Marumo C K, Otsuki D A, Fantoni D T, Margarido C B, Ambrósio A M, Pelosi P, Auler J O C
Laboratory of Medical Investigation LIM08, Faculdade de Medicina, Universidade de São Paulo, Brazil.
Acta Anaesthesiol Scand. 2009 Feb;53(2):190-202. doi: 10.1111/j.1399-6576.2008.01842.x. Epub 2008 Dec 15.
Positive end-expiratory pressure (PEEP) and sustained inspiratory insufflations (SI) during acute lung injury (ALI) are suggested to improve oxygenation and respiratory mechanics. We aimed to investigate the hemodynamic effects of PEEP with and without alveolar recruiting maneuver in a mild ALI model induced by inhalation of hydrochloric acid.
Thirty-two pigs were randomly allocated into four groups (Control-PEEP, Control-SI, ALI-PEEP and ALI-SI). ALI was induced by intratracheal instillation of hydrochloric acid. PEEP values were progressively increased and decreased from 5, 10, 15 and 20 cmH2O in all groups. Three SIs maneuvers of 30 cmH2O for 20 s were applied to the assignable groups between each PEEP level. Transesophageal echocardiography (TEE), global hemodynamics, oxygenation indexes and gastric tonometry were measured 5 min after the maneuvers had been concluded and at each established value of PEEP (5, 10, 15 and 20 cmH2O).
The cardiac index, ejection fraction and end-diastolic volume of right ventricle were significantly (P < 0.001) decreased with PEEP in both Control and ALI groups. Left ventricle echocardiography showed a significant decrease in end-diastolic volume at 20 cmH2O of PEEP (P < 0.001). SIs did not exert any significant hemodynamic effects either early (after 5 min) or late (after 3 h).
In a mild ALI model induced by inhalation of hydrochloric acid, significant hemodynamic impairment characterized by cardiac function deterioration occurred during PEEP increment, but SI, probably due to low applied values (30 cmH2O), did not exert further negative hemodynamic effects. PEEP should be used cautiously in ALI caused by acid gastric content inhalation.
急性肺损伤（ALI）期间的呼气末正压（PEEP）和持续吸气充盈（SI）被认为可改善氧合和呼吸力学。我们旨在研究在吸入盐酸诱导的轻度ALI模型中，有或没有肺泡复张手法时PEEP的血流动力学效应。
32只猪被随机分为四组（对照组-PEEP、对照组-SI、ALI-PEEP和ALI-SI）。通过气管内滴注盐酸诱导ALI。所有组的PEEP值从5、10、15和20 cmH₂O逐渐增加和降低。在每个PEEP水平之间，对可分配组应用三次30 cmH₂O持续20秒的SI手法。在手法结束后5分钟以及每个设定的PEEP值（5、10、15和20 cmH₂O）时，测量经食管超声心动图（TEE）、整体血流动力学、氧合指数和胃张力测定。
在对照组和ALI组中，PEEP均使心脏指数、射血分数和右心室舒张末期容积显著降低（P < 0.001）。左心室超声心动图显示，在PEEP为20 cmH₂O时舒张末期容积显著降低（P < 0.001）。SI在早期（5分钟后）或晚期（3小时后）均未产生任何显著的血流动力学效应。
在吸入盐酸诱导的轻度ALI模型中，PEEP增加期间出现了以心功能恶化为特征的显著血流动力学损害，但SI可能由于应用值较低（30 cmH₂O），未产生进一步的负面血流动力学效应。在因吸入胃酸引起的ALI中，应谨慎使用PEEP。
