Effects of dexmedetomidine on oxygenation during one-lung ventilation for esophagectomy

Objective To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction and oxygenation during one-lung ventilation (OLV) undergoing esophagectomy. Methods Fifty-six adult patients undergoing esophagectomy and requiring OLV were selected. During inhalational anesthesia with sevoflurane, patients were randomized to receive either dexmedetomidine(dexmedetomidine group, 28 patients) or saline placebo(control group, 28 patients). The bolus dose of 0.3 μg/kg over 10 min followed by a maintenance dose of 0.6 μg/(kg·h) was used in dexmedetomidine group. The arterial blood gas samples were obtained to evaluate the effects of dexmedetomidine on oxygenation in three times: T1: double-lung ventilation 10 min after anesthetic intubation; T2: OLV 10 min; T3: 60 min after continuous infusion of dexmedetomidine. Outcomes included differences in hemodynamic parameters (heart rate and mean arterial pressure), end-tidal sevoflurane concentration, ephedrine dose and atropine dose. Results The levels of pH, arterial partial pressure of carbon dioxide (PaCO2) in two groups had no significant differences (P > 0.05). The level of oxygenation index in two groups at T3 had significant difference: (153.29 ± 19.00) mmHg (1 mmHg=0.133 kPa) vs. (117.79 ± 12.00) mmHg, 1 mmHg= 0.133 kPa, P 0.05). Conclusions Dexmedetomidine may provide clinically relevant benefits by improving oxygenation and decreasing the requirement of inhalational anaesthetic agents, thereby limiting its effect on hypoxic pulmonary vasoconstriction during OLV in adults undergoing esophagectomy surgical procedures. Key words: Dexmedetomidine; Oxygenation index; One-lung ventilation; Hypoxic pulmonary vasoconstriction