الفهرس 
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Abstract
Many of the surgical procedures are done daily all over the world. Patients get benefit from the amazing advances in both surgical and anesthesia techniques. However, despite the progress in understanding the physiology of pain and the pharmaceutical properties of painkillers many patients are still suffering from severe postoperative pain after surgery.
Postoperative pain leads to a lot of complications as immobility, respiratory dysfunction, deep venous thrombosis and excess catecholamine that that increases the cardiac work. Most of these complications can be avoided by killing postoperative pain.
The traditional methods in the face of postoperative pain depend on giving painkillers after the end of surgery and at the beginning of pain sensation. But preemptive analgesia aims to prevent the pain before it occurs; this leads to prevention of pain processing and facilitation in the central nervous system.
Regional anesthesia remains the gold standard; it provides suitable intraoperative conditions and perfect postoperative analgesia. Also, with regional anesthesia patients with chronic diseases as chronic renal failure, chronic liver failure and chronic heart failure avoid exposure to the risks of general anesthesia.
The use of ultrasound is considered an amazing advance in anesthesia. Complications of regional anesthesia as intravascular or intraneural or extraneural injection and pneumothorax decreased dramatically after ultrasound use.
As local anesthetics provide a limited postoperative analgesia time, it became favorite to study the effect of addition of some drugs that have some analgesic properties to determine its ability to prolong the postoperative analgesia.
This clinical study was carried out in Assuit university hospital between June 2013 and December 2015. The aim of this study was to evaluate the effects of addition of dexmedetomedine or fentanyl to bupivacaine in ultrasound guided infraclavicular brachial plexus block. The study included ninety patients undergone orthopedic upper limb surgery. Patients were randomly allocated into three groups’ thirty patients each:
group B (control group):- Patients received 30 ml 0.5% bupivacaine normal saline (2ml).
group BD (dexmedetomedine group):- Patients received 30 ml 0.5% bupivacaine + 1µg/kg dexmedetomedine (2ml).
group BF (fentanyl group):- Patients received 30 ml 0.5% bupivacaine + 1µg/kg fentanyl citrate (2ml).
Inclusion criteria:
• Age group 18-70 years.
• ASA grade 1 and 2.
• Orthopedic upper limb surgery below shoulder.
Exclusion criteria:-
Patients with the following conditions were excluded from the study:
• Consent not given.
• ASA Grade 3 or more.
• Severe respiratory disease.
• Neural deficit involving brachial plexus.
• History of allergy to local anesthetics.
• Contraindications to regional block (coagulopathy, infection at the needle insertion site, contralateral pneumothorax).
• Bilateral limb surgery is a contraindication for the block.
• Altered conscious level.
• Pregnancy.
• BMI >35.
• Patients who have difficulty in understanding the study protocol.
• Patients with known contraindication to study medications.
• Block failure or inadequate block.
• Patients on alpha agonist or antagonist medications.
Measurements
1) Intraoperative haemodynamics: arterial blood pressure, heart rate and oxygen saturation.
2) Onset of sensory block.
3) Duration of sensory block.
) Onset of motor block.4
5) Duration of motor block.
6) Duration of analgesia.
7) Possible side effects of brachial plexus block.
8) Sedation score.
9) Patient satisfaction.
The present study showed that dexmedetomedine had minimal effect on the hemodynamics, blood pressure and heart rate which decreased by less than 20% started 10 minutes after injection and returned to its base line after 4 hours. Also, the study showed that no significant changes in the hemodynamics were found in fentanyl group before and after block.
The study showed that the addition of dexmedetomedine or fentanyl to local anesthetics hastened the onset of the sensory block, but dexmedetomedine was more effective with a mean complete sensory block onset of 11.20 ± 1.16 minutes in the dexmedetomedine group compared to 14.03 ± 1.77 minutes and 14.77 ± 2.56 minutes in the fentanyl and the control groups respectively.
The study also showed that only dexmedetomedine hastened the onset of complete motor block, with a mean complete motor block onset of 17.73 ± 2.52 minute in the dexmedetomedine group compared to 23.23 ± 1.63 minutes in the fentanyl and 26.40 ± 3.64 minutes in the control group.
In this study both dexmedetomedine and fentanyl were found to prolong the duration of motor block, but dexmedetomedine has more prolonged motor block duration. The mean motor block duration in the three groups were found to be 14.50 ± 1.59 hours, 11.40 ± 1.96 hours and 7.90 ± 1.27 hours for groups BD, BF and B respectively.
As regard analgesia duration, the present study showed that both dexmedetomedine and fentanyl group prolonged the analgesia duration, but dexmedetomedine was more effective with mean analgesia duration of 17.40 hours in the dexmedetomedine group compared to 14.57 and 10.77 hours in the fentanyl and the control group respectively.
Conclusion:
In conclusion, both dexmedetomedine and fentanyl citrate were found to be good adjuvants for bupivacaine in infraclavicular brachial plexus block, but dexmedetomedine demonstrated better results than fentanyl citrate as regard the block characteristics. The present study showed that the addition of dexmedetomedine and fentanyl citrate to ultrasound guided infraclavicular block shortened the onset of sensory block but only dexmedetomedine shortened the onset of motor block. Both of them prolonged the duration of motor block, they provided postoperative analgesia, delayed the time of first analgesic request and decreased the consumption of analgesics postoperatively, but dexmedetomedine was found to be more effective than fentanyl with a mean postoperative analgesia of 17.4 hours compared to 14.57 hours for fentanyl and 10.77 hours in the control group.
We would like to state that dexmedetomidine besides shortening the onset time of block, prolongs the duration of sensory and motor block, post-operative analgesia and enhances the quality of block as compared with fentanyl when used as an adjuvant to bupivacaine in infraclavicular brachial plexus block without significant side effects.