The impact of endotracheal suctioning on gas exchange and hemodynamics during lung-protective ventilation in acute respiratory distress syndrome.

Objective: To evaluate the respiratory and hemodynamic effects of open suctioning (OS) versus closed suctioning (CS) during pressure-control (PC) and volume-control (VC) ventilation, using a lung-protective ventilation strategy in an animal model of acute respiratory distress syndrome (ARDS).
Setting: Animal laboratory in a university hospital.
Design: Randomized cross-over evaluation.
Animals: Eight female Dorset sheep.
Interventions: Lung lavage was used to simulate ARDS. We applied VC and PC mechanical ventilation with a tidal volume of 6 mL/kg and positive end-expiratory pressure (PEEP), adjusted based on a table of PEEP versus fraction of inspired oxygen (FIO2). Suctioning was performed for 10 s with a suction pressure of -100 mm Hg, during both OS and CS. OS and CS were randomly performed with each animal. Hemodynamics and arterial blood gases were recorded before, during, and after endotracheal suctioning.
Results: The PaO2/FIO2 ratios before suctioning were similar in all groups, as were the PEEP and FIO2. PaO2/FIO2 was lower after OS than after CS/VC or CS/PC. There was no post-suctioning difference in oxygenation between CS/VC and CS/PC. PaCO2 recorded 10 min after suctioning was greater than the presuctioning value, in all groups. Intrapulmonary shunt fraction increased between baseline and 10 min post-suctioning with OS and CS/VC, but did not significantly increase with CS/PC. There were no significant changes in hemodynamics pre-suctioning versus post-suctioning with OS, CS/VC, or CS/PC.
Conclusion: PaO2/FIO2) was better maintained during CS with both VC and PC modes during lung-protective ventilation for ARDS, as compared with OS, and shunt fraction post-suctioning changed least with PC.