Alveolar recruitment maneuvers under general anesthesia: a systematic review of the literature.

BACKGROUND: The sigh is a normal homeostatic reflex that maintains lung compliance and decreases atelectasis. General anesthesia abolishes the sigh reflex with rapid onset of atelectasis in 100% of patients. Studies show a strong correlation between atelectasis and postoperative pulmonary complications, raising health-care costs. Alveolar recruitment maneuvers recruit collapsed alveoli, increase gas exchange, and improve arterial oxygenation. There is no consensus in the literature about the benefits of alveolar recruitment maneuvers. A systematic review is necessary to delineate their usefulness.

METHODS: The search strategy included utilizing PubMed, CINAHL, the Cochrane Library, the National Guideline Clearinghouse, and all subsequent research reference lists up to January 2014. Inclusion criteria involved studies that compared the use of an alveolar recruitment maneuver with a control group lacking an alveolar recruitment maneuver in adult surgical subjects not suffering from ARDS or undergoing cardiac or thoracic surgeries.

RESULTS: Six randomized controlled trials of the 439 studies initially identified achieved a score of ≥ 3 on the Jadad scale and were included in this review. Alveolar recruitment maneuvers consisted of a stepwise increase in tidal volume to a plateau pressure of 30 cm H2O, a stepwise increase in PEEP to 20 cm H2O, or sustained manual inflations of the anesthesia reservoir bag to a peak inspiratory pressure of 40 cm H2O. Subjects in the alveolar recruitment maneuver groups experienced a higher intraoperative PaO2 with improved lung compliance. Different alveolar recruitment maneuvers were equally effective. There was a significant advantage when alveolar recruitment maneuvers were followed by PEEP application.

CONCLUSIONS: Alveolar recruitment maneuvers followed by PEEP should be instituted after induction of general anesthesia, routinely during maintenance, and in the presence of a falling SpO2 whenever feasible. They allow the anesthesia provider to reduce the FIO2 while maintaining a higher SpO2 , limiting the masking of shunts. Utilization of alveolar recruitment maneuvers may reduce postoperative pulmonary complications and improve patient outcomes.