Comparison of the effects of dexmedetomidine and ketamine on oxygenation and lung mechanics in moderate COPD patients undergoing lung cancer surgery

In this study, we aimed to compare the effects of dexmedetomidine and ketamine on oxygenation, lung mechanics, and postoperative complications in patients diagnosed with moderate chronic obstructive pulmonary disease (COPD) undergoing lobectomy. Following ethical committee approval, a retrospective analysis was conducted on 173 patients who underwent lung cancer surgery between January 1, 2024, and January 1, 2025. A total of 42 patients were included in the study: 21 patients in the dexmedetomidine group (Group D) and 21 in the ketamine group (Group K). Group D received a 1 mcg/kg loading dose of dexmedetomidine over 10 minutes after induction, followed by a continuous infusion at a rate of 0.5 mcg/kg/h. Group K received a 1 mg/kg bolus of ketamine, followed by a continuous infusion at 0.5 mg/kg/h. Heart rate, mean arterial pressure (MAP), partial arterial oxygen pressure (PaO₂), end-tidal sevoflurane concentration (EtSEVO), and peak inspiratory pressure (Ppeak) were recorded before the initiation of one-lung ventilation (OLV), and at the 30th and 60th minutes of OLV. Dynamic compliance, shunt fraction (Qs/Qt), and dead space ventilation (Vd/Vt) were also calculated at these time points. The incidence of postoperative atelectasis, pneumonia, and acute lung injury (ALI) was evaluated. Heart rate and MAP were significantly higher in the ketamine group. EtSEVO levels decreased over time in both groups with no significant difference between them. PaO₂, dynamic compliance, and shunt fraction were similar between the two groups and showed increases over time within each group. Dead space ventilation was comparable between the groups and did not change significantly over time. Postoperative complications were also similar in both groups. Both agents improved lung mechanics and enhanced oxygenation. Considering their hemodynamic profiles and patient characteristics, both drugs can be used in combination with volatile agents during one-lung ventilation. Thus, it prevents the inhibition of volatile agents on hypoxic pulmonary vasoconstriction and helps the mechanism to work effectively. Keywords: one-lung ventilation, COPD, dexmedetomidine, ketamine