Dexmedetomidine to Prevent Agitation After Free Flap Surgery

The Effect of Dexmedetomidine on Agitation and Delirium in Patients After Free Flap Reconstructive Surgery

Reconstruction using microvascular free tissue flap has been an important management in patients with maxillofacial tumor. It is often characterised as long operation time, more traumatic and require restriction of patient's head movement postoperatively in order to prevent disruption of microvascular anastomosis. Agitation and delirium are common in patients with free flap surgery, which may lead to serious consequences such as self extubation, injury or even failure of the flap. Dexmedetomidine is a sedative and co-analgesic drug with high specificity for α2-adrenoceptor. It is widely used in ICU sedation in general hospital. However its use after free flap surgery is not well documented. Furthermore the effect of Dexmedetomidine on preventing delirium has not been proved. The investigators hypothesized that the use of Dexmedetomidine would reduce emergence agitation and prevent delirium in patients after free flap surgery.

agitation, delirium, dexmedetomidine, head and neck surgery, microvascular free tissue transfer, flap

Dexmedetomidine(4㎍/mL) : 0.5㎍/kg/hr infusion for 1 hour before operation is completed and 0.2-0.7㎍/kg/hr infusion continuously until 6:00am the next day.

Drug: Normal saline 0.9% (guess as 4㎍/mL) : 0.5㎍/kg/hr infusion for 1 hour before operation is completed and 0.2-0.7㎍/kg/hr infusion continuously until 6:00am the next day.

Dexmedetomidine(4㎍/mL) : 0.5㎍/kg/hr infusion for 1 hour before operation is completed and 0.2-0.7㎍/kg/hr infusion continuously until 6:00am the next day.

Normal saline 0.9% (guess as 4㎍/mL) : 0.5㎍/kg/hr infusion for 1 hour before operation is completed and 0.2-0.7㎍/kg/hr infusion continuously until 6:00am the next day

Patients are kept calm and cooperative in the PACU. Agitation is defined as Riker-Agitation Scale(SAS)>=5.

Patients are sent back to wards the next morning after operation and followed up on each of the 5 days postoperatively. Delirium will be confirmed based on CAM-ICU method.

Patient's vital signs including heart rate, blood pressure, pulse oxygen saturation and respiratory rate are monitored continuously in PACU and recorded on 1,2,4,6,12 hour after PACU admission.

extra analgesics and sedatives will be given when patients are agitated or if the patients ask for them.

Patients' pain score are evaluated by a numerous scale(0-10) at 8am the next day, just before they leave PACU.

Participants are followed for 5 days after operation and their sleep quality are evaluated every afternoon on each of the 5 days.

Participants are followed for 5 days after operation and their pain score are evaluated by VAS method every afternoon on each of the 5 days. Patients' pain score on maxillofacial region and flap donation region are evaluated respectively.

Inclusion Criteria: patients undergoing selected maxillofacial surgery with free flap reconstruction American Society of Anesthesiologist(ASA) classification I and II Exclusion Criteria: bradycardia (< 50 bpm) severe heart block low blood pressure(SBP<80mmHg) Known allergy to alpha 2 agonists