Clinical Implication of Sniff Nasal Inspiratory Pressure in Patients with Amyotrophic Lateral Sclerosis

ABSTRACT

OBJECTIVE: To evaluate sniff nasal inspiratory pressure (SNIP) in patients with amyotrophic lateral sclerosis (ALS), to analyse the relationship between SNIP and other pulmonary function test and to verify the usefulness of SNIP in patients with ALS. METHOD: Twenty-eight patients with ALS able to follow command were studied. SNIP and maximal inspiratory pressure (MIP) were measured using respiratory pressure meter in sitting position. Forced vital capacity (FVC) and peak cough flow (PCF) were evaluated using spirometer and peak flow meter respectively. The relationship between SNIP and other pulmonary function parameters were analysed. RESULTS: The mean value of SNIP was -20.7 cmH2O (21.7% predicted) and the mean value of MIP was -16.3 cmH2O (8.0% predicted). SNIP correlated with MIP (r=0.776, p= 0.000). When expressed absolute value, SNIP was higher than MIP in twenty-one of the twenty-eight patients with ALS. Difference of SNIP and MIP was 4.4 cmH2O and it was statistically significant (p=0.001). SNIP and MIP correlated with FVC. SNIP and MIP correlated with PCF as well. CONCLUSION: SNIP in patients with ALS is useful method to assess inspiratory muscle strength in addition to MIP.