[Noninvasive monitoring using echocardiography. II. Determination of cardiac output and comparison of volatile anesthetics].

In order to prove definitely that echocardiography is a noninvasive and safe method that can be used in the perioperative period to assess cardiac function and evaluate the effects of pharmacologic agents on the heart, we have carried out further sonographic studies concerning cardiac output and the effects of volatile anesthetics on left ventricular contractility. In series A (n = 12), we compared different sonographic techniques (uni-dimensional, two-dimensional, pulse Doppler echocardiography) with invasively measuring cardiac output by thermodilution in ICU patients and in the immediate preoperative phase before CABG with a Swan Ganz catheter that was already inserted. M-mode echocardiography proved to be best and correlated well with invasively gained values (y = 0.57 + 0.96x, r = 0.795, p less than 0.01). Use of the Teichholtz formula to estimate left ventricle volumes seems to be imperative. The two-dimensional technique yielded less favorable results, the pulse Doppler method being least informative. In series B (n1 = n2 = n3 = 6) the effects of halothane, enflurane and isoflurane MAC 1.0 and 1.5 on left ventricular performance were assessed in patients undergoing cholecystectomy or gastrectomy under standard anesthetic conditions. The results support the already well-known pharmacologic effects of these drugs, with minimal decrease in contraction with isoflurane. Critical interpretation of the different sonographic parameters, however, is just as important as considering various existing interdependances. Finally, when comparing our numerical values with other 1.0 MAC effects reported in the literature, there was also very good agreement.(ABSTRACT TRUNCATED AT 250 WORDS)