Effects of dexmedetomidine on oxygenation and lung mechanics in patients with moderate chronic obstructive pulmonary disease undergoing lung cancer surgery: A randomised double-blinded trial

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a risk factor that increases the incidence of postoperative cardiopulmonary morbidity and mortality after lung resection. Dexmedetomidine, a selective α(2)-adrenoreceptor agonist, has been reported previously to attenuate intrapulmonary shunt during one-lung ventilation (OLV) and to alleviate bronchoconstriction. OBJECTIVE: The objective is to determine whether dexmedetomidine improves oxygenation and lung mechanics in patients with moderate COPD during lung cancer surgery. DESIGN: A randomised, double-blinded, placebo-controlled study. SETTING: Single university hospital. PARTICIPANTS: Fifty patients scheduled for video-assisted thoracoscopic surgery who had moderate COPD. Patients were randomly allocated to a control group or a Dex group (n = 25 each). INTERVENTIONS: In the Dex group, dexmedetomidine was given as an initial loading dose of 1.0 μg kg(−1) over 10 min followed by a maintenance dose of 0.5 μg kg(−1) h(−1) during OLV while the control group was administered a comparable volume of 0.9% saline. Data were measured at 30 min (DEX-30) and 60 min (DEX-60) after dexmedetomidine or saline administration during OLV. MAIN OUTCOME MEASURES: The primary outcome was the effect of dexmedetomidine on oxygenation. The secondary outcome was the effect of dexmedetomidine administration on postoperative pulmonary complications. RESULTS: Patients in the Dex group had a significantly higher PaO(2)/FiO(2) ratio (27.9 ± 5.8 vs. 22.5 ± 8.4 and 28.6 ± 5.9 vs. 21.0 ± 9.9 kPa, P < 0.05), significantly lower dead space ventilation (19.2 ± 8.5 vs. 24.1 ± 8.1 and 19.6 ± 6.7 vs. 25.3 ± 7.8%, P < 0.05) and higher dynamic compliance at DEX-30 and DEX-60 (P = 0.0001 and P = 0.0184) compared with the control group. In the Dex group, the PaO(2)/FiO(2) ratio in the postoperative period was significantly higher (P = 0.022) and the incidence of ICU admission was lower than in the control group. CONCLUSION: Dexmedetomidine administration may provide clinically relevant benefits by improving oxygenation and lung mechanics in patients with moderate COPD undergoing lung cancer surgery. TRIAL REGISTRATION: ClinicalTrial.gov identifier: NCT 02185430.