6533b829fe1ef96bd128a23f

RESEARCH PRODUCT

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

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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 were stratified according to a SNIP ≥40 cm H2O (group 1) or Results: Group 1 included 13 patients (SNIP=49.0±7.7 cm H2O) and group 2 the remaining 27 subjects (SNIP=18.2±7.2 cmH2O). AHI did not differ between groups (4.6 [1.9-16.3] vs 4.7 [2.4-29.3], respectively, p= 0.35), but group 2, as compared to group 1, had fewer obstructive events (OAHI: 0.5 [0.0-24.4] vs 0.0 [0.0-1.2], respectively, p=0.02). In group 2, at multiple regression analysis, diurnal BE (β =-0.49, p=0.004) and SNIP (β =0.35, p=0.03) proved significant predictors of mean nocturnal SpO2; while diurnal PaCO2 (β =0.42, p=0.02) and SNIP (β =-0.36, p=0.04) predicted peak PtCO2. Conclusions: In ALS patients with SNIP