Physiologic Aspects of Porcine Hemorrhage. IV. Blood Gas and Acid-Base Status of the Conscious Animal Following 30 and 50 Percent Blood Loss

摘要

A porcine animal model, designed to simulate physiologic characteristics of the combat casualty, was used to assess the effects of moderate and severe blood loss on arterial blood gas and acid-base status in the absence of anesthesia or other interventions. Chronic catheters were placed surgically in the aorta, via the carotid artery, in three groups of young, domestic pigs. Seven to ten days after surgery, each animal was brought into the laboratory and the catheter was connected to a three-day stopcock and pressure transducer for blood removal and hemodynamic recording. After 30 minutes of unrestrained and uninterrupted supine rest, control measurements were made every 10 minutes for the next 30 minutes. Thereafter, the pig was subjected to one of three 1-hour treatments: 30 percent loss of the estimated blood volume; 50 percent blood loss; or left undisturbed (control group). Subsequent to the hemorrhage or control period, all measurements were repeated at 0, 30, 60, 120, 180, 240 and 300 minutes of spontaneous recovery. Immediately after the hemorrhage episode, the blood gas and acid-base status of pigs subjected to 30 percent hemorrhage was unaltered relative to their own control values or the values recorded in the control group of pigs. Fifty percent blood loss led to a metabolic acidosis that was largely compensated.