Anesthesia and analgesia
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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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Anesthesia and analgesia · Sep 1991
Neuromuscular effects of succinylcholine on the vocal cords and adductor pollicis muscles.
To quantify the effects of succinylcholine at the laryngeal adductor muscles and the adductor pollicis, 17 adult patients were studied during propofol-fentanyl anesthesia. Train-of-four stimulation was applied to the ulnar nerve at the wrist and the recurrent laryngeal nerve at the notch of the thyroid cartilage. Laryngeal response was measured as pressure changes in the cuff of the tracheal tube positioned between the vocal cords. ⋯ Time to 90% recovery of T1 after a bolus of 0.5 mg/kg was similar at the vocal cords (4.3 +/- 0.5 min) and the adductor pollicis (5.2 +/- 0.8 min) (NS). The ED50 was less at the laryngeal adductors (0.170 mg/kg) than at the adductor pollicis (0.278 mg/kg). It is concluded that, in adults, succinylcholine-induced blockade is more rapid and more intense at the laryngeal muscles than at the adductor pollicis.
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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.