Fig. 3From: Pulmonary ultrasound and pulse oximetry versus chest radiography and arterial blood gas analysis for the diagnosis of acute respiratory distress syndrome: a pilot study a “A lines”: distinct horizontal reflections in a patient with normal lungs (arrows). b “B lines”: three vertical lines in a single frame extending from the pleura to the bottom of the screen in a patient with ultrasound interstitial syndrome (between arrows)Back to article page