WITHDRAWN: Effectiveness of Intraoperative Dexmedetomidine on Early Postoperative Cognitive Dysfunction in Elderly Patients Undergoing Video-Assisted Thoracoscopic Lobectomy: A Randomized Controlled Trial

Abstract

Background: Postoperative cognitive dysfunction (POCD) is the decline in cognitive ability that occurs between one week and one year following surgery. POCD has been reported to occur in 5% to 26% of elderly surgical patients and its incidence varies with demographic, clinical, and surgical variables. Previous studies have shown that dexmedetomindine (DEX), a highly selective α2 adrenergic receptor agonist, has many effects that include opioid-sparing properties, decreased required anesthetic medication, and neuroprotection in animal models. Ultimately, DEX may benefit cognitive ability in the postoperative period. Therefore, we hypothesized that intraoperative infusion of DEX would reduce early POCD and interleukin-6 (IL-6) levels in elderly surgical patients compared to placebo. Methods: This randomized, double-blind, controlled trial enrolled 96 elderly patients that underwent video-assisted thoracoscopic lobectomy (VATL) between May 2017 and April 2018. The enrolled subjects were randomly assigned in a 1:1 ratio to receive intravenous dexmedetomidine (DEX Group) or placebo (0.9% normal saline, Saline Group) as a continuous infusion at a rate of 0.5μg/kg/hr starting at anesthesia induction until incision closure. All subjects received total intravenous anesthesia (TIVA) during surgery and patient controlled epidural analgesia (PCEA) following surgery. The primary outcomes were to determine the incidence of POCD and IL-6 expression at postoperative day (POD) 1, 2, and 7. The secondary outcomes were to evaluate the degree of pain on POD 1 and 2, as well as adverse events throughout the study. Results: 96 eligible subjects (48 per group) were randomized, dosed with study medication, and evaluated per protocol. There was a significant difference on POCD between the DEX and saline groups on POD 1 (6.3% vs. 20.8%, p-value <0.05) and POD 2 (4.2% vs. 16.7%, p-value <0.05). The IL-6 levels were significantly lower in the DEX group when compared with saline group during POD 1 and 2 (p-value <0.05). IL-6 returned to baseline levels on POD 7. There was no significant difference in POCD on POD7, and overall there were no significant differences in the incidence of adverse events between both groups.Conclusions: The administration of intraoperative DEX in elderly patients undergoing VATL decreased the incidence of early POCD. Clinical Trial Registry: This study was registered on Chinese Clinical Trial Registry with the ID ChiCTR-IPR-17010958.