A pediatric trauma model of continuous hemorrhage.

This report describes a new experimental model of hemorrhage in immature animals. Puppies were subjected to continuous hemorrhage equivalent to 1% of calculated blood volume per minute. In the control group there was no change in mean arterial pressure, central venous pressure, cardiac output, hematocrit, pH, or core temperature. In the experimental group the response to hemorrhage was gradual and in proportion to blood loss until 25% to 30% blood volume reduction. At this critical point, the fall in mean arterial pressure and cardiac output accelerated and death occurred. These observations suggest that the response to blood loss has break points beyond which sudden deterioration is rapid and dramatic. This model of hemorrhage should be useful for future study of the effects of treatment of hemorrhagic shock in immature subjects.