Volume expansion and plasma protein clearance during intravenous infusion of 5% albumin and autologous plasma.

Autologous plasma may be used to replace plasma volume and plasma proteins during surgery, but its effectiveness is largely unknown. In the present study, the characteristics of predonated frozen and thawed autologous plasma were compared with those of 5% albumin in 15 male volunteers who received 10 ml/kg of body weight of these colloids as intravenous infusions over 30 min. Venous blood was sampled and urine was collected over 8 h to outline the volume expansion and blood-interstitial fluid space transport of three plasma proteins (albumin, fibrinogen and antithrombin) by means of mass balance analysis. The maximum plasma dilution of 5% albumin and autologous plasma averaged 17 and 21% respectively, and their half-lives were 2.5 and 2.9 h respectively (P<0.03). The between-subject variability in dilution was most pronounced for autologous plasma. Transport of protein from blood to the interstitial space occurred faster when the infused fluid contained the protein in question. The rate was highest at 60 min, and the process was still in progress at 8 h when approx. 60% of the infused albumin, 45% of the fibrinogen and 75% of the infused antithrombin had been translocated to the interstitial fluid space. In contrast with the proteins, excess plasma water was removed by urinary excretion. It is concluded that the volume expansion is equivalent for the two colloid fluids, although it is more predictable for 5% albumin. The transport of protein outlasted the volume expansion.

Tranexamic acid does not prevent rebleeding in an uncontrolled hemorrhage porcine model.

BACKGROUND: Fluid resuscitation after uncontrolled hemorrhage might promote rebleeding and irreversible shock. Tranexamic acid is a procoagulant drug that limits blood loss after surgery of the hip, knee, and heart. We hypothesized that pretreatment with tranexamic acid reduces the rebleeding in uncontrolled hemorrhage and thereby allows safe administration of crystalloid fluid resuscitation. METHODS: A 120-minute intravenous infusion of 100 mL/kg of Ringer's solution was given to 24 pigs (mean weight, 20 kg) 10 minutes after lacerating the infrarenal aorta. The animals were randomized to receive an intravenous injection of 15 mg/kg of tranexamic acid or placebo just before starting the resuscitation. Rebleeding events were monitored by two ultrasonic probes positioned proximal and distal to the laceration. RESULTS: Tranexamic acid had no effect on the number of rebleeding events, bled volume, or mortality. The initial bleeding stopped within 4 minutes after the injury. The five animals that died suffered from 4.4 rebleeding events on average, which tripled the total blood loss, whereas the survivors had only 1.3 such events during fluid resuscitation (p < 0.02). At autopsy, death was associated with a larger total hemorrhage; the blood recovered from the abdomen weighed 1.4 kg (median) in nonsurvivors and 0.6 kg in survivors (p < 0.001), with the difference being attributable to rebleeding. CONCLUSION: Rebleeding events increased the amount of blood lost and the mortality in uncontrolled aortic hemorrhage. Tranexamic acid offered no benefit.