Accuracy of Three Pulse Oximeters During Exercise and Hypoxemia in Patients With Cystic Fibrosis

To evaluate the reliability of noninvasive oximeters during exercise in patients with cystic fibrosis (CF), we studied 9 patients during exercise tests, using 3 devices (Hewlett-Packard 47201A, Biox-Ohmeda 3700, Nellcor 100), comparing oximetry readings with arterial blood co-oximetry. Fifty samples from preexercise, exercise, and recovery were collected; and paired measurements were analyzed for bias (arterial blood gas SaO2 — noninvasive SaO2) and precision (1 SD of the bias). Values were available for the Hewlett-Packard and the Biox-Ohmeda at all 50 collection times. The Nellcor failed to read on four occasions, all during exercise. The accuracy of the Biox-Ohmeda readings was significantly worse during exercise than rest, while the Nellcor and the Hewlett-Packard performance did not differ significantly between exercise and rest. During hypoxemia (SaO2