Recruitment maneuvers in acute respiratory distress syndrome: The safe way is the best way

Table 2 Recruitment maneuver methods and outcomes reported in the literature about experimental studies

Ref.	Population	Design	Interventions	Comparison	Outcome
Rzezinski et al[23]	Animals with mild extrapulmonary lung injury	Randomized experimental study	Prolonged RM stepwise increase in PIP of 15-20-25 cm H2O above a PEEP of 15 cm H2O (maximal PIP = 40 cm H2O)	(1) Animals ventilated with VT = 6 mL/kg and PEEP = 5 cm H2O with no RMs; (2) Sustained inflation (40 cm H2O for 40 s); or (3) Stepwise increase in Paw of 15, 20, 25 cm H2O above a PEEP of 15 cm H2O (maximal PIP = 40 cm H2O), with interposed periods of Paw = 10 cm H2O above a PEEP = 15 cm H2O	Prolonged RM improved lung function, with less damage to alveolar epithelium, resulting in reduced pulmonary injury
Steimback et al[18]	Animals with extrapulmonary lung injury	Randomized experimental study	Sigh with different PIP and frequencies	(1) Animals ventilated with VT = 6 mL/kg and PEEP = 5 cm H2O with no RMs; (2) Sustained inflation (40 cm H2O for 40 s); (3) RM (180 sighs/h) and PIP (40 cm H2O) (S180/40); (4) RM (10 sighs/h) and PIP (40 cm H2O) (S10/40); and (5) RM (10 sighs/h) and PIP (20 cm H2O) (S10/20)	The reduction in sigh frequency led to a protective effect on the lung and distal organs
Silva et al[8]	Animals with pulmonary and extrapulmonary lung injury	Randomized experimental study	Stepwise RM (5 cm H2O/step, 8.5 s at each step during 51 s); Stepwise RM (5 cm H2O/step, 5 s at each step during 30 s)	(1) Sustained inflation (30 cm H2O for 30 s; (2) Stepwise PIP increase 30 cm H2O over 51 s (STEP-51); and (3) Stepwise PIP increase over 30 s with maximum PIP sustained for a further 30 s (STEP-30/30)	Stepwise RM prevented fibrogenesis and endothelial cell damage

Summary of the results of clinical and experimental studies comparing different recruitment maneuver (RM) methods, according to population, intervention, comparison, outcome criteria. PEEP: Positive end-expiratory pressure; PIP: Peak inspiratory pressure; V_T: Tidal volume.