Effect of lung recruitment on respiratory mechanics and extravascular lung water index in patients with ARDS

Objective To study the effects of recruitment maneuver (RM) strategy on respiratory mechanics and extravascular lung water index (EVLWI) in patients with ARDS. Method Thirty patients with ARDS were randomly divided into RM group and non-RM group. In the RM group, the patients were stabilized with basic mechanical ventilation support for 30 minutes, and then the RM was carried out and repeated once every 12 hous for 3 days. In the non-RM group, patients were supported with mechanical ventilation without RM. The variables of oxygenation index (PaO2/FiO2), peak inspiration pressure (PIP), plateau pressure (Pplat), static pulmonary compliance (Cst) and EVLWI of patients in both groups were determined before treatment and 12 h,24 h, 48 h and 72 h after treatment, and were compared them between two groups. The hemodynamic changes were monitored before and after RM.One-way ANOVA, t -test and Fisher probabilities in 2/2 table were used to process the data. Results ( 1 ) The PaO2/FiO2 and Cst in two groups showed upward trend after treatment, but they were higher in RM group than those in non-RM group ( P ＜ 0. 05 ). The PIP and Pplat of two groups both had downward trend after treatment, but they were significantly lower in RM group than those in group non-RM (P ＜0.05). (2) The EVLWI of two groups showed downward trend after treatment ( P ＜ 0.05), and the differences were significant at all intervals (F: 22.392, 8.147, P ＜ 0.01). The EVLWIs in group RM were lower than those in group non-RM at the intervals of 12 h,24 h, 48 h and 72 h separately (P ＜0.05 or P ＜ 0.01). (3) There were transient hemodynamic changes occurred during RM, and compared with pre-RM, the changes were significantly different ( P＜ 0.01 ). Compared with pre-RM, the hemodynanic changes were not significantly different 120 seconds after the end of RM ( P ＞ 0.05). Conclusions RM could reduce the EVLWI, increase oxygenation and lung compliance.The effect of RM on hemodynamics was transient. Key words: Lung recruitment maneuver;  Acute;  Respiratory distress syndrome;  Respiratory mechanics;  Extravascular lung water index;  Hemodynamic;  Lung protective ventilation;  Oxygenation index