Background: The new guidelines for prehospital care of combat casualties in shock recommend administration of whole blood or blood components to increase blood pressure to a permissible hypotensive level (i.e., hypotensive resuscitation [HR]). We investigated if 2 h of HR using limited volumes of whole blood, plasma, or albumin would lead to full recovery and long-term survival of rabbits subjected to severe hemorrhagic shock (HS).
Methods: Following instrumentation, laparotomy was performed on IV-anesthetized spontaneously breathing New Zealand white rabbits (3.0 kg -3.5 kg). Next, ∼40% of rabbits' blood volume was removed producing HS (mean arterial pressure [MAP]∼20 mm Hg). Fifteen minutes later, rabbits were resuscitated with a limited volume (12.5 mL/kg) of rabbit whole blood (fresh whole blood [FWB]), rabbit fresh frozen plasma (FFP), or 5% human albumin (ALB) to a target pressure (MAP) of 60 mm Hg (n=8/grp) and monitored for 2 h. Liver bleeding time was measured at baseline and 10 min after HR. Subsequently, animals were fully resuscitated (blood + lactated Ringer [LR]), surgically repaired, and recovered for 8 days. An untreated group (n = 6) was also included.
Results: Following HS, lactate and base deficit levels were increased to 8.2 ± 1.6 and 12.9 ± 3.1 mM respectively with no difference among groups. A lower volume of FWB volume was required to reach the target MAP (P < 0.05 vs. ALB) but MAP declined during the HR period (P < 0.01 vs. ALB). FWB provided higher hematocrit and platelets but it did not reduce lactate level faster than other fluids. Beside higher fibrinogen, no differences were found in hemostatic or resuscitative effects of FFP versus ALB. Bleeding time was prolonged with ALB and FFP fluids but unchanged with FWB. Untreated rabbits died during shock or shortly after. All treated rabbits except one recovered and lived for 8 days with normal blood tests and similar tissue histology.
Conclusions: Two hours of HR using a limited volume of FWB, FFP, or ALB led to full recovery and long-term survival of rabbits subjected to HS. Apart from bleeding time, no clinically significant differences were found among the three fluids. Five percent human albumin solutions are isotonic, iso-oncotic, ready-to-use, stable, and compatible with all blood types and should be considered for prehospital resuscitation where blood products are not available or not accepted.