Effects of dexmedetomidine combined with subanesthetic dose of ketamine on emergence agitation in patients undergoing thoracotomy

Abstract

Objective To evaluate the effects of dexmedetomidine combined with subanesthetic dose of ketamine on the emergence agitation in the patients undergoing thoracotomy. Methods Eighty ASA physical status Ⅱ or Ⅲ patients, aged 55-75 yr, weighing 50-75 kg, scheduled for elective esophageal cancer resection, were randomly divided into 4 groups (n=20 each) using a random number table: normal saline group (NS group), dexmedetomidine group (group D), subanesthetic dose of ketamine group (group K), and dexmedetomidine combined with ketamine group (group DK). In DK and K groups, ketamine 0.5 mg/kg was injected intravenously (within 1 min) at 10 min before the end of the operation. In DK and D groups, dexmedetomidine 0.5 μg/kg was infused intravenously over 10 min starting from 10 min before the end of operation. In group NS, the equal volume of normal saline was infused intravenously over 10 min starting from 10 min before the end of operation. The emergence time, extubation time, duration of ICU stay, occurrence and degree of agitation, and development of cardiovascular events and hypoxemia within 24 h after operation were recorded. Ramsay sedation scores were recorded before induction of anesthesia (T1), immediately after completion of administration at the end of surgery (T2), and at 0, 5, 10 and 30 min after extubation (T3-6). Results There was no significant difference in the emergence time, extubation time, and duration of ICU stay between the four groups. Compared with group NS, Ramsay sedation scores were significantly increased at T3-6, the incidence and degree of agitation were decreased, and the incidence of cardiovascular events and hyoxemia was decreased in D, K and DK groups. Compared with D or K group, Ramsay sedation scores were significantly increased at T3-6, the incidence and degree of agitation were decreased, and the incidence of cardiovascular events and hyoxemia was decreased in group DK. Conclusion Dexmedetomidine combined with subanesthetic dose of ketamine can prevent the emergence agitation in the patients undergoing thoracotomy, which provides better efficacy than either alone. Key words: Dexmedetomidine; Ketamine; Anesthesia recovery period; Psychomotor agitation; Thoracic surgical procedures