The Effects of Hemodilution With Hemolink™ Upon Hemodynamics and Blood Flow Distribution in Anesthetized Dogs

Abstract

Hemoglobin based oxygen-carrying solutions (HBOCs) as hemoglobin replacement therapeutics are being tested for clinical use. Some of these products are associated with elevations in both systemic and pulmonary vascular resistances but their effect on the distribution of blood flow to major organs in larger animals have not been extensively described. We tested two formulations of o-raffinose cross-linked human hemoglobin, Hemolink (frozen Hemolink-1 and refrigerated Hemolink-2) and compared them to Pentaspan, a colloid volume expander in extensive clinical use. Cardiovascular measurements and the distribution of blood flow (radionuclide-labeled microspheres) to the major organs were determined in Beagle dogs (n=5 per group). After baseline measurements, either Hemolink-1, or Hemolink-2, or Pentaspan was exchange transfused in an isovolemic manner (resulting in hematocrit reduction to approximately 20-25%); measurements were made 30, 60, 120 and 180 min post-exchange. There was no significant difference in cardiac output, mean arterial pressures and systemic or pulmonary vascular resistance after exchange in any of the three groups. Myocardial blood flow increased in all three groups post-exchange but the increase was more sustained in the Hemolink groups. Endocardial/epicardial flow ratios were also maintained after exchange in all groups. Thus, Hemolink is ideally suited for volume replacement when used in conjunction with acute normovolemic hemodilution because under these circumstances, the adverse hemodynamic effects are alleviated while extra hemoglobin is added to the blood.

Acute normovolemic hemodilution

“…Better guidelines and standards would be set with more reliable data production. In the future, the addition of artificial oxygen carriers 45,46 to ANH may broaden the technique further, but safety and efficacy data are needed.…”

Haemoglobin-based oxygen carriers and myocardial infarction

“…In contrast, in vivo coronary blood flows are maintained or even increased in rats [33], dogs [34,35], cats [36] and swine [37][38][39] after infusion of various HBOC preparations. Moreover, cardiac function was well supported after exchange transfusion [34,39], haemorrhagic shock resuscitation [38], angioplasty [37] and myocardial ischemia/reperfusion protocols [35]. In two small studies conducted in human patients with heart disease, coronary blood flow and artery diameter were unaffected by peripheral or intracoronary perfusion of HBOC-201 [40,41].…”

Effect of haemodilution with diaspirin cross‐linked haemoglobin on the oxygen reserve in a rodent model of surgical blood loss

“…DCLHb (a haemodiluent with oxygen‐carrying properties) is used in this study as an alternative to colloid. Other oxygen‐carrying solutions are currently being studied as an alternative haemodiluent to colloid in combination with acute normovolaemic haemodilution (Habler et al ., 1998; Brecher et al ., 1999; Kingma et al ., 2001).…”