Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1994
Changes in heart rate variability under propofol anesthesia: a possible explanation for propofol-induced bradycardia.
We propose to study the bradycardia associated with propofol anesthesia. Ten women undergoing laparoscopy for benign disease were studied using ambulatory electrocardiogram monitoring. Anesthesia was induced with an intravenous bolus of propofol and maintained with an infusion. ⋯ We conclude that high-frequency variability reflects parasympathetic tone. Propofol anesthesia reduces parasympathetic tone to a lesser degree than sympathetic tone. This autonomic milieu predisposes the patient to developing bradycardia in response to parasympathetic stimuli.
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Anesthesia and analgesia · Aug 1994
Randomized Controlled Trial Clinical TrialRecovery from outpatient laparoscopic tubal ligation is not improved by preoperative administration of ketorolac or ibuprofen.
The analgesic efficacy of a single dose of ketorolac or ibuprofen given preoperatively was assessed in healthy outpatients undergoing general anesthesia for laparoscopic tubal ligation. Fifty patients were randomized to receive either ketorolac 60 mg intravenously (i.v.), ibuprofen 800 mg orally, or placebo in a double-blind manner. Anesthesia was induced with fentanyl 2 micrograms/kg, thiopental 5 mg/kg, and either vecuronium 0.1 mg/kg or succinylcholine 1.5 mg/kg i.v. and was maintained with nitrous oxide 67% in oxygen and isoflurane. ⋯ The dose of parenteral morphine required in the PACU was not different between the control (7 +/- 1.2 mg), ibuprofen (5.7 +/- 1.4 mg), and ketorolac (6.1 +/- 1.4 mg) groups. There was no difference between groups in terms of pain visual analog scale (VAS) scores, fatigue VAS scores, recovery times, or the incidence of postoperative nausea and vomiting. The preoperative administration of either parenteral ketorolac or oral ibuprofen did not decrease postoperative pain or side effects when compared to placebo in this outpatient population.
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Anesthesia and analgesia · Aug 1994
Randomized Controlled Trial Clinical TrialEffectiveness of low levels of nonventilated lung continuous positive airway pressure in improving arterial oxygenation during one-lung ventilation.
Continuous positive airway pressure (CPAP) of 5 and 10 cm H2O applied to the nonventilated lung is effective in improving arterial oxygenation during one-lung ventilation (1-LV). The effectiveness of lower levels of CPAP on improving oxygenation, however, has not been reported, possibly because of limitations of previous methods of CPAP delivery. Recently, a disposable, self-assembled CPAP system capable of delivering CPAP over a wide range of pressures has been introduced (Mallinckrodt Medical, Inc., St. ⋯ Application of CPAP followed 20 min of stable 1-LV in the lateral decubitus position. Compared with two-lung ventilation, PaO2 (mean +/- SD) was significantly less with 1-LV (Group I, 126 +/- 75 mm Hg, and Group II, 173 +/- 79 mm Hg). Application of the assigned CPAP resulted in an increase in PaO2 compared to 1-LV (Group I, 270 +/- 112 mm Hg, and Group II, 386 +/- 66 mm Hg; P < or = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Aug 1994
Midazolam pharmacokinetics in patients undergoing abdominal aortic surgery.
Fentanyl and its analogs are eliminated slowly by patients having abdominal aortic surgery. This is principally due to larger volumes of distribution, compared to the pharmacokinetics determined in other surgical patients. Midazolam, like these opioids, is a lipophilic organic base, suggesting that it may also have a larger volume of distribution in patients undergoing abdominal aortic reconstruction. ⋯ The volume of the central compartment (Vc) and the volume of distribution at steady state (Vdss) were 5.8 +/- 5.3 L and 118.2 +/- 70.4 L, respectively. The elimination half-life was 6.3 +/- 3.6 h, 1.5- to 3-fold longer than has been previously reported in patients undergoing surgery. Compared to previously published studies of other groups of patients, metabolic clearance of midazolam was slower in patients undergoing abdominal aortic surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Aug 1994
Isoflurane modulates phorbol myristate acetate-, prostaglandin D2-, and prostaglandin E2-induced alterations in hepatic flow and metabolism in the perfused liver in fasted rats.
Protein kinase C (PKC) is thought to play an important role in the regulation of hepatic flow and metabolism in the liver. The activation of PKC has been implicated in pathologic responses of the organisms to immunologically active substances including endotoxin. The effects of volatile anesthetics on the hemodynamic and metabolic alterations associated with PKC activation were studied using isolated liver perfusion. ⋯ A similar inhibition of the PMA-induced alterations was observed in the liver treated with halothane at 2%. Isoflurane attenuated the flow reduction and stabilized the oxygen consumption after the administration of prostaglandin D2 (PGD2) and E2 (PGE2), possible mediators of PMA. Isoflurane, and presumably other volatile anesthetics, may elicit beneficial effects on the liver by attenuating the PKC-mediated alterations in hepatic hemodynamics and metabolism when PKC in the liver is activated through pathologic mechanisms.