The primary objective was to evaluate the effects of permissive hypercapnia on inflammatory biomarkers in bronchoalveolar lavage fluid and serum during one-lung ventilation. The secondary objective was to assess the influence of different ventilation modes on these inflammatory responses.
Methods: Forty patients undergoing elective lung surgery requiring OLV were prospectively enrolled an allocated to either a normocapnic (n=20) or hypercapnic group group (n=20). BAL concentrations of TNF-α, IL-1β, IL-6, and IL-8 were measured before and after intervention. Serum IL-6, C-reactive protein (CRP), and leukocyte counts were also assessed. Patients were further stratified according to ventilation mode (PC or VC).
Outcome measures: Primary outcome: change of bronchoalveolar lavage (BAL) levels of preselected biomarkers for inflammation (TNF-α , IL-1β, IL-6, and IL-8) as well as in serum (IL-6, CRP, and WBC) between the normocapnic and hypercapnic groups during one-lung ventilation. Secondary outcome: whether the inflammatory response differed according to the ventilation mode (pressure-controlled versus volume-controlled ventilation).