Continuous emergency department monitoring of arterial saturation in adult patients with respiratory distress.

Continuous measurement of arterial oxygen saturation (SaO2) using pulse oximetry has become a common monitoring and management technique in critically ill hospitalized patients. To determine the impact of SaO2 monitoring on emergency patient management, we conducted a prospective uncontrolled clinical trial on 40 adult patients presenting to the emergency department with acute respiratory illness, such as emphysema, asthma, or pulmonary edema. Recorded data included hemograms, arterial blood gases, subsequent therapy, and response to treatment. Additionally, the "early warning" capability of SaO2 monitoring was analyzed by recording the severity and outcome of hypoxemic events during treatment. Mean duration of usage for the 40 oximeters in the ED was 1.8 hours; all probes functioned reliably over a wide range of systolic pressures (80 to 206 mm Hg), heart rates (40 to 180 beats per minute), and hematocrits (20% to 58%). There was good correlation between simultaneous pulse oximeter values and both directly measured SaO2 (r = 0.95) and saturations derived from measured arterial PaO2 (r = 0.94). The device detected several otherwise unrecognized drops in arterial saturation that were confirmed by laboratory analysis. Other clinical situations in which the pulse oximeter was found useful in the ED are reviewed. We conclude that continuous measurement of SaO2 can improve the monitoring of ED patients, increase the precision of therapy, detect hypoxemia during intubation, suctioning, and other treatments, and detect clinically unsuspected changes in arterial oxygenation.