Ann Thorac Surg 2005;79:680-681
© 2005 The Society of Thoracic Surgeons
Lars G. Svensson, MD, PhD
Marfan and Connective Tissue Disorder Clinic, The Cleveland Clinic Foundation, 9500 Euclid Ave, F25, Cleveland, OH 44195, USA
Bisleri and colleagues have described a pump circuit that can be used for atriofemoral bypass, atriofemoral oxygenated blood partial bypass, and complete cardiopulmonary bypass. This does allow for flexibility in choosing the optimal bypass circuit before placing the patient on bypass but at an additional cost of several hundred dollars, and for most patients these additional circuits would not be needed. It is important to stress that once the patient is on atriofemoral bypass and a major problem arises, such as cardiac arrest, then perfusion methods have to be rapidly changed for full cardiopulmonary bypass since the aorta is cross clamped. First, the ascending aorta must be cannulated after opening the pericardium for arterial inflow; and second, the blood has to be drained from the right heart side. If the patient has not had previous cardiac surgery, the easiest is to place a purse-string suture around the right auricle and insert a two-stage venous cannula. If a previous heart operation has been done, because of the adhesions, the femoral vein must be cannulated with a long venous cannula fed up into the right atrium. If time allows, it is preferable to use the right femoral vein and to position the cannula tip in the right atrium with the aid of transesophageal echocardiography visualization. Thus, the suggested circuit needs an arterial "Y" for switching from femoral to proximal aortic inflow.
The other deficit in the circuit is that a heat exchanger is not included. Three of our studies have shown that one of the most beneficial methods for protecting the spinal cord is to cool the patients systemically to 30°C to 32°C and then rewarm the patient with the circuit. We found this temperature range was as protective as deep hypothermia with circulatory arrest.