Time dependency of the ratio of umbilical vein/maternal artery concentrations of vecuronium in caesarean section.

BACKGROUND: The ratio of umbilical vein (UV) and maternal artery (MA) concentrations of vecuronium may more accurately determine the placental transfer ratio during caesarean section. This ratio potentially correlates with the time from induction of anaesthesia to delivery (I-D time). The aim of this study was to determine the UV/MA ratio of vecuronium and its relationship with the I-D time. METHODS: Eighteen pregnant women at full term undergoing caesarean section were studied. The parturient was given intravenously 0.01 mg/kg vecuronium as a priming dose, followed 180 s later by 0.11 mg/kg vecuronium as an intubation dose and 4 mg/kg thiamylal. The time from the injection of the intubation dose to the clamping of the umbilical cord was regarded as the I-D time. At the time of clamping the umbilical cord, blood samples were collected and the UV and MA of vecuronium were measured. RESULTS: The UV/MA ratio and the I-D time, expressed as the mean (SD), were 0.056 (0.016) and 280 (57) s, respectively. The regression equation indicated y = 0.0083 + 0.00017 x (R2 = 0.381, r = 0.617, P = 0.0063, I-D time (s) = x, UV/MA = y). CONCLUSION: The present study demonstrated that the UV/MA ratio of vecuronium as an index of the placental transfer becomes smaller as the delivery time after injection of this drug becomes shorter during caesarean section.

Epidural block during general anesthesia attenuates urinary trypsin inhibitor excretion in lower abdominal surgery.

PURPOSE: The aim of this study was to elucidate whether urinary trypsin inhibitor excretion differs between general anesthesia (GA) and epidural block during general anesthesia (EPI) in lower abdominal surgery. METHODS: Sixteen women undergoing abdominal total hysterectomy were assigned to the GA and EPI groups. The GA group received propofol induction and maintenance with isoflurane, nitrous oxide, and vecuronium. The EPI group received epidural block, followed by propofol induction and maintenance with isoflurane and nitrous oxide. The levels of adrenocorticotropic hormone and cortisol during anesthesia and on postoperative days 1, 2, and 3, and the levels of urinary trypsin inhibitor in 12-h urine from the day of surgery to postoperative day 3, were measured. RESULTS: As compared with the EPI group, the GA group had a higher level of adrenocorticotropic hormone at the completion of anesthesia, higher levels of cortisol at the completion of anesthesia and postoperative day 2, and higher excretion of urinary trypsin inhibitor on the day of surgery and postoperative days 1 and 2. CONCLUSION: The present results suggest that excretion of urinary trypsin inhibitor into the urine under epidural block during general anesthesia is lower than that under general anesthesia alone in lower abdominal surgery. This is probably due to the difference in endocrine response to surgery between the two types of anesthesia.

[Placental transfer of vecuronium administered with priming principle regimen in patients undergoing cesarean section].

Eight women having cesarean section under general anesthesia received vecuronium (VCB) 0.01 mg.kg-1 as a priming dose, followed 180 s later by 0.11 mg.kg-1 as an intubation dose. Subsequently, VCB concentrations of umbilical venous and maternal arterial blood at delivery were assayed. The time from the injection of intubation dose to delivery was 283 +/- 55 (mean +/- SD) s. Umbilical and maternal VCB concentrations at delivery were 79.4 +/-36.1 1ng.ml-1 (UV) and 1258.3 +/- 464.1 ng.ml-1 (MA). respectively. Thus, the umbilical venous to maternal arterial VCB concentration ratio (UV.MA-1) was 0.07 +/- 0.02. One-min and 5-min Apgar scores were 8-9 and 9-10, respectively. Judging from previous reports concerning VCB administration during cesarean section, total of VCB 0.12 mg.kg-1 may be an overdose. We concluded therefore that of total VCB 0.10 mg.kg-1 seems to be an appropriate dose for cesarean section.