Retrospective analysis of eliminating modified ultrafiltration after pediatric cardiopulmonary bypass

Abstract

Modified ultrafiltration (MUF) is a technique which is commonly used immediately post-cardiopulmonary bypass (CPB) for open heart surgery in children. There are many advantages of MUF, but there are also a number of less reported disadvantages. At our institution, after considering all of the available data, a decision was made to no longer perform MUF. The primary motivation being the simplified and miniaturized CPB circuit would reduce hemodilution, decrease our likelihood of reaching our transfusion trigger during CPB and, potentially, improve safety. This study reports the before and after data from this practice change. A total of 160 patients less than 8kg were studied over 38 months and divided into neonatal and pediatric cohorts. Parameters reported in this study include: demographics, hematocrit, blood product transfusion, hemostasis, hemodynamics and outcomes. Although retrospective, our analysis supports an advantage of preventing hemodilution (via circuit miniaturization) versus reversing hemodilution (via MUF) at our institution with the patient population we examined.

Reevaluating the Importance of Modified Ultrafiltration in Contemporary Pediatric Cardiac Surgery

“…As far as we are aware, this is first prospective study that evaluates the significance of MUF within these new CPB characteristics. Previous studies that compared CUF to CUF+MUF were characterized by significant utilization of hypothermia and deep hypothermic circulatory arrest [6,11,18,21]. Deep hypothermia with circulatory arrest, isolated myocardial and cerebral perfusion within our group of patients are reserved exclusively for children necessitating reconstruction of the ascending aorta and aortic arch (e.g., Hypoplastic heart syndrome, interrupted aortic arch).…”

“…During the last decade, greater knowledge about CPB related pathology has led to great advances in technology. Patients are exposed to less hemodilution and foreign surface resulting in reduced inflammation and post CPB edema [18,19]. There is also a reduced dependence on hypothermia [20].…”

“…Apart from potentially greater volume removed MUF does not have any proved benefit over CUF [21]. New retrospective studies demonstrate that elimination of MUF from simplified miniaturized CPB circuit have not led to negative outcomes [18]. Nevertheless there are no prospective studies that could validate clinical importance of MUF with the improved CPB characteristics.…”

Decreased blood product usage during extracorporeal life support with reduced circuit volumes

“…We hypothesis these more efficient ECLS circuits will be easier to achieve the desired coagulation variables. McRobb and colleagues reported a major advantage in a safer simplified cardiopulmonary bypass circuitry. They concluded that a reduced cardiopulmonary bypass circuit priming volume, surface area, and exposure decreased the likelihood of transfusion.…”

<p>Minimizing the need for transfusion in pediatric congenital heart surgery</p>

“…45 More recently, the significance of MUF has been questioned in one paper where the authors concluded that if the MUF circuit requires additional circuit prime volume, it may be better not to perform the technique. 46 It is important to note that there are numerous methods of performing MUF, and therefore its influence on a practice will vary. At the very least, most MUF circuits improve the patient's hematocrit after bypass with patient whole blood and not just red blood cells (RBCs) as is the case with cell saver blood or RBC transfusions.…”