Exhaled breath condesate nitric oxide end products and pH in controlled asthma

ABSTRACT

Asthma imposes a growing burden on the society in terms of morbidity, quality of life, and healthcare costs. It has the highest morbidity amongst inflammatory lung diseases and its prevalence continues to increase over the world. Inquiry into recent day or nighttime symptoms alone underestimates the burden of asthma and may lead to inadequate treatment of asthma. The aim of the present work is to evaluate the role of nitric oxide [NO] and hydrogen ion concentration [pH] levels in exhaled breath condensate [EBC] in cases of controlled bronchial asthma. The present study was conducted on 49 controlled asthmatic patients and 12 control subjects. All patients were subjected to thorough history taking, complete clinical examination and plain postero-anterior chest X-ray. All asthmatics and control subjects were subjected to routine laboratory investigations, spirometric study, EBC collection, processing and analysis for its content of both nitric oxide end products nitrite and nitrate [NOx] and pH. All asthmatics represented Group IT which was further divided into Group Ia 34 patients on regular inhaled corticosteroid [ICS] therapy and Group Ib 15 patients on no regular therapy. The control subjects represented Group II. The forced vital capacity [FVC], forced expiratory volume in the first second [FEV1], FEV1/FVC, peak expiratory flow rate [PEFR] and forced expiratory flow during the middle portion of a forced expiration [FEF 25-75%] were significantly lower in asthmatics than control subjects. The EBC-NOx mean +/- SD in micro mol/L in Group IT [5.99 +/- 1.63], in Group Ia [5.27 +/- 1.26] and in Group Ib [7.63 +/- 1.15] were significantly higher than in Group II [3.66 +/- 0.67] with, respectively [p = 0.000], [p = 0.000] and [p = 0.000]; and was significantly higher in Group Ib than Group Ia [p = 0.000]. The EBC-pH mean +/- SD in Group IT [7.32 +/- 0.27], in Group Ia [7.35 +/- 0.25] and in Group Ib [7.27 +/- 0.3] were significantly lower than in Group II [7.82 +/- 0.09] with, respectively [p = 0.000], [p = 0.000] and [p = 0.000]; with no significant difference between Group Ia and Group Ib. The EBC-NOx was significantly directly correlated to eosinophils count [p = 0.017] and neutrophils count [p = 0.002]; and inversely correlated to FEV1 [p = 0.016], FEV1/FVC [p = 0.001], PEFR [p = 0.030] and EBC-pH [p = 0.003]. The EBC-pH was significantly inversely correlated to eosinophils count [p = 0.017] and neutrophils count [p = 0.036]; and directly correlated to FVC [p = 0.004], FEV1 [p = 0.004] and PEFR [p = 0.000]. EBC-NOx is significantly higher and EBC-pH is significantly lower in asthmatic patients than in control subjects. Asthmatics receiving ICS have a lower EBC-NOx level than those not. EBC-NOx and EBC-pH were significantly correlated and both of them showed significant correlations with spirometric parameters of airway obstruction