急性呼吸窘迫综合征绵羊模型的建立

目的探讨静脉泵入小剂量内毒素(LPS)建立绵羊急性呼吸窘迫综合征(ARDS)模型的可行性。方法13只绵羊在全麻和肌松后，3μg/kgLPS于30分钟或6μg/kgLPS于60分钟内静脉泵入，每0.5小时监测血流动力学和氧代谢、肺气体交换和肺机械力学参数的变化，观察4小时内是否达到ARDS诊断标准以及动物的血流动力学和肺机械力学是否稳定。结果静脉泵入LPS后(3.1±1.2)小时内，10只绵羊达到ARDS诊断标准。与基础值相比，LPS静脉泵入后1小时，氧合指数明显下降(P<0.05)，之后缓慢降低，3小时后稳定；心排血指数明显下降(P<0.05)，3.5小时后恢复至基础值水平并稳定；氧输送也显著降低(P<0.05)，3.5小时后稳定。实验过程中，肺动脉楔压为1.10～1.60kPa，中心静脉压为0.90～1.70kPa。与基础值相比，LPS静脉泵入后1.5小时，气道阻力、气道峰值压和平均气道压明显上升，动态肺顺应性明显下降(t值分别2.8、4.2、5.3和3.1,P均<0.05)，分别于3.0小时和2.5小时后平稳，均无显著改变。达到ARDS诊断标准后(8.1±1.4)小时内，该模型动物血流动力学和肺机械力学均处于稳定状态。结论全麻和肌肉松弛状态下，小剂量LPS静脉泵入可快速复制血流动力学和肺机械力学均稳定的ARDS绵羊动物模型。

Experimental model of acute respiratory distress syndrome in sheep induced by a low dose of lipopolysaccharide

Objective:To establish a sheep model of acute respiratorydistress syndrome (ARDS) by intravenously infusing a low dose of lipo polysaccharide (LPS).Methods:In 13 anaesthetized sheep,36 μg/kg LPS were intravenously in fused within 3060 minutes.Hemodynamics,lung mechanics and gas exchan ge were observed every half an hour.Results:After (3.1±1.2) hours of LPS infusion,ARDS model was successfully reproduced in 10 sheep conforming to ARDS criteria.Oxygenation index significantly decreased after 1.0 hour of LPS infusion (P<0.05),and reached const an tvalues 3.0 hours later.Cardiac index significantly decreased after 1.0 houe level at 3.5 hours;so did oxygen delivery (P<0.05 ) and became constant 3.5 hours later.After 1.5 hours of LPS infusion,airway resistance,peak inspiratory pressure and mean airway pr essu re significantly increased (t=2.8,4.2,5.3,all P<0.05),but dynamic compliance markedly decreased (t=3.1,P<0.05), becoming constant gradually at 3.0 hours,2.5 hours respectively.Conclusions:It is practical and stable ARDS sheep model by intraveno usly infusing a low does of LPS.