Noninvasive ventilatory management of the acute respiratory distress syndrome: a new era or just another tease!

Since its first clinical description, we have made great strides in the management of the patient with the acute respiratory distress syndrome (ARDS). These strides have resulted in a decrease in overall mortality from a rate of about 60% during the 1980’s to arguably a rate today in the 40% range for all patients with ARDS regardless of cause or comorbidities (1). This has been accomplished by advances in ventilatory support and careful attention to the setting of delivered tidal volume (4 to 8 mL/kg predicted body weight), maintaining the plateau airway pressure less than 28 cmH2O, the driving pressure [plateau pressure minus positive end-expiratory pressure (PEEP)] less than 15 cmH2O and setting the level of PEEP based on the individual patient respiratory system mechanics after a recruitment maneuver (2,3). Still most of us consider a mortality of 40% to high for this syndrome and have explored other approaches to further decrease mortality, such as liquid ventilation, high frequency ventilation, and aerosolized/inhaled agents to modify pulmonary vascular resistance (4,5), none of which have resulted in improved survival and some arguably may actually decrease survival. Many have also promoted the use of extracorporeal membrane oxygenation (ECMO) in patients with severe ARDS, but the best that can be stated regarding ECMO is that ARDS patients should be managed in centers with extensive experience in managing ARDS. Management in the community compared to these centers that do have ECMO capabilities results in poorer patient outcome (6).