UNASSIGNED: Our aim was to confirm whether extreme hyperoxemic events had been associated with excess mortality in our diverse critical care population.
UNASSIGNED: Retrospective analysis of 9 years of data collected in the pediatric and cardiothoracic ICUs in Children\'s Hospital Los Angeles was performed. The analysis was limited to those mechanically ventilated for at least 24 h, with at least 1 arterial blood gas measurement. An extreme hyperoxemic event was defined as a PaO2 of ≥300 torr. Multivariable logistic regression was used to assess the association of extreme hyperoxemia events and mortality, adjusting for confounding variables. Selected a-priori, these were Pediatric Risk of Mortality III predicted mortality, general or cardiothoracic ICU, number of blood gas measurements, as well as an abnormal blood gas measurements (pH < 7.25, pH > 7.45, and PaO2 < 50 torr).
UNASSIGNED: There were 4,003 admissions included with a predicted mortality of 7.1% and an actual mortality of 9.7%. Their care was associated with 75,129 blood gas measurements, in which abnormal measurements were common. With adjustments for these covariates, any hyperoxemic event was associated with excess mortality (p < 0.001). Excess mortality increased with multiple hyperoxemic events (p < 0.046). Additionally, treatment resulting in SpO2 > 98% markedly increased the risk of a hyperoxemic event.
UNASSIGNED: Retrospective analysis of critical care admissions showed that extreme hyperoxemic events were associated with higher mortality. Supplemental oxygen levels resulting in SpO2 > 98% should be avoided.

UNASSIGNED: Questions about the accuracy of pulse oximeters in measuring arterial oxygen saturation ( SpO 2 ) in individuals with darker skin pigmentation have resurfaced since the COVID-19 pandemic. This requires investigation to improve patient safety, clinical decision making, and research.
UNASSIGNED: We aim to use computational modeling to identify the potential causes of inaccuracy in SpO 2 measurement in individuals with dark skin and suggest practical solutions to minimize bias.
UNASSIGNED: An in silico model of the human finger was developed to explore how changing melanin concentration and arterial oxygen saturation ( SaO 2 ) affect pulse oximeter calibration algorithms using the Monte Carlo (MC) technique. The model generates calibration curves for Fitzpatrick skin types I, IV, and VI and an SaO 2 range between 70% and 100% in transmittance mode. SpO 2 was derived by inputting the computed ratio of ratios for light and dark skin into a widely used calibration algorithm equation to calculate bias ( SpO 2 - SaO 2 ). These were validated against an experimental study to suggest the validity of the Monte Carlo model. Further work included applying different multiplication factors to adjust the moderate and dark skin calibration curves relative to light skin.
UNASSIGNED: Moderate and dark skin calibration curve equations were different from light skin, suggesting that a single algorithm may not be suitable for all skin types due to the varying behavior of light in different epidermal melanin concentrations, especially at 660 nm. The ratio between the mean bias in White and Black subjects in the cohort study was 6.6 and 5.47 for light and dark skin, respectively, from the Monte Carlo model. A linear multiplication factor of 1.23 and exponential factor of 1.8 were applied to moderate and dark skin calibration curves, resulting in similar alignment.
UNASSIGNED: This study underpins the careful re-assessment of pulse oximeter designs to minimize bias in SpO 2 measurements across diverse populations.

Gastroenterology nurses working across a variety of clinical settings are responsible for periprocedural monitoring during moderate to deep procedural sedation and analgesia (PSA) to identify signs of respiratory compromise and intervene to prevent cardiorespiratory events. Pulse oximetry is the standard of care for respiratory monitoring, but it may delay or fail to detect abnormal ventilation during PSA. Continuous capnography, which measures end-tidal CO2 as a marker of alveolar ventilation, has been endorsed by a number of clinical guidelines. Large clinical trials have demonstrated that the addition of continuous capnography to pulse oximetry during PSA for various gastroenterological procedures reduces the incidence of hypoxemia, severe hypoxemia, and apnea. Studies have shown that the cost of adding continuous capnography is offset by the reduction in adverse events and hospital length of stay. In the postanesthesia care unit, continuous capnography is being evaluated for monitoring opioid-induced respiratory depression and to guide artificial airway removal. Studies are also examining the utility of continuous capnography to predict the risk of opioid-induced respiratory depression among patients receiving opioids for primary analgesia. Continuous capnography monitoring has become an essential tool to detect early signs of respiratory compromise in patients receiving PSA during gastroenterological procedures. When combined with pulse oximetry, it can help reduce cardiorespiratory adverse events, improve patient outcomes and safety, and reduce health care costs.

BACKGROUND: Hypoxaemia occurs frequently during paediatric laryngeal microsurgery.
OBJECTIVE: The oxygen reserve index is a noninvasive and continuous parameter to assess PaO2 levels in the range of 100 to 200 mmHg. It ranges from 0 to 1.0. We investigated whether monitoring the oxygen reserve index can reduce the incidence of SpO2 90% or less.
METHODS: Randomised controlled trial.
METHODS: A tertiary care paediatric hospital.
METHODS: Paediatric patients aged 18 years or less scheduled to undergo laryngeal microsurgery.
METHODS: The patients were randomly allocated to the oxygen reserve index or control groups, and stratified based on the presence of a tracheostomy tube. Rescue intervention was performed when the oxygen reserve index was 0.2 or less and the SpO2 was 94% or less in the oxygen reserve index and control groups, respectively.
METHODS: The primary outcome was the incidence of SpO2 90% or less during the surgery.
RESULTS: Data from 88 patients were analysed. The incidence of SpO2 ≤ 90% did not differ between the oxygen reserve index and control groups [P = 0.114; 11/44, 25% vs. 18/44, 40.9%; relative risk: 1.27; and 95% confidence interval (CI): 0.94 to 1.72]. Among the 128 rescue interventions, SpO2 ≤ 90% event developed in 18 out of 75 events (24%) and 42 out of 53 events (79.2%) in the oxygen reserve index and control groups, respectively (P < 0.001; difference: 55.2%; and 95% CI 38.5 to 67.2%). The number of SpO2 ≤ 90% events per patient in the oxygen reserve index group (median 0, maximum 3) was less than that in the control group (median 0, maximum 8, P = 0.031).
CONCLUSIONS: Additional monitoring of the oxygen reserve index, with a target value of greater than 0.2 during paediatric airway surgery, alongside peripheral oxygen saturation, did not reduce the incidence of SpO2 ≤ 90%.

BACKGROUND: According to the World Health Organization\'s recommendation, delayed cord clamping in term newborns can have various benefits. Cochrane metaanalyses reported no differences for mortality and early neonatal morbidity although a limited number of studies investigated long-term neurodevelopmental outcomes. The aim of our study is to compare the postnatal cerebral tissue oxygenation values in babies with early versus delayed cord clamping born after elective cesarean section.
METHODS: In this study, a total of 80 term newborns delivered by elective cesarean section were included. Infants were randomly grouped as early (clamped within 15 s, n:40) and delayed cord clamping (at the 60th second, n:40) groups. Peripheral arterial oxygen saturation (SpO2) and heart rate were measured by pulse oximetry while regional oxygen saturation of the brain (rSO2) was measured with near-infrared spectrometer. Fractional tissue oxygen extraction (FTOE) was calculated for every minute between the 3rd and 15th minute after birth. (FTOE = pulse oximetry value-rSO2/pulse oximetry value). The measurements were compared for both groups.
RESULTS: The demographical characteristics, SpO2 levels (except postnatal 6th, 8th, and 14th minutes favoring DCC p < 0.05), heart rates and umbilical cord blood gas values were not significantly different between the groups (p > 0.05). rSO2 values were significantly higher while FTOE values were significantly lower for every minute between the 3rd and 15th minutes after birth in the delayed cord clamping group (p < 0.05).
CONCLUSIONS: Our study revealed a significant increase in cerebral rsO2 values and a decrease in FTOE values in the delayed cord clamping (DCC) group, indicating a positive impact on cerebral oxygenation and hemodynamics. Furthermore, the DCC group exhibited a higher proportion of infants with cerebral rSO2 levels above the 90th percentile. This higher proportion, along with a lower of those with such parameter below the 10th percentile, suggest that DCC may lead to the targeted/optimal cerebral oxygenetaion of these babies. As a result, we recommend measuring cerebral oxygenation, in addition to peripheral SpO2, for infants experiencing perinatal hypoxia and receiving supplemental oxygen.

UNASSIGNED: Local retinal oxygen saturation is a research technique, which has the potential as a biomarker for diabetes. However, normative data has not been established. This study examined differences in oxygen saturation around the macula and characterizes the relationship between age, race, refractive error (RE), sex, blood pressure (BP), prediabetic status and oxygen saturation.
UNASSIGNED: Fifty-nine subjects aged 22-69 (38.8 ± 14.7 years) were included who were racially diverse and with equal gender distribution. None had eye disease. Oxygen saturation was taken with the Zilia Ocular in 4 locations around the macula 3.1 degrees from the fovea and they were also averaged. BP, RE, and HbA1c were noted. Regression analyses for oximetry and other factors were completed as were t-tests with multiple comparison corrections.
UNASSIGNED: There were significant variations in oximetry measures by race, with higher pigmentation levels associated with lower oximetry values (p < 0.01). There was no relationship between oximetry and sex (p = 0.34), RE (p = 0.67), BP (systolic p = 0.61, diastolic p = 0.71) nor prediabetic status (p = 0.87). Oximetry was associated with age when controlling for race (P < 0.002). Nasal-temporal variations showed nasal oximetry to higher than temporal measures (P < 0.01).
UNASSIGNED: This study revealed race/pigmentation is an important influence on oximetry measures. Retinal location also caused variations, likely due to proximity to larger vessels nasally. No differences in sex, RE nor BP were observed to alter local oxygen saturation. However, age was correlated when considered with race. This study will inform our future work in different disease states and is an important first step in evaluating this technology.
This study evaluates a new research instrument (Zilia Ocular) which measures how much oxygen is in the very small blood vessels of the retina. Our group wanted to evaluate healthy people to find out if the measurements the instrument takes are different in different sexes, ages, races, glasses prescriptions and blood pressures. We also looked at if they were changed in people with prediabetes and if it is different in different locations on the retina. We found that the measures are different in different races and ages. The measures also change with location in the eye. The other factors did not change the measurements of oxygen saturation on this instrument. We need to know this information because we want to detect changes in the retina in diabetes in diverse patient groups; however, we need to know about normal variations to better understand and collect that data.

BACKGROUND: Long-haul flights have been associated with a two- to four-fold increased risk of aviation-related thrombosis (ART). Several studies have investigated the extent to which hypoxic hypobaric exposure, dehydration and prolonged immobilisation during air travel induce changes in haemostasis.
OBJECTIVE: To investigate the role of high altitude as a risk factor for ART.
METHODS: Healthy volunteers aged ≥18 years (N=40), without risk factors for venous thromboembolism, were exposed to an exacerbated altitude of 18 000 feet (5 486 m) for 1 hour. During the flight, the oxygen (O2) levels of the participants, who received supplemental O2, were measured by pulse oximetry and maintained at >92%. Venous blood and urine samples were collected prior to departure and immediately after flying in an unpressurised twin-engine airplane. D-dimer levels, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity and urine osmolality were measured.
RESULTS: The participants were 19 men and 21 women, with a mean (standard deviation) age of 46 (14) years. A significant difference in D-dimer levels, VWF activity, urine osmolality and TEG parameters (reaction (R) time, kinetic (K) time and maximum amplitude (MA)) before and after the 1-hour flight was observed (p<0.001). Urine osmolality correlated positively with VWF activity levels (r=0.469; p<0.002).
CONCLUSIONS: Air travel at high altitude induced a hypercoagulable state in healthy volunteers. Future research should focus on whether thromboprophylaxis can significantly obviate the activation of coagulation in response to high altitude.

OBJECTIVE: This study aims to evaluate the performance of the fabian-Predictive-Intelligent-Control-of-Oxygenation (PRICO) system for automated control of the fraction of inspired oxygen (FiO2).
METHODS: Multicentre randomised cross-over study.
METHODS: Five neonatal intensive care units experienced with automated control of FiO2 and the fabian ventilator.
METHODS: 39 infants: median gestational age of 27 weeks (IQR: 26-30), postnatal age 7 days (IQR: 2-17), weight 1120 g (IQR: 915-1588), FiO2 0.32 (IQR: 0.22-0.43) receiving both non-invasive (27) and invasive (12) respiratory support.
METHODS: Randomised sequential 24-hour periods of automated and manual FiO2 control.
METHODS: Proportion (%) of time in normoxaemia (90%-95% with FiO2>0.21 and 90%-100% when FiO2=0.21) was the primary endpoint. Secondary endpoints were severe hypoxaemia (<80%) and severe hyperoxaemia (>98% with FiO2>0.21) and prevalence of episodes ≥60 s at these two SpO2 extremes.
RESULTS: During automated control, subjects spent more time in normoxaemia (74%±22% vs 51%±22%, p<0.001) with less time above and below (<90% (9%±8% vs 12%±11%, p<0.001) and >95% with FiO2>0.21 (16%±19% vs 35%±24%) p<0.001). They spent less time in severe hyperoxaemia (1% (0%-3.5%) vs 5% (1%-10%), p<0.001) but exposure to severe hypoxaemia was low in both arms and not different. The differences in prolonged episodes of SpO2 were consistent with the times at extremes.
CONCLUSIONS: This study demonstrates the ability of the PRICO automated oxygen control algorithm to improve the maintenance of SpO2 in normoxaemia and to avoid hyperoxaemia without increasing hypoxaemia.

BACKGROUND: Monitoring blood oxygenation is essential in immobilised rhinoceros, which are susceptible to opioid-induced hypoxaemia. This study assessed the reliability, clinical performance and trending ability of the Nonin PalmSAT 2500 A pulse oximeter\'s and the Masimo Radical-7 pulse co-oximeter\'s dual-wavelength technology, with their probes placed at two measurement sites, the inner surface of the third-eyelid and the scarified ear pinna of immobilised white rhinoceroses. Eight white rhinoceros were immobilised with etorphine-based drug combinations and given butorphanol after 12 min, and oxygen after 40 min, of recumbency. The Nonin and Masimo devices, with dual-wavelength probes attached to the third-eyelid and ear recorded arterial peripheral oxygen-haemoglobin saturation (SpO2) at pre-determined time points, concurrently with measurements of arterial oxygen-haemoglobin saturation (SaO2), from drawn blood samples, by a benchtop AVOXimeter 4000 co-oximeter (reference method). Reliability of the Nonin and Masimo devices was evaluated using the Bland-Altman and the area root mean squares (ARMS) methods. Clinical performance of the devices was evaluated for their ability to accurately detect clinical hypoxemia using receiver operating characteristic (ROC) curves and measures of sensitivity, specificity, and positive and negative predictive values. Trending ability of the devices was assessed by calculating concordance rates from four-quadrant plots.
RESULTS: Only the Nonin device with transflectance probe attached to the third-eyelid provided reliable SpO2 measurements across the 70 to 100% saturation range (bias - 1%, precision 4%, ARMS 4%). Nonin and Masimo devices with transflectance probes attached to the third-eyelid both had high clinical performance at detecting clinical hypoxaemia [area under the ROC curves (AUC): 0.93 and 0.90, respectively]. However, the Nonin and Masimo devices with transmission probes attached to the ear were unreliable and provided only moderate clinical performance. Both Nonin and Masimo devices, at both measurement sites, had concordance rates lower than the recommended threshold of ≥ 90%, indicating poor trending ability.
CONCLUSIONS: The overall assessment of reliability, clinical performance and trending ability indicate that the Nonin device with transflectance probe attached to the third-eyelid is best suited for monitoring of blood oxygenation in immobilised rhinoceros. The immobilisation procedure may have affected cardiovascular function to an extent that it limited the devices\' performance.

BACKGROUND: Rett syndrome is a progressive neurological disorder associated to several comorbidities that contribute significantly to impair lung function. Respiratory morbidity represents a major cause of death in this population. Little is known about the benefit of noninvasive ventilation.
METHODS: We retrospectively enrolled patients with Rett syndrome who underwent a pneumological evaluation combined with a cardiorespiratory polygraphy and/or a pulse oximetry and capnography from 2012 to 2022.
RESULTS: Medical records of 11 patients with Rett syndrome, mean age 13 ± 6 years, were evaluated. Most patients presented with both epilepsy and scoliosis. Five patients showed a pathologic sleep study and/or impaired night gas exchange: mean obstructive apnea-hypopnea index was 4 ± 3 events/hour; mean and minimal SpO2 were, respectively, 93% ± 2% and 83% ± 6%, while mean and maximal transcutaneous carbon dioxide monitoring (PtcCO2) were, respectively, 51 ± 5 mm Hg and 55 ± 8 mm Hg; and mean oxygen desaturation index was 13 ± 11 events/hour. These patients started noninvasive ventilation with clinical benefit and improved gas exchange mostly in terms of PtcCO2 (mean PtcCO2 51 ± 5 mm Hg before and 46 ± 6 mm Hg after noninvasive ventilation).
CONCLUSIONS: Noninvasive ventilation is a suitable option for patients with Rett syndrome.