Adaptation to Acute Severe Hemodilution With Dextran 75 in Dogs

VARIOUS plasma substitutes have been introduced for the treatment of hemorrhage in the absence of cross-matched blood to avoid serum hepatitis from pooled plasma and to prevent or correct aggregation of erythrocytes in the microcirculation associated with shock.

Treatment of moderate hemorrhage with plasma substitutes can maintain adequate arterial pressure and increase cardiac output, but reduces oxygen carrying capacity.^1,2 The degree of acute reduction of hemoglobin which can be tolerated has not been reported under controlled conditions. Previous experiments from this laboratory were concerned with acute, progressive fatal hemodilution with dextran 75 replacement.³ Hemodilution was tolerated until the mean arterial oxygen content had fallen to 4 vol %, corresponding to a hemoglobin content of approximately 3.0 gm/100 cc with air ventilation and 2.0 gm/100 cc with oxygen ventilation. Asystole occurred at an arterial oxygen content of 3 vol %.

How the animals maintained circulation and metabolism and whether they could