HYPERTONIC ACETATE-ALPHA-ALPHA-HEMOGLOBIN FOR SMALL-VOLUME RESUSCITATION OF HEMORRHAGIC-SHOCK

Hypertonic acetate solution in small volumes greatly improves cardiac output and corrects acid-base disturbances in hemorrhaged animals. We hypothesized that the combination of alpha alpha-crosslinked human hem oglobin (alpha alpha Hb), an oxygen carrier and vasoconstrictor, with hypertonic sodium acetate (HAHb), a vasodilator, may be effective for small volume resuscitation of hemorrhagic shock. Six pigs hemorrhaged to a mean arterial pressure of 40 mmHg for 60 min (bled volume: 23.6 /- 2.5 ml . kg(-1)) received a single bolus of 4 ml . kg(-1) of HAHb i nfused over two min. HAHb restored arterial pressure, increased system ic vascular resistance and caused a modest increase in cardiac output and SvO(2), while pulmonary arterial pressure and vascular resistance were markedly increased. In two animals, transient severe hypotension and low cardiac output may have been due to acute pulmonary hypertensi on during injection. Compared to our previous study, in which animals received 4 ml . kg(-1) of alpha alpha Hb alone, HAHb produced higher c ardiac output and a smaller increase in systemic and pulmonary vascula r resistance. However, slower, titrated infusions may be needed when h emoglobin solutions are combined with drugs or solutions that cause va sodilatation in order to decrease the likelihood of acute hemodynamic instability.