Exhaled breath condensate acidification in acute lung injury

Abstract

Lung injury in ventilated lungs may occur due to local or systemic disease and is usually caused by or accompanied by inflammatory processes. Recently, acidification of exhaled breath condensate pH (EBC-pH) has been suggested as marker of inflammation in airway disease. We investigated pH, ammonia, Lactate, pCO2, HCO3-, IL-6 and IL-8 in EBC of 35 ventilated patients (AECC-classification: ARDS: 15, ALI: 12, no lung injury: 8). EBC-pH was decreased in ventilated patients compared to volunteers (5.85 +/- 0.32 vs. 7.46 +/- 0.48; P < 0.0001). NH4+, lactate, HCO3-, pCO2, IL-6 and IL-8 were analyzed in EBC and correlated with EBC-pH. We observed correlations of EBC-pH with markers of local (EBC IL-6: r = -0.71, P < 0.0001, EBC IL-8: r = -0.68, P < 0.0001) but not of systemic inflammation (serum IL-6, serum IL-8) and with indices of severity of lung injury (Murray's Lung Injury Severity Score; r = -0.73, P < 0.0001, paO2/FiO2; r = 0.54, P < 0.001). Among factors potentially contributing to pH of EBC, EBC-lactate and EBC-NH4+ were found to correlate with EBC-pH. Inflammation-induced disturbances of regulatory mechanisms, such as glutaminase systems may result in EBC acidification. EBC-pH is suggested to represent a marker of acute lung injury caused by or accompanied by pulmonary inflammation.

Normative values for exhaled breath condensate pH and its relationship to exhaled nitric oxide in healthy African Americans

“…This assertion is based on comparison of our data with published studies of white populations (Table I). 6,9,[26][27][28][29] All of the other published studies were performed in predominantly white subjects, 6,9,[26][27][28][29] with the exception of Paget-Brown et al, 9 which included 8.5% African American subjects. The study by Paget-Brown et al 9 represents the best comparison to our cohort because it used similar EBC collection methods and was performed in the same region of the United States.…”

Acid stress in the pathology of asthma

“…Low pH of EBC (acidopnea) occurs in acute exacerbations of asthma 8 and chronic obstructive pulmonary disease (COPD), 19 as well as in stable and moderate asthma, bronchiectasis, COPD, 20 cystic fibrosis, 21 and acute respiratory distress syndrome. 22 Additionally, EBC pH normalizes in asthmatic patients after treatment with corticosteroids. Much technical work has been performed to ensure that these effects are not caused by CO 2 tension, airflow obstruction, or a loss of oral ammonia.…”

Determination of hydrogen peroxide in exhaled breath condensate by flow injection analysis with fluorescence detection

“…A saliva trap was also connected in order to avoid contamination from hydrogen peroxide in saliva. Salivary contamination was not checked by amylase determination, but according to Gessner et al EBC samples do not exhibit amylase activity [16]. The temperature in the tube was between −25 and −20 • C. Prior to gravimetrical determination of the volume, the collected sample was centrifuged at 1200 rpm for 5 min.…”