Valores de referência da pressão inspiratória nasal em crianças saudáveis: um estudo multicêntrico

Abstract

Introduction: The sniff nasal inspiratory pressure (SNIP) is an easy to perform test that estimates esophageal pressure and predicts inspiratory muscle strength, being complementary to maximal inspiratory and expiratory pressure measurements (MIP and MEP, respectively). In Brazil, its reference values for children have not yet been proposed. Objective: To propose SNIP prediction equations for healthy Brazilian children and determine the reference values for this population. Methods: A multicenter (Natal, Recife e Belo Horizonte), cross-sectional observational study was carried out to evaluate healthy children 6 to 11 years old, of both sexes, stratified into three subgroups by age group (6-7, 8-9, 10-11 years) within each sex. All performed after anamnesis with sociodemographic and anthropometric evaluation (percentile for body mass index), the spirometry test, followed by the measurement of respiratory muscle strengths, composed of MIP (Functional Residual Capacity (FRC) and Residual Volume (RV)), MEP (Total Lung Capacity (TLC)) and SNIP. Subsequently, they answered two questionnaires to assess the level of physical activity and socioeconomic level through the IPAQ (International Physical Activity Questionnaire) and BECC (Brazil Economic Classification Criteria), respectively. Finally, two 6-minute walk tests (6MWT) were performed to assess functional exercise capacity. Statistical analysis: We used the Kolmogorov-Smirnov test for normality of the data, the t-test for intergroup analyzes and one-way ANOVA for intragroup analyzes. The pearson (r) correlation was used to observe relationships between SNIP and the other study variables. Results: The results presented are only for the Natal/RN population. Thirty-nine children were recruited, of which 121 (62 girls) comprised the sample, 54% presented percentile <85 and 46%> 85th percentile, higher than expected. SNIP values were similar between genders (91.1 ± 21.0 cmH2O in girls and 87.7 ± 19.4 cmH2O in boys). Girls presented SNIP measurements larger than those of the PImax CRF (p <0.0001), while in boys the mean of both variables was similar. We found a positive correlation between SNIP and the percentile (r = 0.25, p = 0.04) in girls, unlike boys, where no correlation was observed. Conclusions: According to what was found, SNIP reference values were defined for healthy Brazilian children aged 6 to 11 years. The BMI percentile seems to positively influence the inspiratory muscle strength measured by SNIP only in girls.