Sartain J B, Barry J J, Howat P W, McCormack D I, Bryant M
Department of Anaesthesia, Intensive Care and Perioperative Medicine, Cairns Base Hospital, The Esplanade, Cairns, QLD 4870, Australia.
Br J Anaesth. 2008 Dec;101(6):822-6. doi: 10.1093/bja/aen273. Epub 2008 Oct 9.
The optimal dose of oxytocin at Caesarean section is unclear. Oxytocin may cause adverse cardiovascular effects, including tachycardia and hypotension, whereas an inadequate dose can result in increased uterine bleeding. We compared the effects of two doses of oxytocin in a randomized double-blind trial.
Eighty patients undergoing elective Caesarean section received an i.v. bolus of either 2 or 5 units (u) of oxytocin after delivery, followed by an oxytocin infusion of 10 u h(-1). All received combined spinal-epidural anaesthesia with arterial pressure maintained by a phenylephrine infusion. We compared changes in heart rate (HR), mean arterial pressure (MAP), blood loss, uterine tone, the need for additional uterotonic drugs, and emetic symptoms.
There was a greater increase in mean (sd) HR in patients who received 5 u of oxytocin [32 (17) beats min(-1)] than in those who received 2 u [24 (13) beats min(-1)] (P=0.015). There was a larger decrease in MAP in patients who received 5 u [13 (15) mm Hg] than in those who received 2 u [6 (10) mm Hg] (P=0.030). The frequency of nausea and antiemetic use was higher after 5 u (32.5%) than 2 u (5%) (P=0.003). There were no differences in blood loss, uterine tone, or requests for additional uterotonic drugs (17.5% in both groups).
In elective Caesarean section, a 2 u bolus of oxytocin results in less haemodynamic change than 5 u, with less nausea and no difference in the need for additional uterotonics.
剖宫产时缩宫素的最佳剂量尚不清楚。缩宫素可能会引起不良心血管效应，包括心动过速和低血压，而剂量不足则会导致子宫出血增加。我们在一项随机双盲试验中比较了两种剂量缩宫素的效果。
80例行择期剖宫产的患者在分娩后静脉推注2或5单位（u）缩宫素，随后以10 u/h的速度输注缩宫素。所有患者均接受腰麻-硬膜外联合麻醉，通过去氧肾上腺素输注维持动脉压。我们比较了心率（HR）、平均动脉压（MAP）、失血量、子宫张力、额外使用宫缩剂的需求以及呕吐症状的变化。
接受5 u缩宫素的患者平均（标准差）HR升高幅度[32（17）次/分钟]大于接受2 u缩宫素的患者[24（13）次/分钟]（P = 0.015）。接受5 u缩宫素的患者MAP下降幅度[13（15）mmHg]大于接受2 u缩宫素的患者[6（10）mmHg]（P = 0.030）。5 u缩宫素后恶心和使用止吐药的频率（32.5%）高于2 u缩宫素后（5%）（P = 0.003）。两组在失血量、子宫张力或额外使用宫缩剂的需求方面无差异（两组均为17.5%）。
在择期剖宫产中，2 u缩宫素推注引起的血流动力学变化小于5 u，恶心症状较少，且在额外使用宫缩剂的需求方面无差异。
