Recruitment is a strategy aimed at re-expanding collapsed lung tissue, and then maintaining high PEEP to prevent subsequent 'de-recruitment'. In order to recruit collapsed lung tissue, sufficient pressure must be imposed to exceed the critical opening pressure of the affected lung.Recruitment, not only improves pulmonary gas exchange, but also tends to limit tissue stress and ventilator-induced lung injury when the lung is repeatedly exposed to high end-inspiratory tidal pressures. Successful recruiting techniques recognize that sustained benefit depends not only on the magnitude of transpulmonary pressure applied during recruitment, but also on the duration and pattern of its application and the level of post-recruitment PEEP. A wide variety of RMs have been described; the best technique is currently unknown and may well vary with specific circumstances. Not all RMs are equivalent, either from the standpoint of efficacy or adverse side effects. Although a reasonable RM is unlikely to damage the lung, the risk of hemodynamic compromise occurring during and for a short while after the maneuver is considerable, especially with sustained high inflating pressure applied to less recruitable lungs.