The accuracy of pulse oximetry in the emergency department.
ABSTRACT The objective of this retrospective study was to identify factors affecting the accuracy of pulse oximetry in the ED. Over a 3-year period, 664 consecutive emergency department (ED) patients had simultaneous arterial blood gas (ABG) and pulse oximeter readings taken. Pulse oximeter saturations (SpO2) were compared with ABG CO-oximeter saturations (SaO2) for accuracy. Multiple variables including age, sex, hemoglobin, bicarbonate, pH, and carboxyhemoglobin (COHb) were analyzed to see if they affected SpO2 accuracy. ROC curves were used to determine the best pulse oximeter threshold for detecting hypoxia. Using multivariate analysis, COHb was the only statistically significant factor affecting the accuracy of pulse oximetry. In patients with COHb <2%, SpO2 overestimated SaO2 by more than 4% in 8.4% of cases. In patients with COHb > or = 2%, SpO2 overestimated SaO2 by more than 4% in 35% of cases. The best pulse oximetry threshold for detecting hypoxia is 92%. At this threshold, if COHb is <2%, pulse oximetry has a sensitivity of 0.92 and specificity of 0.90. If COHb is > or =2%, sensitivity is 0.74 and specificity is 0.84. For patients likely to have a COHb < 2, pulse oximetry is an effective screening tool for detecting hypoxia. However, more caution must be exercised when using pulse oximetry in patients likely to have a COHb > or = 2%.
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ABSTRACT: 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.Respirology 11/2013; · 2.78 Impact Factor
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ABSTRACT: El principal problema al monitorizar la frecuencia cardiaca mediante fotopletismografía durante el ejercicio físico son los artefactos por movimiento. Hemos registrado fotopletismogramas por transmisión en atletas durante pruebas de esfuerzo máximo en tapiz rodante, con un nuevo sistema sensor basado en tres diodos láser con emisiones en longitudes de onda del infrarrojo cercano. Los valores obtenidos de frecuencia cardiaca coinciden los de electrocardiografía. The main problem to monitor heart rate by photoplethysmography during physical exercise is the presence of movement artefacts. We have recorded transmittance photoplethysmogramms in athletes along a maximal exercise test by treadmill ergometer using a new sensory system with multiple near infrared laser diodes. The obtained heart rates agree with those by electrocardiography.Optica Pura y Aplicada 01/2005; 38(1):31-39.
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ABSTRACT: El principal problema al monitorizar la frecuencia cardiaca mediante fotopletismografía durante el ejercicio son los artefactos por movimiento. Hemos registrado fotopletismogramas por transmisión en atletas durante pruebas de esfuerzo máximo en tapiz rodante, con un nuevo sistema sensor basado en tres diodos láser con emisiones en longitudes de onda del infrarrojo cercano. Los valores de frecuencia cardiaca obtenidos con un algoritmo de procesamiento desarrollado para este fin, coinciden los de electrocardiografía.XXIII Congreso Anual de la Sociedad Española de Ingeniería Biomédica (CASEIB 2005), Madrid; 07/2005