PHYSIOLOGICAL RESPONSES, ORGAN DISTRIBUTION, AND CIRCULATION KINETICS IN ANESTHETIZED RATS AFTER HYPOVOLEMIC EXCHANGE TRANSFUSION WITH TECHNETIUM-99m-LABELED LIPOSOME-ENCAPSULATED HEMOGLOBIN

摘要

ABSTRACTPhysiological responses and circulation properties of liposome-encapsulated hemoglobin (LEH) labeled with technetium-99m (99mTc) were measured in rats after a 10percnt; (170 mg/kg hemoglobin, 430 mg/kg phospholipid) or a 50percnt; (450 mg/kg hemoglobin, 2.3 g/kg phospholipid) hypovolemic exchange transfusion (n equals; 5 per exchange group). Mean arterial pressure returned to baseline values (105 plusmn; 8 mmHg) by 90 min post-infusion for both groups. By 20 h, mean arterial pressure remained at baseline values for the 10percnt; group, but dropped to 30 plusmn; 14 mmHg for the 50percnt; group. For both groups, bradycardia was seen after the exchange period, but heart rate recovered by 30 min for the 10percnt; group and by 90 min for the 50percnt; group. The99mTc-LEH remained in circulation longer for the 50percnt; group (18.2 h half-life) than for the 10percnt; group (2.4 h half-life). Removal of99mTc-LEH from the bloodstream was via the liver and spleen. At 20 h,99mTc-LEH accumulation in these organs was greater for the 10percnt; group (liver, 36.2 plusmn; 1.7percnt;; spleen, 37.5 plusmn; 2.5percnt;) than for the 50percnt; group (liver, 17.0 plusmn; 1.4percnt;; spleen, 17.1 plusmn; 1.4percnt;). The data show that there is less clearance of99mTc-LEH from the bloodstream by the reticuloendothelial system after a 50percnt; hypovolemic exchange transfusion, thus supporting the possible use of LEH as an oxygen-carrying resuscitative fluid in situations of severe blood loss.