Effects of Dexmedetomidine on Stress Response and Postoperative Analgesia

• Postoperative pain at rest [ Time Frame: At 1,3 postoperative hours ] [ Designated as safety issue: Yes ]
  The patients were instructed to give the number that represented the pain level at rest by using visual analogue scale（VAS）and prince-henry score
• dosage Dosage of analgesics [ Time Frame: during 3 postoperative hours ] [ Designated as safety issue: Yes ]
• Recovery time [ Time Frame: At the moment of the eyes opend when calling the names ] [ Designated as safety issue: Yes ]
• Postoperative sedation [ Time Frame: at 0,1,3 postoperative hours ] [ Designated as safety issue: Yes ]
  It was assessed by Ramsay Sedation Score(RSS)
• Extubation time [ Time Frame: at the moment of extubation ] [ Designated as safety issue: Yes ]
• Breathing recovery time [ Time Frame: when autonomous respiration recovered ] [ Designated as safety issue: Yes ]

Dexmedetomidine is a highly selective α2 adrenoreceptor agonist approved by the US FDA for short-term postoperative sedation and analgesia.It can also reduce the stress response without respiratory depression.

In this prospective, randomized, double-blind, placebo-controlled study，we gave dexmedetomidine or saline placebo 1h before operations were over and assessed the effects of dexmedetomidine on stress response and postoperative analgesia in patients undergoing thoracotomy during anesthesia recovery period.

Dexmedetomidine can significantly reduce the emergence agitation and postoperative pain in patients who received chest surgery

• Restlessness
• Pain

• Drug: dexmedetomidine

  In this arm,midazolam(0.03-0.05mg/kg), propofol(1.5-2.5mg/kg),sufentanil(0.6-0.82μg/kg )and rocuronium(0.8-1.0mg/kg) were used in anesthesia induction.

  Anaesthesia was maintained with propofol（4-6mg kg-1h-1），remifentanil (0.1-0.2 μg kg-1 min-1）and sevoflurane（1%).Propofol was titrated to maintain intraoperative Narcotrend values between 20 and 46.

  Patients in this arm received dexmedetomidine 0.2μg/kg i.v. during 10 minutes 1 hour before the end of surgery

  Other Name: dexmedetomidine
• Drug: saline placebo

  In this arm,midazolam(0.03-0.05mg/kg), propofol(1.5-2.5mg/kg),sufentanil(0.6-0.82μg/kg )and rocuronium(0.8-1.0mg/kg) were used in anesthesia induction.

  Anaesthesia was maintained with propofol（4-6mg kg-1h-1），remifentanil (0.1-0.2 μg kg-1 min-1）and sevoflurane（1%).Propofol was titrated to maintain intraoperative Narcotrend values between 20 and 46.

  Patients in this arm received saline placebo of the same volume i.v. during 10 minutes 1 hour before the end of surgery

  Other Name: saline placebo

• Experimental: Group-DEX
  Patients in this arm received dexmedetomidine 0.2 microgram per kg i.v. during 10 minutes 1 hour before the end of surgery
  Intervention: Drug: dexmedetomidine
• Placebo Comparator: Group-PLB
  Patients in this arm received saline placebo 0.05 ml per kilogram i.v. during 10 minutes 1 hour before the end of surgery
  Intervention: Drug: saline placebo

Inclusion Criteria:

• American Society of Anaesthesiologists Physical Status (ASA-PS) I or II
• undergoing selective thoracotomy
• weight between 45 and 75kg
• operation time 2-4 hours

Exclusion Criteria:

• history of neurologic disease
• history of chronic analgesics intake
• history of allergic reactions to the experimental durgs
• history of renal insufficiency
• history of hepatic dysfunction
• history of coagulation disorders
• women in lactation
• participating in other studies