Hemodilution and oxygen transport to tissue in shock.

Shock was induced in sixty dogs by laparotomy, splenectomy and exteriorization of the small intestine for three hours. Resuscitation following different plasma substitutes was assessed by measuring hemodynamic parameters (mean arterial blood pressure, plasma volume, oxygen consumption, cardiac output and hematocrit). To justify a comparison, the colloids (albumin, ACD-plasma, dextran 40, dextran 70, gelatine) were given at the same concentration and dose (3.5 % solutions in saline at a dose of 1.5 g/kg or 43 ml/kg). Ringer's acetate was given in a three times larger volume (129 ml/kg). After reposition of the intestine, the infusion was given over a 20 minute period. During shock hemoconcentration developed, increasing from 50 to 59 % in hematocrit; mean arterial blood pressure dropped from 144 to 95 mm Hg; plasma volume decreased to 67 %; total body oxygen consumption decreased to 59 % and cardiac output to 21 % of initial values. Reposition of the intestine did not in itself improve these values. Ringer's acetate was effective up to about 30 minutes after infusion but did not differ from no infusion at four hours. Gelatine and ACD-Plasma had a similar effect up to two hours. Albumin, dextran 40 and dextran 70 increased and maintained plasma volume and oxygen consumption at preexperimental levels for up to at least four hours. It is concluded that a single infusion of albumin, dextran 40 or dextran 70 is superior to ACD-plasma gelatine or Ringer's acetate in restoring and maintaining oxygen consumption and hemodynamic functions, when given in comparable doses and volumes.