Kaisers U, Kuhlen R, Keske U, Sommerer A, Mohnhaupt A, Falke K J, Rossaint R
Klinik für Anästhesiologie und Operative Intensivmedizin, Virchow-Klinikum, Medizinische Fakultät der Humboldt Universität zu Berlin, Germany.
Eur Respir J. 1998 May;11(5):1035-42. doi: 10.1183/09031936.98.11051035.
This study was undertaken to determine the effects of superimposing incremental levels of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) on gas exchange, respiratory mechanics and morphological changes in experimental acute lung injury (ALI). In a prospective trial, six pigs weighing 30+/-5 kg (mean+/-SD) were tracheotomized, submitted to pressure-controlled mechanical ventilation (pc-CMV) and depleted of surfactant by lung lavage. Animals were then mechanically ventilated with three levels of PEEP: 0.5, 1.0 and 1.5 kPa. PLV was then initiated by intratracheal instillation of 30 mL x kg(-1) perfluorocarbon, followed by pc-CMV with PEEP 0.5, 1.0 and 1.5 kPa. Computed tomography (CT)-based analyses of lung volumes and density were obtained after lung lavage, in PLV and during the combined application of PLV and PEEP. Simultaneously, haemodynamics, gas exchange, dynamic compliance (Cdyn) and dynamic resistance (Rdyn) were determined. Statistical analysis was performed using multivariate analyses of variance for repeated measures (p<0.05). In ALI and before PLV, the application of PEEP significantly reduced cardiac output and intrapulmonary shunt. Arterial oxygen tension (Pa,O2) was increased from 6.9 kPa (52 (42, 54) mmHg) (median, (25th and 75th percentile)) to 8.6 kPa (65 (52, 133) mmHg) (PEEP 1.0 kPa) and 15.6 kPa (117 (90, 195) mmHg) (PEEP 15 kPa) (p<0.05). The lung volume obtained by CT increased, CT density was reduced (p<0.05), Cdyn tended to increase and Rdyn to decrease (nonsignificant). PLV increased arterial carbon dioxide tension and reduced pH (p<0.05). CT lung volume and lung density were increased (p<0.05). Superimposing PEEP on PLV increased Pa,O2 from 9.3 kPa (70 (52,124) mmHg) (PEEP 0.5 kPa) to 12.9 kPa (97 (55, 233) mmHg) (PEEP 1.0 kPa) and 403 kPa (303 (64, 426) mmHg) (PEEP 1.5 kPa) (p<0.05), but had no significant effect on CT lung volume and density. It was concluded that in experimental lung injury, positive end-expiratory pressure provided alveolar recruitment. The combined application of positive end-expiratory pressure and partial liquid ventilation significantly augmented oxygenation and might eventually allow either a reduction in the volumes of perfluorocarbons required, or a reduction in positive end-expiratory pressure necessary to maintain pulmonary gas exchange in acute lung injury.
本研究旨在确定在部分液体通气（PLV）过程中叠加递增水平的呼气末正压（PEEP）对实验性急性肺损伤（ALI）时气体交换、呼吸力学及形态学变化的影响。在一项前瞻性试验中，对6头体重为30±5 kg（均值±标准差）的猪进行气管切开，给予压力控制机械通气（pc-CMV），并通过肺灌洗去除表面活性物质。然后动物接受三种水平的PEEP机械通气：0.5、1.0和1.5 kPa。随后通过气管内注入30 mL·kg⁻¹全氟碳化合物开始PLV，接着进行PEEP为0.5、1.0和1.5 kPa的pc-CMV。在肺灌洗后、PLV期间以及PLV与PEEP联合应用期间，基于计算机断层扫描（CT）分析肺容积和密度。同时，测定血流动力学、气体交换、动态顺应性（Cdyn）和动态阻力（Rdyn）。采用重复测量的多变量方差分析进行统计分析（p<0.05）。在ALI且PLV之前，应用PEEP显著降低心输出量和肺内分流。动脉血氧分压（Pa,O2）从6.9 kPa（52（42,54）mmHg）（中位数，（第25和75百分位数））升至8.6 kPa（65（52,133）mmHg）（PEEP 1.0 kPa）和15.6 kPa（117（90,195）mmHg）（PEEP 1.5 kPa）（p<0.05）。CT测得的肺容积增加，CT密度降低（p<0.05），Cdyn有增加趋势，Rdyn有降低趋势（无统计学意义）。PLV使动脉血二氧化碳分压升高，pH降低（p<0.05）。CT肺容积和肺密度增加（p<0.05）。在PLV基础上叠加PEEP使Pa,O2从9.3 kPa（70（52,124）mmHg）（PEEP 0.5 kPa）升至12.9 kPa（97（55,233）mmHg）（PEEP 1.0 kPa）和40.3 kPa（303（64,426）mmHg）（PEEP 1.5 kPa）（p<0.05），但对CT肺容积和密度无显著影响。研究得出结论，在实验性肺损伤中，呼气末正压可使肺泡复张。呼气末正压与部分液体通气联合应用可显著增强氧合，最终可能减少急性肺损伤中维持肺气体交换所需的全氟碳化合物量或呼气末正压。
