EFFECT OF NEO RED-CELLS ON HEMODYNAMICS AND BLOOD-GAS TRANSPORT IN CANINE HEMORRHAGIC-SHOCK AND ITS SAFETY FOR VITAL ORGANS

The purpose of this study was to evaluate the effects of liposome enca psulated hemoglobin named ''Neo Red Cells (NRC)'' on canine hemorrhagi c shock model and its safety for the vital organs in a whole blood exc hange model. HEMORRHAGIC SHOCK: Nine adult mongrel dogs were used. Und er mechanical ventilation inhaling room air, blood was withdrawn via a n artery at a rate of 40 ml / min in order to induce hemorrhagic shock (systolic pressure below 60(mm)Hg) and then NRC was transfused. For e ach animal, three to five cycles of bloodletting and NRC transfusion w ere performed. After blood exchange, total peripheral resistance index (TPRI) decreased and cardiac index (CI) increased. These changes were more marked in the high exchange group (exchange rate over 88%; five animals) than in the low exchange group (less than 88%; four animals), indicating that the low viscosity NRC reduced the load on the circula tory system. The A-V difference in oxygen content per Ig hemoglobin wa s greater after blood exchange, indicating that oxygen binding capacit y of NRC is higher than that of red blood cells. WHOLE BLOOD EXCHANGE: Five beagles were used for the blood exchange. The blood was withdraw n from an artery at a rate of 15 ml /min and NRC was infused at the sa me time. A dog whose blood was exchanged with hydroxyethylstarch inste ad of NRC died within 15 hours after blood exchange. Three dogs whose blood was exchanged with NRC (exchange rate was from 82 to 90%) have b een living over a year without any side effects. A dog sacrificed on t he 15th postoperative day for autopsy, microscopically showed no side effects in vital organs. We conclude that NRC is more suitable than na tural blood for treatment of hemorrhagic shock and safe for vital orga ns.