Evaluation of the Hemobag: a novel ultrafiltration system for circuit salvage.

Following termination of bypass, the CPB circuit contains a significant volume of diluted blood. Various methods have been used to salvage this blood, including direct transfusion or centrifugation /washing of the circuit volume. These techniques produce a reinfusion product that is either dilute or free of plasma proteins. The purpose of this study is to evaluate the Hemobag ultrafiltration system, which may overcome these limitations. Yorkshire pigs (n = 4, approximately 40 kg) were placed on CPB (prime volume 1.5 L) for 60 min. Following CPB, control blood samples (Pre) were collected from the circuit. The circuit contents were then transferred into a Hemobag and processed. Blood samples (post) were then collected from the Hemobag. Pre- and post-samples were analyzed and compared using a Student's t-test. Parameters that were significantly different (p < .05) pre-Hemobag versus post-Hemobag were as follows: hematocrit 20.4+/-3.4% vs. 54.1+/-11.6%, total protein 2.4+/-0.4 vs. 8.2+/-2.9 gms/DL, fibrinogen 92.0+/-0.3 vs. 305.8+/-37.2 mg/DL. Parameters that were not significantly different but trended toward an increase post-Hemobag were platelet counts, heparin levels, white cell count, and plasma free hemoglobin. Parameters that showed no differences or trends included sodium, potassium, chloride, bicarbonate, and osmolarity. Processing times were measured at approximately 10 minutes. This device effectively concentrates post-bypass circuit volume, providing a product that is high in red blood cells and plasma proteins and may provide an alternative to current techniques for circuit volume salvage.