Effect of dexmedetomidine on postoperative pulmonary function in patients undergoing laparoscopic operation

Objective To evaluate the effect of dexmedetomidine on the postoperative pulmonary function in patients undergoing laparoscopic operation. Methods Eighty American Society of Anesthesiologists physical statusⅠ or Ⅱ patients, aged 45-64 yr, weighing 45-70 kg, undergoing laparoscopic radical resection of rectal cancer, were divided into 2 groups(n=40 each)using a random number table: control group(group C)and dexmedetomidine group(group Dex). General anesthesia combined with epidural anesthesia was used.In group Dex, dexmedetomidine was intravenously infused as a bolus of 0.3 μg/kg over 10 min after epidural catheterization and before induction of general anesthesia, followed by an infusion of 0.4 μg·kg-1·h-1 starting from the end of tracheal intubation until 30 min before the end of operation.The equal volume of normal saline was given instead in group C. After epidural catheterization and before infusion of dexmedetomidine(T0), immediately before termination of pneumoperitoneum(T1)and at 1, 6 and 24 h after operation(T2-4), blood samples were taken from the peripheral vein for determination of concentrations of serum interleukin-6(IL-6), IL-10, tumor necrosis factor-alpha and malondialdehyde, and arterial blood gas analysis was performed simultaneously.Respiratory index and oxygenation index(OI)were calculated, and the occurrence of OI ≤ 300 mmHg was recorded. Results Compared with group C, the serum IL-6 and tumor necrosis factor-alpha concentrations and respiratory index were significantly decreased, and IL-10 concentrations and OI were increased at T1-4, and malondialdehyde concentrations were decreased at T1-3, and the incidence of OI ≤ 300 mmHg was decreased in group Dex(P<0.05). Conclusion Dexmedetomidine can inhibit inflammatory responses and improve the postoperative pulmonary function in patients undergoing laparoscopic operation. Key words: Dexmedetomidine; Pneumoperitoneum, artificial; Respiratory function tests; Postoperative complications