Modified Ultrafiltration Is Beneficial for Adults Undergoing Cardiac Surgery
Abstract
Hemodilution and Volume Overload
The use of CPB necessitates priming of the CPB circuit, which is typically accomplished using 1-to-2 liters of a crystalloid solution. In addition, 1-to-3 liters of cardioplegia (CP) are primed within a separate arm of the CPB circuit, all of which eventually make their way into the overall circulating volume of the patient. The addition of these solutions to the patient’s native intravascular volume when placed on CPB results in significant hemodilution, clinically seen as a rapid drop in
Hemorrhage and Transfusion
Reducing the iatrogenic volume-overloaded state is important not only for end-organ systems but for the circulatory system as well. The hemoconcentration effect of MUF has been shown to reduce the number of postoperative blood transfusions in addition to an overall reduction in bleeding in adults undergoing cardiac surgery.24 This is clearly beneficial to all patients but can be particularly important in certain patient populations who are less likely to be amenable to receiving blood products
Removal of Inflammatory Mediators
Perhaps one of the most deleterious effects of extracorporeal circulation is the production of inflammatory mediators and the subsequent clinical systemic inflammatory response that ultimately takes place. The reason for this response is multifactorial, including surgical trauma, ischemic reperfusion injury, endotoxemia, and the contact of blood components with the extracorporeal circuit.31 This leads to the activation of inherent coagulation pathways, complement factors, and a robust immune
Multisystem Organ Benefits
The multiorgan benefits of MUF have been shown to extend beyond the cardiovascular system. Studies examining pulmonary complications have shown significant improvement in patients undergoing MUF. In a study of >500 patients, those who underwent MUF for 20 minutes to a goal reduction in net bypass volume of >50%, had a dramatic reduction in respiratory failure rates postoperatively of nearly 60%. They also reported statistically significant reductions in gastrointestinal and neurologic
Conclusions
The practice of MUF has been shown repeatedly to be beneficial and necessary in the pediatric cardiac surgery population.4,43,44 Although there are many physiologic differences between infant and adult cardiac surgical patients, it is logical that some benefit remains. The inflammatory milieu removed, in concert with hemoconcentration, has been shown to reduce bleeding, transfusion, reexploration, and cost. Additional cardiac, renal, and pulmonary protective effects have been clearly..