Five unit bolus oxytocin at cesarean delivery in women at risk of atony: a randomized, double-blind, controlled trial.

BACKGROUND: I.v. bolus oxytocin is used routinely during cesarean delivery to prevent postpartum hemorrhage. Its adverse hemodynamic effects are well known, resulting in a recent change in dose from 10 IU to 5. Whether a 5 IU bolus has any advantages over infusion alone is unclear. We tested the hypothesis that a 5 IU i.v. bolus of oxytocin before the initiation of a continuous infusion decreases the need for additional uterotonic drugs in the first 24 hours after delivery in women with risk factors for uterine atony undergoing cesarean delivery, compared with infusion alone. METHODS: A prospective, randomized, double-blind, controlled trial was conducted in 143 subjects undergoing cesarean delivery with at least 1 risk factor for uterine atony. Subjects received 5 IU bolus of oxytocin or normal saline i.v. over 30 seconds after umbilical cord clamping. All subjects received an infusion of 40 IU oxytocin in 500 mL normal saline over 30 minutes, followed by 20 IU in 1 L over 8 hours. The primary outcome was the need for additional uterotonics in the first 24 hours after delivery. Secondary outcomes included uterine tone as assessed by the surgeon (5-point Likert scale: 0 = "floppy," 4 = "rock hard"), estimated blood loss, side effects of bolus administration, and the oxytocin bolus-placental delivery interval. RESULTS: There was no difference in the need for additional uterotonic drugs in the first 24 hours between groups. There was a significant difference in uterine tone immediately after placental delivery (P < 0.01) (2.8 in the oxytocin group [95% confidence interval 2.6-3.0] vs 2.2 in the saline group [95% confidence interval 1.8-2.5]), which disappeared after 5 minutes. There were no differences in observed or reported side effects between groups. CONCLUSIONS: We found that a 5 IU i.v. bolus of oxytocin added to an infusion did not alter the need for additional uterotonic drugs to prevent or treat postpartum hemorrhage in the first 24 hours in women undergoing cesarean delivery with risk factors for uterine atony, despite causing an initial stronger uterine contraction. Our study was not powered to find a difference in side effects between groups. These results suggest that an oxytocin infusion may be adequate without the need for a bolus, even in high-risk patients.

Is there thermal benefit from preoperative warming in children?

AIM: We aimed to quantify the impact of a raised preoperative ambient temperature (T(ambient)) on core temperature (T(core)) after induction of anesthesia in children. BACKGROUND: It has been suggested that prewarming of patients before anesthesia induction reduces postinduction drop in T(core). Neither the prewarming temperature nor its duration is established for adults or children. Nevertheless, it remains common practice to either warm the operating theatre and induction room or employ radiant heaters prior to induction of anesthesia, particularly for infants and neonates. We aimed to quantify the benefit, if any, of this warming practice. METHODS: We conducted a prospective clinical study to assess T(core) behavior in children randomized to either raised or standard ambient temperature as a prewarming technique prior to induction and until the operation commenced. We have called this 'preoperative' warming. Well, children scheduled for elective surgery where presurgical anesthetic duration exceeded 20 min were randomized to a T(ambient) of either 26 or 21 degrees C. Esophageal temperature was monitored continuously until the operative procedure commenced. RESULTS: There were 30 children in each group. Those in the warmed group (26 degrees C) had a statistically significant higher initial T(core) (0.4 degrees C warmer) and less drop in their T(core) (0.18 degrees C benefit at 20 min). Although younger/lighter/shorter individuals were more likely to drop their T(core), a warmer T(ambient) had only 0.1 degrees C thermal benefit irrespective of age. CONCLUSIONS: There are statistically significant thermal advantages to preoperative environmental warming. This study provides data to assist the anesthetist in deciding when these are likely to be clinically relevant.