Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1991
Randomized Controlled Trial Clinical TrialAntiemetic efficacy of ondansetron after outpatient laparoscopy.
The safety and efficacy of ondansetron were evaluated for the treatment of postoperative nausea and vomiting after laparoscopic surgical procedures. Seventy-one healthy, consenting outpatients were randomly assigned to one of two treatment groups according to a double-blind, placebo-controlled protocol. A standardized anesthetic technique consisting of alfentanil-thiopental-succinylcholine for induction and alfentanil-nitrous oxide-succinylcholine for maintenance of anesthesia was used. ⋯ In the placebo-treated group, 92% of the patients experienced subsequent episodes of vomiting in the postanesthesia care unit compared with 51% of the patients in the ondansetron group. Finally, only 43% of the ondansetron-treated patients required a "rescue" antiemetic compared with 86% in the placebo group. Thus, ondansetron (8 mg IV) was associated with a decreased incidence of nausea and vomiting after outpatient laparoscopic procedures.
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Anesthesia and analgesia · Sep 1991
Comparative StudyPsychomotor performance after desflurane anesthesia: a comparison with isoflurane.
Recovery and psychomotor performance were studied in 80 ASA physical status I-III adult patients undergoing outpatient surgery. Patients were divided into four equal groups: thiopental induction of anesthesia followed by desflurane in nitrous oxide and oxygen (Th-DES-N2O/O2), thiopental induction of anesthesia followed by isoflurane in nitrous oxide and oxygen (Th-ISO-N2O/O2), thiopental induction of anesthesia followed by desflurane in oxygen (Th-DES-O2), and desflurane inhaled induction followed by desflurane in oxygen (DES-DES-O2). Patients were excluded from analysis if they required opioids or antiemetics postoperatively. ⋯ Critical flicker fusion threshold, however, showed no difference between groups. The use of thiopental was associated with delayed recovery. Compared with isoflurane, desflurane anesthesia is associated with more rapid initial awakening and less impairment of choice reaction time.
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Anesthesia and analgesia · Sep 1991
Breathing pattern and occlusion pressure waveform in humans anesthetized with halothane or sevoflurane.
To examine the ventilatory effects of sevoflurane, breathing pattern, airway occlusion pressure waveform, and the mechanical variables of the respiratory system were determined in seven subjects anesthetized with sevoflurane and in an additional seven subjects anesthetized with halothane. All patients breathed 1 MAC of anesthetic using oxygen as the carrier gas, and the measurements were performed in the absence of surgical stimulation. The durations of inspiration and expiration were significantly longer during sevoflurane than during halothane administration. ⋯ There was no evidence of an active Hering-Breuer reflex with either anesthetic. Mechanical variables of the respiratory system were essentially identical between the two anesthetics. We conclude that (a) the ventilatory effects of halothane and sevoflurane are different, (b) the difference in the respiratory timing and depth of breathing originates from the action of the anesthetics on the central respiratory neural network, and (c) the different shape of the tracheal occlusion pressure may be largely due to the different effects of halothane and sevoflurane on the muscles of the rib cage.
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Isoflurane anesthesia in humans markedly decreases the threshold temperature triggering peripheral thermoregulatory vasoconstriction (i.e., central temperature triggering vasoconstriction). However, it is not known whether the sweating threshold remains unchanged (e.g., near 37 degrees C), decreases along with the vasoconstriction threshold, or increases during anesthetic administration. Accordingly, the hypothesis that isoflurane anesthesia increases the thermoregulatory threshold for sweating was tested. ⋯ The sweating threshold was prospectively defined as the distal esophageal temperature at which significant sweating was first observed. Sweating was observed in each patient at a mean central temperature of 38.3 +/- 0.3 degrees C and an end-tidal isoflurane concentration of 1.1% +/- 0.2%. The interthreshold range (difference between vasoconstriction and sweating thresholds) without anesthesia is approximately 0.5 degrees C; isoflurane anesthesia increases this range to approximately 4 degrees C.