Comparison of the lung strain with incremental positive end expiratory pressure (PEEP) and decremental positive end expiratory pressure (PEEP) recruitment maneuver in acute respiratory distress syndrome (ARDS) patients: prospective observational trial

ventilator induced lung injury (VILI) is the damage to the lung tissue caused by the external energy to lung parenchyma in the form of tidal volume and application of PEEP during mechanical ventilation. lung strain has been identified as surrogate marker to determine VILI. determining lung strain can help in personalizing the ventilation parameters in ARDS patients and reducing the likelihood of VILI. the aim of the study  was to compare dynamics of lung strain changes after incremental and decremental PEEP recruitment maneuver.  the patients enrolled for the study were mechanically ventilated using GE CARESCAPE 860 ventilator which is equipped with an integrated airway gas module which records the data and calculates end expiratory lung volume (EELV). the patients were allocated into two groups I and D based on computer generated randomization. The ventilator parameters were adjusted as per standard ARDS protocol using assist control volume control mode and patients were sedated and paralysed using fentanyl and atracurium and baseline vitals, ventilation parameters, ABG values and airway pressures and compliance of the lung were noted. in Group I, incremental PEEP maneuver from 5 cm H2O to 25 cm H2O with change of 5 cm H2O at each step was performed  and in Group D , decremental PEEP maneuver from 25 cm H2O to 5 cm H2O with a change of 5 cm H2O at each step was performed on day 1. On the second day, decremental PEEP maneuver was performed in Group I patients and Incremental PEEP maneuver was performed in Group D .

the parameters studied were EELV, compliance, peak airway pressure at each level of PEEP, lung strain, post-recruitment values of airway pressures, ABG analysis including pH, PaCO2, PaO2 and static compliance of lung.