To determine if the increased blood pressure associated with application of a pneumatic antishock garment (PASG) affects outcome in thoracic hemorrhage, we assessed hemodynamics, blood loss, and survival in three groups of eight anaesthetized piglets with a 2.5-mm laceration of the descending thoracic aorta. Baseline measurements were made before aortic hemorrhage. During one hour of aortic hemorrhage or until death of the animal, the PASG was not inflated in Group I while the PASG in the other two groups was inflated to maintain carotid artery pressure at 15 torr below baseline (Group II) and at baseline (Group III), respectively. Survival was 100% in Group I, 50% in Group II, and 0% in Group III. Hemorrhage at 22.5 ± 4.0 mL/min stopped after 18–24 minutes in Group I; the survivors in Group II bled at a rate of 32.5 ± 3.0 mL/min compared with 43.6 ± 4.0 mL/min over 26–35 minutes in the Group II nonsurvivors. Group III pigs bled at 107.5 ± 8.0 mL/min over the 10–18 minutes of survival. The intended blood pressure could not be maintained beyond 30 minutes. Bleeding stopped in Group I when the blood pressure fell to 58.2 ± 4.5 torr from a baseline of 119.0 ± 10.0 torr. The blood pressure fell to 48.0 ± 5.0 torr in the four Group-II survivors. After a transient maintenance of baseline blood pressure in Group III, a precipitous drop in blood pressure with death in 10–18 minutes occurred in all these animals. In this porcine model of thoracic aortic injury, PASG inflation increases hemorrhage and mortality. The increase in blood pressure with PASG increases hemorrhage without improving survival, which was higher at the lower carotid artery blood pressures.
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