Intermittent intra-aortic balloon tamponade during hemorrhagic shock

The use of intermittent intra-aortic balloon tamponade was evaluated during resuscitation of hemorrhagic shock in a sheep model. Twenty adult sheep were exposed to severe hemorrhagic shock and they were all treated with crystalloids (8% of body wt) during one hour. Ten of these were also treated with intermittent supraceliac intra-aortic balloon tamponade during the initial 30 min (group A) while the other 10 were used as a controls (group B). In the group treated with intra-aortic tamponade the mean arterial pressure (MAP) was rapidly increased as the balloon was inflated, but it dropped to the same level as in the control group during deflation. In this group there were also great fluctuations in systemic vascular resistance (SVR), pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) when the aortic balloon was inflated/deflated, while central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) were hardly affected at all. After final deflation of the aortic balloon (at 30 min), MAP remained 35% lower than the baseline value (p less than 0.01), similar to the control group. Cardiac index (CI) increased continuously during the first 30 min, at which time it reached the pre-shock level in both groups. At the end of the resuscitation period there was no significant difference between the two groups in any of the cardiovascular parameters measured. Four animals died in group A and 3 in group B within 24 hours, after which time the survivers were sacrificed. Both groups had high incidence of pathological changes in the kidneys, liver, intestine, and lungs. Six animals in group A had hind limb paralysis and loss of anal sphinter tone after the resuscitation. It was concluded that intermittent supraceliac aortic occlusion for 30 minutes did not decrease morbidity or mortality in sheep exposed to severe hemorrhagic shock compared with a control group treated in a traditional way with fluid replacement.