Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
The neonatal neurobehavioral effects of bupivacaine, mepivacaine, and 2-chloroprocaine used for pudendal block.
The neonatal neurobehavioral effects of bupivacaine, mepivacaine, and 2-chloroprocaine used in random sequence for pudendal block anesthesia were studied. The neurobehavioral status of 54 infants was studied 4 and 24 hours after delivery. ⋯ Mean mepivacaine levels in neonatal capillary blood at 4 hours of age were low (0.10 +/- .02 microgram/ml) compared with those in previous studies because of the short interval between maternal injection and delivery (13 +/- 3 min). Bupivacaine gave higher neonatal capillary blood levels (0.15 microgram/ml at 4 hours of age) than previously reported, but the drug still produced no detectable neonatal neurobehavioral effects.
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The authors examined the thesis that a dose of dantrolene producing 95 per cent of maximal muscle relaxation (ED95) would effectively prevent or treat malignant hyperthermia (MH). In one group of four pigs sensitive to malignant hyperthermia (MHS) a dose response to intravenous dantrolene was determined by quantitation of toe twitch tension. From these data, the ED95 relaxant dose (3.5 mg/kg) was derived. ⋯ Finally, each pig was challenged without dantrolene prophylaxis or therapeusis, and all succumbed from MH. Previous studies have shown the efficacious use of dantrolene in prevention or treatment of porcine MH, but doses used have varied, without rationale. The present study shows that in MHS pigs the ED95 muscle relaxant dose of dantrolene (3.5 mg/kg) successfully prevents and treats MH.