REFERENCE VALUES FOR SNIFF NASAL INSPIRATORY PRESSURE IN HEALTHY CHILDREN: A MULTICENTER STUDY
child, muscle strength, nasal inspiratory pressure.
Introduction: The sniff nasal inspiratory pressure (SNIP) is an easy test to perform, which estimates esophageal pressure and predicts inspiratory muscle strength, being complementary to the measurements of maximal inspiratory and expiratory pressures (PImáx and PEmáx, respectively). It’s considered a complementary test to assessments in different populations, and at Brazil, reference values for children haven’t yet been proposed. Aim: To propose SNIP prediction equations for healthy Brazilian children and to determine the reference values for this population. Methods: Multicenter study (Natal, Recife e Belo-Horizonte), cross-sectional observational, where healthy children between 6 and 12 years of age, of both sexes, will be evaluated. They will be stratified into three subgroups (6-7, 8-9, 10-11 years) within each sex. All will perform after anamnesis with sociodemographic and anthropometric evaluation (percentile), spirometry test, followed by manovacuometry, composed of PImax (Functional Residual Capacity (FRC) and Residual Volume (RV)), PEmax and SNIP. Finally, two 6-minute walk tests (6MWT) will be done in order to assess functional exercise capacity. Statistical analysis: We will use the Kolmogorov-Smirnov test for normality of the data, and the t test to test intergroup relations and one-way ANOVA for intragroup analysis. Linear regression analysis will be used to obtain predictive equations for the independent variables that correlate with nasal inspiratory pressure. Results: As preliminary results, we evaluated 67 volunteers, (7 excluded) of which 33 girls (55%) and 27 boys (45%). The girls had slightly higher SNIP values when compared to boys (88.64 ± 21.41 vs 84.04 ± 20.60 cmH2O), with no statistical significance. The boys presented higher values of PImaxCRF, PImaxVR and PEmáx when compared to girls (96.17 ± 31.05 vs 78.28 ± 26.35, 107.6 ± 29.78 vs 84.09 ± 29.82, 112, 8 ± 23.89 vs. 98.82 ± 27.22 cmH2O, respectively) with p <0.05. In the correlations between SNIP and age, weight, height and percentile, SNIP correlated only as percentile (p = 0.04, r = 0.34) in the female sex. Despite the correlation found, SNIP values did not differ between percentile levels.