PULSE OXIMETRY - ACCURACY OF METHODS OF INTERPRETING GRAPHIC SUMMARIES

Although pulse oximetry has been used to determine the frequency and e xtent of hemoglobin desaturation during sleep, movement artifact can r esult in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pu lmonologists' and technicians' interpretations of graphic displays of desaturation events, derived an objective method for interpreting such events, and validated the method on an independent data set. Eighty-s even randomly selected desaturation events were classified as valid (5 8) or artifactual (29) based on cardiorespiratory recordings (gold sta ndard) that included pulse waveform and respiratory inductive plethysm ography signals. Using oximetry recordings (test method), nine pediatr ic pulmonologists and three respiratory technicians (''readers'') aver aged 50 +/- 11% (SD) accuracy for event classification. A single varia ble, the pulse amplitude modulation range (PAMR) prior to desaturation , performed better in discriminating valid from artifactual events wit h 76% accuracy (P<0.05). Following a seminar on oximetry and the use o f the PAMR method, the readers' accuracy increased to 73 +/- 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% ar tifactual), the PAMR method of assessing oximetry graphs yielded 82% a ccuracy; transcutaneous oxygen tension records confirmed a drop in oxy genation during 49 of 54 (89%) valid desaturation events. In conclusio n, the most accurate method (91%) of assessing desaturation events req uires recording of the pulse and respiratory waveforms. However, a pra ctical, easy-to-use method of interpreting pulse oximetry recordings a chieved 76-82% accuracy, which constitutes a significant improvement f rom previous subjective interpretations. (C) 1996 Wiley-Liss, Inc.