The Effect Of Lung Recruitment On Extravascular Lung Water Index And Serum Lung Surfactant Protein A In Patients With ARDS

Objective To investigate the effects of recruitment maneuvers (RMs) strategy on extravascular lung water index and serum surfactant protein A (SP-A) in patients with acute respiratory distress syndrome (ARDS). Methods Thirty patients with early ARDS from January 2007 to August 2008 were enrolled in the study. They were randomized into two groups. Group RM(n=15):After stabilizing by basic mechanical ventilation for 30 minutes, RM was performed by regulating FiO2 to 1.00, applying 20cmH2O of inspiratory pressure(Pressure above PEEP 20cmH2O)and 20cmH2O of PEEP for 120 seconds, and then resuming the previous mechanical ventilation settings. This modality was repeated once every 12 hours lasting 3 days. Group Non- RM(n=15): Lung protective strategy was conducted without RM. Monitoring of patients before the trial, test 12h, 24h, 48h, 72h (2 hours after RM) blood gas analysis (PaCO2, PaO2, PaO2/FiO2) and respiratory mechanics (PIP, Pplat, Cst) targets, comparison before and after RM hemodynamics (MAP, CVP, CI, HR) changes; Monitoring EVLWI before and at 12h, 24h, 48h, 72h of the test; using Westetrn blot test detected serum pulmonary surfactant protein A (SP-A) of two groups at 72h and before testing; APACHEⅡscores and LIS of two groups were compared before test and at test 72h. Results①Two groups showed an upward trend in PaO2/FiO2, at 12h, 24h, 48h, 72h, which were significantly different from basic values (P<0.05 or P <0.01); at 12h, 24h, 48h, 72h two sets of PaO2/FiO2 were significant difference (P<0.05 or P<0.01); two groups showed an upward trend in PaCO2, at 12h, 24h, 48h, 72h which were significantly different from basic values(P<0.01), but there was no significant difference between two group(P>0.05); RM Group PIP and Pplat decline,Cst increased at 12h, 24h, 48h, 72h and at the same time two groups of PIP, Pplat, Cst were significant difference(P<0.05 or P<0.01).②There were transient hemodynamic changes during RM, compared with pre-RM the changes were significantly different (P<0.01), but 120 seconds after the end of RM differences were not significant (P>0.05).③Two groups showed an downward trend in EVLWI and at 12h, 24h, 48h, 72h there were significantly different from basic values (P<0.05 or P<0.01). At 12h, 24h, 48h, 72h EVLWI compared,two groups were significantly different (P<0.05 or P<0.01).④T wo groups of patients with serum SP-A before the trial were no significant difference(P>0.05); at 72h two groups of serum SP-A gray-scale values were significantly different(P<0.01).⑤At 72h of the test APACHEⅡscores of two group were no significant difference from basic values (P>0.05); between two groups at 72h test APACHEⅡscores were not significantly different(P>0.05); at 72h of the experiment LIS of two group were both significant difference from basic values (P<0.05 or P<0.01); two groups of LIS compared at 72h of the test were significantly different(P<0.01).⑥Serum SP-A was a negative correlation with PaO2/FiO2 and Cst (r =-0.492, P<0.01 and r =-0.436, P<0.05), positive correlation with the LIS(r = 0.683, P<0.01); EVLWI was a negative correlation with PaO2/FiO2 and Cst(r =-0.612, P<0.01 and r =-0.537, P<0.01), positive correlation with the LIS(r = 0.761, P<0.01). Conclusion RM can reduce extravascular lung water index, reduce serum pulmonary surfactant protein A concentration, increase lung gas exchange, increase oxygenation and lung compliance, decrease the degree of LIS; EVLWI and serum surfactant protein were a negative correlation with PaO2/FiO2 and Cst, positive correlation with the LIS. EVLWI and serum pulmonary surfactant protein A may reflect the severity of ARDS patients. They can become one of the diagnosis indicators of ARDS, but also can be used as clinical efficacy and sensitive indicator of ARDS with RM.