Detection and removal of intracardiac residual air during open heart surgery with CPB under the guidance of echocardiography.

Abstract

Embolism from air retained within the open heart has been recognized as a potential hazard in direct vision intracardiac surgery. To assess whether Mmode echocardiography can accurately detect intracardiac air and serve as a means to remove it, we made experiments on 8 dogs and performed echocardiography on 12 patients undergoing open heart surgery. The standard M-mode echocardiogram was obtained from the experiment on an isolated dog’s heart. Intracardiac air could be recognized by the presence of linear echoes and loss of echo free area. In the experiment with the dogs’ hearts in situ, 392 random observations were made. When l.0 ml of air was injected intracardially, sensitivity and specificity were 93.2% and 95.0% respectively, and decreased to 85.7% and 80.6% when 0.25 ml was injected. The success rate of detecting and removing intracardiac air was 95.7% (110/115). During open heart surgery, the intracardiac air of the left ventricle was detected by echocardiography in all 12 patients before its removal. After evacuation, only 2 patients exhibited some residual intracardiac air which needed to be reevacuated. Clearly, M-mode echocardiography may serve as a sensitive and specific tool for the detection and removal of intracardiac air.