Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Jun 1992
Pharmacokinetics of alfentanil before and after cardiopulmonary bypass in pediatric patients undergoing cardiac surgery: Part I.
Changes induced by cardiopulmonary bypass (CPB) may markedly affect the pharmacokinetics of drugs. Therefore, the pharmacokinetics of alfentanil before and after CPB were compared in infants and children undergoing cardiac surgery, who had been anesthetized with nitrous oxide in oxygen and low inspiratory concentrations of halothane. Six infants and six children were investigated. ⋯ The initial volume of distribution before CPB was smaller (68 +/- 37 mL/kg in infants and 80 +/- 32 mL/kg in children) than after CPB (235 +/- 58 mL/kg in infants and 179 +/- 99 mL/kg in children; P less than 0.001). The normalized area under the plasma concentration-time curve from 0 to 45 minutes was larger before CPB (17.9 +/- 2.9 mg.min/L in infants and 18.3 +/- 5.4 mg.min/L in children) than after CPB (11.1 +/- 2.9 mg.min/L in infants and 12.9 +/- 3.4 mg.min/L in children; P less than 0.001). Despite intravenous administration of atropine, arterial blood pressure and heart rate decreased significantly after alfentanil was given.
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J. Cardiothorac. Vasc. Anesth. · Jun 1992
ReviewAlpha 2-adrenergic agonists in cardiovascular anesthesia.
At this time, the unique attributes of alpha 2-agonists in anesthesia lie in their ability to blunt the adrenergic response to the stresses of major surgery, in patients in whom this response is especially undesirable, without incurring the penalty of respiratory depression that attends the use of opioids. It has become more and more apparent that sympathetic/adrenergic activation often has adverse consequences for patient morbidity and mortality, and modification of such activation by drugs may be a valuable option for the anesthesiologist. However, at present, the evidence supporting this statement is "soft," such as improved hemodynamic and metabolic stability. ⋯ In these cases, it is not the choice of a specific anesthetic agent or technique, but rather the competence and diligence of the anesthesiologist that is most important for outcome. In contrast, in major cardiovascular surgery in high-risk patients, the optimal anesthetic approach attains more importance, and is still undecided. The final consensus as to whether or not this optimal approach will include the use of alpha 2-adrenergic agonists will depend on the results of more extensive clinical investigations.
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J. Cardiothorac. Vasc. Anesth. · Jun 1992
Perioperative evaluation of a new mixed venous oxygen saturation catheter in cardiac surgical patients.
Fiberoptic pulmonary artery flotation catheters have gained clinical acceptance for continuous monitoring of mixed venous oxygen saturation (SvO2), especially in the management of hemodynamically unstable patients. Therefore, the performance of the oximetry system used is extremely important. The accuracy and stability of a new two-wavelength oximetry pulmonary artery catheter and SAT-2 oximeter were assessed in adult patients during and following cardiac surgery. ⋯ A total of 604 paired data points from 52 patients were analyzed, 572 (94.7%) of which were within the 95% confidence interval. Overall bias was -1.7% +/- 3.5% (SD). The results suggest that over the time course of the study, in vivo SvO2 values obtained with the two-wavelength catheter and the SAT-2 oximeter closely approximated SvO2 measured with a reference oximeter from mixed venous blood samples (r = 0.917; SEE 3.5%) in cardiac surgical patients in whom marked physiological changes occur.
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J. Cardiothorac. Vasc. Anesth. · Jun 1992
Continuous thermodilution cardiac output measurement in intensive care unit patients.
A new continuous thermodilution cardiac output measurement technique and companion flow-directed pulmonary artery catheter were evaluated in intensive care unit (ICU) patients. Continuous cardiac output was monitored for 6 hours in each patient, and, at selected intervals, a series of bolus thermodilution cardiac output determinations was made and averaged for comparison. A total of 222 data pairs was obtained in 54 patients. ⋯ The mean relative error was 0.3%, and the standard deviation of the relative error was 11.5%. The absolute measurement bias was 0.02 L, and the 95% confidence limits were 1.07 and -1.03 L. The results demonstrated that the new continuous thermodilution cardiac output measurement technique provided acceptable accuracy and was considerably easier to use in the clinical situations studied in the ICU.