持续性静-静脉血液滤过防治犬海水型呼吸窘迫综合征的实验研究

Experimental Canine Models of Respiratory Distress Syndrome Induced by Immersion in Seawater and Treated with Continuous Blood Purification

目的用床边透析机行持续性静-静脉血液滤过（CVVH），防治犬海水型呼吸窘迫综合征（SW—RDS）。方法实验动物随机分成A组（治疗组，n=7）与B组（模型组，n=7）。采用BM-25连续性床边血滤机（Baxter，USA）进行CVVH。犬灌完海水15min后，CVVH干预治疗4h，累计净超水量50～100ml（扣除灌人海水量）。在不同时间点观察动脉血气分析、血内皮素（ET）、氧自由基，并进行病理学检查。结果A组犬全部存活，B组有2只犬在海水灌注4h时死亡。犬灌人海水15min后，动脉血气显示明显的代谢性酸中毒、持续性低氧血症，pH、氧分压（Pa02）、血氧饱和度（SO2）、实际碳酸氢盐（AB）、剩余碱（BE）明显下降。4h后测一氧化氮（NO）、超氧化物歧化酶（SOD）下降，ET、丙二醛（MDA）上升，经CVVH治疗4h，与对照组相比，pH、AB、BE基本上恢复正常，PaO2、SO2有所回升，但尚未恢复正常。ET、MDA下降，SOD上升（P〈0．05），NO虽有上升，但差异无统计学意义（P〉0．05）。经CVVH治疗4h后，肺组织病变从外观、光镜、电镜均较模型组明显轻。结论本疗法防治犬SW-RDS，具有纠正酸碱平衡失调和改善低氧血症、清除血管外肺积水，显著减轻肺损伤的作用。

Objective To study the experimental Canine models of respiratory distress syndrome （RDS） induced by immersion in seawater （SW） （SW-RDS） and treated with continuous blood purification （CBP）. Methods Hybrid dog SW-RDS models were randomly assigned into trial group with continuous venous-to-venous hemofiltration （ CVVH ） （ n = 7 ） and control group （ n = 7 ）. Fifteen minutes after immersion in SW, the dogs in the trial group were purely removed 50 - 100 ml fluid during four hours＇ CVVH treatment. The changes in blood gas analysis, endothelin （ET） and oxyradical were compared between the two groups, as well as the histological changes in the lung tissues. Results All the dogs in the trial group survived, however two dogs in the control group died after four hours＇ immersion in seawater. Fifteen minutes after immersion, blood gas analysis reported markedly metabolic acidosis, hypoxemia and decrease in the arterial pH, oxygen partial pressure （ PaO2 ）, saturation of blood oxygen （ SO2 ）, actual bicarbonate （AB） and base excess （BE）. Afer four hours＇ immersion, nitrogen monoxide （NO） and superoxide dismutase （SOD） decreased, whereas ET and malondialdehyde （MDA） ascended. Compared with that of the control group, pH, AB and BE of the trial group were retrieved roughly to normal after four hours＇ CVVH, PaO2 and SO2 ascended （ not retrieved to normal） , ET and MDA significantly decreased, and SOD ascended notably. In the trial group, lung histological changes including the shape and the findings under light microscope and electron microscope were significantly lessened when compared with that in the control group. Conclusion The CBP treatment for SW-RDS dogs can retrieve acid-base balance, ameliorate hypoxemia, eliminate the fluid in lungs and palliate the injury of lungs.