الفهرس 
Introduction.Only 14 pages are availabe for public view
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Abstract
The peri-operative period is stressful state, characterized by complex autonomic, hormonal and physiological disturbance. Patients undergoing thoracic surgery specially who have associated cardiac and respiratory problems, which pose them to increase risk(222).
Thoracotomy is associated with severe postoperative pain, which is one of the factors causing postoperative impairment of ventilatory mechanics and gas exchange(223).
Patients who are administered thoracic epidural anesthesia may require adjuvant drugs because various degrees of anxiety are observed. One of the drugs that, by their qualities, can be used as adjuvant in anesthesia include alpha-2-adrenergic agonists which provide sedation, anxiolysis, hypnosis and analgesia(224).
Clonidine has been used as an adjuvant in regional anesthesia in various settings. It is an α-2 adrenergic agonist that produces analgesia via a non-opioid mechanism. The combination of epidural clonidine with bupivacaine for analgesia has been extensively studied and it has been shown to improve analgesia when added also to epidural ropivacaine(224-225).
Dexmedetomidine is a highly selective α-2adrenoceptor agonist in a range of 1,600:230 in relation to the clonidine. It is a lipophlic agent, so it is rapidly absorbed into the bloodstream causing possibly systemic effects even after subarachnoid or epidural administration(226-227).
Dexmedetomidine by epidural route reduces the latency time of the block, increases the duration of analgesic effect, improves the analgesic quality and causes sedation without causing respiratory depression(228).
Patient and method:
60 patients divided into 3 groups fentanyl group(control group), clonidine group and dexmedetomidine group vital signs measured at 5, 10, 15, 20 and 30 minutes following the epidural injection .
General anesthesia was induced, Intraoperative top up doses in the form of (4-5 ml bupivacaine o.125%) will be given every 1.5 hours. If signs of light anesthesia noted intravenous fentanyl will be given. Patient was admitted to ICU and followed up 24 hours. Post operative analgesia was given according to the Visual Analogue Score when more than 5 in the form of 4-5 ml bupivacaine(0.625%) plus 0.5μg/kg fentanyl in the control group, 1μg/kg dexmedetomidine group or 1μg/kg clonidine group.
Patient still in pain (vas >5) will receive 1 gm perflgan and if no response will receive 30 mg ketorlac.
We found that although dexmedetomidine decrease heart rate and blood pressure but also it gives better analgesia and sedation for longer duration postoperative. The decrease in heart rate and blood pressure not serious and easily reversed by atropine and ephedrine.