Background
Sniff nasal inspiratory pressure (SNIP) is a voluntary inspiratory maneuver measured through a plug occluding one nostril. The investigation of the number of maneuvers necessary to reach the highest peak of SNIP in pediatric populations has been inconsistent. Thus, our goal was to assess the reliability SNIP in healthy children aged 6 to 11 years and compare with regard to sex and age group, as well as to determine the adequate number of maneuvers.
Methods
This cross-sectional study included healthy children with normal pulmonary function. Were performed 12 to 20 maneuvers SNIP near functional residual capacity, with a 30 s rest between each. Reliability was tested using intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), and Bland-Altman analysis for agreement.
Results
A total of 121 children (62 girls [51%]) were included. The ICC and corresponding confidence interval (CI) between the highest measure and the first reproducible maneuver was 0.752 (0.656–0.824), SEM of 10.37 cmH2O and MDC of 28.74 cmH2O. For children aged 6–7 and 8–11 years, the ICC (CI) was 0.669 (0.427–0.822), SEM = 10.76 cmH2O and MDC = 29.82 cmH2O, and 0.774 (0.662–0.852), with SEM = 9.74 cmH2O and MDC = 26.05 cmH2O, respectively. For girls, the ICC (CI) was 0.817 (0.706–0.889), SEM = 9.40 cmH2O and MDC = 26.05 cmH2O; for boys, 0.671 (0.487–0.798), SEM = 11.51 cmH2O and MDC = 31.90 cmH2O. Approximately 80% of the total sample reached the highest SNIP before the 10th maneuver.
Conclusions
SNIP demonstrated moderate reliability between the maneuvers in children aged 6 to 11 years. Otherwise, older children and girls reached the SNIP peak faster. Finally, results suggested that 12 maneuvers were sufficient for healthy children aged 6 to 11 years to achieve the highest SNIP peak.