Evaluation of the clinical effect of different mechanical ventilation modes in the treatment of severe thoracic injury complicated with acute respiratory distress syndrome in elderly patients

Objective: To investigate the clinical effects of three kinds of mechanical ventilation modes in the treatment of severe thoracic injury complicated with acute respiratory distress syndrome(ARDS).Methods: Ninety elderly patients with severe thoracic injury complicated with ARDS were treated with mechanical ventilation by breathing machine,and three different ventilation modes were implemented according to the patient's situation.Thirty patients were treated with synchronous intermittent mandatory ventilation(SIMV) combined with positive end expiratory pressure(PEEP) (SIMV+PEEP group),30 patients were treated with continuous airway ventilation(CPAP) combined with pressure support(PSV)(CPAP+PSV group),and 30 cases were treated with pressure controlled ventilation(PCV)(PCV group).The clinical effects,respiratory mode parameters and blood gas analysis before and after treatment between three groups were compared.Results: The differences of the clinical effects between three groups were not statistically significant(P>0.05),one case in SIMV+PEEP group and one case in CPAP+PSV group and no case in PCV group died.The levels of Minvol(MV),alveolar oxygen partial pressure(PaO₂) and arterial oxygen saturation(SaO₂) in CPAP+PSV group were higher than those in SIMV+PEEP group and PCV group(P<0.05 to P<0.01),while the levels of proximal interphalangeal(PIP) and partial pressure of carbon dioxide in artery(PaCO₂) in CPAP+PSV group were lower than those in SIMV+PEEP group and PCV group(P<0.05 to P<0.01).Compared with before treatment,the PaO₂,PaCO₂,SaO₂ and PaO₂/FiO₂(fraction of inspiration O₂) in 3 groups were significantly improved after treatment(P<0.01).The PaO₂/FiO₂ in CPAP+PSV group was higher than that in SIMV+PEEP group and PCV group(P<0.01 and P<0.05).Conclusions: All three kinds of mechanical ventilation modes can improve the hypoxia in elderly patients with severe thoracic injury complicated with ARDS.The CPAP+PSV mode has advantage over the another two ventilation modes in reducing the peak inspiratory pressure,which is more suitable for the treatment of flail chest.