Analysis of hemodynamic changes during beating heart surgical procedures.

BACKGROUND: Coronary artery bypass grafting on the beating heart causes significant hemodynamic compromise during displacement of the heart. The precise mechanisms causing altered hemodynamics have not been clearly understood. The purpose of this study was to define the hemodynamic changes caused by displacing the heart in patients undergoing beating heart surgical procedures. METHODS: Forty-four patients (35 men, 9 women; mean age, 64.5 +/- 9.6 years) underwent off-pump coronary artery bypass grafting. The hemodynamic variables were collected before and after positioning the heart for anastomosis of the left anterior descending, circumflex, and posterior descending coronary arteries. RESULTS: There was a significant increase in right ventricular end-diastolic pressure during positioning for all vessels, and in left ventricular end-diastolic pressure during positioning for the left anterior descending and circumflex coronary arteries. Positioning for the circumflex artery showed the largest increase of left and right ventricular end-diastolic pressure, resulting in the greatest hemodynamic compromise. CONCLUSIONS: In the clinical setting of diseased human hearts, there is a biventricular contribution to altered hemodynamics. The increase of right ventricular end-diastolic pressure in all positions suggests that the major cause of hemodynamic changes is disturbed diastolic filling of the right ventricle, especially by direct ventricular compression.

Anesthetic techniques for thoracoscopy.

With the advent of laparoscopic techniques for application in the chest, as well as the development of new video equipment and instrumentation technology, the cardiothoracic surgeon can now perform procedures that, until very recently, were performed only by thoracotomy. Modern thoracoscopy has not reached its final resolution, but a growing number of procedures have been performed that permit some initial recommendations to be made and that define areas of research for the anesthesiologist. A review of the physiology of the lateral decubitus position will act as a basis for developing rational decisions concerning the conduction of anesthesia for thoracoscopy. Future research and experience in thoracoscopy will help to further define appropriate anesthetic techniques.