Size makes a difference: use of a low-prime cardiopulmonary bypass circuit and autologous priming in small adults

Abstract

Low hematocrit (Hct < 20) during cardiopulmonary bypass (CPB) is associated with higher mortality and other adverse outcomes. More frequently, low Hct is encountered in patients with small body size and women patients. This prompted us to take an aggressive approach in our care of these patients, involving a strategy for predicting patients at risk of low Hct, with the aid of an electronic worksheet that accurately predicts CPB Hct, and two prevention strategies: use of a low-prime CPB circuit (LP) for all adult patients with a body surface area (BSA) < 1.7 m(2) and use of autologous circuit priming (AP), in addition to the low-circuit volume in some patients. The two cohorts of patients in whom these techniques were employed were compared to a group matched for body size where our standard adult circuit (STD) was used. There were 233 patients in the standard group, 139 in the LP group, and 68 in the LP/AP group. The CPB circuit prime volume was 1,710 ml for the STD group and 1,110 ml for the LP group. Use of autologous priming techniques further reduced the prime volume by 545 +/- 139 ml. The incidence of low Hct (<20%) during CPB was thus reduced from 70% to 15% (p = 0.001) when using both techniques together without increasing red blood cell (RBC) transfusions. These changes in perfusion management resulted in a reduction in the incidence of renal complications (STD = 9.4%, LP = 6.5% (ns) and LP/AP = 0%,

Pre-filling of the extracorporeal circuit with autologous blood is safe, but not effective in optimizing biocompatibility in high-risk patients

“…3 In order to reduce this volume, the technique of retrograde autologous priming (RAP) was successfully investigated in several studies. 1,2,4,5 RAP reduces haemodilution during the start-up phase of CPB by prior reduction of the priming volume. This is achieved by retrograde arterial or venous filling of the heart-lung machine (HLM) after cannulation, by a slow exchange of the crystalloid priming solution with the patient's own blood.…”

Perfusato autólogo retrógrado no circuito de circulação extracorpórea em pacientes adultos

“…This has advantages for blood flow and organ preservation, but results in a mixture with the patient's blood, causing a hemodilution, and, paradoxically, may lead to the need for blood transfusions during surgery. Although this method is widely used as standard CPB, hemodilution is associated with significant mortality and other adverse conditions, especially when the hematocrit reaches values below 20% [1].…”

“…Retrograde autologous priming (RAP) is a method of CPB, at low cost, which has been described [1,7] as modification of the method proposed, in 1959, by Panico and Neptune [8]. Previous studies have shown that this method reduces hemodilution during CPB, the reduction of blood transfusions by increasing the hematocrit intraoperatively, especially in patients who have risk factors as anemia, small body surface area, and refuses to receive blood products [1].…”

“…Previous studies have shown that this method reduces hemodilution during CPB, the reduction of blood transfusions by increasing the hematocrit intraoperatively, especially in patients who have risk factors as anemia, small body surface area, and refuses to receive blood products [1]. This method uses the patient's own blood during of the pump system setting up.…”

Demonstration and Operative Influence of Low Prime Volume Closed Pump

“…To reduce the deleterious effects of CPB, various improvements have been made. [5][6][7][8] Utilizing these improvements, we devised a less invasive CPB (low prime volume closed CPB; LPVP). In this article, we demonstrate the decreased invasiveness and improved effi cacy of LPVP using molecular biological techniques.…”