with their performance advantage predictably dissipating into the third month of residency. Discussion Utilizing this resource resulted in objective gains in task-specific confidence and test performance at course conclusion, which, importantly, translated to improved performance upon residency matriculation. These data emphasize the significant impact of these competency-based surgical internship preparation materials in formally preparing senior medical students for the care of surgical inpatients.

Introduction: the development of this research is base on the growing interest in understanding the adaptations to chronic hipoxia mainly in the range of intermediate altitudes (1 500-3 000 m.s.n.m) and the need to establish parameters of normality in the variables [Hb], Hct and SO2 for diagnostic and characterization of the population purposes.Objective: to analyze the behavior of the [Hb], Hct and SaO2 at different intermediate altitudes (970 m.s.n.m, 1 520 m.s.n.m, 1 728 m.s.n.m, 1 923 m.s.n.m, 2 180 m.s.n.m and 2 600 m.s.n.m) in order to contribute to the knowledge of the high altitude physiology and the clinical field to support the diagnosis of anemia.Methods: clinically healthy subjects with low levels of physical activity and food consumption report containing iron. Total of 264 participants of both genders between 18 and 30 years. The blood samples were collected from the antecubital vein and the earlobe and analyzed in a radiometer. A non-parametric statistical analysis was performed.Results: with increasing of altitude, [Hb] and Hct values were increased while the SO2 decreased. Men showed higher values than women in [Hb] and Hct, related to lower values of SO2 than women.Discussion: a threshold variable was not found, perhaps because of the small distance between the altitudes. The values reported were similar but not identical to other studies. This difference could be explained by genetic diversity among populations.Conclusions: this study allows for the first values of characterization of the study population. All altitudes were above the cutoff for the diagnosis of anemia ([Hb] 12 g/dl). [ABSTRACT FROM AUTHOR]

Background: Noninvasive transcutaneous carbon dioxide monitoring has been shown to be accurate in infants and children, limited data are available to show the usefulness and limitations of partial transcutaneous carbon dioxide tension (PtCO2) value. Objectives: The current study prospectively determines the effectiveness and accuracy of PtCO2 measurements in newborns. Materials and Methods: Venous blood gas sampling and monitoring of the PtCO2 level (TCM TOSCA, Radiometer) were done simultaneously. All measurements are performed on mechanically ventilated infants. Partial venous carbon dioxide tension (PvCO2) values divided into three groups according to hypocapnia (Group 1: < 4.68 kPa), normocapnia (Group 2: 4.68–7.33 kPa), hypercapnia (Group 3: > 7.33 kPa) and then PvCO2 and PtCO2 data within each group were compared separately. Results: A total of 168 measurements of each PvCO2 and PtCO2 data were compared in three separated groups simultaneously (13 in Group 1, 118 in Group 2, and 37 in Group 3). A bias of more than ± 0.7 kPa was considered unacceptable. PtCO2 was related to PvCO2 with acceptable results between the two measurements in hypocapnia (mean difference 0.20 ± 0.19 kPa) and normocapnia (0.002 ± 0.30 kPa) groups. On the other hand in hypercapnia group PtCO2 values were statistically significant (P < 0.001) and lower than PvCO2 data (mean difference 0.81 ± 1.19 kPa) Conclusions: PtCO2 measurements have generally good agreement with PvCO2 in hypocapnic and normocapnic intubated infants but there are some limitations especially with high level of CO2 tension. Monitoring of PtCO2 is generally a useful non-invasive indicator of PvCO2 in hypocapnic and normocapnic infants. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Pulmonology / Jornal Brasileiro de Pneumologia is the property of Sociedade Brasileira de Pneumologia e Tisiologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: A method of non-contact mapping of venous oxygen saturation (SvO2) is presented. A CCD camera is used to image skin tissue illuminated alternately by a red (660nm) and an infrared (800nm) LED light source. Low cuff pressures of 30–40mmHg are applied to induce a venous blood volume change with negligible change in the arterial blood volume. A hybrid model combining the Beer–Lambert law and the light diffusion model is developed and used to convert the change in the light intensity to the change in skin tissue absorption coefficient. A simulation study incorporating the full light diffusion model is used to verify the hybrid model and to correct a calculation bias. SvO2 in the fingers, palm, and forearm for five volunteers are presented and compared with results in the published literature. Two-dimensional maps of venous oxygen saturation are given for the three anatomical regions. [Copyright &y& Elsevier]

Background and objective Although long-term oxygen therapy is one of few treatments known to improve survival in COPD, no patient subgroup likely to derive benefit has been identified in over 30 years. We assessed the prognostic value of point measurement of PaO2 and proportion of ambulatory oximetry with saturations below 90% in this context. Methods Subjects were community-living patients with COPD and PaO2 56-70 mm Hg when stable. Baseline assessments included clinical, physiological and laboratory assessments, as well as 24-h ambulatory oximetry. Patients were followed to death from any cause, first exacerbation and first admission. Results Despite poor survival overall, there was no significant difference in prognosis between mildly hypoxaemic and moderately hypoxaemic patients. There were also no significant differences for secondary end-points (exacerbation and hospital admission). On multivariate analysis, trends were observed towards improved survival, with higher PaO2 and greater proportion of ambulatory oximetry below 90%. Conclusions Neither resting PaO2 nor proportion of ambulatory oximetry below 90% saturation effectively predicted survival in COPD. [ABSTRACT FROM AUTHOR]

Background: In various fields of medicine the transcutaneous measurement (pCO) of carbon dioxide pressure (pCO) has been accepted as a reliable measuring method while for other disciplines the method has been doubted. Nevertheless, some minor therapeutic interventions, such as electroconvulsive therapy and breathing biofeedback used in psychiatry could benefit considerably from transcutaneous monitoring. The study presented here investigated the accuracy of transcutaneous measurement as compared to end-tidal (pCO) and capillary (pCO) measurements in hyperventilation. Methods: In this study 22 healthy volunteers underwent a hyperventilation procedure with assessment of pCO, pCO, pCO, breathing and pulse rates. The three measurement methods of pCO were compared pairwise by Bland-Altman diagrams before and at the end of hyperventilation. The time delay between pCO and pCO was determined for each individual participant by a stepwise shifting the time course of pCO until an optimal congruence with pCO was reached. Results: The study group consisted of 10 men and 12 women with a mean age of 30.5 ± 9.4 years. The experimental procedure lasted an average of 27.7 min including 1.9 min for the baseline measurement and 11.6 min for the actual hyperventilation procedure. The course of pCO from baseline to the end of the hyperventilation phase and back to normal baseline followed a U-curve in all individuals. The pCO could be reduced by a mean of approximately 45 % for the 3 measurement methods from the individual baseline of 35 mmHg. The breathing and pulse frequencies increased by 26.8 % and 17.3 %, respectively. A total of 91 pCO values (mean 4 values per person) and 1,218 pairs of pCO and pCO values (mean 55 values per person) could be evaluated. The difference of the pCO values for two measurement methods revealed similar standard deviations in the Bland-Altman diagrams of about 2.5 mmHg for the 3 pairwise comparisons. The absolute measurement differences between pCO and pCO, pCO and pCO as well as pCO and pCO were averaged for each single participant and afterwards across all individuals resulting in values of 2.0, 2.5 and 2.3 mmHg, respectively. When the baseline and hyperventilation periods were examined separately in this analysis they did not show any relevant differences. The individually determined delays of pCO in regard to pCO averaged 53 s. The time delay exceeded 1 min in only two study participants. Conclusions: In the presented hyperventilation experiment the agreement between the pCO values and the pCO and pCO measurements were comparable to the agreement between the latter two. Altogether, the comparability of the measurement methods seemed satisfactory. The delay between the time courses of pCO and pCO of <1 min for most participants was short and is acceptable for clinical practice. Because only healthy subjects were tested these results might not be the same in children and critically ill patients and could differ from the presented results. [ABSTRACT FROM AUTHOR]

Aim. The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces the need for arterial blood sampling. Drawbacks are high electrode temperature causing risks of skin burning. The aim was to determine the accuracy and precision of tcPCO2 at reduced electrode temperature. Methods. Forty newborns (GA 24.9-41.7) were included. Two tc-monitors were applied (TCM4, Radiometer, Copenhagen). Arterial blood gas sampling and monitoring of tcPCO2-level at different electrode temperatures was done simultaneously (39°C, 40°C, 41°C, 42°C, 44°C). Difference of PaCO2 - tcPCO2 was expressed as a percentage of the mean. Results. Mean PaCO2 was 5.8kPa [3,2; 7.9]. Bias (PaCO2 - tcPCO2) increased from 5% at 44°C to 17% at 39°C, but did not differ significantly between 41°C and 40°C. The precision of the tcPCO2 at each temperature ranged from ++7-10%. After correction for the temperature-dependent overreading, we found increasing PaCO2 - tcPCO2 difference with increasing PaCO2, approx. 2% pr. kPa increase of CO2. Only mild transient erythema was observed. Conclusion. A lower electrode temperature in tcPCO2-monitoring increases systematic overreading of the tc-electrode. However, in very preterm babies, monitoring at 40°C or 41°C is possible provided a bias correction of 12-15% is applied. [ABSTRACT FROM AUTHOR]

Copyright of Der Pneumologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Background: Pulse oximeters are routinely used in severely ill patients to detect hypoxemia early. In various clinical situations, however, conventional devices may be unable to display valid values or any value whatsoever. The usefulness of the Signal Extraction Technology (SET) in these situations has not yet been investigated. Method: Twenty-five adult patients requiring norepinephrine, regardless of the reason or dosage, or having a defective signal with a conventional oximeter were equipped with both their conventional saturation sensor (Oxymax Nellcor™) and a SET saturation sensor (Masimo™) connected to its monitor. Saturation values displayed by each pulse oximeter and the SaO2 measured concomitantly by cooximetry were gathered on inclusion and then whenever one of the two sensors did not display a value, or when the difference between the values was greater than five saturation points, or at any time a blood gas analysis was done. Results: During the study period, 83 measures were collected. Using the Bland and Altman method, SaO2 estimates by the SET system were more accurate than those by the conventional system (bias±2 S.D. of 0.0%±3.1% vs 2.1%±11.0%, respectively), even when only valid values (values accompanied by a satisfactory quality index) were considered (0.0%±2.7% vs 1.2%±7.0%). Conclusions: In situations at risk of producing defective signals when using conventional sensors, the SET system provided more valid SaO2 estimates. [Copyright &y& Elsevier]