Method:
We conducted a retrospective review of the medical records and bronchoalveolar lavage cell profiles of all children 3-36 months of age who underwent flexible bronchoscopy and BAL analysis for uncontrolled recurrent wheezing, between September 2009 and August 2011.
Patients’ records were selected from among those being seen in the University of Arizona Pediatric Pulmonology outpatient clinics, with persistent wheezing on ICS, and who were scheduled for diagnostic bronchoscopy and BAL examination as part of the clinical workup for the persistence of symptoms. The decision to perform a diagnostic bronchoscopy was made by a pediatric pulmonologist based on clinical grounds after detailed assessment of symptoms, self-reported adherence to therapy, dosage of ICS and assurance of adequate technique of inhaled medication administration. Sweat chloride determination was normal for patients who were tested. Uncontrolled wheezing was defined by the persistence of symptoms despite treatment with low to moderate doses of ICS (doses as defined by GINA guidelines: fluticasone propionate 44mcg 2 puffs bid or 110 mcg 2 puffs bid or budesonide nebs 0.25 mg bid or 0.50 mg bid) for at least 4 weeks, and the need to use short acting bronchodilator therapy more than two days per week. Patients with comorbidities were excluded, including those with a history of congenital airway anomaly, known immunodeficiency, congenital heart disease, chronic lung disease of prematurity or prematurity with prolonged endotracheal intubation, and neurological and chromosomal abnormalities. None of the patients were symptomatic at the time of bronchoscopy or had received antibiotics in the 4 weeks preceding the procedure. The modified asthma predictive index 8 was used to classify patients into API positive (+ve) and negative (-ve) groups by retrospective chart review. BAL differential cell counts, bacterial cultures, viral cultures, and proportion of lipid laden macrophages (LLM) were analyzed. A positive bacterial culture indicating infection was defined by the presence of ≥104 colony forming units (CFU) per ml of a single organism. Elevated LLM proportion was defined as ≥ 20%. (A proportion of 20% in our lab correlates with LLM index between 80-100). No control group of healthy infants was available for this retrospective analysis. Therefore, our findings were compared to normal values published in the pediatric pulmonary literature22. We defined normal cell count percentages as follows: neutrophils < 10%, lymphocytes <8%, macrophages 80-90% and eosinophils <2%22.