Can Ventilator Settings Influence Lung Damage Biomarkers KL-6 and CRP during One Lung Ventilation?

Background: Volume-controlled (VCV) or pressure-controlled ventilation (PCV) modes are most often used during OLV.This is a prospective observational analytical study of patients undergoing thoracic surgery with OLV. Method: 40 patients underwent thoracic surgery using one lung ventilation (OLV) from December 2023 to February 2024. All patients received lung protective ventilation (PLV) with a tidal volume of 6 ml/ kgPBW during OLV with PEEP 5-7 cmH2O and were divided into two groups: one with a ventilator in volume-controlled mode (VCV) and the other with pressure-controlled mode (PCV). KL-6, CRP, and p/f ratio were measured before OLV, 2 hours after OLV, and 24 hours after the operation was completed. Respiratory variables during OLV were recorded. Results: KL-6 and CRP levels in PCV and VCV groups were significantly different. There were significant differences in the values of P_peak (p <0.001), PEEP (p = 0.008), C_stat (p = 0.004) and driving pressure (p <0.001) in both groups. The correlation between changes in KL-6 and CRP levels and the P/F ratio were very weak and insignificant. Cytokines play an important role in the inflammatory response in the lungs. Several determining factors of blood flow are gravity, lung disease, surgery, and hypoxic pulmonary vasoconstriction. Duration of OLV may affect the pulmonary inflammatory response and is correlated with the duration of OLV. Conclusion: There is no association found between KL-6 and CRP in PCV and VCV mode during thoracotomy with OLV.