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Physiologic responses to exchange transfusion with hemoglobin vesicles as an artificial oxygen carrier in anesthetized rats

1996; Lippincott Williams & Wilkins; Volume: 24; Issue: 11 Linguagem: Inglês

10.1097/00003246-199611000-00017

1530-0293

Yotaro Izumi, Hiromi Sakai, Kenichi Hamada, Shinji Takeoka, Takeshi Yamahata, Ryoichi Kato, Hiroyuki Nishide, Eishun Tsuchida, Koichi Kobayashi,

Methemoglobinemia and Tumor Lysis Syndrome

Objectives To evaluate the oxygen transporting capabilities of hemoglobin vesicles by studying the physiologic responses to exchange transfusion with hemoglobin vesicles in anesthetized rats. Exchange transfusions with phosphate buffered saline, hemoglobin vesicles containing methemoglobin (and therefore, deprived of oxygen transporting capabilities), and washed rat red blood cells were used as controls. Design Prospective, randomized, controlled trial. Setting Department of Surgery, School of Medicine, Keio University. Subjects Twenty-seven male Wistar rats. Interventions The rats were anesthetized with an intraperitoneal injection of sodium pentobarbital (50 mg/kg). Catheters (PE-20 tubing, outer diameter 0.8 mm, inner diameter 0.5 mm) were introduced into the right jugular vein for infusion and the right common carotid artery for blood withdrawal and mean arterial pressure measurements. The left kidney was exposed by median abdominal incision, and a needle-type polarographic oxygen electrode was placed in the left renal cortex for renal cortical tissue oxygen tension measurements. Measurements and Main Results Phosphate buffered saline and methemoglobin vesicles were administered as nonoxygen-carrying fluids, and rat red blood cells as oxygen-carrying fluid. Measurements included mean arterial pressure, arterial blood gas analysis, and renal cortical tissue oxygen tension as an indicator of systemic oxygen transport. In the rat red blood cell and hemoglobin vesicles groups, mean arterial pressure was sustained at the end of the exchange transfusion (82.3 +/- 27.5% and 73.5 +/- 11.5%, respectively, from the basal values). However, in the phosphate buffered saline and methemoglobin vesicles groups, mean arterial pressure decreased significantly (p < .05) (33.9 +/- 13.8% and 35.7 +/- 8.2%, respectively). Renal cortical tissue oxygen tension in the rat red blood cell and hemoglobin vesicles groups was sustained at a significantly higher level (p < .05) (83.5 +/- 9.3% and 75.0 +/- 11.9%, respectively) compared with the phosphate buffered saline and methemoglobin vesicles groups (44.9 +/- 12.8% and 58.3 +/- 6.2%, respectively) at the end of the exchange transfusion. Metabolic acidosis was more progressive in the phosphate buffered saline and methemoglobin vesicles groups, manifested as lower pH and base excess values. Platelet counts tended to decrease slightly in the hemoglobin vesicles and methemoglobin vesicles groups, but the changes were not significant. Conclusions Hemoglobin vesicles have an oxygen transporting capability almost equivalent to rat red blood cells and can be considered as a potential artificial oxygen carrier. (Crit Care Med 1996; 24:1869-1873)