Pediatric pulse oximetry-based OSA screening at different thresholds of the apnea-hypopnea index with an expression of uncertainty for inconclusive classifications.

BACKGROUND: Assessments of pediatric obstructive sleep apnea (OSA) are underutilized across Canada due to a lack of resources. Polysomnography (PSG) measures OSA severity through the average number of apnea/hypopnea events per hour (AHI), but is resource intensive and requires a specialized sleep laboratory, which results in long waitlists and delays in OSA detection. Prompt diagnosis and treatment of OSA are crucial for children, as untreated OSA is linked to behavioral deficits, growth failure, and negative cardiovascular consequences. We aim to assess the performance of a portable pediatric OSA screening tool at different AHI cut-offs using overnight smartphone-based pulse oximetry. MATERIAL AND METHODS: Following ethics approval and informed consent, children referred to British Columbia Children's Hospital for overnight PSG were recruited for two studies including 160 and 75 children, respectively. An additional smartphone-based pulse oximeter sensor was used in both studies to record overnight pulse oximetry [SpO2 and photoplethysmogram (PPG)] alongside the PSG. Features characterizing SpO2 dynamics and heart rate variability from pulse peak intervals of the PPG signal were derived from pulse oximetry recordings. Three multivariate logistic regression screening models, targeted at three different levels of OSA severity (AHI ≥ 1, 5, and 10), were developed using stepwise-selection of features using the Bayesian information criterion (BIC). The "Gray Zone" approach was also implemented for different tolerance values to allow for more precise detection of children with inconclusive classification results. RESULTS: The optimal diagnostic tolerance values defining the "Gray Zone" borders (15, 10, and 5, respectively) were selected to develop the final models to screen for children at AHI cut-offs of 1, 5, and 10. The final models evaluated through cross-validation showed good accuracy (75%, 82% and 89%), sensitivity (80%, 85% and 82%) and specificity (65%, 79% and 91%) values for detecting children with AHI ≥ 1, AHI ≥ 5 and AHI ≥ 10. The percentage of children classified as inconclusive was 28%, 38% and 16% for models detecting AHI ≥ 1, AHI ≥ 5, and AHI ≥ 10, respectively. CONCLUSIONS: The proposed pulse oximetry-based OSA screening tool at different AHI cut-offs may assist clinicians in identifying children at different OSA severity levels. Using this tool at home prior to PSG can help with optimizing the limited resources for PSG screening. Further validation with larger and more heterogeneous datasets is required before introducing in clinical practice.

Oxygen therapy for acutely ill medical patients: a clinical practice guideline

What is the best way to use oxygen therapy for patients with an acute medical illness? A systematic review published in the Lancet in April 2018 found that supplemental oxygen in inpatients with normal oxygen saturation increases mortality.1 Its authors concluded that oxygen should be administered conservatively, but they did not make specific recommendations on how to do it. An international expert panel used that review to inform this guideline. It aims to promptly and transparently translate potentially practice-changing evidence to usable recommendations for clinicians and patients.2 The panel used the GRADE framework and following standards for trustworthy guidelines.3

Research: Comparison of the Accuracy of a Pocket versus Standard Pulse Oximeter.

BACKGROUND: Pulse oximetry has become an essential tool in clinical practice. With patient self-management becoming more prevalent, pulse oximetry self-monitoring has the potential to become common practice in the near future. This study sought to compare the accuracy of two pulse oximeters, a high-quality standard pulse oximeter and an inexpensive pocket pulse oximeter, and to compare both devices with arterial blood co-oximetry oxygen saturation. METHODS: A total of 95 patients (35.8% women; mean [±SD] age 63.1 ± 13.9 years; mean arterial pressure was 92 ± 12.0 mmHg; mean axillar temperature 36.3 ± 0.4°C) presenting to our hospital for blood gas analysis was evaluated. The Bland-Altman technique was performed to calculate bias and precision, as well as agreement limits. Student's t test was performed. RESULTS: Standard oximeter presented 1.84% bias and a precision error of 1.80%. Pocket oximeter presented a bias of 1.85% and a precision error of 2.21%. Agreement limits were -1.69% to 5.37% (standard oximeter) and -2.48% to 6.18% (pocket oximeter). CONCLUSION: Both oximeters presented bias, which was expected given previous research. The pocket oximeter was less precise but had agreement limits that were comparable with current evidence. Pocket oximeters can be powerful allies in clinical monitoring of patients based on a self-monitoring/efficacy strategy.

Relación entre pulsioximetría y determinación de la saturación arterial de oxígeno. influencia de los fármacos vasoactivos presores sobre la correlación sattco2-sato2 / Relationship between pulse oximetry and determination of arterial oxygen saturation. influence of vasoactive drugs on the sattco2-sato2 correlation

Objetivo. Estudiar la relación existente entre la saturación de oxígeno obtenida por pulsioximetría (SattcO2) y la obtenida por cooximetría (SatHbO2), o por cálculo de la saturación de oxígeno por el análisis convencional de la gasometría sanguínea (SatO2) y evaluar la posible influencia que en esta relación puedan tener las infusiones de fármacos vasoactivos presores. Pacientes y método. El estudio se llevó a cabo en una UCI polivalente de 15 camas de un hospital docente de referencia, desde diciembre de 1998 a abril de 1999. Se obtuvieron 104 pares simultáneos de muestras procedentes de pacientes ingresados por causa médica o quirúrgica (urgente o programada). De estos pacientes, 57 estaban sometidos a la administración de infusiones presoras vasoactivas. Los datos recogidos fueron: SattcO2, SatHbO2 (por cooximetría) y SatO2 (por análisis convencional de muestra de sangre arterial). El estado hemodinámico de los pacientes se estimó mediante el registro de la presión arterial, la frecuencia cardíaca y la temperatura axilar. Se recogieron el tipo y la dosis de los fármacos vasopresores administrados (noradrenalina, dopamina o dobutamina, o combinaciones de ellas). Tras la obtención de los datos se estableció la correlación entre SattcO2 y SatHbO2 y entre SattcO2 y SatO2, mediante una ecuación de regresión y la concordancia por método de Bland-Altman, y se estudiaron las diferencias existentes entre las saturaciones obtenidas por uno u otro método (diferencia media de saturación de O2).Resultados. El análisis demostró que la administración o no de infusiones de aminas vasoactivas presoras no interfiere en la concordancia y correlación de las saturaciones de oxígeno obtenidas por uno u otro de los métodos mencionados. Las diferencias medias de saturaciones de oxígeno obtenidas fueron menores del 3 por ciento, con rangos de concordancia de 5,35 y 10,38 entre SattcO2 y SatHbO2, según los pacientes recibieran o no aminas vasopresoras, y con rangos de concordancia de 6,23 y 10,42 entre SattcO2 y SatO2 en los mismos subgrupos de pacientes. Conclusión. En nuestro estudio, los datos obtenidos por pulsioximetría constituyen un buen reflejo de la saturación de oxígeno real de la sangre arterial (medida o calculada), aunque la sobrestiman ligeramente (menos del 3 por ciento); esta concordancia es independiente de la utilización de aminas vasoactivas presoras (AU)

¿Disminuye la pulsioximetría el número de cesáreas? / Does pulse oximetry reduce the number of caesarean sections?

Se presentan las indicaciones y los posibles resultados obtenidos si se utilizase rutinariamente la pulsi-oximetría, un nuevo método para controlar el estado fetal intraparto. Se muestran registros de pulsioximetría en casos en los que su uso es imprescindible para un buen control del estado fetal como bloqueo auriculoventricular, brevedad o circular de cordón y presentación de nalgas. Como la frecuencia de estas anomalías es muy baja, el control obstétrico usado en las mismas no altera el porcentaje de cesáreas. Se estudian todas las cesáreas practicadas en nuestro medio en 1999, así como sus indicaciones, y en aquellas en las que el uso de pulsioximetría pudiera haber influido (alteraciones de la FCF, presentación de nalgas, alteraciones del EAB) se hace un cálculo teórico de los resultados presumiblemente obtenibles en dependencia del número de cesáreas evitable. Al comparar el número real de cesáreas (23,1 por ciento) con las obtenidas si se hubiese usado pulsioximetría (en el mejor de los casos 22,07 por ciento) no se obtienen diferencias estadísticamente significativas. Se concluye que el uso de la pulsioximetría no disminuye el número de cesáreas en nuestro medio, pero es imprescindible para la realización de una obstetricia en la actualidad (AU)

Oximetry: state-of-the-art.

Measuring arterial hemoglobin saturation via traditional arterial blood gas testing or co-oximetry complements the fundamental physical examination process. Within the last two decades, advancements in diagnostic technologies made possible the dynamic, noninvasive assessment of hemoglobin saturation through pulse oximetry. Technology assessment teams must determine the relative cost-effectiveness of these techniques and their effect on patient outcome.