Splanchnic blood flow response to intraaortic balloon pump assist of hemorrhagic shock

Hemorrhagic shock results in marked changes in splanchnic arterial blood flow. We studied the effects of intraaortic balloon pump assist (IABP) upon splanchnic blood flow during sustained hemorrhagic shock and following volume resuscitation. Hemorrhagic shock was induced (mean blood pressure = 30 mm Hg) for 120 min in 20 dogs. Controls (n = 11) underwent resuscitation with shed blood and lactated Ringers solution only. In the study group (n = 9), IABP was begun after 60 min of hemorrhagic shock and continued throughout a 90-min period after resuscitation. Hemodynamic parameters were assessed and splanchnic blood flow was estimated (radioactive microsphere technique) at baseline, through 120 min of sustained hypotension, and during the resuscitation period. Splanchnic blood flow was significantly reduced in both the control and the IABP groups during the period of hemorrhagic shock. Interestingly, the IABP group was found to have a return to preshock splanchnic viscera perfusion without the hyperemic reperfusion phenomenon seen in control animals resuscitated with shed blood and Ringers lactate alone. IABP assist of hemorrhagic shock appears to improve vasomotor control of splanchnic blood flow in this experimental preparation of shock. This may result in less reperfusion injury to the splanchnic viscera during the resuscitation of severe hemorrhagic shock.