Pulse oximetry: Accuracy of methods of interpreting graphic summaries

Abstract

Although pulse oximetry has been used to determine the frequency and extent of hemoglobin desaturation during sleep, movement artifact can result in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pulmonologists' 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‐seven randomly selected desaturation events were classified as valid (58) or artifactual (29) based on cardiorespiratory recordings (gold standard) that included pulse waveform and respiratory inductive plethysmography signals. Using oximetry recordings (test method), nine pediatric pulmonologists and three respiratory technicians (“readers”) averaged 50 ± 11% (SD) accuracy for event classification. A single variable, the pulse amplitude modulation range (PAMR) prior to desaturation, performed better in discriminating valid from artifactual events with 76% accuracy (P < 0.05). Following a seminar on oximetry and the use of the PAMR method, the readers' accuracy increased to 73 ± 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% artifactual), the PAMR method of assessing oximetry graphs yielded 82% accuracy; transcutaneous oxygen tension records confirmed a drop in oxygenation during 49 of 54 (89%) valid desaturation events. In conclusion, the most accurate method (91%) of assessing desaturation events requires recording of the pulse and respiratory waveforms. However, a practical, easy‐to‐use method of interpreting pulse oximetry recordings achieved 76–82% accuracy, which constitutes a significant improvement from previous subjective interpretations. Pediatr Pulmonol. 1996; 21:121–131. © 1996 Wiley‐Liss, Inc.

Snoring and obstructive sleep apnea in Thai school‐age children: Prevalence and predisposing factors

“…A pulse oximeter that can provide trend graphs and 12-hr summaries of arterial oxygen saturations (SaO 2 ), pulse rate, and pulse amplitude is the most accurate method to distinguish true from false desaturations. 19,20 This kind of pulse oximeter was not available in our hospital.…”

A fuzzy system for detecting distorted plethysmogram pulses in neonates and paediatric patients

“…Nurses and doctors usually evaluate SaO 2 readings based on their experience in judging the correctness and regularity of the shape of the plethysmogram. Lafontine and Brouillette (1996) concluded that the most accurate method of detecting artefacts in the SaO 2 includes Very smooth Very smooth Valid observation of the pulse waveform. Oxygen saturation readings are usually rejected when the majority of its associated plethysmogram pulses are distorted, but accepted when the majority of these pulses are smooth and consistent.…”

“…Consequently, poor signalling will be obtained or an optical shunt might occur Southall 1994, Sinex 1999). Poor readings can also result from movement of the patient or the probe, with a possible overestimation of desaturation (Lafontine and Brouillette 1996). Wiklund et al (1994) argued that the majority of low SaO 2 alarms are usually false.…”

“…Since plethysmogram pulses usually become distorted by patient/probe movement, the availability of the plethysmogram traces is an important feature in detecting artefacts (Lafontine and Brouillette 1996). Therefore, in medical practice, artefacts in saturation readings are usually detected if the associated plethysmogram pulses are highly variable in their altitude and rate.…”