Abstract
BACKGROUND: Finger clip pulse oximetry sensors are commonly used to obtain functional oxygen saturation readings (SpO2), but these sensors may perform poorly if the digit is poorly perfused or there is excessive hand movement. I have increasingly witnessed clinicians obtaining SpO2 readings by placing the finger clip sensor on the patient's ear when an SpO2 reading cannot be obtained from a finger.
OBJECTIVE: Determine if reliable SpO2 readings can be obtained from a finger clip sensor placed on the ear.
METHODS: This was a prospective study with patients undergoing pulmonary function testing. The calculated functional oxygen saturation values from arterial blood gas analysis (SaO2) were compared with SpO2 readings from a finger clip sensor placed on a finger (finger SpO2) and on the upper portion of an ear (ear SpO2). SpO2 data were included in the study only if (1) the pulse rate from finger SpO2 and ear SpO2 differed by ≤ 5 beats/min and (2) the photoplethysmographic waveform was stable and acceptable.
RESULTS: Data were obtained from 30 adult white patients. The number of SpO2 readings that differed from the SaO2 values by ≥ 3% were 1 (3.3%) finger SpO2 reading and 24 (80%, 95% CI 61%–92%) ear SpO2 readings (p < 0.001). Bland-Altman analysis showed better agreement between SaO2 and finger SpO2 (mean ± 2 SD limits of agreement −2.35 to 2.35) than between SaO2 and ear SpO2 (limits of agreement −7.24 to −0.08) or finger SpO2 and ear SpO2 (limits of agreement −7.56 to −0.23).
CONCLUSION: A pulse oximeter finger clip sensor placed on the ear does not provide clinically reliable SpO2 readings.
Footnotes
- Correspondence: Jeffrey M Haynes RRT RPFT, Department of Respiratory Therapy, St Joseph Hospital, 172 Kinsley Street, Nashua NH 03060. E-mail: jhaynes{at}sjh-nh.org.
- Copyright © 2007 by Daedalus Enterprises Inc.
