Non-invasive ventilation after cardiac surgery

Anaesthesia and surgery induce major changes in respiratory function, in particular when the thorax or the upper abdomen are involved. Pulmonary volumes decrease, and atelectasis can develop. Postoperative pain and diaphragm dysfunction further worsen the respiratory function, contributing to the risk of acute respiratory failure. non-invasive ventilation proved to be beneficial in the postoperative period, reducing atelectasis, decreasing the work of breathing and finally improving gas exchange. Both continuous positive airway pressure and pressure support were studied with positive results when correctly used. Postoperative non-invasive ventilation can be applied to prevent acute respiratory failure in high-risk patients (elderly, obese, or with pre-existing poor lung or heart function) or to treat it. Cardiac surgery is associated with marked alteration of lung function. So far, few studies evaluated the benefits of non-invasive ventilation after cardiac surgery: all of them took place in intensive care unit in the immediate postoperative phase early after tracheal extubation, to prevent acute respiratory failure. Some studies reported positive results on perioperative oxygenation, atelectasis, pulmonary function tests, venous admixture, while other authors found continuous positive airway pressure ineffective on atelectasis, pulmonary function and oxygenation. Despite the contradictory results non-invasive ventilation appears a promising tool to prevent acute respiratory failure after cardiac surgery: in the most recent randomized study, zarbock et al. (1) reported a significant reduction in pulmonary complication, re-intubation E di to ri al non-invasive ventilation after cardiac surgery