title: The influence of gastroesophageal reflux in the lung: a case-control study.
abstract: OBJECTIVE
  Many researchers have investigated the pH of exhaled breath condensate but direct measurement of pH in the lung has not been performed in vivo in humans. We hypothesized that the pH measured directly in the lung would differ between healthy subjects and patients with gastroesophageal reflux disease (GERD). We also wished to determine whether an acidic environment in the lung influences pulmonary function and DL(CO), and whether microaspiration of gastric contents directly influences non-specific inflammation in the lung.
  
  
  METHODS
  The patients were otherwise healthy individuals who had been newly diagnosed with GERD. The control subjects were mostly volunteers who underwent bronchoscopy for different reasons. For all subjects (n = 63) a medical history was taken, and physical examination, oesophagogastroduodenoscopy, fibre-optic bronchoscopy and pulmonary function testing were performed.
  
  
  RESULTS
  In patients with GERD the average pH in the lung was 5.13 +/- 0.43; this was significantly lower than the pH in the lung of controls 6.08 +/- 0.39 (P = 0.001). Patients with GERD had lower FEV(1)% (P = 0.035), PEF (P = 0.001), FEF(50%) (P = 0.002) and FEF(25%) (P = 0.003), while the differences in FVC% and FEF(75%) were not significant. DL(CO) (P = 0.003), as well as transfer coefficient of the lung (P = 0.001), was lower in patients with GERD. LDH levels in bronchoalveolar aspirate were higher in the patients with GERD (P = 0.001).
  
  
  CONCLUSIONS
  This study found evidence of cell and tissue injury in the lung, a lowering of pH and higher bronchoalveolar aspirate LDH levels in patients with GERD compared with healthy subjects. These findings suggest that pulmonary function, and especially DL(CO), should be evaluated in patients presenting with GERD.
authors.affiliation: Clinical Department for Respiratory Diseases, Split University Hospital, Split, Croatia. kornelijamise@yahoo.com
authors.forename: Kornelija
authors.initials: K
authors.lastname: Mise
authors.forename: Vesna
authors.initials: V
authors.lastname: Capkun
authors.forename: Anamarija
authors.initials: A
authors.lastname: Jurcev-Savicevic
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Sundov
authors.forename: Anteo
authors.initials: A
authors.lastname: Bradaric
authors.forename: Suzana
authors.initials: S
authors.lastname: Mladinov
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053120:Respiratory Aspiration / Q000503:physiopathology; D012129:Respiratory Function Tests