Accuracy and response time of a portable pulse oximeter. The Pulsox-7 with a finger probe.
We studied the performance of a portable pulse oximeter in 123 consecutive adult patients by spot-checking with a finger probe and by spectrophotometry of oxygen saturation on a simultaneous arterial blood sample. 88 patients were overtly hypoxemic (HbO2 less than 90%) and 26 showed severe hypoxemia (HbO2 36-70%). The differences between the two methods showed a skewed distribution with a positive tail due to the over-estimation of lower saturation values by the pulse oximeter. Overall, the 95% confidence interval for the median difference ranged from -0.6 to +0.5%. The limits of agreement (distribution-free 95% confidence interval for the sample) were -5.8 to +11.6%. Pulse oximetry can be recommended as a first assessment of the respiratory balance only if a cut-off value of HbO2 equal to 90% in nonsmoking, air-breathing subjects is acceptable. The finger probe implies a response delay of approximately 30 s, making the instrument rather insensitive to short hypoxemic transients. With a predictive value around 90%, the pulse oximeter may be a useful portable screening tool.
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Servizio di Fisiopatologia Respiratoria, Ospedale Cervello, Palermo, Italy.
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D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000032:analysis; D013053:Spectrophotometry
D010108:Oxyhemoglobins; D010100:Oxygen