RESPIRATORY AND HAEMODYNAMIC CHANGES DURING DECREMENTAL RECRUITMENT IN PATIENTS WITH ACUTE RESPIRATORY DISTRESS SYNDROME

The aim of the paper was to investigate the haemodynamic and respiratory changes during lung recruitment and decremental positive endexpiratory pressure (PEEP) titration for open lung ventilation in patients with acute respiratory distress syndrome (ARDS). A prospective, clinical trial was performed involving 10 adult patients with ARDS treated in the surgical intensive care unit in our hospital.Recruitment (pressure-controlled ventilation with fixed PEEP at 20 cmH2O and increased driving pressures at 20, 25 and 30 cmH2O for two minutes each) and PEEP titration (PEEP lowered by 2 cmH2O every two minutes, with tidal volume set at 6 ml/kg) were applied. The open lung PEEP (OL-PEEP) was defined as the PEEP level achieving maximum dynamic respiratory compliance plus 2 cmH2O. Gas exchange, respiratory mechanics and central haemodynamics were measured at the following steps: at baseline (T0), during the final recruitment step with PEEP at 20cmH2O and driving pressure at 30 cmH2O (T20/30), at OL - PEEP, following another recruitment manoeuvre (TOLP).The ratio of partial pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2) increased from T0 to TOLP (130 ± 49 versus 156 ± 64 mmHg, P < 0.005); dynamic respiratory compliance also increased (23 ± 5 versus 27 ± 6 ml/cmH2O, P < 0.005). At constant PEEP (14 ± 3 cmH2O) and tidal volumes, peak inspiratory pressure decreased (32 ± 3 versus 29 ± 3 cmH2O, P < 0.005), although partial pressure of arterial carbon dioxide (PaCO2) was unchanged (58 ± 22 versus 53 ± 18mmHg). No significant decrease in mean arterial pressure was noted.A standardised open lung strategy increased oxygenation and improved respiratory system compliance. No major haemodynamic compromise was observed.