Oka Y, Inoue T, Hong Y, Sisto D A, Strom J A, Frater R W
J Thorac Cardiovasc Surg. 1986 Mar;91(3):329-38.
Retained intracardiac air is a continuing hazard for cardiopulmonary bypass. M-mode transesophageal echocardiography of the left atrium, left ventricle, and aorta is a highly sensitive method for detecting retained intracardiac air bubbles. In 15 patients having valve operations and 18 having coronary bypass, M-mode transesophageal echocardiography was used to record air bubbles during and for 15 minutes after bypass. Routine air clearing methods were used: needle aspiration of the ascending aorta (combined coronary and valve operations) and left atrial, left ventricular, and aortic aspiration after careful passive chamber filling (valve operations). Air was detected in 12 of 15 (79%) patients having valve operations and two of 18 (11%) patients having coronary bypass. One with air in the aorta had visible right coronary air embolism. Three patients with positive echograms had transient central nervous system disturbances. In a further 11 patients having valve operations, an ascending aorta-venous shunt was created before bypass was discontinued, but air continued to be present in the left atrium. Finally, in seven patients, we added the following maneuvers to our routine: positive chamber filling with echocardiographic demonstration of left atrial stretching, vigorous chamber ballottement, specific echo-directed chamber aspiration, and maintenance of cardiopulmonary bypass until transesophageal echocardiography showed no retained air. Although small amounts of atrial air could still be detected for a minute or two in some patients, this technique appears finally to have eliminated significant retained air and its consequences. A sensitive technique for intracardiac air detection reveals retained air surprisingly often after cardiopulmonary bypass. There are both possible and probable adverse consequences of this air. After valve operations, it is most difficult to eliminate air from the left atrium. There are three essential elements of air removal: First is mobilization of the air; positive chamber filling, stretching of the atrial wall, and ballottement are critical. Second is removal of mobilized air; continuous ascending aorta-venous shunting and nonsuction venting of the left atrium are very important. Third is proof of elimination of air before cardiopulmonary bypass is terminated; transesophageal echocardiography is vital for this.
心腔内残留空气对体外循环来说始终是一种危险。对左心房、左心室和主动脉进行M型经食管超声心动图检查是检测心腔内残留气泡的一种高度敏感的方法。在15例行瓣膜手术的患者和18例行冠状动脉搭桥手术的患者中，在体外循环期间及体外循环后15分钟，使用M型经食管超声心动图记录气泡情况。采用常规的排气方法：对升主动脉进行针吸（冠状动脉和瓣膜联合手术），以及在小心被动充盈腔室后对左心房、左心室和主动脉进行针吸（瓣膜手术）。在15例行瓣膜手术的患者中有12例（79%）检测到空气，在18例行冠状动脉搭桥手术的患者中有2例（11%）检测到空气。其中1例主动脉内有空气的患者出现了可见的右冠状动脉空气栓塞。3例超声心动图阳性的患者出现了短暂的中枢神经系统紊乱。在另外11例行瓣膜手术的患者中，在停止体外循环前建立了升主动脉 - 静脉分流，但左心房中仍有空气存在。最后，在7例患者中，我们在常规操作基础上增加了以下措施：积极充盈腔室并通过超声心动图显示左心房扩张、有力地摆动腔室、特定的超声引导下腔室抽吸，以及维持体外循环直至经食管超声心动图显示无残留空气。尽管在一些患者中仍能在一两分钟内检测到少量心房空气，但这项技术似乎最终消除了大量残留空气及其后果。一种用于检测心腔内空气的敏感技术显示，体外循环后残留空气的情况出人意料地常见。这种空气存在可能的和很可能的不良后果。在瓣膜手术后，最难从左心房排出空气。排气有三个关键要素：首先是使空气移动；积极充盈腔室、拉伸心房壁和摆动腔室至关重要。其次是排出移动的空气；持续的升主动脉 - 静脉分流和左心房的非吸引排气非常重要。第三是在停止体外循环前证明空气已排出；经食管超声心动图对此至关重要。
