Aortic compressor for aortic occlusion in hemorrhagic shock.

The aortic compressor is a device that allows rapid, simple, immediately reversible occlusion of the thoracic aorta, without the aortic dissection required to use an aortic cross-clamp. We evaluated the aortic compressor in a controlled study using a canine hemorrhagic shock model. Twelve mongrel dogs were exsanguinated to a mean arterial pressure (MAP) of 47 mm Hg and maintained at that level for 20 minutes. At that point, all animals had a left lateral thoracotomy. Six study animals had the thoracic aorta occluded at the diaphragm using the compressor. Five minutes after thoracotomy, with or without occlusion, the shed blood was reinfused. Application of the aortic compressor was the only variable. Use of the aortic compressor led to an immediate and statistically significant doubling of the study animals' MAP. The increased afterload of aortic occlusion did not impair cardiac output. The cardiac index of the study animals rose slightly, while that of the control animals fell. At the same time the compressor prevented blood flow to the abdominal aorta. If the canine model can be extrapolated to human application, then the aortic compressor would be expected to enhance perfusion of the heart and brain during hemorrhagic shock, prevent further arterial blood loss from intra-abdominal injury or ruptured abdominal aortic aneurysm, and preserve already diminished cardiac output. Because the aorta does not need to be dissected out to use the compressor, there is no risk of injury to nearby vascular structures.