Anesthesia and analgesia
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Anesthesia and analgesia · May 1994
Mild intraoperative hypothermia does not change the pharmacodynamics (concentration-effect relationship) of vecuronium in humans.
To investigate the effect of mild hypothermia on the neuromuscular junction sensitivity to vecuronium, we determined the pharmacodynamics (concentration-effect relationship) of vecuronium in 10 patients (ASA physical class I or II; age range, 21-46 yr; weight range, 54-104 kg), during isoflurane-nitrous oxide-fentanyl anesthesia. Five were cooled to a mean temperature of 34.4 degrees C and five were maintained normothermic at a mean temperature of 36.8 degrees C. Neuromuscular function was monitored by measuring the evoked mechanical response of the adductor pollicis muscle after supramaximal train-of-four stimulation of the ulnar nerve at the wrist. ⋯ Results for the hypothermic and normothermic groups were compared by Mann-Whitney U-test. There were no differences in any pharmacodynamic variable between the hypothermic and normothermic patients. For the hypothermic and normothermic patients, respectively, steady-state plasma concentrations of vecuronium producing 50% neuromuscular block (Css50) were 73 +/- 13 ng/mL (mean +/- SD) and 79 +/- 31 ng/mL; the rate constants for equilibration of vecuronium between the plasma and the neuromuscular junction (Keo) were 0.27 +/- 0.14 per min-1 and 0.26 +/- 0.11 per min, and the power functions representing the slope of the concentration-effect relationship (gamma) were 5.7 +/- 1.9 and 4.4 +/- 1.8.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · May 1994
Randomized Controlled Trial Comparative Study Clinical TrialProphylactic antiemetic therapy with patient-controlled analgesia: a double-blind, placebo-controlled comparison of droperidol, metoclopramide, and tropisetron.
This placebo-controlled, randomized, double-blind trial was designed to evaluate the efficacy of three prophylactic antiemetic regimens on postoperative nausea and vomiting (PONV) during patient-controlled analgesia (PCA) with morphine. We studied 286 elective surgical patients for 36 h postoperatively. Group 1 was saline control. ⋯ Metoclopramide had a marginally significant effect under these conditions. Only droperidol decreased the need for rescue medication (P < 0.01), although rescue with tropisetron was highly effective. Side effects and patient satisfaction were comparable among the groups, but patients receiving droperidol were sleepier (P < 0.05) than control patients and recalled somewhat more anxiety (P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · May 1994
ReviewCardiovascular and coronary physiology of acute isovolemic hemodilution: a review of nonoxygen-carrying and oxygen-carrying solutions.
Acute isovolemic hemodilution is used increasingly to avoid the potentially serious side effects of homologous blood transfusions. Cardiovascular physiology during hemodilution is characterized by a marked increase in cardiac output and organ blood flow to compensate for the decrease in arterial oxygen-carrying capacity. During advanced hemodilution an increased oxygen extraction is also observed, such that oxygen consumption generally is maintained even during advanced hemodilution. ⋯ Cardiac output is generally constant and oxygen extraction is increased to maintain oxygen consumption during hemodilution with hemoglobin solutions. In most studies, some vasoconstriction was observed also, which might result from interaction of the hemoglobin molecule with the EDRF/NO system. However, with enhanced purification, chemical modification or microencapsulation of the hemoglobin molecule, vasoconstriction can be limited.
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Anesthesia and analgesia · May 1994
Comparative StudyThe premature infant: anesthesia for cesarean delivery.
The influence of anesthetic technique (general [GA] versus epidural [EPI]) on neonatal outcome was assessed for singleton infants of gestational age 32 wk or less, delivered by cesarean section. Neonates were identified from a prospectively collected perinatal database from 1986 to 1991. The independent effect of anesthetic technique on low 1-min Apgar scores after controlling for other risk factors was assessed by ordinal logistic regression. ⋯ GA as compared to EPI was associated with higher risk of low (0-3) 1-min score after controlling for confounding factors (relative odds = 2.92, [1.99, 4.27 95% confidence intervals]). Other factors significantly related to low 1-min Apgar scores included malpresentation, maternal diabetes, primiparity, low gestational age, and associated neonatal outcomes (presence of respiratory distress syndrome and intraventricular hemorrhage). When there is a choice to be made in cesarean delivery of the premature infant, EPI is associated with higher 1- and 5-min Apgar scores compared to GA.
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Anesthesia and analgesia · May 1994
Randomized Controlled Trial Clinical TrialRenal function and proteinuria after cardiopulmonary bypass: the effects of temperature and mannitol.
We studied three groups of patients without previous renal impairment, undergoing elective coronary artery bypass surgery. Group H (n = 7) underwent open heart surgery using moderate hypothermia (28 degrees C); Groups N and M (n = 8, each) were managed at normothermia. The extracorporeal circuit was primed with Hartmann's solution 2.5 L with the addition of mannitol 0.5 g/kg in Group M. ⋯ However, there were overall significant changes in measured variables over time compared to baseline. We conclude that CPB is associated with a significant alteration in renal function as shown by increased FENA, microalbuminuria, and urinary NAG. The use of hypothermic or normothermic CPB and the use of prophylactic mannitol did not produce any significant modification of these changes.