| |
Editors' Note |
 |
|
|
|
| |
by Alan P. Kypson, M.D.
East Carolina University, Greenville, North Carolina, USA |
| |
|
|
Minimally Invasive Cardiopulmonary Bypass - Oxymoron or Not?
The development of the cardiopulmonary bypass (CPB) machine by John Gibbon just over 50 years ago hails as one of the greatest contributions in medicine during the 20th century. Furthermore, it allowed the field of cardiac surgery to develop into what we know it as today. By definition, CPB is invasive - cannulae are placed into the heart and surrounding great vessels and a machine temporarily replaces the heart and lungs. Few things occur in medicine that are this invasive. How then can we entertain the thought of "minimally invasive" CPB?
Over the past decade, there has been a shift in the way cardiac surgery is performed. Incisions have been altered in size and location, yet we continue to rely on CPB and cardioplegic arrest, especially for intra-cardiac procedures. To utilize CPB in minimal access surgery, where traditional cannulation methods are not feasible, a new platform for CPB had to be established. Specialized endovascular cannulae were developed that allow the surgeon to remotely cannulate the arterial and venous system (through the femoral vessels, for example). Specifically, one of the initial systems was HeartPort (currently Cardiovations, Inc.). This system contains specialized venous and arterial cannulae, as well as an aortic endovascular balloon clamp that allows the surgeon to arrest the heart using antegrade cardioplegia. Thereafter, companies developed cannulae for minimal access surgery as well. Linda B. Mongero, CCP and James R. Beck, CCP, from Columbia Presbyterian Hospital in New York City, provide an excellent account of a perfusionist's perspective on cannulation and perfusion techniques for robotic and minimally invasive surgery, respectively. Ultimately, teamwork between the surgeon, anesthesiologist, and perfusionist is paramount when utilizing minimally invasive CPB.
Although tremendous advances have been achieved, some of these novel cannulation and perfusion techniques have unfortunately resulted in complications. As a result, our team at East Carolina University has made certain modifications. For example, a major concern of the endovascular balloon clamp is its potential to migrate and cause a dissection. Therefore, we devised an external cross-clamp (Chitwood clamp) that is placed through the chest wall and across the aorta much like a traditional cross-clamp.
Besides alterations in cannulation and perfusion methods in minimally invasive cardiac surgery, another interest exists in reducing the negative systemic effects of CPB through the use of miniaturized CPB machines. Major hemodilution is a problem not only for red blood cell gas transport, and platelet and humeral factor-dependent coagulation, but also for protein-dependent intravascular oncotic pressure as well. Reduction of priming volume through the use of mini CPB is one potential solution. Major companies such as Jostra and Medos have already developed mini CPB systems that have been used clinically. These systems reduce perfusion circuits to the most fundamental components and can be primed with as little as 600ml. They allow the benefits of traditional CPB with less impairment of all organ systems. Dr. Andreas Liebold from Germany provides an excellent overview of this emerging technology.
In summary, as surgical technology advances and allows cardiac surgeons to perform surgery in a less invasive (minimal access) manner, supporting technology must also continue to evolve to meet current and future demands. Despite the inherent invasiveness of CPB, significant research has resulted in alternate cannulation methods as well as mini CPB circuits. Ultimately, these changes will continue to ensure the best outcomes for our patients.
« Perfusion in Robotic Surgery
« Perfusion in Minimally Invasive Surgery
« Mini-CPG Systems Around the Corner?
« What is your team's experience with new perfusion techniques? Join the discussion... |
|
|
|