Fluid resuscitation after an otherwise fatal hemorrhage: I. Crystalloid solutions.

One half of deaths among trauma victims occur within 1 hour of injury and are due to rapid hemorrhage or CNS trauma. We developed a rapid hemorrhage model in unanesthetized swine to simulate human exsanguination. We compared the ability of four crystalloid solutions to prevent death after an otherwise fatal hemorrhage: normal saline (NS), Ringer's lactate (RL), Plasmalyte-A (PA), and Plasmalyte-R (PR). Five days before hemorrhage swine received an aortic sideport and a central venous treatment catheter. Aortic blood (54 ml/kg) was removed in 15 minutes from 116 swine. The percentages of shed blood replaced were 14% in 5 minutes with NS, 100% in 20 minutes with NS, and 300% in 30 minutes with NS, RL, PA, or PR. We found that all mortalities were determined within 2 hours after hemorrhage and that RL provided the best survival rate of 67% (NS 300% = 50%, PR = 40%, and PA = 30%.) After an analysis of arterial blood gas, lactate, acid-base, heart rate, and aortic pressure measurements, we conclude that RL is the superior crystalloid solution because of its decreased chloride load (compared to NS) and because of the absence of acetate or magnesium (compared to PA and PR).