[The incidence of postoperative respiratory depression in patients undergoing intravenous or epidural analgesia with opioids].

BACKGROUND AND OBJECTIVES Intravenous or epidural patient-controlled analgesia (PCA) is a safe and effective technique in the treatment of postoperative pain. However, the use of opioids is not devoid of risks,and respiratory depression represents the most feared complication. The objective of the present study was to describe the incidence of respiratory depression associated with postoperative analgesia with the intravenous or epidural administration of opioids and the characteristics of the patients who developed this complication. METHODS This is a retrospective, incidence study in patients who underwent surgeries at the Hospital SARAH Brasília from December 1999 to December 2007 and treated with intravenous or epidural PCA with opioids. Respiratory depression was defined as: respiratory rate < 8 bpm, need to use naloxone, or peripheral oxygen saturation below 90%. RESULTS Two thousand seven hundred and ninety patients were evaluated; 635 of those patients received intravenous PCA and 2155 epidural analgesia. Seven patients developed postoperative respiratory depression (0.25%). Six of those patients were treated with intravenous PCA with morphine, while the last one received epidural analgesia with fentanyl. Patients had a mean age of 30.5 +/- 24.7 years; the mean time between the end of anesthesia and the development of respiratory depression was 18.1 +/- 26.3 hours. The incidence of respiratory depression was significantly higher in PCA with intravenous morphine (p = 0.001) and age below 16 years (p < 0.05). CONCLUSIONS The incidence of respiratory depression was similar to that described in the literature; it is more frequent in children and adolescents, and with intravenous PCA.