Lung recruitment during small tidal volume ventilation allows minimal positive end-expiratory pressure without augmenting lung injury

OBJECTIVES:Ventilation with positive end-expiratory pressure (PEEP) above the inflection point (Pinf) has been shown to reduce lung injury by recruiting previously closed alveolar regions; however, it carries the risk of hyperinflating the lungs. The present study examined the hypothesis that a new strategy of recruiting the lung with a sustained inflation (SI), followed by ventilation with small tidal volumes, would allow the maintenance of low PEEP levels ( Pinf. MEASUREMENTS AND MAIN RESULTS:In groups 2 and 4, static compliance decreased after ventilation (p < .01). Histologically, group 2 (PEEP < Pinf without SI) showed significantly greater injury of small airways, but not of terminal respiratory units, compared with group 1. Group 3 (PEEP < Pinf after a SI), but not group 4, showed significantly less injury of small airways and terminal respiratory units compared with group 2. CONCLUSIONS:We conclude that small tidal volume ventilation after a recruitment maneuver allows ventilation on the deflation limb of the pressure/volume curve of the lungs at a PEEP < Pinf. This strategy a) minimizes lung injury as well as, or better than, use of PEEP > Pinf, and b) ensures a lower PEEP, which may minimize the detrimental consequences of high lung volume ventilation.