Validation of an app-based portable spirometer in adolescents with asthma

Abstract

Objectives

Objective measurements of asthma impairment could aid teens in recognition of changes in asthma status over time. Ready access to a conventional spirometer is not realistic outside of the clinical setting. In this proof-of-concept study, we compared the performance of the VitalFlo mobile spirometer to the nSpire KoKo® sx1000 spirometer for accuracy in measuring Forced Expiratory Volume in one second (FEV₁) and Forced Vital Capacity (FVC) in adolescents with asthma.

Methods

Two hundred forty pulmonary function measurements were collected from 48 adolescents with persistent asthma from the University of North Carolina’s pediatric allergy and pulmonology subspecialty clinics. Participants performed spirometry with the nSpireKoKo® sx1000 spirometer and the VitalFlo spirometer during their clinic visits. 119 simulated FVC maneuvers were conducted on both devices to standardize measurements. Pearson correlations, Bland-Altman procedure, and two-sample comparison tests were performed to assess the relationship between the two spirometers.

Results

VitalFlo measurements were significantly highly correlated with nSpireKoKo® spirometer values for FEV_1, (r²=0.721, [95% CI, 0.749 ± 0.120], P < 0.001) and moderately for FVC (r²= 0.617, [95% CI, 0.640 ± 0.130], P < 0.001) measurements. There were no statistically significant differences of the mean FEV₁ (M = 0.00764, SD = 0.364, t(59)=0.16, P = 0.87) and FVC measurements (M = 0.00261, SD = 0.565, t(59)=0.036, P = 0.97.) between the VitalFlo and nSpireKoKo® systems. Both devices demonstrated significantly high correlation when comparing the automated FVC (r² = 0.997, [95% CI, 1.00 ± 0.00974], P < 0.001) measurements. Bland-Altman plots did not demonstrate significant bias between devices for both FEV₁ (0.00764 L) and FVC (0.00261 L) measurements.

Conclusions

Lung function measurements from the VitalFlo mobile spirometer were comparable to a commercially-available spirometer commonly used in clinical settings. This validated app-based spirometer for home use has the potential to improve asthma self-management.

Keywords:

• Asthma
• bronchial diseases
• respiratory tract disease
• obstructive lung diseases
• respiratory hypersensitivity
• immediate hypersensitivity
• control
• adolescent

ClinicalTrials.gov:

• NCT02671643
• NCT02662413

Disclosure statement

Dr. Dieffenderfer developed the VitalFlo spirometer. He is the Chief Technology officer for VitalFlo, Inc. Dr. Hernandez is an unpaid medical advisor for VitalFlo, Inc.

Additional information

Funding

This work was supported by a grant from the American Academy of Allergy, Asthma and Immunology Foundation, NHLBI 5 R01 HL135235 03, and NSF ASSIST Nanosystems Award Number EEC-1160483.