Sniff test is used in ?

Sniff testThe fluoroscopic'sniff test, also known as diaphragm fluoroscopy, is a quick and easy real time fluoroscopic assessment of diaphragmatic motor function (excursion).It is used most often to confirm absence of muscular contraction of the diaphragm during expiration in patients with phrenic nerve palsy or breathing difficulties following stroke.Chest radiograph demonstrating a newly elevated hemidiaphragm often precedes a sniff test.