Hindawi Publishing Corporation Anesthesiology Research and Practice Volume 2013, Article ID 236089, 8 pages http://dx.doi.org/10.1155/2013/236089 Clinical Study The Effect of Prophylactic Dexmedetomidine on Hemodynamic Disturbances to Double-Lumen Endotracheal Intubation: A Prospective, Randomized, Double-Blind, and Placebo-Controlled Trial Tanyong Pipanmekaporn, 1,2 Yodying Punjasawadwong, 2 Somrat Charuluxananan, 3 Worawut Lapisatepun, 2 and Pavena Bunburaphong 3 1 Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Tailand 2 Department of Anesthesiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Tailand 3 Department of Anesthesiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Tailand Correspondence should be addressed to Tanyong Pipanmekaporn; tanyong24@gmail.com Received 22 February 2013; Revised 29 April 2013; Accepted 3 June 2013 Academic Editor: Peter Andrews Copyright © 2013 Tanyong Pipanmekaporn et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te purpose of this study was to determine the efect of dexmedetomidine on hemodynamic responses to DLT intubation compared to placebo and to assess the adverse efects related to dexmedetomidine. Sixty patients were randomly allocated to receive 0.7 g/kg dexmedetomidine ( = 30) or normal saline ( = 30) 10 minutes before general anesthesia. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and rate pressure product (RPP) between groups were recorded. During intubation and 10 minutes aferward (T1-T10), the mean SBP, DBP, MAP, HR, and RPP in the control group were signifcantly higher than those in the dexmedetomidine group throughout the study period except at T1. Te mean diferences of SBP, DBP, MAP, HR, and RPP were signifcantly higher in the control group, with the value of 15.2 mmHg, 10.5 mmHg, 14 mmHg, 10.5 beats per minute, and 2,462.8 mmHg min −1 . Four patients in the dexmedetomidine group and 1 patient in the control group developed hypotension, while 2 patients in the dexmedetomidine group had bradycardia. Prophylactic dexmedetomidine can attenuate the hemodynamic responses to laryngoscopy and DLT intubation with minimal adverse efects. Tis trial is registered with ClinicalTrials.gov NCT01289769. 1. Introduction A double-lumen endotracheal tube (DLT) is a device fre- quently used in thoracic surgery. It efectively provides lung separation and facilitates changing from two- to one-lung ventilation [1]. A previous study found that both laryn- goscopy and DLT intubation could stimulate signifcant hemodynamic responses and increase the plasma concen- tration of catecholamines [2]. Although these hemodynamic responses including tachycardia and hypertension are tran- sient, they can be harmful to patients with hypertension, myocardial ischemia, or cerebrovascular disease [3, 4]. Te supplement of an inhaled anesthetic agent during anesthetic induction and intubation using a nondepolarizing muscle relaxant is a normal practice at our hospital. However, we observe that this practice is found inefective to attenuate the hemodynamic responses to intubation and rescue treatment is frequently required. Terefore, some measures should be added in order to optimize this condition. Several drugs have been used to attenuate the hemody- namic responses to laryngoscopy and DLT intubation. Dex- medetomidine, a highly selective 2 receptor agonist, pro- duces sedative, analgesic, and central sympatholytic efects. It reduces norepinephrine release at the neuroefector junc- tion, inhibits neurotransmission of sympathetic nerves, and decreases plasma catecholamines, which results in a slight