Does ambient light affect the accuracy of pulse oximetry?
OBJECTIVE: Determine whether ambient light affects the accuracy of pulse oximetry readings. DESIGN: Prospective, repeated-measures study. SETTING: A photographic darkroom. SUBJECTS: Forty-five faculty and students at a university, none of whom had pale skin, dark skin, or evidence of cardiopulmonary disease. Any nail polish was removed. METHODS: Five light sources were individually tested: incandescent, quartz-halogen, infrared, fluorescent, and bilirubin light. A pulse oximetry probe was placed on the subject’s finger, and the finger and probe were placed sideways under each light source, on a predetermined mark. RESULTS: The greatest difference in pulse oximetry reading between any of the light sources was 0.5%. Repeated-measures analysis of variance yielded a p value of 0.204. CONCLUSIONS: Ambient light has no statistically significant effect on pulse oximetry readings. Even had the differences been statistically significant, the magnitude of the differences was small and thus clini
