Importance of Sniff Nasal Pressure (SNIP) as predictor of nocturnal respiratory function in amyotrophic lateral sclerosis (ALS)

Background: In ALS, respiratory disturbances during sleep have an important role in the natural history of the disease. Diurnal and nocturnal blood gases are weakly correlated, but nocturnal respiratory disorders are difficult to predict. Aim: To evaluate if SNIP, an important parameter reflecting respiratory muscle strength, is related to nocturnal respiratory disorders and whether it contributes to predict nocturnal blood gas alterations in addition to daytime blood gas levels in ALS. Methods: Forty patients with ALS, after a daytime respiratory function evaluation, including arterial blood gases and SNIP, underwent a polysomnography with transcutaneous capnography (tcPCO2). The patients …