Diffusing capacity in patients with GERD

Gastroesophageal reflux (GER) is associated with respiratory diseases, particularly with asthma and chronic posterior laryngitis. Continuous aspiration of acid or bulk fluid in to the airways can cause chronic inflammation in the lung parenchyma and alveolar tissue. In the airways it may also cause airway obstruction and gas exchange impairment. To assess the influence of gastroesophageal reflux on lung function and gas diffusion capacity in children with asthma and chronic laryngitis. In 22 children (8– 17 years, both sexes, BMI 16– 27.2) with asthma and chronic laryngitis suggestive for GER, 24-h pH probe was administered. Detailed history, clinical examination, lung function testing, diffusing capacity for CO (DLCO), body pletismography, FENO were performed in all patients during the same visit. All patients were positive for GER (either positive fraction time with pHo4, Boix-Ochoa score, or Johnson-DeMeesters score). DLCO ranged 74– 128% and FENO 6.4– 54.3 ppb. Inverse correlation was found for all reflux indexes with DLCO (_0.71, _0.71, _0.76 ; Po0.001 for all, respectively). Patients with severe reflux (greater than median) had significantly lower values of DLCO (Po0.001). No association was found between reflux indexes and lung function parameters, FENO or BMI. Our results suggest that in patients with significant GER, DLCO should be measured because their dyspnea could be related to gas exchange impairment, despite normal lung function.