Treatment of anesthesia-induced lung collapse with lung recruitment maneuvers

摘要

General anesthesia causes atelectasis and airway closure in dependent areas of the lung. Both kinds of collapse induce a deterioration of gas exchange characterized by a decrease in arterial oxygenation and an increase in dead space. The severity of this lung dysfunction is proportional to the amount of collapsed tissue that depends on anesthesia, surgical and patient's factors. Lung collapse can be partially prevented by decreasing FiO_2 and/or by applying CPAP during the induction of anesthesia. However, only lung recruitment maneuvers can resolve atelectasis completely. These recruitment maneuvers are ventilatory strategies aimed to restore the normal aeration of the lungs. The maneuvers consist in a brief and controlled increase in airway pressure to open up those pulmonary areas with collapse. Afterward, the lungs are ventilated with a protective strategy setting keeping the lungs open in time with enough positive-end expiratory pressure and low driving pressure. This article describes the physiological and clinical background of lung recruitment maneuvers applied during the intra-operative period.