Anesthesiology
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Randomized Controlled Trial Clinical Trial
The role of epidural morphine in the postcesarean patient: efficacy and effects on bonding.
This study was designed to determine in postcesarean patients whether in addition to superior analgesic effects, epidural morphine administration results in secondary benefits in maternal well-being and maternal-infant interaction. Following elective cesarean section with bupivacaine epidural anesthesia, 40 healthy mothers received 5 mg preservative-free morphine sulfate in 10 ml of saline, either by the epidural (Group 1, n = 20) or the intravenous (Group 2, n = 20) route, in a randomized, double-blind fashion. Each received a simultaneous injection of saline by the alternate route. ⋯ Itching occurred in 58% of Group 1 patients and only 16% of Group 2 patients (P less than 0.01); the incidences of nausea, vomiting, and urinary retention were not statistically different between the groups. No respiratory depression was observed. Benefits of epidural morphine in this patient population appear limited to the provision of improved analgesia and earlier mobility.
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The author tested the hypothesis that in a canine lobar hypoxic pulmonary vasoconstriction (HPV) model, the passage of time alone would eliminate a previously observed association between increasing lobar HPV and repeated intermittent hypoxia of the lung lobe. The HPV model included electromagnetic measurement of the fraction of the cardiac output perfusing the left lower lobe (QLLL/Qt) and ventilation of the left lower lobe (LLL) independent of, but still synchronous with, the rest of the lung. Following surgical preparation of the model, the LLL and the rest of the lung were ventilated with 100% O2 and no further manipulations or procedures were performed for 120-150 min. ⋯ The first three LLL hypoxic exposures caused a significant progressive increase in LLL HPV response (from 37.8 to 54.7 to 61.3%) while the second LLL HPV response required significantly less time (16.6 min) to reach a stable decreased QLLL/Qt value compared with the first LLL HPV response (26.4 min). Animals with the smallest initial LLL HPV response increased their HPV response the most, and animals with the largest initial LLL HPV response increased their HPV response the least with repeated LLL hypoxic exposures. The conclusion that intermittent hypoxia increases HPV has important implications for the conduct of HPV experiments and the interpretation of blood-gas changes during one-lung ventilation for thoracic surgery.