单指示剂法与重力法测定急性呼吸窘迫综合征犬血管外肺水的比较研究

目的 比较单指示剂法与重力法测定不同急性呼吸窘迫综合征（ARDS）模型犬血管外肺水（EVLW）的差异。方法 33只犬按随机数字表法分成对照组、油酸静脉注射复制ARDS模型组（油酸组）和盐酸吸入复制ARDS模型组（盐酸组）。用单指示剂法测定ARDS成模前、成模时及成模后10hEVLW；成模后10h处死动物，用重力法（金标准）测定EVLW；并监测血流动力学、血气分析和呼吸力学指标变化。结果 单指示剂法和重力法测定的EVLW呈显著正相关（r=0．8820，P〈0．05）；与重力法相比，单指示剂法测定的EVLW显著增高。对照组单指示剂法和重力法测定的EVLW呈显著正相关（r=0．9870，P〈0．05）；油酸组单指示剂法和重力法测定的EVLW呈显著正相关（r=0．9360，P〈0．05）;盐酸组单指示剂法和重力法测定的EVLW呈显著正相关（r=0．7950，P〈0．05），但其相关性较前两组差。ARDS10h时，盐酸组肺内分流和动脉血二氧化碳分压显著高于油酸组（P〈0．05）。而氧合指数却显著低于油酸组（P〈0．05）。结论 单指示剂法与重力法测定ARDS的EVLW有正相关性，但不同原因导致的ARDS其相关性不同。

Comparison of single-indicator thermodilution versus gravimetric measurement in determination of extra-vascular lung water in dogs with acute respiratory distress syndrome

OBJECTIVE: To compare the measurement of extra-vascular lung water (EVLW) by a single-indicator dilution technique and measurement obtained by gravimetry in different types of acute respiratory distress syndrome (ARDS). METHODS: Thirty-three dogs were randomly assigned to three groups: control group, oleic acid group and hydrochloric acid group. ARDS was reproduced by either intravenous injection of oleic acid or intratracheal instillation of hydrochloric acid. EVLW was measured before ARDS, at the onset of ARDS and 10 hours after ARDS by a single indicator dilution technique. Ten hours after ARDS, dogs were sacrificed and then EVLW was quantitated by a gravimetric measurement (golden standard). Hemodynamics and pulmonary gas exchange were determined. RESULTS: There was a close positive correlation (r=0.8820, P<0.05) between single indicator dilution and gravimetric measurements. However, the measurement with the single indicator dilution was consistently higher than the gravimetric measurement. In the control group, there was a positive correlation (r=0.9870, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the oleic acid group, there was also a significant correlation (r=0.9360, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the hydrochloric acid group, correlation (r=0.7950, P<0.05) was also found between EVLW as measured by the two methods. However, the correlation found was lower in the hydrochloric acid group than those in other two groups. Hydrochloric acid instillation resulted in a significant increase in shunting and the partial pressure of carbon dioxide in artery (PaCO(2)) compared with oleic acid group at 10 hours after ARDS. CONCLUSION: The results of measuring EVLW using single indicator dilution measurement are closely related with those of gravimetric measurement in ARDS, however, the correlations varies with the methods of reproduction of ARDS.