Quantitative Measurement of Bleeding Following Hypertonic Saline Therapy in 'Uncontrolled' Hemorrhagic Shock

The effect of small volume hypertonic saline in “uncontrolled” hemorrhagic shock (UCHS) induced by partial resection of the tail was studied in rats. The rats were divided into three groupsin group 1 (n = 15) 10% of the terminal portion of the animalʼs tail was resected to induce UCHS. In group 2 (n = 14) UCHS was induced as in group 1 and after 5 min 5 ml/kg NaCl 0.9% (NS) was infused intravenously. In group 3 (n = 22) UCHS was induced as in group 1 and after 5 min, 5 ml/kg NaCl 7.5% (HTS) was infused intravenously. Resection of the animalʼs tail was followed by bleeding of 3.5 ± 0.3 ml within 5 min, fall in MAP to 63 ± 4 torr (p < 0.001) and pulse to 300 ± 18 per min (p < 0.05). The amount of bleeding, fall in MAP, and pulse after 5 min were similar in the three groups. Further blood loss after 60 min in group 1 was 3.7 ± 0.8 ml, in group 2, 2.9 ± 0.5 ml, and in group 3, 6.5 ± 0.8 (p < 0.01). Increased bleeding in group 3 showed two peaksan early peak of 1.3 ± 0.2 ml after 15 min (p < 0.05) and a late peak of 1.2 ± 0.4 ml at 45 min (p < 0.05) and 1.7 ± 0.5 ml at 60 min (p < 0.01). MAP fell after 60 min to 54 ± 7 torr in group 1 (p < 0.01). It increased to 68 ± 7 torr (p < 0.05) in group 2 and decreased to 50 ± 7 torr (p < 0.05) in group 3. Increased bleeding and a fall in MAP following HTS infusion resulted in an early death of 73% of the animals with a mean survival time of 115 ± 11 min. The mortality of the animals in group 1 was 20% and in group 2 12% with a mean survival time of 166 ± 7 and 176 ± 4 min, respectively. The mean survival time in group 3 was significantly lower than in group 1 (p < 0.01) or group 2 (p < 0.01).It is concluded that HTS infusion in “uncontrolled” hemorrhagic shock leads to increased blood loss from injured vessels, fall in MAP, and early mortality.