[Evaluation of postoperative hypoxemia with a pulse oximeter].

We investigated postoperative hypoxemia by monitoring of SPO2 with a pulse oximeter for the first 5 hours in the ward. Forty-eight adults were divided into the general anesthesia along (G) group and the combination of epidural and general anesthesia (E) group. The patients were randomly administered either 3 l. min(-1) oxygen with face mask for the initial 3 hours or room air. Postoperative Spo2 values in the patients who breathed room air in both groups were less than 94% in 33% of G group and 50% of E group. 3 l. min(-1) oxygen inhalation through the face mask was enough to avoid postoperative hypoxemia in both groups; the mean values of Spo2 were 99% in G group and 97.9% in E group. Spo2 rapidly and significantly decreased after stopping the oxygen inhalation to under 94% in 25% of G group and 58% of E group. Significant correlations were found between Spo2 levels and both age (R = 0.75) and preanesthetic Spo2 (R = 0.66) in G group. Spo2 was significantly lower in the patients whose anesthesia was stopped after 5 p.m. than in those who were weaned before 5 p.m. In conclusion, there is a high incidence of postoperative hypoxemia for several hours in the ward, which can be relieved by 3 l. min(-1) oxygen inhalation with face mask.