Journal of cardiothoracic and vascular anesthesia
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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.