Department of Anaesthesiology and Critical Care, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
Department of Obstetrics and Gynaecology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
Anaesth Intensive Care. 2021 May;49(3):183-189. doi: 10.1177/0310057X20984480. Epub 2021 May 2.
Most research in this field has focused on finding oxytocin doses for initiating uterine contractions. Only limited data are available regarding the optimal rate of oxytocin infusion to maintain adequate uterine tone. This randomised, double blind study included 120 healthy term pregnant patients with uncomplicated, singleton pregnancy undergoing elective caesarean section under spinal anaesthesia. Following an initial 1 IU bolus, the patients received oxytocin infusion at 1.25 IU/hour (group 1.25), 2.5 IU/hour (group 2.5) or 5.0 IU/hour (group 5) for four hours. Uterine tone was assessed as adequate or inadequate at various intervals. If found inadequate, additional uterotonics were administered. Estimated blood loss was mean (standard deviation) 499 (172) ml, 454 (117) ml and 402 (151) ml in groups 1.25, 2.5 and 5, respectively ( value groups 1.25 versus 5 = 0.012). Oxytocin infusion at 5 IU/hour resulted in a significantly lower incidence of minor postpartum haemorrhage, defined as blood loss greater than 500 ml, than 1.25 IU/hour ( = 0.009). No patient had major/severe haemorrhage (>1000 ml blood loss). No significant difference was seen in haemoglobin levels ( = 0.677) and uterine tone. Fifteen, six and nine patients, respectively, required additional oxytocin ( = 0.151). The incidence of tachycardia ( = 0.726), hypotension ( = 0.321) and nausea/vomiting ( = 0.161) was comparable. To conclude, 5 IU/hour was more effective than 1.25 IU/hour in reducing total blood loss and the incidence of minor postpartum haemorrhage. Thus 5 IU/hour appears to be an optimal oxytocin infusion rate following 1 IU slow intravenous oxytocin injection for the maintenance of adequate uterine contraction in patients undergoing elective caesarean section under spinal anaesthesia.
大多数该领域的研究都集中在寻找引发子宫收缩的催产素剂量上。只有有限的数据可用于维持足够的子宫张力的最佳催产素输注率。这项随机、双盲研究纳入了 120 名健康足月、单胎妊娠、行择期脊髓麻醉下剖宫产的孕妇。初始给予 1IU 负荷剂量后，患者以 1.25IU/小时（1.25 组）、2.5IU/小时（2.5 组）或 5.0IU/小时（5.0 组）的速度输注催产素 4 小时。在不同时间间隔评估子宫张力是否足够。如果发现不足，给予额外的宫缩剂。估计失血量的平均值（标准差）分别为 1.25 组 499（172）ml、2.5 组 454（117）ml 和 5.0 组 402（151）ml（组 1.25 与 5 比较，P=0.012）。5IU/小时的催产素输注与 1.25IU/小时相比，显著降低了产后出血量大于 500ml 的轻度产后出血发生率（P=0.009）。无患者发生大出血/严重出血（>1000ml 失血）。血红蛋白水平（P=0.677）和子宫张力无显著差异。分别有 15、6 和 9 名患者需要额外的催产素（P=0.151）。心动过速（P=0.726）、低血压（P=0.321）和恶心/呕吐（P=0.161）的发生率相似。总之，5IU/小时比 1.25IU/小时更有效地减少总失血量和轻度产后出血的发生率。因此，在脊髓麻醉下择期剖宫产中，静脉缓慢注射 1IU 催产素后，以 5IU/小时的速度输注催产素似乎是维持子宫收缩足够的最佳催产素输注率。
