摘要
目的探讨以不同肺牵张指数(lung stress index)选择的呼气末正压(PEEP)与急性呼吸窘迫综合征(ARDS)肺复张容积与氧合的关系。方法油酸静脉注射复制犬ARDS模型,容量控制通气,流速恒定的压力-时间(P-t)曲线吸气支,回归法计算得方程P=a×timeb+c,b为肺牵张指数。调整PEEP水平使b=1。采用控制性肺膨胀实施肺复张手法,复张后再次调整PEEP水平分别达到b=1、0．6<b<0．8与1．1<b<1．3,稳定通气30 min后用压力-容积(P-V)曲线法测定复张容积,同时观察血流动力学、呼吸力学和肺气体交换。结果肺复张前b=1时,PEEP为(5．0±3．0) cm H2O(1 cm H2O=0．098 kPa),肺复张容积为(27±15)ml,而肺复张后b=1时,PEEP为(10．8±2．3)cm H2O,肺复张容积为(166±84)ml,与复张前比较差异有统计学意义(q=3．18,P=0．007)。在1．1<b<1．3时,PEEP为(16．8±1．1)cm H2O,肺复张容积为(262±57)ml,与复张后b=1时的肺复张容积比较差异有统计学意义(q=2．54,P=0．023);0．6<b<0．8时,PEEP为(5．6±2．2)cm H2O,肺复张容积为(58±45)ml,与复张后b=1时比较显著降低(q=2．85,P=0．013)。与复张前b=1比较,复张后b=1、0．6<b<0．8和1．1<b<1．3时的动脉血氧分压(PaO2)均显著升高(q均为2．81,P均<0．05)。与复张后b=1比较,0．6<b<0．8时PaO2显著降低(q=2．81,P=0．005),而1．1<b< 1．3时PaO2比较差异无统计学意义(q=0．153,P>0．05)。在呼吸力学方面,与复张后b=1相比, 1．1<b<1．3时气道峰值压(PIP)与平台压(Pplat)明显升高(q分别为6．02、5．72,P均<0．05),复张前b=1与复张后0．6<b<0．8的PIP与Pplat则显著降低(q分别为2．62、2．94、2．75、2．86,P均< 0．05)。结论复张后b=1时可获得最好的氧合和较低的气道压,可指导肺复张后的PEEP选择。
Objective To determine the relationship of stress index with lung recruitment and gas exchange in dogs with acute respiratory distress syndrome （ARi）S）. Methods The ARDS model was induced by infusion of oleic acid intravenously in anesthetized dogs. During volume control ventilation with constant inspiratory flow,the pressure-time（P-t） curve was fitted to a power equation： P = a · time^b ± c, where coefficient b（ stress index） describes the shape of the curve： b = 1, straight curve; b 〈 1, progressive increase in slope ; and b 〉 1, progressive decrease in slope. Tidal volume （ VT ） was 6 ml/kg, and positive end-expiratory pressure（PEEP） was set to obtain a b value between 0. 9 and 1.1 before（ b = 1 ） and after （b = 1 after recruiting maneuver） application of a recruiting maneuver（ RM ）. PEEP was changed to obtain 0.6 〈 b 〈 0. 8 and 1.1 〈 b 〈 1.3. Experimental condition sequence was random. Recruited volume （ RV ） was measured by static pressure-volume curve method. Hemodynamics, pulmonary mechanics and gas exchange were observed at the same time. Results At b = 1 without RM, the PEEP was （ 5.0 ± 3. 0 ） cm H2O, the RV was （27 ± 15 ）ml, and the RV increased to （166 ± 84 ）ml significantly at b = 1 after RM [ PEEP （10.8 ±2.3）cm H2O （1 cm H2O =0.098 kPa）,q=3.18,P〈0.01]. At 1.1 〈b〈1.3 after RM,the PEEP was （ 16. 8 ± 1.1 ） cm H2O and the RV was （ 262 ± 57 ） ml, which was higher than that at b = 1 after RM （q = 2.54, P = 0. 023）. At 0. 6 〈 b 〈 0. 8 after RM, the PEEP was （5.6 ± 2. 2） cm H2O and the RV was lower than that at b = 1 after RM（q =2. 85,P =0. 013）. The partial pressure of oxygen in arterial blood （PaO2） inb=1,0.6〈b〈0.8 and 1.1 〈b〈1.3 after RM were （319±49）mm Hg （1 mm Hg=0.133 kPa）, （246 ± 57 ）mm Hg and （314 ± 27 ）mm Hg respectively, which was higher than the PaO2 at b = 1 without RM[ （ 153 ±64）mm Hg,all q =2. 81 ,all P 〈0. 05]. The PaO2 at 0.6 〈 b 〈0. 8 was lower than that at b = 1 after RM（q =2. 81 ,P =0. 005） ,while there was no significant difference between the PaO2 at 1.1 〈 b 〈 1.3 and that at b = 1 after RM. The peak airway pressure and plateau pressure at 1.1 〈 b 〈 1.3 were higher than those at b = 1 after RM （ q = 6.02,5. 72, all P 〈 0. 05 ）. Conclusion In the b = 1 after RM, there were better PaO2 and lower airway pressure, suggesting that b = 1 after RM may be a good indicator for PEEP titration.
出处
《中华结核和呼吸杂志》
CAS
CSCD
北大核心
2006年第8期554-557,共4页
Chinese Journal of Tuberculosis and Respiratory Diseases
基金
教育部新世纪优秀人才支持基金(NCET-04-0476)
江苏六大人才高峰基金(1190000009)
江苏省医学重点课题(H200102)
关键词
呼吸窘迫综合征
急性
正压呼吸
肺复张手法
肺牵张指数
犬
recruitment maneuver
Respiratory distress syndrome, acute
Positive-pressure respiration
Lung stress index
Dogs
