Oxyhemoglobin Saturation following Cesarean Section in Patients Receiving Epidural Morphine, PCA, or im Meperidine Analgesia

Abstract

The frequency and severity of oxyhemoglobin desaturation was compared in 49 patients receiving epidural morphine, 5 mg (n = 21); patient-controlled analgesia (PCA) using meperidine (n = 20); or intramuscular (im) meperidine (n = 8) for postoperative analgesia following elective cesarean section performed with epidural anesthesia. Oxygen saturation (SpO2) was monitored for 24 h using a pulse oximeter; data were continuously collected and stored every 30 s via an interface connected to a computer. For analysis purposes, SpO2 was divided into five categories: 96-100%, 91-95%, 86-90%, 81-85%, and less than or equal to 80%. Although SpO2 remained above 95% for the majority of the monitored period, patients in all groups experienced periods of desaturation. PCA patients spent the longest cumulative time with SpO2 between 91 and 95%, 231 +/- 49 min (mean +/- SEM), compared with only 112 +/- 30 min and 152 +/- 42 min for the epidural and im groups, respectively (P less than 0.05 vs. epidural group). PCA patients also spent longest with SpO2 at 86-90% (19 +/- 10 min, vs. 6 +/- 3 and 0.5 +/- 0.3 min for the epidural and im groups, respectively), although this difference was not statistically significant. Severe desaturation episodes, defined as SpO2 less than or equal to 85% for more than 30 s, occurred in 71% of patients in the epidural group, 30% in the PCA group, and 63% in the im group (P less than 0.05 PCA vs. epidural and im).(ABSTRACT TRUNCATED AT 250 WORDS)