The use of muscle-relaxing drugs in complicated deliveries.

Abstract Tubarine.— 1. a. Tubarine, a highly purified form of curare, was used in fifty selected cases as an adjunct to anesthesia (nitrous oxide and oxygen, or nitrous oxide, oxygen, and ether) to provide muscle relaxation at the time of delivery. The results in vaginal delivery were: good, 83 per cent; fair, 14.5 per cent; poor, 2.5 per cent. The fair and poor results were obtained in heavier patients in the early part of the study. When larger doses were used as suggested in weight dosage table, the results were far better. 2. b. The average time interval of 12 minutes, lapsing between the intravenous administration of Tubarine and delivery of the baby, would indicate that the drug should be given after the physician has finished scrubbing, when he can watch the patient for signs of perineal relaxation. 3. c. Tubarine, from clinical observations, tends to relax the perineal muscles before the muscles of the lower extremities are affected. 4. d. There is much less trauma to maternal soft parts at the time of delivery, and repair of the episiotomy is much easier when Tubarine is used. The perinea, when checked six weeks post partum, were much better supported and healed than if Tubarine had not been used. 5. e. Positive signs of curarization in the newborn infant were not found: however, it is possible, since analgesics were used in most cases during labor, that early signs may have been masked by the analgesic agents. There were no deaths and the six weeks' examinations of babies were satisfactory. 6. f. No adverse reactions were noted. Uterine contractions were not inhibited and blood loss after delivery was probably decreased because of the ease with which the episiotomy was repaired. 7. g. The use of Tubarine in cesarean section cases gave good relaxation of the abdominal muscles, but the time lapsing between the beginning of the anesthesia, the injection of Tubarine intravenously, and the moment the baby could be delivered was felt to be too long. Syncurine.— 1. a. Syncurine, a synthetic muscle-relaxing drug, was used in 67 cases: abdominal delivery, 18; vaginal delivery 49; as an adjunct to the anesthesia (nitrous oxide and oxygen, or nitrous oxide, oxygen, and ether) to provide muscle relaxation at the time of delivery. The results in vaginal delivery were: good, 76.5 per cent; fair, 21.2 per cent; poor, 2.3 per cent. Despite a variation in doses, the quick action of the drug, its short duration, and its seemingly variable effect on the perineal muscles made the standardization of dosage almost impossible. 2. b. The average time interval of 8½ minutes (longest 20 minutes and shortest 3 minutes) between the giving of the drug and the delivery of the infant indicates to some extent the variability with which the perineal muscles responded. 3. c. The anal sphincter muscles showed considerable twitching when Syncurine was used. The perineal muscles did not relax earlier than the muscles of the lower extremities. 4. d. No sign of Syncurine effect was observed in the newborn infant, but here again the analgesics used during labor may have masked any slight effect. Fluoroscopic chest studies on the infant, carried out within the first 24 hours after delivery, showed no difference between babies delivered from mothers having Syncurine at the time of delivery and those delivered under the usual conditions. Six weeks' follow-up of babies showed good results. 5. e. No adverse side effects were noted when Syncurine was used. Uterine contractions continued strong. Blood pressure either stayed the same, dropped 10 mg., or increased 10 to 20 mg. Pulse rate remained about constant, respirations were occasionally moderately depressed. 6. f. The use of Syncurine in cesarean section proved almost ideal because of the good muscle relaxation obtained, light plane of anesthesia needed, and the quick action of the drug. No sign of Syncurine effect was observed in these babies.