Anesthesia and analgesia
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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.
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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
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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Anesthesia and analgesia · Sep 1991
Randomized Controlled Trial Clinical TrialTreatment of postoperative nausea and vomiting with ondansetron: a randomized, double-blind comparison with placebo.
Postoperative nausea and vomiting are common after recovery from general anesthesia. The antiemetic effect and safety of ondansetron, a selective serotonin type 3 (5-HT3) receptor antagonist, was determined in 36 patients suffering from nausea or vomiting during recovery from intravenous anesthesia by giving either a single intravenous dose of ondansetron (8 mg, n = 18) or placebo (n = 18) over 2-5 min in a randomized, double-blind manner. A "rescue" antiemetic was provided in case of continued vomiting or at the patient's request. ⋯ Ondansetron was an effective antiemetic in 78% (14/18) and placebo was effective in 28% (5/18) of the patients. Laboratory studies 24 h later showed no signs of hematologic, hepatic, or renal alterations. Ondansetron at a dose of 8 mg administered intravenously over 2-5 min appears to be a safe and effective antiemetic for the treatment of nausea and/or vomiting after intravenous anesthesia.
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Anesthesia and analgesia · Sep 1991
Randomized Controlled Trial Clinical TrialIs premedication with oral glycopyrrolate as effective as oral atropine in attenuating cardiovascular depression in infants receiving halothane for induction of anesthesia?
The authors conducted a double-blind study to compare premedication with oral glycopyrrolate and oral atropine in prevention of bradycardia and hypotension during induction of anesthesia with halothane-N2O in 90 outpatient infants and children aged 1-18 mo who were randomized into three groups to receive either an oral placebo, oral atropine (0.02 mg/kg), or oral glycopyrrolate (0.05 mg/kg) approximately 1 h before induction of anesthesia. Heart rate and mean arterial pressure were measured before drug administration, just before induction of anesthesia, and every minute until surgical stimulation occurred. Glycopyrrolate, at the dose used, was significantly less effective than atropine in attenuating bradycardia during induction; neither glycopyrrolate nor atropine altered the incidence or degree of hypotension. Antisialagogic activity and side effects were comparable, except for significantly more flushing with atropine.