A comparison of resuscitation with packed red blood cells and whole blood following hemorrhagic shock in canines.

Resuscitation with crystalloid and packed red blood cells has for the most part replaced the use of plasma and whole blood in the initial treatment of hemorrhagic shock. The effects of such changes on cardiovascular function following hemorrhagic shock remain largely unexplored. We examined cardiovascular function in anesthetized canines subjected to severe hemorrhagic shock. Mongrel canines of either gender were anesthetized with isoflurane and instrumented for measurement of arterial pressure, cardiac output, coronary flow, and left ventricular pressure and volume for the determination of end systolic elastance (Ees). Following a 30-min stabilization period, blood was rapidly removed to induce fixed pressure (mean arterial pressure = 35 mmHg) hemorrhagic shock for 90 min or until an arterial lactate of 7.0 mM was achieved. Animals were then resuscitated with 2/3 of the shed volume as lactated Ringer's and an equal volume of either whole blood (WB, n = 8) or packed red blood cells (PRBC, n = 10) resuspended in lactated Ringer's (LR) solution to replace expressed plasma volume. PRBC resuscitated dogs showed lower values of mean arterial pressure, cardiac output, rates of ventricular contraction and relaxation and myocardial work. Increasing the maintenance infusion rate of LR (10 mL/kg/h) following PRBC infusion normalized mean arterial pressure, but not other indices of cardiovascular function. Thus, WB, but not PRBC resuscitation restores normal myocardial function during resuscitation from severe hemorrhagic shock.