Comparative study between bronchoalveolar lavage and induced sputum in the diagnosis of inflammatory lung diseases

Abstract

Background Airway sampling is implicated in the workup of inflammatory lung diseases. Objective The aim of this study was to compare between induced sputum (IS) and bronchoalveolar lavage (BAL) in the diagnosis of inflammatory (including infectious) lung diseases regarding safety, cell composition (total and differential), microbiology workup, and cytology. Patients and methods This was a prospective comparative study that was carried out between February 2015 and February 2016. We enrolled 30 patients with inflammatory (including infiltrative and infectious) lung diseases whom presented to the Chest Department of Alexandria Main University Hospital. IS was performed in all included patients by inhalation of hypertonic saline (3%), using an ultrasonic nebulizer. In the same cohort, BAL was performed using flexible bronchoscopy within 1 week of IS. Samples from both techniques were sent for cytological (total and differential cell counts), microbiological, and cytopathological workup. Results The study sample included 26 (86.7%) female and 4 (13.3%) male patients. Their mean age was 43.57±16.30 years. BAL samples were more voluminous than IS samples (52.83±18.69 and 15.33±5.03 ml, respectively; P<0.001). Total cell counts were significantly higher in IS than in BAL (292.5 and 105.5 cell/cm 2 , respectively; P<0.001). No statistically significant differences were noted between both groups regarding the differential cell counts, culture results, or cytology. Complications in the form of hemorrhage occurred in two (6.67%) patients during BAL. No complications were recorded in the IS group. Conclusion IS is comparable to BAL. Although BAL is more voluminous, the total cell count in IS is higher. No differences were noted between both techniques regarding differential cell count, culture, and cytology results. IS is safe and can replace BAL in the workup of inflammatory, including infiltrative and infectious, lung diseases.