Clinical factors influencing the efficacy of lung recruitment maneuver with high-level PEEP in patients with 2009 influenza A (H1N1)-associated acute respiratory distress syndrome / 中华急诊医学杂志

ABSTRACT

Objective To investigate the clinical factors dominant in the efficacy of lung recruitment maneuver (RM) with high-level positive end-expiratory pressure (PEEP) under pressure control ventilation in patients with 2009 influenza A (H1N1)-associated acute respiratory distress syndrome (ARDS) by analyzing the clinical data of 24 patients treated with mechanical ventilation.Methods A retrospective study was carried out in a 16-bed capacity emergency intensive care unit (EICU) of the First Affiliated Hospital of China Medical University from October 2009 to January 2010.Twenty-four patients with influenza-associated ARDS were included.During pressure control ventilation,when SpO2 persisted lower than 88％ for more than 30 min,RM with high-level PEEP was initiated to normalize lung volume at 30 cmH2O for 60 s.The RM was responded as SpO2 increased more than 3％ within 15 min; otherwise,the increase below 3％ in SpO2 would be considered non-responded.Variations in respiratory mechanics,oxygen metabolism and hemodynamic parameters were measured before and after RM.Results Of 24 patients with influenza-associated ARDS,16 survived and 8 deceased.The median duration of mechanical ventilation (DMV) in EICU was 5.5 days (range from 3.5 to 12.0 days).During the entire study period,a total of 158 RMs with high-level PEEP were done,including 76 (48.1％) responded RMs (the responded group) and 82 (51.9％) non-responded RMs (the non-responded group).In survivor group,the ratio of effective RM was higher than in nonsurvivors group (66.2％ vs.33.3％,P ＜ 0.01).Compared with the data before RM,HR was increased (92.6 ± 11.8) vs.(73.0 ± 12.6),P =0.038 and MAP was decreased (66.1 ±9.3) mmHg vs.(73.9 ± 11.4) mmHg,P=0.049 during RM,and these difference were not statistically significant at 3 min after RM.The decrease in SpO2 after 134 procedures of RMs in 85.9％ patients,and the minimum value of SpO2 occurred at (2.1 ±0.6) min after RM.In the responded group,the maximum SpO2 were higher than that before RM by (6.9 ± 1.6) ％ occurred at (12.7 ±2.6) min after RM.Compared with the data before RM,SpO2 were increased (90.4 ± 4.4) ％ vs.(86.7 ± 7.6) ％,P =0.047) in responded group at 30 min after RM.The initial PEEP level in the responded group was lower than that of the non-responded group (8.6 ± 3.4) cmH2O vs.(11.3 ±4.2) cmH2O,P=0.028.The initial mean DMV in the responded group was also shorter than that in the non-responded group (4.1 ± 3.1) d vs.(5.8 ± 2.5) d,P =0.011.Furthermore,the initial dynamic lung-thorax compliance (Cdyn) was obviously higher in the responded group than that in the non-responded group (30.8 ±6.2) mL/cmH2O vs.(26.1 ±5.1) mL/cmH2O,P=0.038.Conclusion The lung RM with high-level PEEP may cause temporary hemodynamic changes and the initial PEEP level,DMV,and Cdyn may be potential factors influencing the efficacy of lung RM.