Which one of the following distinguishes ARDS (acute/adult respiratory distress syndrome) from cardiogenic pulmonary oedema?
Cardiogenic pulmonary edema is characterised by increased pulmonary aerial pressure with evidence of increased intracardiac pressures(S3 gallop,elevated JVP,peripheral edema) which are absent in ARDS-pulmonary edema. The chest radiograph in cardiogenic edema shows an enlarged cardiac silhouette,vascular redistribution,interstitial thickening and perihilar alveolar infiltrates;pleural effusions are common.In ARDS-pulmonary edema,hea size is normal,alveolar infiltrates are distributed more uniformly throughout the lungs,and pleural effusions are uncommon. Finally,the hypoxaemia of cardiogenic pulmonary edema is largely due to V/Q mismatch and responds to athe administration of supplemental oxygen.In contrast,hypoxaemia in ARDS-pulmonary edema is due to intra pulmonary shunting and typically persists despite high concentrations of inhaled O2. Reference:Harrison's Medicine-20th edition,page no:2032
Normal Pao2
Normal pulmonary aerial pressure
Normal aeriala-alveolar gradient
Normal Paco2
Respiratory system