Initial clinical trial of substernal epicardial echocardiography: SEEing a new window to the postoperative heart

Background. Postoperative echocardiography windows are often of poor quality because of intervening air spaces around the heart and great vessels. We assessed the utility of a new commercially available adult chest drainage tube that has been modified with the addition of a sterile sleeve to accommodate the introduction of a nonsterile pediatric transesophageal echocardiography (TEE) probe. The TEE probe lies in a substernal epicardial position on the postoperative heart allowing one to perform substernal epicardial echocardiography (SEE). Methods. Informed consent was obtained from 21 consecutive adult cardiac operation patients. At the completion of the operation the SEE drainage tube was inserted through the rectus muscle and into the pericardium. After chest closure, all patients underwent a full echo examination using an Acuson pediatric biplane probe in the SEE position. Views obtained and ease of insertion were judged on a 1 to 10 (worst to best) scale. Results. Full SEE examinations were completed in an average of 12 minutes. Ease of probe entry and manipulation was excellent (ratings of 9.3 and 9.6, respectively). The quality of the anatomic images was also excellent. Substernal epicardial echocardiography tube positioning was integral to the orientation of the images obtained. There were no complications related to the placement of the SEE tubes or TEE probes. In 4 of 21 patients (19%) the SEE methodology was used serially in the intensive care unit to accurately assess ventricular function and filling during weaning of an intraaortic balloon and inotropic agents. Conclusions. Substernal epicardial echocardiography is a safe and highly effective methodology for the serial echocardiographic assessment of the postoperative heart.