FLUID COMPARTMENTS IN HEMORRHAGED RATS AFTER HYPEROSMOTIC CRYSTALLOIDAND HYPERONCOTIC COLLOID RESUSCITATION

Postresuscitation organ failure may be associated with detrimental cha nges in body fluid compartments. We measured how shock and resuscitati on acutely alters the interstitial, cellular, and plasma compartments in different organs. Nephrectomized, anesthetized rats were bled to 50 mmHg mean arterial pressure for 1 h, followed by 60 min of resuscitat ion to restore blood pressure using 0.9% normal saline (NS, n = 10), 7 .5% hypertonic saline (HS, n = 8), 10% hyperoncotic albumin (HA, n = 8 ), or 7.5% hypertonic saline and 10% hyperoncotic albumin (HSA, n = 7) . A 2-h Cr-51-EDTA distribution space estimated extracellular fluid vo lume (ECFV), and a 5-min I-125-labeled albumin distribution space meas ured plasma volume (PV). Total tissue water (TW) was measured from wet and dry weights; interstitial fluid volume (ISFV) and cell water were calculated. NS resuscitation required 7 times more fluid (50.9 +/- 7. 7 vs. 8.6 +/- 0.7 for HA, 5.9 +/- 0.4 for HS, and 3.9 +/- 0.5 ml/kg fo r HSA), but there were no differences between solutions in whole anima l PV, ECFV, or ISFV. Fluid shifts within tissues depended on resuscita tion solution and type of tissue. TW was significantly reduced by hype rtonic saline groups in heart, muscle, and liver (P < 0.05). ISFV was significantly reduced by HA groups in the skin. In all tissues, mean c ell water in groups receiving HS was smaller; this was significant for heart, lung, muscle, and skin. In conclusion, I)HS solutions mobilize fluid from cells while expanding both PV and ISFV, and 2) TW and cell ular water increase with both isotonic crystalloids and hyperoncotic c olloids in many tissues.