METABOLIC ACIDOSIS AND SEVERE HYPOTENSION: INFLUENCE ON SURVIVAL TIME AND SHOCK PERIOD DURING HEMORRHAGE IN THE CAT

Metabolic acidosis and severe hypotension are the main causes of irreversibility during hemorrhagic shock. The influence of these two factors on durations of shock period and survival time were studied in four groups of anesthetized cats. In group I the animals were made hypotensive by reducing mean arterial blood pressure (Pa) to 45 mmHg with concurrent metabolic acidosis. [n group II the same level of hypotension was produced, along with an intravenous infusion of 12% sodium bicarbonate solution (0.25 ml/kg/min.) thus metabolic acidosis was prevented and arterial blood pH (pHa) was kept within its normal range. In group III the Pa was kept at 50 mmHg in the presence of metabolic acidosis, and in group IV, the Pa was kept at 50 mmHg (the same as group Ill) but acidosis was prevented. Durations of shock period and survival times of all groups were compared. The results of this study show that I) preventing metabolic acidosis increased survival time by 400%, 2) keeping the Pa at 50 mmHg increased survival time by 800 percent, and 3) prevention of metabolic acidosis at a Pa of 50 mmHg still augmented survival time by more than 250 percent. We therefore conclude that control of pHa and prevention of severe hypotension may increase survival rates in patients suffering from hemorrhage.