Effects of early invasive mechanical ventilation on anoxia and prognosis of acute respiratory distress syndrome after chest injury

Objective To explore the clinical significance of early invasive mechanical ventilation for acute respiratory distress syndrome (ARDS) caused by thoracic trauma.Methods We retrospectively analyzed the clinical data of 93 patients of invasive mechanical ventilation in those with ARDS caused by thoracic trauma,and divided them into delayed invasive mechanical ventilation group (n =45) and timely invasive ventilation group (n =48) by the time of invasive mechanical ventilation.We compared the blood gas analysis,oxygen index,heart rate,lactic acid,muscle use score of the two groups before and after invasive mechanical ventilation and the differences of mechanical ventilation time,incidence of complications,mortality and length of hospital stay between the two groups.Results Each index of the delayed invasive mechanical ventilation group and the timely invasive ventilation group was calculated:PaO2 (63.2 ± 12.3,74.2 ± 12.1)mm Hg,PaCO2 (39.4 ±8.7,38.9 +7.6) mm Hg,PaO2/FiO2 (196.2 ± 17.8,231.4 ± 18.2),respiratory rate (27.4 ±3.7,21.1 ± 3.4) beats/min,heart rate (117.2 ± 26.8,96.0 ± 25.1) beats/min,accessory muscle use score (2.69 ± 0.15,1.67 ± 0.10),lactic acid (4.23 ± 1.70,2.12 ± 0.80) mmol/L Except for PaCO2,the differences of each index were statistically significant (t values were respectively 4.346,9.420,3.949,5.436,38.809,7.736; P ＜ 0.05).The duration of mechanical ventilation treatment (10.21 ± 1.50,6.47 ± 1.20) d and the length of hospital stay (21.53 ± 1.90,16.32 ±2.10) d of the delayed group and the timely group were significantly different (t values were respectively 12.518,13.318; P ＜ 0.01).The timely group had significantly lower mortality rate (26.7％ (12/45),14.6％ (7/48)),VAP (46.7％ (21/45),22.9％(11/48)),acute gastric mucosal lesions (33.3％ (15/45),12.5％ (6/48)),MODS (40.0％ (18/45),16.7％ (8/48)) than the delayed group (x2 values were respectively 3.86,5.81,4.49,5.70; P ＜ 0.05).There is no significant difference on the incidence of pneumothorax between the two groups (11.1％ (5/45),8.3％ (4/48)).Conclusion Invasive mechanical ventilation is an effective treatment of ARDS caused by chest trauma.Early invasive mechanical ventilation can reduce the mortality rate and shorten the duration of mechanical ventilation and hospital stay of the patients with ARDS after severe thoracic trauma. Key words: Chest injury;  Acute respiratory distress syndrome;  Mechanical ventilation