Postoperative noninvasive ventilation.

POSTOPERATIVE hypoxemia and/or acute respiratory failure (ARF) mainly develop after abdominal and/or thoracic surgery. Anesthesia, postoperative pain, and surgery will induce respiratory modifications: hypoxemia, decrease in pulmonary volume, and atelectasis associated with a restrictive syndrome and a diaphragm dysfunction. These modifications of the respiratory function occur early after surgery and are more often transient and could lead to ARF. The clinical result (severity of the ARF) is the product of perioperative-related ventilatory impairment and severity of the preoperative pulmonary condition. Maintenance of adequate oxygenation in the postoperative period is of major importance, especially when pulmonary complications such as ARF occur. Although invasive endotracheal mechanical ventilation has remained the cornerstone of ventilatory strategy for many years for severe ARF, several studies have shown that mortality associated with pulmonary disease is largely related to complications of postoperative reintubation and mechanical ventilation. Therefore, major objectives for anesthesiologists are first to prevent the occurrence of postoperative complications and second to ensure oxygen administration and carbon dioxide removal while avoiding intubation if ARF occurs. Noninvasive ventilation (NIV) does not require an artificial airway (endotracheal tube or tracheotomy), and its use is well established to prevent ARF occurrence (prophylactic treatment) or to treat ARF to avoid reintubation (curative treatment) (fig. 1). Studies show that patient-related risk factors, such as chronic obstructive pulmonary disease, age older than 60 yr, American Society of Anesthesiologists class of II or higher, obesity, functional dependence, and congestive heart failure, increase the risk for postoperative pulmonary complications. 4 Pulmonary conditions are a key problem for patients who require high-risk surgery for ventilatory function. Then postoperative NIV should be beneficial to these patients at high risk, especially after “aggressive” surgery. Rationale for postoperative NIV use is the same as the postextubation NIV use plus the specificities due to the respiratory modifications induced by surgery and anesthesia. Postoperative NIV improves gas exchange, decreases work of breathing, and reduces atelectasis. The aims of this article are (1) to review the main respiratory modifications induced by surgery and anesthesia, which justify postoperative NIV use, (2) to offer some recommendations to safely apply postoperative NIV, and (3) to present the results obtained with preventive and curative NIV in a surgical context.