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Recently, decision support system (DSSs) have become more widely accepted as a support tool for use with telehealth systems, helping clinicians to summarize and digest what would otherwise be an unmanageable volume of data. One of the pillars of a home telehealth system is the performance of unsupervised physiological self-measurement by patients in their own homes. Such measurements are prone to error and noise artifact, often due to poor measurement technique and ignorance of the measurement and transduction principles at work. These errors can degrade the quality of the recorded signals and ultimately degrade the performance of the DSS system, which is aiding the clinician in their management of the patient. Developed algorithms for automated quality assessment for pulse oximetry and blood pressure (BP) signals were tested retrospectively with data acquired from a trial that recorded signals in a home environment. The trial involved four aged subjects who performed pulse oximetry and BP measurements by themselves at their home for ten days, three times per day. This trial was set up to mimic the unsupervised physiological self-measurement as in a telehealth system. A manually annotated "gold standard" (GS) was used as the reference against which the developed algorithms were evaluated after analyzing the recordings. The assessment of pulse oximetry signals shows 95% of good sections and 67% of noisy sections were correctly detected by the developed algorithm, and a Cohen's Kappa coefficient (κ) of 0.58 was obtained in 120 pooled signals. The BP measurement evaluation demonstrates that 75% of the actual noisy sections were correctly classified in 120 pooled signals, with 97% and 91% of the signals correctly identified as worthy of attempting systolic and/or diastolic pressure estimation, respectively, with a mean error and standard deviation of 2.53±4.20 mmHg and 1.46±5.29 mmHg when compared to a manually annotated GS. These results demonstrate the feasibility, and highlight the potential benefit, of incorporating automated signal quality assessment algorithms for pulse oximetry and BP recording within a DSS for telehealth patient management.

Study Objectives: For children with trisomy 21, polysomnography at age 4 to assess obstructive sleep disordered breathing (OSDB) is the standard of care. Oximetry alone has been used to screen for disease among children without trisomy 21. This study evaluates the potential usefulness of oximetry scoring in diagnosing OSDB among children with trisomy 21., Methods: A McGill oximetry score from 1 to 4 was derived from a full overnight PSG done on 119 consecutive pediatric subjects with trisomy 21. Most were referred to the sleep laboratory because of suspicion for OSDB. Oximetry scorers were blinded to the child's full PSG and clinical course. Results of the complete PSG were then compared to oximetry scores., Results: Obstructive apnea-hypopnea index (OAHI) was ≥ 2.5 for 50% of all subjects. Fifty-nine subjects (49.6%) had McGill Score 1 ("inconclusive"); median OAHI was 1.0 (IQR 0.4-3.3). McGill Score was 2 for 43 subjects (36.1%); median OAHI was 4.5 (IQR 1.3-8.8). Seventeen subjects (14.3%) had McGill Scores of 3 or 4; median OAHI was 16.1 (IQR 9.3-45.5, range 2.1 to 101.1). Ten percent of subjects had a considerable number of central events (≥ 2.5 respiratory events/h but OAHI < 2.5), including 7 with McGill Score 2., Conclusions: In a retrospective cohort of children with trisomy 21, McGill oximetry scores of 3 or 4 reliably identified patients with marked OSDB. The possibility of central apneas causing hypoxemia must be considered in those with McGill Score 2. With these caveats, oximetry screening should be considered when developing streamlined protocols for early intervention to treat OSDB in this population., (© 2014 American Academy of Sleep Medicine.)

Objective: To investigate whether the pleth variability index (PVI), derived noninvasively from a pulse oximeter probe, would predict fluid responsiveness in patients undergoing noncardiac surgeries., Design: A clinical, prospective, observational study., Setting: Operating room of a tertiary care hospital., Participants: Twenty-nine adult patients undergoing a range of noncardiac surgeries, requiring general anesthesia, tracheal intubation, and mechanical ventilation., Interventions: Intravenous volume expansion with 500 mL of colloid following induction of general anesthesia and after a period of hemodynamic stability before the start of surgery., Measurements and Main Results: Baseline values for PVI and stroke volume index, derived from an esophageal Doppler monitor, were compared with final values after the volume expansion. Patients were classified into fluid responders and nonresponders based on a stroke volume index increase of ≥ 10%. The optimal cut-off value for baseline pleth variability index for predicting fluid responsiveness was determined. There were 17 responders (59%) to the 500-mL volume expansion. Baseline PVI value was significantly different between responders and nonresponders (16.5 ± 6.4% v 10.3 ± 2.7%; p = 0.004). Receiver operating characteristic analysis demonstrated significant predictive ability of an increase in stroke volume index for PVI with area under the curve of 0.84 (95% confidence interval = 0.69-0.99). The optimal cut-off value for baseline PVI was 10.5%, with a sensitivity of 88% and a specificity of 67%., Conclusions: Pleth variability index is predictive of fluid responsiveness in adult patients undergoing noncardiac surgery., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: In clinical practice, oxygen saturation as measured by photoplethysmography and arterial oxygen tension as determined by blood gas analysis are the parameters used frequently to estimate the oxygen status of a patient. Additionally, the cardiac output CO and the arterial oxygen content CaO2 are critical for the delivery of oxygen ḊO2 to organs and tissues. So far, CaO2 reference values published by Mertzlufft and Zander (1984) and Siggaard-Andersen (1990) are widely used. The aim of the present study was to reevaluate previously published results using the results of a population-based study. Furthermore, the impact of smoking on CaO2 will be assessed., Patients and Methods: Data of 1018 volunteers from the Study of Health in Pomerania (SHIP) were analyzed. CaO2 was calculated from blood gas analysis of capillary blood obtained from a hyperemised ear lobe. Reference value equations controlled for sex, age and smoking were derived with quantile regression analysis and fractional polynomials., Results: Lower limits of normal (LLN) decline with age. Current smoking has no significant influence on LLN for CaO2., Conclusion: Sex, age and smoking-specific normal values can be calculated using the current equations., (© Georg Thieme Verlag KG Stuttgart · New York.)

Aim: Despite there being evidence that pulse oximetry screening is better than clinical examination alone in early detection of CHD, implementation has been slow. The aim of this paper was to evaluate the practice after its implementation into routine care at Royal Prince Alfred Hospital in 2008., Methods: A single pulse oximetry measurement was incorporated in the routine discharge newborn examination or, with early discharge, as a part of the Midwife Discharge Support Programme. An oxygen saturation level greater than or equal to 95% was considered normal, and a level less than 95%, confirmed on a repeat measure, triggered a review and examination by a consultant neonatal paediatrician. The saturation levels were recorded in the hospital database. Ascertainment of major CHD requiring surgery in the first 12 months was performed by searching the cardiac surgery database of the Heart Centre for Children., Results: A total of 18 801 babies were screened over a 42-month period. Of these, four babies with major CHD were diagnosed prior to discharge with the main clinical alert resulting from routine pulse oximetry screening (true positive). Of the 11 cases with saturation <95% but no CHD (false positive cases), six had respiratory pathology. One baby with normal saturation level needed surgery in the first year for a large ventricular septal defect (false negative). The false positive rate of pulse oximetry screening for CHD was 0.13% with sensitivity 80%, specificity of 99.8%, a positive predictive value of 13.3% and a negative predictive value of 99.9%. Nine additional echocardiogram were required over 42 months., Conclusions: These post-implementation data confirm that pulse oximetry screening increases early diagnosis of major CHD as well as other important pathology with a very low false positive rate and minimal requirement for extra echocardiograms. Pulse oximetry screening of apparently well newborns should become a standard of care., (© 2014 The Authors. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).)

Aims: Carbon monoxide (CO) can cause lethal intoxication, but the burden of occult CO poisoning is still unclear. We aimed at prospectively assessing the number of patients with occult CO poisoning presenting to an emergency department within one year., Methods: Prospective, observational study according to the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) statement for cross sectional studies at a European high volume tertiary-care emergency department., Results: Thirty-two thousand three-hundred and ninety-six consecutive patients whose vital signs were assessed at triage, regardless of their complaints. Active screening for CO-poisoning by non-invasive CO-oximetry was performed at triage. A pragmatic diagnosis of CO poisoning was made by attending physicians in 32 cases, representing 99/100,000 emergency department (ED)-patients. Three different definitions of poisoning were developed based on physicians' decision criteria, resulting in 9, 12, and 48 cases, respectively., Conclusions: In our study population, the prevalence of CO poisoning was twice as high as previously reported. The number of cases highly depends on the definition used, with more strict definitions excluding mainly cases during the summer months, where the source of CO often remains unknown. A clear consensus on which patients have to be regarded as 'poisoned' is urgently needed in order to allow comparison across studies., (© 2014 John Wiley & Sons Ltd.)

Background: Continuous home monitoring of oxygen saturation has become a reliable and feasible practice. The objective of this study was to investigate the role of preoperative overnight oximetry in predicting postoperative adverse events., Methods: Following research ethics board approval, consented patients underwent a preoperative overnight monitoring of oxygen saturation with a portable oximeter. Parameters from the oximetry data were extracted and their predictive performance for postoperative adverse events was evaluated., Results: A total of 573 patients were studied with age: 60±12 years and 45% male. Oxygen desaturation index (ODI), cumulative time percentage with SpO2 <90% (CT90) and mean SpO2 were identified as significant predictors for postoperative adverse events. The privilege sensitivity, optimal predictive and privilege specificity cut-offs were: ODI: >3.0 events/h, >9.2 events/h and > 28.5 events/h; CT90: >0.1%, >1.1% and >7.2%; mean SpO2: <96.2%, <94.6% and <92.7%. The odds ratio for corresponding optimal cut-offs was: ODI 1.9 (95% CI: 1.4,2.7); CT90: 1.7 (95% CI: 1.2,2.4) and mean SpO2: 2.7 (95% CI: 1.9,3.8). The patients classified as high risk by ODI or CT90 or mean SpO2 had a significantly higher rate of postoperative adverse events. For ODI >28.5 vs. ODI ⋝28.5 events/h, the odds ratio adjusted with age, gender, body mass index and American Society of Anesthesiologists physical status was 2.2 (95% CI: 1.3-3.9)., Conclusion: Patients with mean preoperative overnight SpO2 <92.7% or ODI >28.5 events/h or CT90 >7.2% are at higher risk for postoperative adverse events. Overnight oximetry could be a useful tool to stratify patients for the risk of postoperative adverse events.

Introduction: Pulse oximetry is a noninvasive method for assessing vascular health based on oxygen saturation level. The method has recently also been used to assess dental pulp vitality, but a median oxygen saturation level suggestive of normal pulp physiology has not been determined. The objective of this study was to make a critical analysis of the published research to establish the median oxygen saturation for the diagnosis of normal dental pulps in maxillary anterior permanent teeth using pulse oximetry., Methods: Studies reporting on the use of pulse oximeters to determine oxygen saturation in dental pulps were retrieved using the MEDLINE, Scientific Electronic Library Online, and Cochrane Central Register of Controlled Trials databases plus a manual search of relevant references cited by selected articles. Different combinations of the terms "oximetry," "oximeter," "pulp," "dental," and "dentistry" were used in the search. Statistical analysis was performed for each group of teeth (central incisors, lateral incisors, and canines) using R statistical software (US EPA ORD NHEERL, Corvallis, OR) and a random effects model (P < .0001) with an I(2) of 99%., Results: Of the 295 articles found, only 6 met the inclusion criteria (472 teeth). Of these, the number of articles included in each analysis (according to tooth group) was as follows: all 6 studies (288 teeth) for central incisors at a median oxygen saturation of 87.73%, 3 studies (90 teeth) for lateral incisors at a median oxygen saturation of 87.24%, and 4 studies (94 teeth) for canines at a median oxygen saturation of 87.26%., Conclusions: The median oxygen saturation in normal dental pulps of permanent central incisors, lateral incisors, and canines was higher than 87%., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

Background: The higher levels of oxygen in cerebrum may contribute to neuro-apoptosis, analogous to direct tissue injury induced by toxic levels of oxygen. Earlier report highlighted the possibility of cerebral "hyperoxygenation" secondary to inhalational induction of anesthesia with sevoflurane in small number of children., Objective: The aim of this retrospective review was whether similar cerebral "hyperoxygenation" trends can be seen in larger and retrospective patients' database., Methods: Data of patients who had undergone cardiac surgeries at Children's Hospital during the two-year period (2010-2011) was retrieved during this retrospective review: (a) stored computer data from INVOS Cerebral/Somatic Oximeter for oximetry numbers and total duration of oximetry monitoring, (b) paper chart perfusion records of the cardiac surgeries for age and sex of the patient, urgency of the surgery, type of induction (inhalational or intravenous), and total duration of cardiopulmonary bypass, (c) general medical records for inpatient setting vs. outpatient setting of the patient, and (d) anesthesia medical records for name of the medications used during induction of anesthesia to segregate the patients who had fentanyl as a lone induction agent and sevoflurane as a lone induction agent, for final statistical calculations and analysis. For the two-year period (2010-2011), data of 358 patients who had cardiac surgeries at Children's Hospital were reviewed. However, after deletions of various patients' data due to various reasons, only 69 patients (0-4 years of age) who had sevoflurane induction were analyzed for final statistical comparisons to 14 patients (0-4 years of age) who had fentanyl induction., Results: Cerebral and renal "hyperoxygenation" occurred during the first 127 minutes with sevoflurane as compared to fentanyl though the percentage changes from pre-induction values in oximetry during this time did not reach level of significance. However, only cerebral "hyperoxygenation" persisted in the last 127 minutes when patients had been induced with sevoflurane as compared to fentanyl., Conclusion: Cerebral "hyperoxygenation" occurs with inhalational induction of anesthesia with vasoparalytic sevoflurane in children 0 to 4 years of age when compared to anesthesia induction with vasoneutral fentanyl.

Objective: The reliability of pulse oximetry in the lower SaO2-ranges has not been fully investigated. We wanted to investigate pulse oximeter performance in a pig model of perinatal asphyxia., Methods: Asphyxia was induced in 22 newborn pigs. Pulse oximetry-values for SpO2, as well as SaO2 from blood gas analyses were recorded multiple times before, during and after asphyxiation. The relationship between SpO2 and SaO2 in normoxia and hypoxia in this model was quantified. Calculations were made for 5% increments of SaO2 increasing successively from ≥95% to ≥20%., Results: The pigs became severely hypoxic, acidotic and hypotensive. The bias in the total data was +13.7 (p < 0.001), i.e. SpO2 was on average higher than SaO2 for the entire interval of SaO2. However, bias was not significantly different from zero in most SpO2-ranges. Accuracy and precision were considerably higher than stated by the manufacturer in all SpO2-ranges, with both accuracy and precision increasing when SpO2-values down to 60% and lower were included., Conclusion: Pulse oximetry was less reliable at SaO2-values below 60%. Tissue acidosis and reduced peripheral perfusion may have contributed to this. It is unknown whether the difference between SpO2 and SaO2 is clinically relevant.

Objective: To better understand the availability of oxygen and pulse oximetry, barriers to use, clinician perceptions and practices regarding their role in the management of childhood pneumonia, and the formal education and training regarding these technologies received by student clinicians in Cambodia., Methods: In the clinician survey, we surveyed 81 clinicians practising at all national paediatric, provincial and district referral hospitals throughout Cambodia. Respondents were primarily physicians whose scope of practice included paediatrics, and most reported the presence of oxygen (93% (95% confidence interval (CI) [87, 98])) but less availability of pulse oximetry (51% (95% CI [39, 61]))., Results: Common barriers to use included a lack of policies and guidelines, as well as a lack of training. In the student clinician survey, 332 graduating medical and nursing students were surveyed, and most reported learning about oxygen (96% (95% CI [94, 98])) and pulse oximetry (72% (95% CI [67, 77])) during their training., Conclusions: Data from both surveys indicate that despite their utility, oxygen and pulse oximetry may be underused in Cambodia. The reported barriers and perceptions of the tools indicate a clear role for improved training for clinicians and students on the use of oxygen and pulse oximetry, the value of oxygen and pulse oximetry for managing childhood pneumonia, and the need for improved policies and guidelines governing their use., (© 2014 John Wiley & Sons Ltd.)

Objective: to evaluate the feasibility of using pulse oximetry (PO) for evaluating infants born in community-based midwifery care., Design: a prospective, observational study of infants born after midwifery supervised (home) births., Setting: 27 midwives from seven practices providing primary care in (home) births used PO at birth or the early puerperal period over a ten-month period. Data were obtained on the effect of PO on outcome, interventions and decision-making. Midwives were surveyed about applicability and usefulness of PO., Participants: 153 infants born in primary midwifery care., Findings: all births were uncomplicated except for one infant receiving supplemental oxygen and another was mask ventilated. In 138/153 (90%) infants PO was successfully used and 88% of midwives found PO easy to use. In 148/153 (97%) infants PO did not influence midwives' clinical judgment and referral policy. In 5/153 (3%) infants, midwives were uncertain of the infant's condition, but PO measurements were reassuring. In case of suboptimal neonatal condition or resuscitation, 100% of midwives declared they would use PO again., Key Conclusions: it is feasible to use PO in community based midwifery care, but not considered an important contribution to routine evaluation of infants. Midwives would like to have PO available during suboptimal neonatal condition or when resuscitation is required., Implications for Practice: PO can be applied in community based midwifery care; it does not lead to insecurity or extra referral. Further research on a larger group of infants must show the effect of PO on neonatal outcomes., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objectives: Near-infrared cerebral oximetry increasingly is used for monitoring during cardiac surgery. Nonetheless, the scientific basis for incorporating this technology into clinical practice, the indications for when to do so, and standard diagnostic and treatment algorithms for defining abnormal values are yet to be rigorously defined. The authors hypothesized that there would be (1) variation in clinical use and practices for near-infrared spectroscopy (NIRS), and (2) variation in management of patients when clinicians are provided with NIRS information. In order to test this hypothesis, they sought to assess the nature and strength of response heterogeneity among anesthesiologists and cardiac perfusionists when provided with cardiac surgery patient scenarios and cerebral oximetry data., Design: A prospectively collected survey., Setting: A hospital-based, multi-institutional, multinational study., Participants: By e-mail, the authors surveyed the membership of the Society of Cardiovascular Anesthesiologists and the online Cardiovascular Perfusion Forum., Interventions: This survey was focused on ascertaining what actions clinicians would take in each scenario, given case information and cerebral oximetry tracings. Questions were based on 11 patient scenarios selected to represent small, large, symmetric, or asymmetric decreases in measured regional cerebral oxygen saturation (rScO2) encountered during cardiac surgery. Information on the respondents' (n = 796; 73% anesthesiologists) clinical practice, demography, and cerebral oximetry utilization was collected. An index of dispersion was used to assess response heterogeneity overall and within demographic subgroups., Measurements and Main Results: The majority of respondents indicated that cerebral oximetry monitoring was either useful or an essential monitor, especially perfusionists and clinicians who used cerebral oximetry most frequently. There were marked differences in responses between perfusionists and anesthesiologists for 4 of the 6 scenarios (p<0.005 for each of these 4 scenarios) occurring during cardiopulmonary bypass. Scenarios having greatest rScO2 reduction or asymmetry in rScO2 were associated with the highest dispersion, indicating least agreement in management. Scenarios with mild or moderate rScO2 reduction were associated with the lowest dispersion, indicating greater agreement in management., Conclusions: Although experimental data gradually are accumulating to support the role for cerebral oximetry monitoring during cardiac surgery, the results of the present survey support the view that its role remains poorly defined, and consensus for its appropriate use is lacking. Importantly, the authors observed marked variation in the use, perceived utility, and management of patients for 4 of the 6 CPB scenarios between perfusionists and anesthesiologists who share the management of CPB. These findings support the need for well-designed, adequately-powered clinical trials examining the value of this technology., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and critical-care medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of age-specific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations. Pulse oximetry does not provide information about the adequacy of ventilation or about precise arterial oxygenation, particularly when arterial oxygen levels are very high or very low. Arterial blood gas analysis is the gold standard in these settings. Pulse oximetry may be inaccurate as a marker of oxygenation in the presence of dyshaemoglobinaemias such as carbon monoxide poisoning or methaemoglobinaemia where arterial oxygen saturation values will be overestimated. Technical considerations such as sensor position, signal averaging time and data sampling rates may influence clinical interpretation of pulse oximetry readings., (© 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.)

Objective: For children with cyanotic congenital heart disease or acute hypoxemic respiratory failure, providers frequently make decisions based on pulse oximetry, in the absence of an arterial blood gas. The study objective was to measure the accuracy of pulse oximetry in the saturations from pulse oximetry (SpO2) range of 65% to 97%., Methods: This institutional review board-approved prospective, multicenter observational study in 5 PICUs included 225 mechanically ventilated children with an arterial catheter. With each arterial blood gas sample, SpO2 from pulse oximetry and arterial oxygen saturations from CO-oximetry (SaO2) were simultaneously obtained if the SpO2 was ≤ 97%., Results: The lowest SpO2 obtained in the study was 65%. In the range of SpO2 65% to 97%, 1980 simultaneous values for SpO2 and SaO2 were obtained. The bias (SpO2 - SaO2) varied through the range of SpO2 values. The bias was greatest in the SpO2 range 81% to 85% (336 samples, median 6%, mean 6.6%, accuracy root mean squared 9.1%). SpO2 measurements were close to SaO2 in the SpO2 range 91% to 97% (901 samples, median 1%, mean 1.5%, accuracy root mean squared 4.2%)., Conclusions: Previous studies on pulse oximeter accuracy in children present a single number for bias. This study identified that the accuracy of pulse oximetry varies significantly as a function of the SpO2 range. Saturations measured by pulse oximetry on average overestimate SaO2 from CO-oximetry in the SpO2 range of 76% to 90%. Better pulse oximetry algorithms are needed for accurate assessment of children with saturations in the hypoxemic range.

Background: Chronic obstructive pulmonary disease (COPD) exacerbations are associated with lung function decline, lower quality of life, and increased mortality, and can be prevented by pharmacological treatment and rehabilitation., Aims: To examine management including examination, treatment, and planned follow-up of COPD exacerbation visits in primary care patients and to explore how measures and management at exacerbation visits are related to subsequent exacerbation risk., Methods: A clinical population of 775 COPD patients was randomly selected from 56 Swedish primary healthcare centres. Data on patient characteristics and management of COPD exacerbations were obtained from medical record review and a patient questionnaire. In the study population of 458 patients with at least one exacerbation, Cox regression analyses estimated the risk of a subsequent exacerbation with adjustment for age and sex., Results: During a follow-up period of 22 months, 238 patients (52%) had a second exacerbation. A considerable proportion of the patients were not examined and treated as recommended by guidelines. Patients with a scheduled extra visit to an asthma/COPD nurse following an exacerbation had a decreased risk of further exacerbations compared with patients with no extra follow-up other than regularly scheduled visits (adjusted hazard ratio 0.60 (95% confidence interval 0.37 to 0.99), p=0.045)., Conclusions: Guidelines for examination and emergency treatment at COPD exacerbation visits are not well implemented. Scheduling an extra visit to an asthma/COPD nurse following a COPD exacerbation may be associated with a decreased risk of further exacerbations in primary care patients.

Tissue hypoxia may cause organ dysfunction, but not much is known about tissue oxygenation in the intraoperative setting. We studied microcirculatory tissue oxygen saturation (StO₂) to determine representative values for anesthetized patients undergoing urological surgery and to test the hypothesis that StO₂ is associated with known perioperative risk factors for morbidity and mortality, conventionally monitored variables, and hypotension requiring norepinephrine. Using near-infrared spectroscopy, we measured StO₂ on the thenar eminence in 160 patients undergoing open urological surgery under general anesthesia (FiO2 0.35-0.4), and calculated its correlations with age, risk level for general perioperative complications and mortality (high if age ≥70 and procedure is radical cystectomy), mean arterial pressure (MAP), hemoglobin concentration (Hb), central venous oxygen saturation (ScvO₂), and norepinephrine use. The time averaged StO₂ was 86 ± 6 % (mean ± SD). In the multivariate analysis, Hb [standardized coefficient (SC) 0.21, p = 0.003], ScvO₂ (SC 0.53, p < 0.001) and high risk level (SC 0.06, p = 0.03) were significant independent variables correlated with StO₂. SStO₂ was partly dependent on MAP only when this was below 65 mmHg (lowest MAP SC 0.20, p = 0.006, MAP area under the curve <65 mmHg SC 0.03, p = 0.02). Finally, StO₂ was slightly lower in patients requiring norepinephrine (85 ± 6 vs. 89 ± 6 %, p = 0.001). Intraoperative StO₂ in urological patients was comparable to that of healthy volunteers breathing room air as reported in the literature and correlated with known perioperative risk factors. Further research should investigate its association with outcome and the effect of interventions aimed at optimizing StO₂.

A retrospective observational study on a sample of 13,413 deliveries analysed the effect of a withdrawal of the CTG additional diagnostic methods of fetal hypoxia (fetal pulse oximetry and ST analysis of the fetal ECG) on operative delivery rates and frequency of the umbilical arterial pH < 7.15. Following the withdrawal, obstetricians are more likely to perform caesarean sections for fetal hypoxia (OR 2.23, 95% CI 1.94-2.55, p < 0.0001) and labour dystocia (OR 1.45, 95% CI 1.18-1.77, p = 0.0003), which increases the overall caesarean rate (OR 1.49, 95% CI 1.38-1.61, p < 0.0001), although decreases the incidence of birth umbilical arterial pH < 7.15 (OR 0.43, 95% CI 0.22-0.85, p = 0.015). This also leads to the significant decline in overall frequency of instrumental vaginal deliveries (OR 0.58, 95% CI 0.48-0.71). In order to decrease the overall caesarean rate, obstetricians need to be supported by more accurate and possibly automated diagnostic tools for intrapartum fetal hypoxia.

Objective: To assess the level of preparedness and resources needed in Minnesota for the implementation of newborn screening for critical congenital heart diseases (CCHDs)., Methods: A cross sectional survey of all birth centers in Minnesota was performed to assess the capacity to deliver care essential for the CCHD screening program. Compliance with the screening algorithm, nursing workload, and cost were assessed by using a pilot program implemented in 6 normal newborn nurseries., Results: Ninety-one of 99 eligible centers participated in the survey and 90 reported the ability to screen newborns in accordance with recommendations. Only 22 centers, with 63% of births, had access to echocardiography and routinely stocked prostaglandins for neonatal use. Our pilot study screened 7549 newborns with 6 failed screens and 1 CCHD diagnosis. Two of the failed screens were due to misinterpretation of the algorithm, 1 failed screen was not reported, and 4 failed screens were not recognized. Repeated screens were required for 115 newborns, with 29% of retesting due to misinterpretation of the algorithm. The mean nursing time required was 5.5 minutes, and the cost was $5.10 per screen., Conclusions: In Minnesota, two-thirds of newborns are born in centers with resources for initial diagnosis and management of CCHD. Implementation of a pilot screening program demonstrated minimal increase in nursing workload, but identified problems with interpretation of the algorithm and data reporting. This pilot project suggests the need for simplification of the algorithm, additional training of health care providers, and development of a centralized reporting mechanism.

Objective: To determine whether resuscitation teams can better maintain newborn transitional oxygen saturation (SpO₂) values within a prespecified target range using a graphical display of the targets and real-time SpO₂ data compared with using only numerical oximeter values., Study Design: Preterm neonates were enrolled in this prospective cohort evaluation of a change in practice. The Transitional Oxygen Targeting System (TOTS) plots real-time SpO₂ values in relation to 10th and 50th percentile SpO₂ curves, which provides a visual target. After introduction of the TOTS, the resuscitation team adjusted the fraction of inspired oxygen to maintain the SpO₂ within the target range, and before its use neonates were resuscitated in attempt to target normal transitional SpO₂ values without using the TOTS monitor. Duration of time within 10th-50th percentile values was compared between 2 cohorts, children evaluated with the TOTS and those not evaluated with the TOTS (controls)., Results: A total of 40 infants were enrolled, including 20 prospectively evaluated with the TOTS and 20 controls. Mean gestational age, birth weight, total resuscitation time, duration of supplemental oxygen administration, changes in oxygen concentration, and respiratory support provided were similar in the 2 groups. The TOTS cohort spent 52% of time within the target range; the control cohort, 37% (P = .03)., Conclusion: SpO₂ values were maintained within a specified target range for significantly longer in preterm neonates resuscitated using the TOTS display compared with those resuscitated without TOTS., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Objectives: The objective was to apply quality indicators in respiratory disease triage during a set time period., Methods: This was a retrospective, descriptive, and comparative study of all patients attending the emergency department of Acosta Ñu Children's Hospital with breathing difficulty, between January 1 and July 31, 2011., Results: Two thousand five hundred eighty-two patients were included in the study. The delay in medical care according to severity of breathing difficulty was as follows: for critical patients, 1 minute (100% compliance); for emergencies, 6.4 minutes (93.4% compared with 95% standard); for urgencies, 15.8 minutes (90% compared with the standard 90%); and for semiurgencies, 35 minutes (92.4% vs. 85% standard). Regarding to the admission-triage time indicator: mean time was 6.1 minutes; 2220 patients (86%) were classified in less than 10 minutes from the time of hospital admission, and 2453 (95%) were evaluated before 15 minutes. Respiratory rate was recorded in 2368 patients (91.7%), and pulse oximetry in 2443 (94.6%). Both parameters were recorded in 2271 children (88%). Errors in classification were detected, mainly tendency to underestimate the risk or exacerbate the clinical situation; 441 patients underwent subtriage (20.5%), and 44 overtriage (1.7%). There were drawbacks to classify emergencies error rate 45.8% (P < 0.00001). Relationship between pathophysiologic diagnosis and triage level was significant (P < 0.00001)., Conclusions: Indicators of triage quality were acceptably met in respiratory disease. Breathing difficulty was identified and classified as urgent, although problems arouse at differentiation between moderate and severe dyspnea.

The photoplethysmography (PPG) signals detected by transesophageal oximetry sensor toward aorta arch (AA), descending aorta (DA), and left ventricle (LV) under the guidance of transesophageal echocardiography (TEE) were investigated, and the effects of filter application on PPG signals were evaluated. Eleven cardiac surgical patients were involved. After anesthesia was induced, the TEE probe with a modified pulse oximetry sensor was inserted. Under the guidance of TEE, the AA PPG, DA PPG and LV PPG were detected respectively when ventilator was on and off. The mean alternating current (AC) amplitudes and direct current (DC) values of original and filtered PPG signals were measured. The ratio of AC and DC value (AC/DC) and ventilation-induced AC variations were calculated. Satisfactory PPG waveforms were obtained in all patients under the guidance of TEE. The AC amplitude in LV PPG was significant larger than in AA and DA PPG, and both AC/DC and ventilation-induced AC variation in LV PPG were significantly higher than in AA PPG or DA PPG either. There were no significant differences of AC amplitude between filtered and ventilation off PPG signals. The AC amplitudes and AC/DC toward LV are significantly higher than transesophageal oximeter toward AA or DA, and the effect of mechanical ventilation on transesophageal PPG can be obviously reduced by filtering techniques.

Background: Although hypoxemic children have high mortality, little is known about hypoxemia prevalence and oxygen administration in African hospitals. We aimed to determine the hypoxemia prevalence and quality of oxygen treatment by local clinicians for hospitalized Malawian children., Methods: The study was conducted in five Malawian hospitals during January-April 2011. We prospectively measured the peripheral oxygen saturation (SpO(2)) using pulse oximetry for all children <15 years old and also determined clinical eligibility for oxygen treatment using WHO criteria for children <5 years old. We determined oxygen treatment quality by Malawian clinicians by comparing their use of WHO criteria for patients <5 years old using two standards: hypoxemia (SpO(2) <90%) and the use of WHO criteria by study staff., Results: Forty of 761 (5.3%) hospitalized children <15 years old had SpO(2) <90%. No hospital used pulse oximetry routinely, and only 9 of 40 (22.5%) patients <15 years old with SpO(2) <90% were treated with oxygen by hospital staff. Study personnel using WHO criteria for children <5 years old achieved a higher sensitivity (40.0%) and lower specificity (82.7%) than Malawian clinicians (sensitivity 25.7%, specificity 94.1%)., Conclusion: Although hypoxemia is common, the absence of routine pulse oximetry results in most hospitalized, hypoxemic Malawian children not receiving available oxygen treatment.

Purpose: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is used to treat severe forms of acute respiratory distress syndrome (ARDS). VV-ECMO management may be confusing due to the lack of information about the interplay between the determinant parameters and their impact on oxygenation. We found a relationship between arterial oxygen saturation (SaO(2)) and its relevant parameters. The aim of this study was to assess the validity of this model., Methods: We report our experience in 17 patients under VV-ECMO for severe ARDS. We compared, at two different levels of pump flow, SaO(2) and the oxygen saturation measured in the pulmonary artery (SpaO(2)) with the predicted saturation using the formula: SpaO(2) = (EF/CO)SmO(2) + (1 - EF/CO)SvO(2) + 10(-2)PmO(2), where PF is pump flow, R is recirculation, EF is effective flow [= (1 - R)PF], SmO(2) is saturation of the oxygenator outgoing blood, CO is cardiac output, SvO(2) is saturation of mixed venous blood, and PmO(2) is oxygen partial pressure of the oxygenator outgoing blood., Results: There was no significant difference between predicted and measured SpaO(2): the mean predicted and measured SpaO(2) values were 90.7 ± 2.8 % and 90.4 ± 2.7 % , respectively (p = 0.696, r = 0.966). Bland-Altman analysis showed good agreement between predicted and measured SpaO(2). Predicted SpaO(2) and SaO(2) was well correlated (r = 0.80)., Conclusions: We have presented an explicit relationship between SaO(2) and its direct determinants during VV-ECMO. Good agreement was found with the measured values of SaO(2), but the model remains to be fully validated before its use in clinical practice.

Objective: The aim of this study was to assess the accuracy of oximetry and the clinical parameters for the prescription of continuous positive airway pressure (CPAP) in patients with suspected obstructive sleep apnea syndrome (OSAS)., Methods: All participants (135) performed oximetry (WristOx 3100™) and polysomnography (PSG) simultaneously in the sleep laboratory. The patients completed the Epworth sleepiness scale, the Berlin questionnaire, and a clinical history. Two blind independent observers decided to prescribe CPAP according to the results of the PSG (gold standard, observer A), oximetry (alternative method, observer B), and the clinical parameters. The accuracy of observer B on the indication of CPAP, using different cutoff points of the adjusted desaturation index (ADI3 and ADI4), was evaluated by the area under the receiver operating characteristics curve (AUC-ROC). The interobserver agreement for the indication of CPAP was assessed using kappa statistics., Results: One hundred nineteen subjects were included (92 men; mean age, 53; median respiratory disturbance index, 22.6; median BMI, 27.5 kg/m(2)). Depending on the criteria used in oximetry, the sensitivity and specificity of observer B to initiate a CPAP trial ranged from 79.8% to 92.5% and of 92% to 96%, respectively. The best performance for the indication of CPAP was noted with the adjusted O(2) desaturation index ≥ 3% (AUC-ROC, 0.923). The inter-rater agreement for the prescription of CPAP was good (kappa, 0.60 to 0.79)., Conclusion: This simulated study has shown that the use of oximetry plus clinical data has made it possible to indicate CPAP reliably in nearly 90% of the population with OSAS.

Background: Delivery room resuscitation of hypoxic newborn infants with pure or 100% oxygen causes oxidative toxicity and increases mortality. Current international resuscitation guidelines therefore recommend that oxygen be used judiciously. However, this requires staff education and special equipment that may not be available in non-tertiary maternity hospitals where the majority of births occur., Aim: To determine current attitudes, practices and available equipment for the use of air and blended oxygen for newborn delivery room resuscitation in non-tertiary maternity hospitals of Australia and New Zealand (ANZ)., Methods: Structured questionnaires sent by mail and e-mail after personal phone contact. A total of 203 eligible hospitals in ANZ were identified. A second mailing was conducted a month later for non-responders. RESPONDERS: Final response rate was 64% (n= 130: 70% physicians, 30% midwives). The majority (121, 93%) of respondents were aware of Australian Resuscitation Council recommendations, but only one in five hospitals had the capacity to deliver blended oxygen and 38% used pulse oximeters at delivery. Only 24 (18.5%) hospitals had guidelines. Air would be used by 68 (57%) hospitals to resuscitate term infants compared to 35 (31%) for preterm infants. Most (111, 91%) advocated the use of blended oxygen despite the lack of facilities., Conclusion: Only one in five ANZ non-tertiary maternity hospitals had the capacity to resuscitate newborn infants with air or blended oxygen. Most are aware of current recommendations and agreed that the use of less oxygen would be beneficial for this purpose. Further study into the necessary infrastructure required to implement these guidelines are recommended., (© 2012 The Authors. Journal of Paediatrics and Child Health © 2012 Paediatrics and Child Health Division (Royal Australasian College of Physicians).)

The variations induced by mechanical ventilation in the arterial pulse pressure and pulse oximeter plethysmograph waveforms have been shown to correlate closely and be effective in adults as markers of volume responsiveness. The aims of our study were to investigate: (1) the feasibility of recording plethysmograph indices; and (2) the relationship between pulse pressure variation (ΔPP), plethysmograph variation (ΔPOP) and plethysmograph variability index (PVI) in a diverse group of mechanically ventilated children. A prospective, observational study was performed. Mechanically ventilated children less than 11 years of age, with arterial catheters, were enrolled during the course of their clinical care in the operating room or in the pediatric intensive care unit. Real time monitor waveforms and trend data were recorded. ΔPP and ΔPOP were manually calculated and the relationships between ΔPP, ΔPOP and PVI were compared using Bland-Altman analysis and Pearson correlations. Forty-nine children were recruited; four (8%) subjects were excluded due to poor quality of the plethysmograph waveforms. ΔPP and ΔPOP demonstrated a strong correlation (r = 0.8439, P < 0.0001) and close agreement (Bias = 1.44 ± 6.4%). PVI was found to correlate strongly with ΔPP (r = 0.7049, P < 0.0001) and ΔPOP (r = 0.715, P < 0.0001). This study demonstrates the feasibility of obtaining plethysmographic variability indices in children under various physiological stresses. These data show a similarly strong correlation to that described in adults, between the variations induced by mechanical ventilation in arterial pulse pressure and the pulse oximeter plethysmograph.

Aim: Polysomnography (PSG) is the current standard for diagnosing sleep apnea syndrome (SAS). A reliable test would be useful to reduce the considerable resources required for PSG., Methods: We developed a new mathematical analysis, which quantifies amplitude variations of pulse oximetry (SpO(2)) and heart rate (HR) throughout the night, allowing measurement of the total time in which ΔSpO(2) >4% and presented as a new oximetric index ventilatory hypoxemic index (VHI). VHI was compared prospectively with standard PSG parameters apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) in 106 patients (aged, 57 ± 14 years; BMI, 29 ± 5 kg/m(2)) suspected of having SAS. The criterion for diagnosis of SAS was AHI >15/h of sleep during PSG. The relationship between ΔSpO(2) and ΔΗR was also investigated., Results: We observed a significant correlation between the AHI and VHI (R = 0.87, p < 0.0001). Using VHI >15 as the criterion for SpO(2), oximetry had a sensitivity of 81%, specificity of 98%, positive predictive value (PPV) of 98%, and negative predictive value (NPV) of 84% as a screening test for SAS. We also observed a clear linear relationship between ΔSpO(2) and ΔΗR, and concomitant use of VHI and the ΔSpO(2)/ΔHR slope improved the NPV to 90%., Conclusions: The present findings from wavelet-aggregate processing of oximeter data and the relationship between ΔSpO(2) and ΔΗR show promise as a useful summary prediction of screening SAS.

Background: Tissue oximetry (StO2) plus a vascular occlusion test is a noninvasive technology that targets indices of oxygen uptake and delivery. We hypothesize that prehospital tissue oximetric values and vascular occlusion test response can predict the need for in-hospital lifesaving interventions (LSI)., Methods: We conducted a prospective, blinded observational study to evaluate StO2 slopes to predict the need for LSI. We calculated the DeO2 slope using Pearson's coefficients of regression (r2) for the first 25% of descent and the ReO2 slope using the entire recovery interval. The primary outcome was LSI defined as the need for emergent operation or transfusion in the first 24 hours of hospitalization. We created multivariable logistic regression models using covariates of age, sex, vital signs, lactate, and mental status., Results: We assessed StO2 in a convenience sample of 150 trauma patients from April to November of 2009. In-hospital mortality was 3% (95% confidence interval [CI], 1.1-7.6); 31% (95% CI, 24-39) were admitted to the intensive care unit, 6% (95% CI, 2.8-11.1) had an emergent operation, and 10% (95% CI, 5.7-15.9) required transfusion. Decreasing DeO2 was associated with a higher proportion of patients requiring LSI. In the multivariate model, the association between the need for LSI and DeO2, Glasgow Coma Scale, and age persists., Conclusion: Prehospital DeO2 is associated with need for LSI in our trauma population. Further study of DeO2 is warranted to determine whether it can be used as an adjunct triage criterion or an endpoint for resuscitation.

Introduction: Available trauma scoring systems that predict need for higher echelons of care require data not available in the field. We hypothesized that analysis of continuous vital sign data in comparison to trauma registry data predicts mortality early in trauma patient management., Methods: A real-time vital signs wave form and data capture system collected trauma patient data during prehospital management from Propaq 206E physiologic monitors. Analysis using statistical and mathematical software calculated receiver operator characteristic curves to evaluate the sensitivity and specificity of continuous vital sign waveforms in predicting mortality. The area under the curve (AUC) was calculated to determine nonsurvival by a particular vital sign (oxygen saturation [SpO2], heart rate, and systolic blood pressure) from these data, compared with a single value in the trauma registry, and to standard trauma scoring systems., Results: The average transport time from field to hospital for all patients was 25 minutes. Eight of 120 patients (7%) died; 5 of 8 patients (62%) died within the first 24 hours. Receiver operator characteristic analysis of mean SpO2 <90% versus mortality yielded an AUC of 0.76 (p = 0.005) with a sensitivity of 62% and specificity of 86% The initial SpO2 <90% measurement from the trauma registry yielded an AUC of 0.59. Preadmission Glasgow Coma Scale score yielded an AUC of 0.74 (p = 0.009). Injury Severity Score and Trauma-Injury Severity Score produced AUCs of 0.91 and 0.96, respectively. Revised Trauma Score gave an AUC of 0.73, no different from automated predictions of mortality from SpO2., Conclusion: Injury Severity Score and Trauma-Injury Severity Score are predictive of mortality but rely on the inclusion of intra-abdominal and intrathoracic diagnostic data that are not readily available during field assessment. Automated vital signs data collection and analysis from a single noninvasive device with decision support has the potential to alleviate the dual burdens of patient triage and documentation required of the prehospital provider.

The pulse oximeter is a well-known device for measuring the level of oxygen in blood. Since their invention, pulse oximeters have been under constant development in both aspects of hardware and software; however there are still unsolved problems that limit their performance [6], [7]. Many fresh algorithms and new design techniques are being suggested every year by industry and academic researchers which claim that they can improve accuracy of measurements [8], [9]. With the lack of an accurate computer-based behavioural model for pulse oximeters, the only way for evaluation of these newly developed systems and algorithms is through hardware implementation which can be both expensive and time consuming. This paper presents an accurate Simulink based behavioural model for a pulse oximeter that can be used by industry and academia alike working in this area, as an exploration as well as productivity enhancement tool during their research and development process. The aim of this paper is to introduce a new computer-based behavioural model which provides a simulation environment from which new ideas can be rapidly evaluated long before the real implementation.

There were 7276 e-mail requests sent to dentists in the United States and Canada requesting participation in a short web-based survey to update earlier information regarding the use of dental outpatient sedation. Participants were questioned regarding their use of dental outpatient sedation, including the frequency of use, type of sedation used, route ofadministration, medications used, physiologic monitoring employed, and availability qfantagonist medications and an automated external defibrillator In comparison to earlier studies, the use of outpatient dental sedation continues to change. The use of enteral sedation may be increasing, but now is differentiated by minimal and moderate sedation with different training requirements. The use of parenteral sedation by practitioners also appears to be increasing.

Background: Goal-directed fluid therapy during major abdominal surgery may reduce postoperative morbidity. The Pleth Variability Index (PVI), derived from the pulse oximeter waveform, has been shown to be able to predict fluid responsiveness in a number of surgical circumstances. In the present study, we sought to determine whether PVI could predict fluid responsiveness in low-risk colorectal surgery patients who had fluid therapy guided by esophageal Doppler stroke volume measurements., Methods: Twenty-five low-risk patients undergoing colorectal resection under general anesthesia were studied. Baseline values for esophageal Doppler stroke volume and PVI taken from finger and ear probes were compared with final values after (a) a 500-mL fluid bolus immediately after induction (steady state) and tracheal intubation before the start of the surgery, and (b) 250-mL boluses given in response to a decrease in stroke volume of 10% during surgery as measured by esophageal Doppler (dynamic). Patients were classified into responders and nonresponders based on a stroke volume increase of >10%., Results: Baseline PVI at the finger was significantly higher in responders in both steady-state and intraoperative conditions. In steady state, PVI at both finger and earlobe had significant predictive ability of an increase in stroke volume: area under the curve for finger 0.96 (95% confidence interval [CI], 0.88-1.00; P=0.011) and for earlobe 0.98 (95% CI, 0.93-1.00; P=0.008). In dynamic intraoperative conditions, PVI at the finger predicted increases in stroke volume, area under the curve 0.71 (95% CI, 0.57-0.85; P=0.006), but PVI at the earlobe had no predictive value., Conclusions: PVI measured at the finger may be able to predict fluid responsiveness during surgery in ventilated patients.

Retinal oximetry offers potential for noninvasive assessment of central venous oxyhemoglobin saturation (SO(2)) via the retinal vessels but requires a calibrated accuracy of ±3% saturation in order to be clinically useful. Prior oximeter designs have been hampered by poor saturation calibration accuracy. We demonstrate that the blue-green oximetry (BGO) technique can provide accuracy within ±3% in swine when multiply scattered light from blood within a retinal vessel is isolated. A noninvasive on-axis scanning retinal oximeter (ROx-3) is constructed that generates a multiwavelength image in the range required for BGO. A field stop in the detection pathway is used in conjunction with an anticonfocal bisecting wire to remove specular vessel reflections and isolate multiply backscattered light from the blood column within a retinal vessel. This design is tested on an enucleated swine eye vessel and a retinal vein in a human volunteer with retinal SO(2) measurements of ∼1 and ∼65%, respectively. These saturations, calculated using the calibration line from earlier work, are internally consistent with a standard error of the mean of ±2% SO(2). The absolute measures are well within the expected saturation range for the site (-1 and 63%). This is the first demonstration of noninvasive on-axis BGO retinal oximetry.

Purpose: Using quality-of-life measures and pulse oximetry, this study developed a two-tiered prediction algorithm with an aim to prioritize sleep-disordered breathing patients for polysomnography., Methods: Data from 355 patients were evaluated to obtain their clinical information, Chinese version of Epworth sleepiness scale, and snore outcomes survey scores against respiratory disturbance index (RDI). In the first-tier screening, receiver-operating characteristics were calculated with an initial strategy of choosing optimal prediction sensitivity. The second-tier strategy investigated the association between pulse oximetry data (desaturation index of 3%) against RDI to optimize prediction specificity., Results: The "SOS score of 55 and ESS score of 9" was the optimal combination that yielded the highest sensitivity (0.603) in the first-tier screening. The strategy can includ 94.93% possible patients (probability = 0.6) with positive predictive value of 0.997. The area under the curve (AUC) was 0.88 (p < 0.001). Desaturation index of 3% would optimized specificity (0.966, probability = 0.5) in the second-tier screening to exclude 54% of innocent patients, with negative predictive values of 0.93 and AUC of 0.951 (p < 0.001). The two-tier screening model jointly excluded 4.8% of innocent subjects and prioritized 40% of severe patients for polysomnography., Conclusions: The prediction model is sufficiently accurate and feasible for large-scale population screening.

Background: Best strategy of sedation/analgesia in gastrointestinal (GI) endoscopy is still debated., Aims of the Study: To evaluate sedation and monitoring practice among Italian gastroenterologists and to assess their opinion about non-anaesthesiologist propofol administration., Methods: A 19-item survey was mailed to all 1192 members of the Italian Society of Digestive Endoscopy (SIED). For each respondent were recorded demographic data, medical specialty, years of practise and practise setting., Results: A total of 494 SIED members returned questionnaires, representing a response rate of 41.4%. The most employed sedation pattern was benzodiazepines for oesophagogastroduodenoscopies (EGDS) in 50.8% of procedures, benzodiazepines plus opioids for colonoscopy and enteroscopy in 39.5% and 35.3% of procedures, respectively, propofol for endoscopic retrograde colangiopancreatography (ERCP) and endoscopic ultrasound (EUS) in 42.3% and 35.6% of procedures, respectively. With regard to propofol use, 66% respondents stated that propofol was exclusively administered by anaesthesiologists. However, 76.9% respondents would consider non-anaesthesiologist propofol administration after appropriate training. Pulse oximetry is the most employed system for procedural monitoring. Supplemental O(2) is routinely administered by 39.3% respondents., Conclusions: Use of sedation has become a standard practise during GI endoscopy in Italy. Pattern varies for each type of procedure. Pulse oximetry is the most employed system of monitoring. Administration of propofol is still directed by anaesthesiologists., (Copyright © 2011 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.)

The British Thoracic Society (BTS) guideline for emergency oxygen use in adult patients was commissioned by the BTS and developed in conjunction with 21 other colleges and societies prior to publication in 2008. One of the specific aims of the Guideline Development Group was to audit the use of oxygen in UK hospitals before the guideline was published and at intervals afterwards.

A prototype fiber-optic reflectance-mode pulse oximetry sensor and measurement system is developed for the purposes of estimating arterial oxygen saturation in the esophagus. A dedicated probe containing miniature right-angled glass prisms coupled to light sources and a photodetector by means of optical fibers is designed and used to record photoplethysmographic (PPG) signals from the esophageal epithelium in anesthetized patients. The probe is inserted simply by an anesthesiologist in all cases, and signals are recorded successfully in all but one of 20 subjects, demonstrating that esophageal PPG signals can be reliably obtained. The mean value of the oxygen saturation recorded from the esophagus for all subjects is 94.0 ± 4.0%. These results demonstrate that SpO(2) may be estimated in the esophagus using a fiber-optic probe.

Objective: The Lightman is intended to test the optical and electrical properties of a pulse oximeter probe including the wavelength of the light emitting diode by means of a micro spectrometer. The aim of this study was to evaluate the ability of the Lightman to detect faulty pulse oximeter finger probes by testing the accuracy of the wavelength of the light emitting diode in isolation from the monitor., Methods: The pulse oximeter measurements of arterial oxygen saturation from the "accurate" and "inaccurate" probes, as identified by the Lightman, were compared with arterial saturation determined by a co-oximeter. Data was analysed from 63 sets of measurements. In addition, we conducted a national survey to determine the testing procedures used by the Biomedical Engineering departments to evaluate the accuracy of pulse oximeter devices., Results: The bias [95% limits of agreement] for accurate, over-reading and under-reading probes were 0.17% [3.6 to -3.3], 1.44% [5.4 to -2.5] and -1.6% [2.6 to -5.8] respectively. The response rate to the national survey was 75% (142/189); a pulse oximeter tester was used by 93/142 (65%) trusts., Conclusions: Our findings suggest that the Lightman can detect faulty probes and predict reasonably accurately the direction of the probe's error. The Lightman may be considered as a useful tool to assess the accuracy of pulse oximeters. The national survey highlighted a wide variation in the testing procedure utilised to evaluate the accuracy of pulse oximeters. Introduction of guidelines regarding the testing procedure would promote a uniform practice.

Objective: To investigate the effect of pregnancy on the pulse wave of the mother., Patients and Methods: Pulse waveforms recorded via a pulse oximeter from the left index finger of non-pregnant women and pregnant women in the three trimesters of pregnancy were Fourier transformed into power spectra. Spectral indices of the power spectra of pulse waveform were obtained and compared among non-pregnant women and pregnant women in the three trimesters of pregnancy., Results: The power of harmonics of pulse wave decayed exponentially with respect to the order of harmonics. The exponent and initial value of exponential decay for the power of harmonics and the power of the 2nd harmonic were increased, whereas the total power of pulse and the powers of higher order harmonics were decreased during pregnancy., Conclusion: The power of harmonics of pulse wave can be described by an exponential decay function with respect to the order of harmonics in both non-pregnant and pregnant women. The effects of pregnancy on the pulse wave are the reduction in the total power of pulse and the power of higher order harmonics, and the increase in the power of lower order harmonics in the power spectrum of pulse wave. This effect of pregnancy on the pulse wave might be caused by the decrease in vascular resistance during pregnancy, the increase in workload on the heart due to increased demand of the growing fetus, and the aortocaval compression caused by the progressively enlarged gravid uterus and fetus.

Objective: To determine the prevalence of newborn screening pulse oximetry (+POx) among military hospitals, including barriers to instituting protocols., Methods: An internet-based questionnaire was forwarded to the senior pediatricians at military hospitals worldwide supporting newborn deliveries., Results: Forty seven of 53 hospitals (88%) supporting deliveries responded to the survey. Thirty percent of hospitals utilize a +POx protocol. Eight centers cited no problems with implementation. All hospitals screened at > or = 24 hours of life. The site of recording, positive values, and follow-up for positive screens varied. Cardiology consult and echocardiogram were not mandated. Most hospitals (34/47) are unable to obtain a pediatric cardiology consult without transfer. Few hospitals (9/47) utilize a telemedicine system. Seventy-five percent (24/32) of hospitals not utilizing a protocol are interested in instituting one., Conclusion: Though slightly less than one-third of military hospitals use a +POx, there is a greater interest in its use. More reliable consultative services and a robust telemedicine system may aid its implementation.

Objective: Pulse oximetry screening of asymptomatic newborns is suggested as a life-saving procedure for the timely detection of critical congenital heart disease (CHD) in asymptomatic newborns. We evaluated this screening and report cases that demonstrate problems with screening in a non-research setting., Study Design: An elective state-directed public health screening program was evaluated in Middle Tennessee; 14 564 infants were screened after 24 h of age and before discharge. The screening was performed in a non-research setting by nurses at the local hospitals. A parallel investigation of the methods and timing of diagnosis in Middle Tennessee revealed a surprisingly high incidence of antenatal diagnosis (66%)., Result: Using a saturation value of 94% as the defined normal, the positive predictive value was less than 1%, with 112 infants having a false positive case and 1 having a true positive case identified (incidence 1/34 775). The one true positive case was not referred for evaluation. One false-positive case resulted in a costly referral and hospitalization. Antenatal diagnosis when combined with physical examination detected 43 of 44 infants with critical CHD during the year-long evaluation., Conclusion: Before universal screening can be implemented, a system of care must be defined to address the educational and referral issues raised by this report.