Introduction: The Lung Clearance Index (LCI) derived from the multiple-breath washout test (MBW), is both feasible and sensitive to early lung disease detection in young children with cystic fibrosis and asthma. The utility of LCI has not been studied in children with sickle cell disease (SCD). We hypothesized that children with SCD, with or without asthma or airway hyper reactivity (AHR), would have an elevated LCI compared to healthy controls. Methods: Children with SCD from a single center between the ages of 6-18 years were studied at baseline health and completed MBW, spirometry, plethysmography and blood draws for serum markers. Results were compared to healthy controls of similar race, age and gender. Results: Control subjects (n=35) had a significantly higher daytime oxygen saturation level, weight and body mass index (BMI) but not height compared to subjects with SCD (n=34). Total Lung Capacity(TLC) z-scores were significantly higher in the healthy controls compared to those with SCD (0.87 (1.13), 0.02 (1.27), p=0.005) while differences in Forced Expiratory Volume in 1 second (FEV1) z-scores approached significance (0.26 (0.97), -0.22 (1.09), p=0.055). There was no significant difference in LCI among the comparison groups (7.29 (0.72), 7.40 (0.69), p=0.514). Conclusion: LCI did not differentiate SCD from healthy controls in children between the ages of 6 and 18 years at baseline health. TLC may be an important pulmonary function measure to follow longitudinally in the pediatric SCD population.
RATIONALE: Outpatient treatment of lower respiratory tract infection (LRTI) in tracheostomy dependent children varies institutionally. The objective of this study was to identify whether only increasing airway clearance (AWC) increased the odds of hospitalization within 28 days of treatment. Our hypothesis was that those treated with antibiotics were less likely to be hospitalized. METHODS: We retrospectively reviewed medical charts of children who were tracheostomy dependent between 2012-2019 and followed at our institution. We recorded recommendations with each sick call, i.e. prescription of antibiotics and/or increase in frequency of airway clearance. Generalized estimating equation models were used to determine whether the recommendation to increase AWC frequency was associated with an increased risk of hospitalization within 4 weeks, as compared to the prescription of oral and/or inhaled antibiotics. RESULTS: Of the eighty -two patients reviewed, there were 283 unique episodes of LRTI. 160 (45%) episodes involved increasing AWC alone and 195 (55%) were given an antibiotic in addition to increasing AWC. Of those who received AWC only, 21.7% were hospitalized within 28 days of treatment, and 13.8% were hospitalized after treatment with increased AWC and oral/inhaled antibiotics, p= 0.08. Those who received only AWC did not have significantly higher odds of hospitalization within 28 days of treatment, compared to those who received an antibiotic: adjusted OR 1.47 (95% CI: 0.75, 2.86); p=.26. CONCLUSIONS: In this retrospective cohort study of pediatric patients with tracheostomy, a recommendation to increase airway clearance only versus initiating an antibiotic was not associated with increased odds of hospitalization.