All the following features are seen in ARDS except
Pulmonary oedema
Reudced lung compliance
Hypercapnia
Stiff lung
ARDS, the presence of alveolar and interstitial fluid and the loss of surfactant can lead to a marked reduction of lung compliance. Without an increase in end-expiratory pressure, significant alveolar collapse can occur at end-expiration, with consequent impairment of oxygenation. In most clinical settings, positive end-expiratory pressure (PEEP) is empirically set to minimise Fio2(inspired O2 percentage) and maximize Pao2(aerial paial pressure of O2). On most modern mechanical ventilators, it is possible to construct a static pressure-volume curve for the respiratory system.The impact of hypercapnia in ARDS. The impact of hypercapnia has not been clearly elucidated and is still controversial given its disparate effects . Neveheless, it has come to be seen as a major factor in ARDS Ref Davidson edition23rd pg 199
Respiratory system