Inhaled nitric oxide and inhaled prostacyclin in acute respiratory distress syndrome: what is the evidence?

The mortality for acute respiratory distress syndrome remains unacceptably high. Two vasodilators, inhaled prostacyclin and inhaled nitric oxide, are reviewed in this article. Knowledge of inhaled prostacyclin has grown substantially in the past 30 years, but less research exists about its utility in acute respiratory distress syndrome. Inhaled prostacyclin and other prostaglandin derivatives are used in acute respiratory distress syndrome with increasing frequency. Currently, only randomized controlled trials exist for inhaled nitric oxide in acute respiratory distress syndrome patients. Randomized controlled trials with consistent dosing methods are needed for both vasodilators to better define their role in the treatment of acute respiratory distress syndrome.

Excessive dynamic airway collapse for the internist: new nomenclature or different entity?

Excessive dynamic airway collapse (EDAC) refers to abnormal and exaggerated bulging of the posterior wall within the airway lumen during exhalation. This condition is pathological if the reduced airway lumen is <50% of the normal. It is a relatively new disease entity that is recognised more easily now with the increased use of multi-detector row CT. EDAC is often asymptomatic and diagnosed incidentally. Although the term excessive dynamic airway collapse is often used interchangeably with tracheobronchomalacia, both entities represent morphologically and physiologically distinct processes. Considering the confusion between the two entities, the prevalence of stand-alone EDAC remains unclear. The prevalence of tracheobronchomalacia and EDAC depends upon the patient population, associated comorbidities and underlying aetiologies, diagnostic tools used and criteria used to define the airway collapse. This review defines EDAC and describes its pathophysiology, precipitating factors, associated symptoms and potential treatments.