Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1994
Randomized Controlled Trial Clinical TrialInterpleural infusion of 2% lidocaine with 1:200,000 epinephrine for postthoracotomy analgesia.
The value of intrapleural analgesia after thoracotomy is still controversial. We investigated the pharmacokinetics of interpleural analgesia in 14 patients with and without thoracic drainage (Groups TD+ and TD-, respectively) to determine the safety of the technique. The infusion led to a high steady-state concentration (Css) of 5.91 +/- 2.46 mg/mL in Group TD-. ⋯ The VAS score was slightly reduced after the bolus (6.6 +/- 1.0 vs 8.7 +/- 0.3; P < 0.05 vs the placebo group) but the cumulative doses of morphine were similar in both groups. There was a slight, but not sustained, improvement in pulmonary function test. In conclusion, interpleural analgesia by continuous infusion of lidocaine is poor after thoracotomy and may lead to blood levels in the toxic range.
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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
Determination of end-tidal sevoflurane concentration for tracheal intubation and minimum alveolar anesthetic concentration in adults.
The purpose of this study was to determine both the concentration of sevoflurane required for tracheal intubation (MACEI) and its minimum alveolar anesthetic concentration (MAC) in adults. The study group consisted of 86 elective surgical patients, ASA physical status I or II, aged 16-59 yr. There was no premedication administered. ⋯ The MAC of sevoflurane was 1.58% (95% confidence limits, 1.14%-1.98%), and the AD95 (anesthetic ED95) was 2.96%. The MACEI/MAC ratio was 2.86 (95% confidence limits, 2.63-3.43). Anesthesia induction followed by tracheal intubation can be accomplished in adults when sevoflurane is administered as a sole anesthetic, but in excess of 8% end-tidal concentration.
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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.