[Hemodynamic parameters in the evaluation of myocardial oxygen consumption during anesthesia]

Direct measurements of myocardial oxygen consumption (MVO2) and of a number of hemodynamic variables were performed in 60 patients with coronary heart disease undergoing three-vessel coronary artery bypass surgery. Anesthetic procedures included halothane, enflurane, isoflurane, propofol fentanyl, midazolam/fentanyl, and morphine anesthesia. The following hemodynamic variables were correlated with MVO2: systolic pressure (Psyst), mean arterial pressure (Part), heart rate (HR), cardiac index (CI), stroke volume index (SVI) and arithmetic combined variables: Psyst x square root (HR), Part x square root (HR), Psyst x HR, Part x HR, Psyst x HR x ta(ejection time), Part x HR x ta, Psyst x CI, Part x CI. The product of Psyst x square root (HR) is equivalent to the tension/time index as modified by Bretschneider and the product Psyst x HR x ta is equivalent to the tension/time index of Sarnoff as modified by Robinson. Production and uptake of lactate as metabolic equivalents of myocardial oxygenation were also correlated with myocardial oxygen consumption. Measurements were performed with the patients awake, after induction of anesthesia without surgical stimulation, during sternotomy and after the operation. We obtained 209 evaluable measurements (MVO2 vs hemodynamic variables). The single hemodynamic variables that correlated best with MVO2 was systolic pressure (r = 0.67). Stroke volume index (r = 0.1) and heart rate (r = 0.32) were poorly correlated. The combined hemodynamic variables that correlated most closely with MVO2 were the tension/time indices modified by Bretschneider (Psyst x square root (HR)) and Robinson (Psyst x HR x ta) (r = 0.72). Production and consumption of lactate were not correlated with myocardial oxygen consumption.(ABSTRACT TRUNCATED AT 250 WORDS)