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.