Fatores associados com a ocorrência de hipoxemia no período pós-anestésico imediato

Abstract

Background and Objectives - Postanesthetic hypoxemia is a critical respiratory event which increases postoperative morbidity. This study aimed to identify hypoxemia-related factors in the immediate postoperative period. Methods - Participated in this study 204 patients admitted to the recovery room while breathing room air. Peripheral oxy-hemoglobin saturation (SpO2), systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) were measured at 5-minute intervals since admission to the recovery room until 20 minutes later. Sedation, pain and ventilation adequacy scores were attributed to patients at the same moments. Hypoxemia was defined as a SpO2 below 92% and recommended oxygen therapy. The following data were recorded for each patient: age, gender, weight, height, smoking, history of diabetes and chronic obstructive pulmonary disease (COPD), preanesthetic SpO2 at arrival in the operating room, type and duration of anesthesia, surgery site, use of neuro-axial opioids and perioperative drugs. The association of those factors to postoperative hypoxemia was defined by logistic regression. Results - Forty-nine patients (24.01%) had SpO2 below 92% during the observation period. The following factors [odds ratio (95% confidence limits)] were considered hypoxemia predictors: more than 55 years old [4.32 (1.70; 10.95)], preanesthetic SpO2 lower than 95% [7.47 (1.50; 37.11)], general anesthesia with enflurane [14.53 (2.54; 82.93)], and clinically detectable hypoventilation [34.82 (11.46; 105.84)]. SBP and HR were significantly higher in hypoxemic patients. Conclusions - There are factors closely related to the incidence of postoperative hypoxemia and the use of pulse oximetry allows for selective oxygen therapy during the immediate postanesthetic period.