Ann Thorac Surg 2007;83:1556-1557
© 2007 The Society of Thoracic Surgeons
How To Do It
Bedside Right Ventricular Assist Device Removal in the Conscious Patient
William E. Cohn, MD*,
Igor D. Gregoric, MD,
Saverio La Francesca, MD,
O.H. Frazier, MD
Department of Cardiopulmonary Transplantation, Texas Heart Institute at St. Luke’s Episcopal Hospital, Houston, Texas
Accepted for publication June 14, 2005.
* Address correspondence to Dr Cohn, Texas Heart Institute at St. Luke’s Episcopal Hospital, PO Box 20345, MC 3-114A, Houston, TX 77225-0345 (Email: wcohn{at}heart.thi.tmc.edu).
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Abstract
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A technique is described for simple bedside removal of a right ventricular assist device system from a conscious patient. This technique allows weaning from the support of the right ventricular assist device without the confounding hemodynamic challenges of positive pressure ventilation and sternal closure.
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Introduction
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Right ventricular failure can be exacerbated by positive pressure ventilation and the attendant elevation in pulmonary vascular resistance. Furthermore, sternal closure can be a significant hurdle in patients with right ventricular compromise and an open chest. Therefore, weaning of a right ventricular assist device (RVAD) is facilitated in marginal patients by extubation and resumption of spontaneous negative-pressure ventilation as well as by avoiding the subsequent hemodynamic challenge of sternal closure. Although percutaneous methods of RVAD support are being developed [1], currently available options require intubation and sternotomy for device implantation and removal. In patients with marginal right ventricular function requiring temporary mechanical support, a system that can be weaned and removed without general anesthesia or opening the chest may be beneficial. This brief report describes a simple RVAD system that we have devised and used successfully, which can be removed at bedside from a conscious patient.
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Technique
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The RVAD system is comprised of an extracorporeal magnetically levitated centripetal pump (Levitronix, Waltham, MA) and appropriate cannulas to take blood from the right atrium and return it to the pulmonary artery (Fig 1). Rather than directly cannulating these structures, we use a partial occluding clamp to attach appropriately sized grafts (Hemashield; Boston Scientific, Boston, MA) to each. We generally use a 14-mm graft for the right atrium and a 10-mm graft for the pulmonary artery. The grafts are tunneled obliquely through the chest wall and brought through the skin wherever convenient. The pulmonary artery cannula and right atrial cannula are then inserted from outside the chest into the appropriate structure through the attached graft. Generally the venous cannula we use (2-stage 24-French; Medtronic, Minneapolis, MN) is long enough to extend through the 14-mm graft such that the tip is positioned in the right atrium. However, the arterial catheter (19-French femoral arterial cannula; Medtronic, Minneapolis, MN) is too short to reach the pulmonary artery, and therefore it is positioned with its tip in the body of the 10-mm graft. The grafts are tied tightly around their respective cannulas with umbilical tapes outside the chest and secured firmly to the chest wall with multiple heavy sutures. The grafts are constructed with 3 to 5 cm of intentional redundancy within the chest. Institution of right ventricular support frequently facilitates chest closure. Definitive multilayer sternal closure is performed when feasible.
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Fig 1. Position of cannulated grafts during right ventricular assist device (RVAD) support. One graft carries blood from the right atrium to the RVAD; the other carries blood from the RVAD to the pulmonary artery.
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The patient is weaned from mechanical ventilation and extubated as tolerated. After an appropriate interval of right ventricular unloading, attempts are made to wean the patient from support. Pulmonary inhaled vasodilators such as epoprostenol (Flolan; GlaxoSmithKline, Philadelphia, PA), and nitric oxide and inotropes such as isoproterinol and melrinone may be of value. Systemic heparin is administered to allow progressively lower levels of RVAD support. Once it is determined that right ventricular support is no longer necessary, the pump lines are clamped, and the point of exit of the two grafts is widely prepared and draped at bedside. Gentle traction on the grafts allow the redundant portions from inside the chest to be exposed. The umbilical tapes are cut and the cannulas are removed. The grafts are then divided at the skin and oversewn. By delivering the redundant portion, the graft is sterile at the point of division. The closed stump is allowed to retract into the oblique chest wall track, and the skin incision is loosely closed. Figure 2
shows the graft stumps after cannula removal.
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Comment
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This technique allows weaning from RVAD support without the confounding hemodynamic challenges of positive pressure ventilation and sternal closure. Potential disadvantages of the retained graft include thrombus liberation and foreign body infection. Although the graft may certainly cause thrombosis, thrombus liberation and embolization have not been problematic in our experience of 10 cases (8 of which involved LVAD patients bridged to transplantation in whom a blind limb of graft was left connected to the descending aorta). The risk of infection should be low if sterile technique is strictly adhered to at bedside.
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References
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- Lima LE, Jatene F, Buffolo E, et al. A multicenter initial clinical experience with right heart support and beating heart coronary surgery Heart Surg Forum 2001;4:60-64.[Medline]
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Abstract
Introduction
