Anesthesiology
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Randomized Controlled Trial Clinical Trial
Depression of ventilation by desflurane in humans.
We studied the ventilatory effects of desflurane (formerly I-653) with and without N2O in healthy male volunteers. After insertion of venous and arterial (radial and pulmonary) catheters, baseline measurements of tidal volume (VT), respiratory rate (RR), ventilatory response to CO2, and arterial and mixed venous blood gases were made. Subjects were randomly assigned to receive either desflurane with O2 (n = 6) or with O2 and 60% N2O (n = 6). ⋯ Similarly, RR increased from 15 +/- 0.5 breaths per min awake to 32 +/- 2 breaths per min at 1.66 MAC without N2O and from 14 +/- 0.5 breaths per min awake to 40 +/- 3 breaths per min at 1.66 MAC with N2O. Desflurane without N2O depressed the ventilatory response to CO2 to 45 +/- 9, 31 +/- 5, and 11 +/- 4% of the awake values at 0.83, 1.24, and 1.66 MAC, respectively. With N2O, values were 52 +/- 14, 23 +/- 5, and 26 +/- 9% of the awake value at 0.83, 1.24, and 1.66 MAC, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Recovery profile after desflurane-nitrous oxide versus isoflurane-nitrous oxide in outpatients.
Thirty-eight healthy outpatients undergoing elective surgical procedures lasting 1-3 h were randomly assigned to receive either desflurane 3% (approximately 0.5 MAC) or isoflurane 0.6% (approximately 0.5 MAC) for maintenance of general anesthesia with nitrous oxide 60% in oxygen after a standardized induction sequence consisting of fentanyl 3 micrograms.kg-1, thiopental 4 mg.kg-1, and succinylcholine 1-1.5 mg.kg-1, intravenously. Although anesthetic conditions were similar during operations in the two treatment groups, significant differences were noted in the recovery profiles as measured by elimination kinetics, psychometric testing, and visual analog scales (to assess subjective feelings). The time required for the end-tidal concentration to decrease by 50% was 2.5 +/- 0.8 min for desflurane vs. 9.5 +/- 3.4 min for isoflurane (mean +/- standard deviation [SD]). ⋯ Postoperatively, patients who received desflurane exhibited less impairment of cognitive function (as measured using the Digit-Symbol Substitution Test) than did those who received isoflurane. Furthermore, visual analog scores indicated that patients receiving desflurane experienced significantly less discomfort (pain), drowsiness, fatigue, clumsiness, and confusion in the early postoperative period. We conclude that desflurane may offer clinical advantages over isoflurane when used for maintenance of anesthesia during outpatient surgical procedures.
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Randomized Controlled Trial Clinical Trial
Effects of residual concentrations of isoflurane on the reversal of vecuronium-induced neuromuscular blockade.
Thirty-six anesthetized patients (ASA physical status 1 or 2) undergoing elective surgery were monitored (isometric adductor pollicis mechanical activity) to detect the effects of discontinuing isoflurane anesthesia upon the reversal of vecuronium-induced neuromuscular blockade. Neuromuscular blockade was produced by vecuronium 100 micrograms/kg and additional doses of 20 micrograms/kg until completion of surgery. The patients were randomly divided into three groups: in the control group (n = 12), only fentanyl/N2O was given; in the "isostable" group (n = 12), isoflurane at an end-tidal concentration of 1.25% was maintained throughout anesthesia; in the "isostop" group (n = 12), isoflurane 1.25% was discontinued before neostigmine administration. ⋯ In the isostable group, final mean train-of-four was significantly less (75%) than in the other patients (88%) (P less than 0.01). Mean tetanic fade at 100 Hz was significantly less in the isostable group (31%) than in the isostop group (57%) (P less than 0.01) and control group (84%) (P less than 0.01). We conclude that discontinuing isoflurane anesthesia for 15 min improves the reversal of a vecuronium paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
The neuromuscular effects of desflurane, alone and combined with pancuronium or succinylcholine in humans.
The neuromuscular effects of desflurane administered alone were studied in ten healthy human volunteers aged 20-27 yr. Also, the dose-response relationships of pancuronium and succinylcholine in surgical patients during anesthesia with desflurane (n = 13) were compared to those during isoflurane anesthesia (n = 14). In the volunteers, we measured the mechanical response of the adductor pollicis muscle to stimulation of the ulnar nerve in a train-of-four (TOF) sequence at 2 Hz and at tetanic frequencies of 50, 100, and 200 Hz, each administered for 5 s. ⋯ The doses of pancuronium that depressed T1 amplitude by 50% (ED50) were similar during anesthesia with 1.25 MAC desflurane, 10.5 +/- 2.8 micrograms/kg (mean +/- SD) and 1.25 MAC isoflurane, 12.3 +/- 5.0 micrograms/kg. The ED50 doses of succinylcholine were similar during anesthesia with desflurane 132 +/- 76 micrograms/kg and isoflurane 123 +/- 36 micrograms/kg. We conclude that desflurane significantly depresses neuromuscular function and augments the action of pancuronium and succinylcholine to a degree similar to that of isoflurane.