ISOLYTE-S, A PHYSIOLOGICAL MULTIELECTROLYTE SOLUTION, IS PREFERABLE TO NORMAL SALINE TO WASH CELL SAVER SALVAGED BLOOD - CONCLUSIONS FROM APROSPECTIVE, RANDOMIZED STUDY IN A CANINE MODEL

Objectives: The purpose of this study is to compare normal saline with Isolyte S as the wash solutions during high-volume cell saver autolog ous blood transfusion. Normal saline, the standard wash solution in ce ll saver autologous blood transfusion, is associated with acid base an d electrolyte derangements. Isolyte S is a physiologic, balanced multi electrolyte crystalloid solution that approximates the electrolyte con tent of plasma. Design: open-label, prospective, randomized study. Set ting: Research laboratory in a Department of Veterans Affairs medical center. Subjects: Fourteen mongrel dogs, weighing 22 to 23 kg each. In terventions: Fourteen mongrel dogs were prospectively randomized to re ceive normal saline (n = I) or Isolyte S (n = 7). Animals were anesthe tized, received heparin for anticoagulation, and underwent 18 cycles o f cell saver autotransfusion. In each cycle, 125 mt of blood was arter ially withdrawn, and washed with either normal saline (mEq/L) (sodium 154, chloride 154) or Isolyte S (mEq/L) (sodium 141, potassium 5, magn esium 3, chloride 98, phosphate 1, acetate 28, and gluconate 23). The washed blood was retransfused. Measurements and Main Results: Acid bas e and electrolyte analyses were performed throughout the study on the systemic blood of each group and compared. By the end of the study, th e Isolyte S group had a normal pH and an increased bicarbonate concent ration (mEq/L: normal values 24 to 32; normal saline 9.0 +/- 1.9 vs. I solyte S 13.2 +/- 3.0 [p <.01]) and an increased magnesium concentrati on (mg/dL: normal Values 1.6 to 2.4; normal saline 1.6 +/- 0.2 vs. Iso lyte S 2.2 +/- 0.2 [p <.0001]). Additionally, the Isolyte S group had a lower chloride concentration (mEq/L: normal values 95 to 110; normal saline 130 +/- 9 vs. Isolyte S 117 +/- 7 [p<.02]) and a lower potassi um concentration (mEq/L: normal values 3.5 to 5.0; normal saline 4.4 /- 0.5 vs. Isolyte S 3.7 +/- 0.3 [p <.01]). There were no significant differences between normal saline or Isolyte S in the Values of PCO2, lactic acid, sodium, total and ionized calcium, inorganic phosphorus, total protein, albumin, hemoglobin, and hematocrit. Conclusions: Fewer systemic acid base and electrolyte derangements were observed when bl ood was washed with Isolyte S. Differences between the normal saline a nd Isolyte S groups are ascribed primarily to the constituents of the wash solution. We conclude that Isolyte S, a physiologic, balanced, mu ltielectrolyte solution, should be considered as the wash solution in high-volume autologous cell saver blood processing and transfusion.