Dopamine infusion during resuscitation of experimental hemorrhagic shock

To compare the effects of starting dopamine administration early or late on organ perfusion by measuring tissue oxygen tensions during standard volume resuscitation of hemorrhagic shock.

Randomized, control trial.

Thirteen piglets (mean weight, 19 kg).

The animals were bled to a state of hemorrhagic shock and resuscitated using crystalloid solution. Cardiac outputs and mean arterial pressures were measured as indicators of volume filling over a period of 80 mins. Dopamine was administered by infusion at 5 micrograms/kg/min from the start of volume correction (early-dopamine group, n = 7) or after the volume deficit was corrected (late-dopamine group, n = 6).

Blood pressures and cardiac output were measured. Tissue oxygen tensions were continuously recorded in the liver, conjunctiva, and via subcutaneous and transcutaneous electrodes in the abdominal region. Mean arterial pressure decreased from 111 +/- 5 (SEM) to 44 +/- 2 mm Hg with the induction of hemorrhagic shock. Cardiac output decreased by 78% during shock. During resuscitation, mean arterial pressure increased to near baseline values in both groups. Cardiac output recovered completely in the late-dopamine group and almost completely in the early-dopamine group. Liver oxygen tension increased to above baseline during resuscitation in the early-dopamine group. Liver oxygen tension in the early-dopamine group was significantly higher than in the late-dopamine group. Similar changes were observed in subcutaneous and transcutaneous oxygen tensions, but not in conjunctival oxygen tensions.

Starting dopamine administration early during volume resuscitation in a model of experimental hemorrhagic shock led to higher liver, subcutaneous, and transcutaneous tissue oxygen levels. This finding indicates enhanced tissue oxygen perfusion, especially in the liver.