Effects of isovolemic resuscitation with hemoglobin-based oxygen carrier Hemoglobin glutamer-200 (bovine) on systemic and mesenteric perfusion and oxygenation in a canine model of hemorrhagic shock: a comparison with 6% hetastarch solution and shed blood

Broadband diffuse optical spectroscopy assessment of hemorrhage- and hemoglobin-based blood substitute resuscitation

“…These findings are consistent with prior studies where Oxyglobin infusion has been shown to restore hemodynamic parameters, including cardiac output and mesenteric arterial blood flow following hemorrhage, with increases in mean arterial blood pressure above baseline, but not to restore total intravascular hemoglobin and arterial blood oxygen content to baseline 20. The hyperoncotic properties of Oxyglobin result in rapid volume expansion with homogeneous microvascular perfusion and the ability to facilitate diffusive oxygen transfer, accelerating metabolic recovery 20.…”

“…This finding was expected due to the increased intravascular volume associated with blood substitute resuscitation, as well as the added hemoglobin content within the blood substitute 10,39. One might have predicted some blunting of this increase in total tissue hemoglobin concentration due to a possible component of NO scavenging-induced vasoconstriction reported with poly-heme-based blood substitutes, such as Oxyglobin, and other potential mechanisms leading to increased vascular resistance 1,20,21,39,41–45. However, such effects, if present, did not appear to substantially alter the increase in DOS-measured total tissue hemoglobin, suggesting that increased vascular volume predominates during blood substitute resuscitation as administered.…”

“…This is not surprising given the fact that the HBOC, Oxyglobin, has a hemoglobin concentration of 13 g/dL, an osmolality of 300, and a colloid osmotic pressure of 43 mmHg 1. Administration of replacement fluid with this combination of hyper-osmolality and a 13 g/dL hemoglobin concentration, which is only slightly above that of the animals following acute hemorrhage (intravascular post hemorrhage hemoglobin concentration, averaged 12.1±0.4 g/dL compared to prehemorrhage baseline values of 14.8±0.4 g/dL), would be expected to draw fluid into the vascular space resulting in substantial increases in intravascular volume, but should cause only slight (if any) increases in intravascular hemoglobin concentration 6–8,20…”

“…The hyperoncotic properties of Oxyglobin result in rapid volume expansion with homogeneous microvascular perfusion and the ability to facilitate diffusive oxygen transfer, accelerating metabolic recovery 20. This would explain the discrepancy between DOS [THb] measurements (which include both intravascular hemoglobin concentration and tissue vascular volume) versus invasively obtained blood sample hemoglobin concentrations (which include only the intravascular hemoglobin concentration component) during blood substitute resuscitation.…”

“…These difficulties in assessing adequacy of hemorrhage resuscitation are further compounded during blood substitute resuscitation due to interaction of complex factors, including differences between blood and cell-free blood substitutes 1,10,13. Some of the factors that may differentially affect tissue perfusion and oxygenation during hemoglobin-based blood substitute treatment include polymerized heme structures, heterogeneous polymer size distribution, NO scavenging, gas transfer from cell stromal free composition, and osmolality effects 1,6,12,13,20,21…”