急性肺损伤犬的压力-容积曲线

Pressure-Volume Curve of Dogs with Acute Lung Injury

目的 研究急性肺损伤 (ALI)犬的压力 -容积 (p V)曲线。 方法 静脉注射油酸制造ALI犬模型 ,以功能残气量 (FRC)为基点测定不同容积时的压力变化 ,并与健康犬比较。结果 健康犬在 p V曲线非常低的位置出现低位拐点 (LIP) ,其压力和容积分别为 (0 .4± 0 .2 )kPa和 (6 0± 2 2 )ml;而ALI犬则在较高的位置出现LIP ,且是一段范围 ,其压力和容积分别为 [(1.0± 0 .4 )～ (1.2± 0 .1) ]kPa (P <0 .0 5 )和 [(130± 5 7)～ (2 15±92 ) ]ml(P <0 .0 5 )。健康犬高位拐点 (UIP)的压力和容积分别为 (2 .5± 0 .2 )kPa和 (12 4 0± 15 2 )ml,ALI犬则相应为 (2 .6± 0 .2 )kPa (P >0 .0 5 )和 (72 0± 12 0 )ml(P <0 .0 5 )。健康犬中间陡直段的顺应性为 (5 6 8.4± 5 5 .1)ml/kPa ,ALI犬下降至 (36 7.3± 5 6 .1)ml/kPa (P <0 .0 5 )。结论 机械通气健康犬和ALI犬分别在FRC上的较低水平和较高水平出现LIP ,且ALI犬的LIP是一段范围 ;两者UIP的压力相似 。

Purpose: To observe the changes of respiratory mechanics of dogs with acute lung injury (ALI). Methods: 10 hybrid dogs were seperated into two groups. In the control group(CG), the lung volumes of normal animals were measured at different pressures. In experimental group(EG), 5 accepted intravenous oleic acid. When PaO2/FiO2 decreased to 40 - 26. 7 kPa, the volumes at different pressures were also measured, then the pressure - volume curves were drawnd and compared with those of CG. Results: In CG, there was lower inflection points (LIP) at lower lung capacity, the pressure and volume of LIP was (0.4 ± 0.2) kPa and (60 ± 22) ml, respectively. The pressure and volume of upper inflection point (UIP), total compliance (C) of chest wall and lung were (2.5 ± 0.2) kPa, (1 240 ± 152) ml, (568. 4 ± 55.1) ml/kPa. In EG, there was LIP at higher lung capacity, and LIP had a certain range instead of a point, the pressure and volume of LIP were [(1.0 ± 0.4) - (1.2 ± 0.1)] kPa (P 0.05), (720 ± 120) ml (P < 0.05). The C decreased to (367.3±56.1) ml/kPa (P < 0.05). Conclusions: In ALI dog, there was a higher LIP above functional residual capacity(FRC), and LIP had a certain range. The volume of UIP and C was significantly decreased, but the pressure of UIP was normal.