title: The effects of nitrous oxide on myocardial metabolism and hemodynamics during fentanyl or enflurane anesthesia in patients with coronary disease.
abstract: Twenty patients about to have coronary artery bypass grafts were studied before and after 15 min of 50% nitrous oxide added to either fentanyl (75 micrograms/kg) or enflurane (0.5%) anesthesia. Arterial and central pressures and cardiac output were measured, plus coronary sinus blood flow and arterio-coronary sinus differences in oxygen, hemoglobin, and lactate contents. Fentanyl-N2O and enflurane-N2O both decreased systemic resistance, heart rate, cardiac output, and hence arterial pressure. Stroke work decreased significantly with little or no change in wedge pressure: ventricular function was impaired. Coronary flow and myocardial O2 consumption decreased with fentanyl-N2O. Oxygen extraction increased with enflurane-N2O, as did lactate contents of coronary sinus blood. Hemodynamic depression occurred from the combined effects of nitrous oxide and fentanyl or enflurane. The beta-blocked myocardia of nonstimulated coronary patients were becoming ischemic globally on 50% oxygen, after significant hypotension. From this and other evidence, we conclude that nitrous oxide may not be benign in patients with coronary arterial disease.
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D001026:Coronary Artery Bypass; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D004737:Enflurane; D005260:Female; D005283:Fentanyl; D006321:Heart / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects
chemical_list: D007773:Lactates; D019344:Lactic Acid; D004737:Enflurane; D009609:Nitrous Oxide; D005283:Fentanyl