Efficacy of nitroglycerine for uterine smooth muscle relaxation in patients undergoing caesarean section

Abstract

Three ASA Ⅱ patients, aged 24-32 yr, weighing 56-74 kg, undergoing caesarean section with nitroglycerine for uterine smooth muscle relaxation, from May 2005 to April 2007 in our hospital, were studied. Among the 3 cases, 2 cases (39 or 40 weeks of gestation) were singleton pregnancy and 1 case (34 weeks of gestation) was twin pregnancy.Combined spinal-epidural block with an injection was used in the 3 patients and the block level was at T4-6-S3-5. The excess contraction of uterine occurred in the patient at 40 week gestation about 140 s after uterus incision and it was difficult in delivery of the fetus, trananasal administration was then performed with nitroglycerine 0.5 nag, but it was inefficient after 60 s observation. Nitroglycerine 0.2 nag was injected intravenously, 32 s later the uterine smooth muscle relaxation was good and the fetus was delivered smoothly. In the patients at 39 and 34 week gestation, nitroglycerine 0.2 mg was injected intravenously when the excess contraction of uterine occurred about 140 s after uterus incision and the 2rid fetus started to be. delivered respectively. The uterine smooth muscle relaxation was good 45 or 35 s after injection and the fetuses were delivered smoothly. Apgar score was 6-8 and 10 at 1 and 5 min after delivery in the 3 patients. The duration from hysterotomy to delivery was 195-240 s. Intravenous drip of oxytocin 20 U was given immediately after delivery, and then uterus contracted. No obvious adverse reactions were found. Key words: Nitroglycerin; Cesarean section; Myometrium; Muscle relaxation