Is routine assessment of arterial oxygen saturation in pulmonary outpatients indicated?

Pulse oximetry was used in 1,675 pulmonary outpatient visits to determine whether routine assessment of arterial oxygen saturation was indicated in detecting unanticipated severe desaturation. An SaO2 less than 85 percent was found in only 18 visits (1.1 percent). Changes in symptoms, pulmonary function or both which alerted the clinician to a possible problem were identified in 16 of those 18 visits. Only two episodes of desaturation were not identified by history or simple spirometric evaluation. Routine pulse oximetry does not appear to be of value in screening large numbers of pulmonary outpatients for unexpected desaturation, since it is uncommon in the absence of associated clinical findings.