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Brody School of Medicine at East Carolina University, Greenville, North Carolina
Address correspondence to L. Wiley Nifong, MD, Division of Cardiothoracic Surgery, Brody School of Medicine, East Carolina University, East Fifth St., Greenville, NC 27858-4353. Address e-mail to nifongl{at}mail.ecu.edu
Around 1995, surgeons began investigating the advantages of minimizing both cardiopulmonary perfusion times and incision size during cardiac surgery. Modifications of the conventional sternotomy were shown independently by Cosgrove, Cohn, and colleagues (1–3) to be safe and effective for mitral and aortic operations. Further advancements in instruments, alternative perfusion techniques, video-assist devices, and robotics have enabled progressively less invasive cardiac procedures. However, minimally invasive valve operations have evolved along a slow pathway because of excellent long-term results after sternotomy. Limitations of minimal-access cardiac surgery include a smaller incision, providing less dexterity, and a frequent need for assisted-vision modalities. These limitations are being overcome by more advanced computer-assisted "robotic" devices, such as the da VinciTM Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA). The article by Mehta et al. (4) from in this issue of Anesthesia & Analgesia clearly describes the current mitral valve repair procedure originated by surgeons at our institution (5).
Successful completion of this procedure requires the involvement of nurses, perfusionists, anesthesiologists, and surgeons. Even the simplest problems encountered may prove detrimental to completion of the robotic procedure; therefore, attention to detail by all involved persons is critical, and active involvement of the anesthesiologist is crucial. Confirmed placement of a left-sided double-lumen endotracheal tube (DLT) is necessary to allow for the single left-sided ventilation required for cardiac exposure both during and after cardiopulmonary bypass (CPB). We prefer a DLT to a bronchial blocker, even though the DLT is usually changed to a single-lumen tube before the patient is transferred to the intensive care unit. Occasionally, intermittent right lung inflation is necessary for adequate oxygenation, especially during weaning from CPB. This is easier with the DLT, because the surgeon requires cardiac visualization during this time, and the pericardial retraction sutures are still in place, displacing the lung. After weaning from CPB, isolation of the right lung may again be necessary to check for bleeding. For these reasons, the DLT is the preferred means for single-lung isolation.
A transthoracic aortic cross-clamp (Chitwood Clamp; Scanlan International, Minneapolis, MN) is used routinely for aortic occlusion, obviating the need for endoaortic balloon occlusion. For those desiring to use aortic balloon occlusion, care must be taken to avoid innominate occlusion, ventricular prolapse of the balloon, or incomplete aortic occlusion. We routinely used the transthoracic clamp in >150 videoscopic mitral valve procedures before working with da Vinci. The clamp is placed through the chest wall in either the second or third intercostal space along the right anterior axillary line. With the da Vinci cases, we have moved the transthoracic clamp even more posterior, toward the posterior axillary line, to avoid potential conflicts with robotic instrument arms. The posterior tine of the clamp must be passed through the transverse sinus (under videoscopic vision). Care in clamp placement is essential. Potential problems include injury to the right pulmonary artery, left atrial appendage, or aortic base near the left main coronary artery. We have had only 1 clamp injury in nearly 300 cases. Early in our robotic experience, poor venous drainage occurred because of cross-clamp impingement of the superior vena cava (SVC) with ventral distraction during valve exposure. Since then, we have moved the clamp to a more posterior position. In addition, we drain the SVC with a 17F cannula placed percutaneously, in the right internal jugular vein, by using the Seldinger technique. As in the accompanying article (4), experienced anesthesiologists place this cannula, and the position is confirmed by transesophageal echocardiography (TEE). The superior venous drainage line is "Y-ed" into the femoral vein line for bicaval drainage. We have encountered no difficulties with increased central venous pressures or head edema with this technique.
The most revolutionary improvement for anesthesiologists and surgeons during valvular surgery is routine use of TEE. TEE deployment is becoming the standard of care in cardiac operating rooms around the world. The TEE probe is placed soon after intubation, and valvular function and anatomy are examined. The team can accurately determine valvular dysfunction, as well as overall baseline cardiac function. TEE is further used to confirm guidewire movement before the placement of caval drainage cannulas. Moreover, cannula position can be confirmed throughout the operation. For institutions using coronary sinus cardioplegia cannulas, TEE is essential to confirm final placement. When retrograde cardioplegia is required, either steerable cannulas can be inserted by the anesthesiologist via the jugular system or the surgeon can place a standard cannula through the atrial wall and position it through the sinus orifice. Both techniques require echocardiographic guidance. After valve repair and closure of the atriotomy, TEE is used to evaluate the completeness of air removal and, ultimately, the adequacy of the valve repair. Overall cardiac function is assessed at the completion of the procedure by using TEE. We use a constant insufflation of carbon dioxide (3–5 L/min) to continuously displace cardiac air.
We have completed 48 mitral valve repairs by using the da Vinci Surgical System at our institution (6). We routinely use the described technique, except that we use only antegrade cardioplegia and have had no complications related to the use of the robotic system. Close teamwork and collaboration with anesthesiologists has made our efforts successful. The involvement of our anesthesia colleagues is crucial as we progress along the path toward a totally endoscopic mitral valve procedure.
References
This article has been cited by other articles:
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  M. Rundgren and M. Engstrom A Thromboelastometric Evaluation of the Effects of Hypothermia on the Coagulation System Anesth. Analg., November 1, 2008; 107(5): 1465 - 1468. [Abstract] [Full Text] [PDF]
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S. A. Chung, H. Yuan, and F. Chung A Systemic Review of Obstructive Sleep Apnea and Its Implications for Anesthesiologists Anesth. Analg., November 1, 2008; 107(5): 1543 - 1563. [Abstract] [Full Text] [PDF]
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