Journal of cardiothoracic and vascular anesthesia
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Postoperative changes in coagulant and anticoagulant factors following abdominal aortic surgery.
The extent and time course of changes in selected procoagulant and anticoagulant factors were investigated in 19 patients undergoing elective abdominal aortic surgery. The coagulation factors were measured preoperatively, and on days two, four, and six postoperatively. It was found that there were no significant changes outside the normal range in prothrombin time, partial thromboplastin time, or thrombin clotting time. ⋯ There were no significant changes in factor V, factor X, alpha 2-antiplasmin, or platelet aggregability. The timing of the changes coincided with a period of high risk of perioperative myocardial infarction in this group of patients. Thus, it is possible that postoperative hypercoagulability contributes to the development of coronary artery thrombosis and myocardial infarction following abdominal aortic surgery.
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Continuous intra-arterial oximetry, pulse oximetry, and co-oximetry during cardiac surgery.
This study evaluated arterial catheter oximetry versus pulse oximetry in eight patients (ASA III-IV) who underwent cardiac surgery. Co-oximeter saturation values served as the standard. Arterial oxygen saturation was determined simultaneously with these three methods at 162 prospectively defined points of measurement before, during, and after cardiopulmonary bypass (CPB). ⋯ The standard deviations of the individual differences between readings of catheter or pulse oximetry and readings of co-oximetry (= precision) were +/- 0.5% to +/- 1.0% for catheter oximetry and +/- 1.0% to +/- 1.2% for pulse oximetry. In summary, catheter oximetry was superior to pulse oximetry with regard to obtaining readings and to reliability of the obtained readings. Invasiveness and high costs influence the decision as to whether to use catheter oximetry, but if reliable and precise measurements of saturation are important at any time during surgery, pulse oximetry is an insufficient method and co-oximetry is a time-consuming method of analysis, whereas catheter oximetry is quick, reliable, and precise.
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Clinical TrialModest doses of nitroglycerin do not interfere with beef lung heparin anticoagulation in patients taking nitrates.
The results of a prior clinical report suggested that nitroglycerin may interfere with the anticoagulant effect of heparin. Therefore, 30 adult patients undergoing cardiac surgery were studied in a controlled, prospective fashion. Thirteen patients on chronic nitrate therapy received an intraoperative nitroglycerin infusion at 1 micrograms/kg/min intravenously. ⋯ There were no differences in automated activated coagulation times or in activated partial thromboplastin times between the groups at any measurement period. The study is limited in that only patients on chronic nitrates were included in the treatment group and that only a modest dose of nitroglycerin was used. However, it is concluded that a modest dose of intravenous nitroglycerin does not interfere with the anticoagulant effect of boluses of beef lung heparin in patients undergoing cardiac surgery.
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J. Cardiothorac. Vasc. Anesth. · Dec 1992
Isoflurane and hypothermic cardiopulmonary bypass: vasodilation without metabolic effects.
During cardiopulmonary bypass, isoflurane may have beneficial effects on systemic oxygen uptake and vascular resistance. For this reason, the effects of isoflurane during low-flow (1.6 L/min/m2), hypothermic (27 degrees to 29 degrees C) cardiopulmonary bypass on systemic hemodynamics and oxygen uptake were studied in 20 patients in a cross-over experiment. Mean arterial and central venous pressures were measured during two consecutive periods of 10 minutes' duration. ⋯ Isoflurane had no significant effect on systemic oxygen uptake. Significant inverse relationships between blood isoflurane concentration and both mean arterial pressure and systemic vascular resistance were found. It is concluded that isoflurane is a vasodilator under the abnormal conditions of hypothermic cardiopulmonary bypass, but has no effect on systemic oxygen uptake.