Anesthesia and analgesia
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The effect of mivacurium after atracurium was evaluated in 36 children anesthetized with halothane-nitrous oxide-oxygen by measuring the force of contraction of the adductor pollicis during train-of-four stimulation at 0.1 Hz. The children were evaluated in two main groups. In Group 1 the effect of bolus doses of mivacurium after equipotent repeat doses of atracurium were evaluated. ⋯ The infusion requirement increased gradually (P < 0.0001) until, at 90 min of infusion, it was 7.4 +/- 0.8 micrograms.kg-1.min-1. In Group 2 the recovery indices were similar to those seen when mivacurium is the sole relaxant given. When mivacurium is given after atracurium, evidence of the residual neuromuscular effects of the atracurium are detected beyond the usual recovery range.
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Anesthesia and analgesia · Aug 1994
Previous wet tap does not reduce success rate of labor epidural analgesia.
Whether unintentional dural puncture (wet tap) during a previous labor epidural increases the failure rate of epidural analgesia for later deliveries is controversial. In this study, charts of 47 women with a previous wet tap who received epidural analgesia for labor were compared to those of 500 consecutive women receiving epidural analgesia in 1991 and, separately, to 44 women matched for month of delivery, previous epidural without a wet tap, and the same anesthesiologist. In comparison to the 500 consecutive control patients, women with a previous wet tap had a lower incidence of epidural catheter manipulation for inadequate block (9% vs 20%), but a similar incidence of catheter removal for failed block (4% vs 6.7%). ⋯ Epidural analgesia was considered successful in 93% of cases and 89% of matched control subjects by chart review. Two women (4%) with previous wet tap experienced a second wet tap during attempted epidural catheterization, compared to 0% in 500 consecutive patients (P < 0.001). These data suggest that there is no decrease in the success rate of epidural analgesia in women with a previous wet tap, although the chance for a repeated wet tap may be increased.
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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
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.