title: Exhaled breath condensate pH in mechanically ventilated patients.
abstract: OBJECTIVE
  In this prospective clinical trial we aimed to answer if spontaneous exhaled breath condensate (EBC) in the trap of the expiratory arm of the ventilator could replace EBC collected by coolant chamber standardized with Argon as an inert gas. Second, if EBC pH could predict ventilator associated pneumonia (VAP) and mortality.
  
  
  METHODS
  We included 34 critically ill patients (males = 26), aged = 54.85 ± 19.86 (mean ± SD) yrs, that required mechanical ventilation due to non-pulmonary direct cause (APACHE II score = 23.58 ± 14.7; PaO(2)/FiO(2) = 240.00 ± 98.29).
  
  
  METHODS
  ICU with 9 beds from a regional teaching hospital.
  
  
  RESULTS
  The patients were followed up until development of VAP, successful weaning or death. There were significant differences between mean EBC pH from the 4 procedures with the exception of spontaneous EBC de-aerated with Argon (n = 79; 6.74 ± 0.28) and coolant chamber deaerated with Argon (n = 79; 6.70 ± 0.36; p = NS by Tukey's Multiple Comparison Test). However, none of the procedures were extrapolated between each other according to Bland & Altman method. The mean EBC pH from the trap without Argon was 6.50 ± 0.28. From the total of 34 patients, 22 survived and were discharged and 12 patients died in the ICU.
  
  
  CONCLUSIONS
  Spontaneous EBC pH could not be extrapolated to EBC pH from coolant chamber and it did not change in subjects who dead, neither subject with VAP in comparison with baseline data. The lack of other biomarker in EBC and the lack of a control group determinate the need for further studies in this setting.
authors.affiliation: Neumonología, Universidad Nacional de Rosario, Hospital Escuela "Eva Perón", Argentina. Electronic address: nanninilj@cimero.org.ar.
authors.forename: L J
authors.initials: LJ
authors.lastname: Nannini
authors.forename: R
authors.initials: R
authors.lastname: Quintana
authors.forename: D H
authors.initials: DH
authors.lastname: Bagilet
authors.forename: M
authors.initials: M
authors.lastname: Druetta
authors.forename: M
authors.initials: M
authors.lastname: Ramírez
authors.forename: R
authors.initials: R
authors.lastname: Nieto
authors.forename: G
authors.initials: G
authors.lastname: Guelman Greta
mesh_terms: D001944:Breath Tests / Q000379:methods; D045853:Exhalation; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D011379:Prognosis; D012121:Respiration, Artificial