A NEW SALUTARY RESUSCITATIVE FLUID - LIPOSOME-ENCAPSULATED HEMOGLOBINHYPERTONIC SALINE SOLUTION

Low-volume resuscitation with hypertonic (7.5%) saline (HTS) is an evo lving therapeutic modality for patients with hemorrhagic shock. This s olution has been shown to exert protective hemodynamic effects in mode ls of controlled hemorrhagic shock and in several clinical trials. How ever, HTS has no oxygen-carrying capacity and therefore does not impro ve oxygen delivery directly. One of the leading strategies in developi ng an oxygen-carrying resuscitative fluid is the encapsulation of hemo globin within phospholipid vesicles (LEH). This preparation has the ad vantage of being blood type and antigen free, easily adaptable to scal e-up production, and remarkably stable with a long shelf life. We ther efore tested the hypothesis that lyophilized LEH reconstituted with HT S will improve tissue oxygenation and survival in rats exposed to a le thal controlled hemorrhagic shock. Shock was induced by withdrawal of 70% of blood volume and therapy (n = 10-16) with HTS (5 mL/kg), LEH (5 mL/kg), lactated Ringer's solution (vol:vol = 1:3), LEH-HTS (5 mL/kg) , or oxygen (100%) was initiated 15 minutes later. The LEH-HTS improve d skeletal muscle oxygen tension directly measured using a thin-film c hamber oxygen sensor (PO2 87 +/-13 mm Hg vs. 40-50 mm Hg in other grou ps, p < 0.05). This was associated with improved blood pressure, reduc ed acidosis, and increased survival at 24 hours (75% vs. 6%-25% in oth er groups, p < 0.05). In conclusion, the study demonstrates a remarkab ly salutary effect of LEH reconstituted with HTS as a blood substitute in the treatment of hemorrhagic shock.