PURPOSE: As reported previously even relatively short term mechanical ventilation during general anesthesia in COPD patients (but not in patients with intact lungs) initiates significant exhaled breath condensate (EBC) acidification probably reflecting inflammatory response of lung tissue to ventilation induced injury (Skrahin A. et al. ERJ 2005; Vol. 26, suppl. 49:88s).In framework of search lung protective strategies for mechanical ventilation in COPD we evaluated influence of mechanical ventilation parameters and receiving preoperative COPD therapy on EBC acidification after general anesthesia with mechanical ventilation.
METHODS: Patients (n=42) with COPD scheduled for surgery (not related to COPD) under general aesthesia with mechanical ventilation entered the study. Patients without COPD (n=10) subjected to elective surgery under general anesthesia served as a control. EBC was collected using R-Tube system with ice as a cooler before anesthesia and after extubation. Samples were pH measured by pH-meter immediately after nitrogen deaeration.
RESULTS: COPD patients in contrast to control group had significant EBC acidification after extubation. Such parameters of mechanical ventilation as tidal volume, airways pressure, PEEP, FiO2 were not found to correlate with EBC pH decrease. COPD patients receiving inhaled corticosteroids preoperatively did not have any decrease in EBC pH after mechanical ventilation.
CONCLUSION: Inhaled corticosteroids prevented decrease in EBC pH after mechanical ventilation in COPD patients. Mechanical ventilation parameters manoeuvring did not prevent EBC acidification after general anesthesia with mechanical ventilation in COPD patients.
CLINICAL IMPLICATIONS: EBC pH is a sensitive noninvasive tool for investigations related to mechanical ventilation. Lung protective strategies search for mechanical ventilation in COPD should be continued.
DISCLOSURE: Aliaksandr Skrahin, None.