We have devised predictive equations for SNIP to be used in adults (20-80 years of age) in Brazil. These equations could help minimize diagnostic discrepancies among individuals.

Objective To determine reference values of sniff nasal inspiratory pressure (SNIP) in healthy children. Methods This cross‐sectional observational study included healthy children aged 6 to 11 years of both sexes. The volunteers underwent a pulmonary function test to rule out respiratory disorders. Respiratory muscle strength was measured using maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), respectively, with MIP close to functional residual capacity (FRC) and residual volume, while MEP to total lung capacity. SNIP was performed through the nostril contralateral to the occlusion, close to FRC. Two 6‐minute walk tests were performed to assess functional exercise capacity. Results The sample comprised 121 healthy children (62 girls); 54% presented body mass index (BMI) percentile less than 85th and 46% more than equal to 85th percentile, higher than expected. SNIP values were similar between sexes (91.1 ± 21.0 cmH2O in girls and 87.7 ± 19.4 cmH2O in boys; P = .36) as well as the means of lower limits of normal (56.88 cmH2O for girls and 56.66 cmH2O for boys). Girls presented SNIP measurements larger than those of the MIP of FRC (P < .0001), while boys presented similar mean values for both. We found a positive correlation between SNIP and BMI percentile (r = .25, P = .04) in girls, unlike boys, in whom no correlation was observed. Conclusions SNIP reference values and mean lower limits of normal were defined for healthy children aged 6 to 11. BMI percentile seems to positively influence the inspiratory muscle strength measured by SNIP in girls only.

In ALS, monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of FVC.

Purpose: To evaluate the concordance between the value of the actual maximum voluntary ventilation (MVV) and the estimated value by multiplying the forced expiratory volume in the first second (FEV 1 ) and a different value established in the literature.Methods: A retrospective study was conducted with healthy subjects and patients with stable chronic obstructive pulmonary disease (COPD). Five prediction formulas MVV were used for the comparison with the MVV values. Agreement between MVV measured and MVV obtained from five prediction equations were studied. FEV 1 values were used to estimate MVV. Correlation and agreement analysis of the values was performed in two groups using the Pearson test and the Bland-Altman method; these groups were one group with 207 healthy subjects and the second group with 83 patients diagnosed with COPD, respectively.Results: We recruited 207 healthy subjects (105 women, age 47 ± 17 years) and 83 COPD patients (age 66 ± 6 years; 29 GOLD II, 30 GOLD III, and 24 GOLD IV) for the study. All prediction equations presented a significant correlation with the MVV value (from 0.38 to 0.86, p < 0.05) except for the GOLD II subgroup, which had a poor agreement with measured MVV. In healthy subjects, the mean difference of the value of bias (and limits of agreement) varied between -3.9% (-32.8 to 24.9%), and 27% (-1.4 to 55.3%). In COPD patients, the mean difference of value of bias (and limits of agreement) varied between -4.4% (-49.4 to 40.6%), and 26.3% (-18.3 to 70.9%). The results were similar in the subgroup analysis.