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Circulatory support


Cannulation for left and right heart bypass

Left or right heart bypass is commonly employed to assist a patient’s failing circulation. This method utilizes readily available cannulae and pumping devices. Pump circuits are extracorporeal, so this type of assisted circulation can be used for only a limited time (usually days).

Figure 3-1, A Left and right heart bypass may be instituted via a right anterior thoracotomy in patients in whom it is desirable not to violate the pericardial space. This may be important if cardiac transplantation is being considered and assisted circulation is being used as a bridge to the definitive procedure. B Thin-walled, metal-tipped, right-angled cannulae (28 or 31 F) are introduced through purse-string stitches with tourniquets. One cannula is placed through the right superior pulmonary vein to the left atrium. The other cannula is placed in the right pulmonary artery. The cannulae are brought through intercostal spaces to the skin on the right side below the primary incision. C Thin-walled percutaneous perfusion cannulae are introduced through the femoral vessels and advanced to the right atrium and the iliac artery. Right heart bypass is instituted by the uptake of blood from the right atrial percutaneous cannula and its return via centrifugal pump to the right pulmonary cannula. Left heart bypass is instituted by the uptake of blood from the left atrial cannula and its return via centrifugal pump to the iliac artery cannula. D The cannulae for left and right heart bypass are more commonly introduced through a midline sternotomy during cardiac operations. When pharmacologic and intraaortic balloon counterpulsation support of the failing circulation is insufficient to sustain life, left or right heart bypass, or both, may be necessary. E Cannulae are usually placed in the right atrium and the aorta during cardiac operations. These are utilized for left and right heart bypass. A thin-walled, metal-tipped, right-angled cannula is introduced into the left atrium via the right superior pulmonary vein through a purse-string stitch with a tourniquet. A 20-degree arterial perfusion cannula is placed in the main pulmonary artery. F Left heart bypass is established by connecting the left atrial cannula to the aortic cannula through a centrifugal pump. Right heart bypass involves connecting the right atrial cannula to the pulmonary artery cannula through a centrifugal pump. The cannulae are brought through the fascia, muscle, and skin into the left and right upper quadrants of the abdomen. Teflon felt strips are placed tightly around the cannulae in the subcutaneous tissues to seal the exit tracts. The midline incision is closed primarily. In some cases the cannulae are brought out through the wound. G The wound may be left open when the heart cannot tolerate the compression of wound closure. An Esmarch or Silastic membrane is attached to the skin edges using staples to seal the mediastinum.

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