Effect of nebulized albuterol on circulating leukocyte counts in normal subjects

Nebulized beta 2-receptor agonists may cause neutrophil demargination and result in misleading total circulating leukocyte counts (WBCs) in patients with acute bronchospasm. Varying underlying adrenergic stimulation in these patients also makes interpretation of these data difficult. This study examined the direct effect of these agents on the measured WBCs of healthy adults without evidence of bronchospasm or illness. A prospective, blinded, randomized study of 30 healthy volunteers (aged 18-50 years) was performed in a controlled environment. Subjects were excluded if they were pregnant, had a known underlying medical disorder or have had a prior reaction to albuterol or similar medications. Participants in the study were given either a nebulized albuterol treatment or nebulized normal saline (control group). Leukocyte counts were then obtained before and after treatments. Paired data were analysed using a one-tailed t-test while considering an increase of 40% in WBCs to be significant, P = 0.05, and beta = 0.10. Mean leukocyte counts were 5.9 (+/- 1.2) before treatment as compared to 6.0 (+/- 1.3) after albuterol nebulization. Using the coefficient of variance of WBCs in normal humans as c. 50% (6000 +/- 3000 cells mm-1) we were unable to demonstrate a significant difference in variation in post-nebulized leukocyte counts between the control group and the nebulized albuterol group. While there is concern that the treatment of patients experiencing acute bronchospasm with beta 2 agonists may result in factitious elevations in peripheral leukocyte counts, were found no direct effect of these agents on measured counts in normal subjects.