Effects of Hemodilution on Red Blood Cell Fragility Index

Twenty patients with coronary artery disease were selected at random to study the effects of hemodilution on red blood cell fragility index before undergoing extracorporeal circulation. The purpose of this study is to establish accurate base line values based on hematocrit ranges as a prelude to studying red blood cell trauma during extracorporeal circulation. For each patient studied, five separate samples were mixed with various amounts of lactated Ringers solution. The dilutions resulted in a separation of approximately 7 hematocrit between the five samples. The samples were then studied within four hours using the modified Dacie's Method. 1•2 Results of the studies show significant differences in RBC fragility values between the samples from 45 hematocrit to 15. A search of the literature dealing with blood trauma reveal no information relating to the significance of hemodilutions to red blood cell trauma. The authors believe that hemodilution is a major factor to consider in evaluating red blood cell trauma studies and a method of this type should be employed in doing so. CLINICAL MATERIAL Twenty patients with coronary artery disease were selected at random for this study. They were chosen because as a group they have I) normal hematocrit values, 2) their blood has not been subject to any trauma like that of the valve patients, and 3) they arc readily available. The twenty patients were, however, screened for their hematological profile3 before their blood was used in this study. METHODS Arterial blood is drawn from the patient before perfusion and put into five separate test tubes labeled A, B, C, D, and E. Each test tube contains 0, 1h, I, 11h, and 2cc. of lactated Ringers respectively. The amount of blood put in each test tube will total 3cc. This will result in various levels of hemodilution. Each sample is then prepared within four hours using the modified Dacie's Method.2 Address reprint request to: Richard Chan, 34 Capitol Heights Rd., Oyster Bay, New York 11771 (516922-0855). VOLUME 11, NUMBER 5, 1979 183