Anesthesiology
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Maitre et al. recently evaluated the accuracy of a set of previously determined population pharmacokinetic parameters for the opioid alfentanil using data from an earlier study in which the drug had been administered using a computer-controlled infusion pump (CCIP). The present study evaluated the accuracy of these same parameters in a CCIP prospectively in two groups of clinically dissimilar patients: 29 healthy female day surgery patients and 11 relatively older and less healthy male inpatients. In addition, another set of pharmacokinetic parameters, previously determined by Scott et al. in the CCIP in 11 male inpatients was also evaluated. ⋯ In the 11 patients studied using the Scott et al. pharmacokinetic parameters, the MDPE was +1% and the MDAPE was 17%. The parameters of Scott et al. were further tested by simulating the serum concentrations that would have been achieved had they been used in the CCIP in the first 40 patients; results indicated MDPE of +2% and an MDAPE of 18%. Therefore, reasonably reliable and accurate target serum concentrations of alfentanil can be achieved using the pharmacokinetic parameters of Scott et al. in a CCIP.(ABSTRACT TRUNCATED AT 250 WORDS)
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The effects of 0.5-2.0 MAC (3.6-15%) desflurane on cerebral function, metabolism, and hemodynamics and on systemic metabolism and hemodynamics were examined in dogs. Desflurane produced a significant dose-related decrease in cerebral vascular resistance from 1.53 +/- 0.21 mmHg.ml-1.min.100 g at 0.5 MAC to 0.50 +/- 0.03 mmHg.ml-1.min.100 g at 2.0 MAC desflurane. This was accompanied by an increase in cerebral blood flow (CBF) from 61 +/- 7 ml.min-1.100 g-1 at 0.5 MAC to 78 +/- 3 ml.min-1.100 g-1 at 1.5 MAC desflurane. ⋯ At 0.5 MAC desflurane, intracranial pressure (ICP) was 15 +/- 5 mmHg, higher than normal, but did not change significantly with increasing concentrations of desflurane. Increasing concentrations of desflurane initially produced on the EEG the common pattern sequence of increasing depth of anesthesia with decreasing frequency and increasing amplitude progressing to burst suppression and then at 2.0 MAC desflurane to regular attenuation with interruption by periodic polyspiking, a pattern similar to that seen with isoflurane. At both 1.5 and 2.0 MAC the EEG pattern initially observed at that concentration changed to one with faster background activity with time.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Effects of ketamine, halothane, enflurane, and isoflurane on systemic and splanchnic hemodynamics in normovolemic and hypovolemic cirrhotic rats.
The effects of ketamine, halothane, enflurane, and isoflurane on systemic and splanchnic hemodynamics in cirrhotic rats that were either normovolemic or hypovolemic following hemorrhage were characterized. Rats received at random either ketamine (30 mg/kg iv, 1.5 mg.kg-1.min-1 iv), halothane, enflurane, or isoflurane (1 MAC). Conscious rats were considered the control group. ⋯ After hemorrhage portal venous tributary blood flow decreased significantly in all groups except in enflurane group. During halothane and enflurane anesthesia hepatic arterial blood flow and hepatic arterial fraction of cardiac output decreased (P less than 0.01) and they were maintained in the other groups. After hemorrhage hepatic arterial fraction of cardiac output in conscious rats was higher than in those receiving ketamine, halothane, or enflurane (P less than 0.05) and was similar to those receiving isoflurane.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
A randomized double-blind comparison of epidural versus intravenous fentanyl infusion for analgesia after cesarean section.
The authors conducted a randomized double-blind controlled study comparing groups of patients receiving iv or epidural fentanyl infusions to determine whether, at comparable levels of analgesia, 1) the severity of side effects was different; and 2) plasma fentanyl concentrations differed between the two groups. Twenty-eight ASA physical status 2 women scheduled to undergo elective cesarean section were randomized into two groups to either receive fentanyl intravenously and saline epidurally or fentanyl epidurally and saline intravenously. After delivery of the infants under epidural anesthesia, each patient received a bolus of fentanyl 1.5 microgram/kg either intravenously or epidurally, and a fentanyl infusion was begun via the same route. ⋯ For the remaining 25 patients, similar infusion rates of fentanyl were required to produce similar levels of analgesia at 12 and 24 h. The severity of nausea, pruritus and sedation, and end-tidal PCO2 were similar for both groups. The plasma concentrations of fentanyl were significantly greater in those who received iv fentanyl at 12 h but not at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Transdermal scopolamine reduces nausea and vomiting after outpatient laparoscopy.
The authors evaluated the effect of transdermal scopolamine on the incidence of postoperative nausea, retching, and vomiting after outpatient laparoscopy in a double-blind, placebo-controlled study. A Band-Aid-like patch containing either scopolamine or placebo was placed behind the ear the night before surgery. Anesthesia was induced with fentanyl (0.5-2 micrograms/kg iv), thiopental (3-5 mg/kg iv), and succinylcholine (1-1.5 mg/kg iv) and maintained with isoflurane (0.2-2%) and nitrous oxide (60%) in oxygen. ⋯ Patients in the scopolamine group were also discharged from the hospital sooner (4 +/- 1.3 vs. 4.5 +/- 1.5 h; P = 0.0487). Side effects were more frequent among those patients treated with the scopolamine patch (91% vs. 45%; P less than 0.05) but were not troublesome. The authors conclude that transdermal scopolamine is a safe and effective antiemetic for outpatients undergoing laparoscopy.