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

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 FEV1, (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.

Age and African-American race impact the validity and reliability of the asthma control test in persistent asthmatics.

BACKGROUND: The Asthma Control Test (ACT) is widely used to assess asthma control, yet the validity and reliability of the test have not been specifically evaluated in adolescents or African-Americans. We conducted a prospective psychometric study of the ACT in African-American (AA) and non-African-American (nAA) adolescents with persistent asthma, with emphasis on the clinical utility of the test for medical decision making. METHODS: Participants completed the ACT and performed spirometry. A physician conducted a guidelines-based assessment of asthma control, blinded to the ACT score. Study procedures were repeated 6-8 weeks later. The ACT-based asthma control assessment was compared to physician assessment. RESULTS: For baseline and follow-up visits, internal consistency, as measured using Cronbach's alpha, was 0.80 and 0.81 in AA teens and 0.80 and 0.83 in nAA teens. Intraclass correlation coefficients were 0.59 and 0.76 in AA and nAA teens, respectively, with stable asthma control over time. Agreement between ACT and physician assessment was moderate in AA teens and fair in nAA teens. An ACT score of ≤19 showed reduced sensitivity for not well controlled asthma in both groups, while a score of ≤21 had the greatest area under the ROC curve. ACT scores were marginally responsive to change in control status. CONCLUSIONS: Concerns for the ACT's ability to detect uncontrolled asthma in adolescents emphasizes the need for a more comprehensive evaluation of asthma control in clinical settings. A higher threshold ACT score to define not well controlled asthma may be needed if the ACT is to be used for medical decision making. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02671643 , NCT02662413 .

Effect of Obesity on Acute Ozone-Induced Changes in Airway Function, Reactivity, and Inflammation in Adult Females.

We previously observed greater ozone-induced lung function decrements in obese than non-obese women. Animal models suggest that obesity enhances ozone-induced airway reactivity and inflammation. In a controlled exposure study, we compared the acute effect of randomized 0.4ppm ozone and air exposures (2 h with intermittent light exercise) in obese (N = 20) (30

Inhaled versus systemic antibiotics and airway inflammation in children with cystic fibrosis and Pseudomonas.

RATIONALE: Inhaled tobramycin has been shown to transiently clear Pseudomonas from lower airways in early cystic fibrosis (CF), but does not markedly reduce lung inflammation, a key factor in disease progression. OBJECTIVE: Test the hypothesis that systemic antibiotics are more effective than inhaled antibiotics for reducing lower airways inflammation. METHODS: Clinically stable CF children with recent Pseudomonas were randomized to receive 4 weeks of inhaled tobramycin or 2 weeks of systemic antibiotics (intravenous ceftazidime and tobramycin). Bronchoalveolar lavage fluid was obtained just before and 4-6 weeks after treatment. The primary outcome was change in % neutrophils in lavage fluid. RESULTS: Fifteen subjects (inhaled = 6, systemic = 9) completed the protocol. Three Systemic Group subjects could not have central venous access established and were treated with oral ciprofloxacin (plus inhaled tobramycin) for 2 weeks as an alternative "systemic" regimen, per protocol. Groups were well matched in age, markers of disease severity, and initial % neutrophils. The Systemic Group showed a modest median change in percent neutrophils (-7%) which was not statistically significant compared to inhaled (+5.4%, P = 0.07). However, the Systemic Group had significantly greater reductions in total cells (-50% vs. -3%, P < 0.01) and neutrophils (-74% vs. -10%, P = 0.02) per ml lavage fluid. Both groups had reduced bacterial quantity after treatment, but there was no significant difference between groups. CONCLUSIONS: In clinically stable children with CF, systemic antibiotics result in greater short-term reduction in lower airways inflammation than inhaled antibiotics.

Repeated measurement of nasal lavage fluid chemokines in school-age children with asthma.

BACKGROUND: Inflammatory processes at the mucosal surface may play a role in maintenance of asthma pathophysiology. Cross-sectional studies in asthmatic patients suggest that chemokines such as interleukin 8 (IL-8) are overproduced by respiratory epithelium. OBJECTIVE: To test the hypothesis that chemokine levels are persistently elevated in the respiratory secretions of asthmatic children at a stable baseline. METHODS: We measured nasal lavage fluid (NLF) levels of chemokines and other mediators at 3- to 4-month intervals in a longitudinal study of asthmatic children, with nonasthmatic siblings as controls. RESULTS: In a linear mixed-model analysis, both family and day of visit had significant effects on nasal mediators. Thus, data for 12 asthmatic-nonasthmatic sibling pairs who had 3 or more same-day visits were analyzed separately. For sibling pairs, median eosinophil cationic protein levels derived from serial measurements in NLF were elevated in asthmatic patients compared with nonasthmatic patients, with a near-significant tendency for elevation of total protein and eotaxin levels as well. However, no significant differences were found for IL-8 or several other chemokines. Ratios of IL-13 or IL-5 to interferon-gamma released by house dust mite antigen-stimulated peripheral blood mononuclear cells, tested on a single occasion, were significantly increased for asthmatic patients. CONCLUSIONS: Substantial temporal and family-related variability exists in nasal inflammation in asthmatic children. Although higher levels of eosinophil cationic protein are usually present in NLF of patients with stable asthma compared with patients without asthma, chemokines other than eotaxin are not consistently increased. Eosinophil activation at the mucosal surface is a more consistent predictor of asthmatic symptoms than nonspecific elevation of epithelium-derived inflammatory chemokine levels.

Chemokines and inflammation in the nasal passages of infants with respiratory syncytial virus bronchiolitis.

This study measured chemokines in nasal lavage fluids (NLF) from infants with respiratory syncytial virus (RSV) bronchiolitis, defined by lung hyperinflation and wheezing. Comparison was made to RSV-positive infants without bronchiolitis and RSV-negative infants with acute respiratory illnesses. RSV-positive illnesses were associated with increased epithelial shedding, increased RANTES/protein ratios, and increased IL-8/protein ratios in NLF compared to RSV-negative illnesses. Among RSV-positive infants, bronchiolitics had greater total cell counts and percentage epithelial cells in NLF than nonbronchiolitics. Bronchiolitics also had roughly twice the NLF RANTES/IL-8 ratio than nonbronchiolitics (P =.043). Semiquantitative reverse transcriptase-polymerase chain reaction of nasal epithelium suggested similar RANTES/IL-8 ratio increases among bronchiolitics. A more mildly affected, RSV-positive outpatient population showed none of these differences. We conclude that RSV bronchiolitis is associated with a shift toward relatively more RANTES in nasal secretions of infants sick enough to require hospitalization, and mucosal epithelium may contribute to this process. Similar processes in the lower airways may enhance inflammation due to RANTES-responsive cell types and affect clinical manifestations.