Effect and safety of liposome-encapsulated hemoglobin neo red cells (NRCs) as a perfusate for total cardiopulmonary bypass.

Abstract

We developed a liposome encapsulated hemoglobin named Neo Red Cells (NRC), NRC (1) readily circulates, (2) shows a high oxygen transport efficiency, and (3) has a strong capsule membrane. In this study, we evaluated the effect of NRC as a priming solution for total cardiopulmonary bypass (TCPB) using a dog. The TCPB was started after removal of 57.1-73.3% of autologous blood and continued for 7 hours. During TCPB using NRC, the vascular resistance (VR) decreased to 1/4 of VR when red blood cells (RBC) were used. This change suggests that NRC, the viscosity of which is lower than that of RBC, reduced the load on the circulation system. The oxygen volume delivered by NRC was higher than that delivered by RBC, resulting in a greater oxygen consumption with NRC. During TCPB using NRC, the serum LDH level was lower than that using RBC. So we concluded that NRC compensated for the reduction in the oxygen transport ability, which is a disadvantage of dilution TCPB, and further increased the circulation improving effect and anti-hemolytic effect, which are advantages of the procedure. It, thus, enhanced both the safety and effectiveness of dilution TCPB.