Articles: general-anesthesia.
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Anesthesia and analgesia · Oct 1983
Succinylcholine-vecuronium (Org NC 45) sequence for cesarean section.
Vecuronium (Org NC 45) was used in 27 parturients undergoing elective cesarean section under general anesthesia. One of the parturients had a twin pregnancy. Neuromuscular transmission was assessed clinically by stimulating the ulnar nerve and observing the contraction of the fingers. ⋯ Nine infants were delivered before the injection of vecuronium; 19 infants were delivered after its injection. There was no significant difference between the Apgar scores in the two groups, suggesting that vecuronium does not cross the placenta in concentrations that affect the newborn. Vecuronium may be advantageous in parturients undergoing cesarean section under general anesthesia because it maintains cardiovascular stability, is noncumulative, is readily antagonized by neostigmine, has no effect on the plasma cholinesterase activity, and has no deleterious effect on the newborn.
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Simultaneous measurement of tracheal and esophageal pressures during occluded inspiratory efforts (occlusion test) was used to assess the validity of the esophageal balloon technique in anesthetized supine subjects. Ten ASA 1 patients undergoing general anesthesia (halothane 1 MAC, nitrous oxide 70%, and oxygen) for minor surgery were studied. Esophageal pressure (Pes) was measured using a 5-cm-long balloon and was plotted against tracheal pressure (Pt). ⋯ In the remaining three, however, the difference between delta Pes and delta Pt ranged between +20% and -40%. By repositioning the balloon to 5 or 15 cm above the cardia, a locus was found in all subjects where the difference is less than 10%. We conclude that the esophageal balloon technique can be used in anesthetized supine subjects to give reliable measurements of changes in pleural pressure, provided that it is validated with the occlusion test.
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The intraoperative and postoperative effects of fentanyl and ketamine administered continuously by infusion were compared with those produced by conventional intermittent bolus administration in 100 patients. After a standardized induction with thiopental 4 mg/kg intravenously, patients received either fentanyl (50 micrograms boluses vs. 2 micrograms/ml infusion) or ketamine (25 mg boluses vs. 1 mg/ml infusion) as intravenous adjuvants to nitrous oxide, 70% in oxygen. With continuous infusion, the doses of fentanyl and ketamine required were decreased 45% and 43%, respectively. ⋯ However, excessive sedation was noted in 48% and 52% of patients in the fentanyl and ketamine bolus groups, respectively, compared with 4% and 8%, respectively, in the infusion groups. Discharge times were decreased by 29% and 13% in the fentanyl and ketamine infusion groups, respectively. The author concludes that continuous infusion fentanyl (0.1 micrograms . kg-1 . min-1) or ketamine (50 micrograms . kg-1 . min-1) significantly decreases the drug dosage requirement, improves intraoperative conditions, and decreases recovery time compared with the traditional intermittent bolus technique.