Journal of cardiothoracic anesthesia
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J Cardiothorac Anesth · Oct 1987
Randomized Controlled Trial Comparative Study Clinical TrialMyocardial metabolism, catecholamine balance, and left ventricular function during coronary artery surgery: effects of nitroprusside and nifedipine.
The effects of nitroprusside and nifedipine on myocardial oxygen consumption (MVO2), catecholamine release, and left ventricular (LV) function (using 2D transesophageal echocardiography) were compared. Thirty-seven patients undergoing coronary artery surgery, anesthetized with fentanyl, 100 micrograms/kg, were studied. All had good LV function and had been receiving long-term oral beta-blocking therapy. ⋯ This was not associated with ECG changes, but in one patient regional wall motion abnormalities developed. No evidence of myocardial ischemia was observed in groups S and N. However, in contrast to nitroprusside, the use of nifedipine was associated with increases in MVO2, myocardial norepinephrine release, and inotropy.
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J Cardiothorac Anesth · Apr 1987
The influence of positive end-expiratory pressure on intrapericardial pressure and cardiac function after coronary artery bypass surgery.
The hemodynamic effects of positive end-expiratory pressure (PEEP) were studied in coronary artery bypass patients by recording intrapericardial and intracardiac pressures, measuring cardiac output by thermodilution, and determining left ventricular volumes by nuclear radiography. An elevation of PEEP to 5, 10, and 15 cm H2O led to a decrease in cardiac output (15% decrease at PEEP 15) as intrapericardial pressure increased and transmural left atrial pressure decreased. Modest volume loading (an increase in left atrial pressure of 3 mm Hg) greatly attenuated the deleterious effects of 15 cm H2O PEEP. ⋯ A predictable increase in intrapericardial pressure was observed as PEEP was applied in these patients. The magnitude of this increase can be estimated by multiplying the change in PEEP (in cm H2O) by 0.4 to estimate the change in intrapericardial pressure (in mm Hg). Using this estimation as a guide, modest volume loading can be used to maintain transmural filling pressures (and cardiac output) when PEEP is used after coronary artery bypass surgery.