الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
Abstract
Spinal anesthesia is the most commonly used technique for lower abdominal surgeries as it is very economical and easy to administer.
However, postoperative pain control is a major problem because spinal anesthesia using only local anesthetics is associated with relatively short duration of action, and thus early analgesic intervention is needed in the postoperative period. Various adjuvants have been added to local anesthetics in spinal anesthesia, such as narcotics, clonidine, midazolam and others have been studied to avoid intraoperative visceral and somatic pain, prolong the effect of spinal anesthesia and to provide prolonged postoperative analgesia.
A common problem during lower abdominal surgeries under spinal anesthesia is visceral pain, nausea, and vomiting. The addition of fentanyl to hyperbaric bupivacaine improves the quality of intraoperative and early postoperative subarachnoid block. The addition of opioids to local anesthetic solution have disadvantages, such as pruritus and respiratory depression. Dexmedetomidine, a highly selective α2-agonist, is under evaluation as a neuraxial adjuvant as it provides stable hemodynamic conditions, good quality of intraoperative and prolonged postoperative analgesia with minimal side effects.
The aim of this work was to compare the onset and duration of sensory and motor block as well as analgesia and adverse effects of Dexmedetomidine(DXM) or fentanyl given intrathecally with 0.5% hyperbaric bupivacaine for spinal anesthesia in lower abdominal surgery.
The present study conducted on 60 patients aged 18-60 years old scheduled for lower abdominal surgery under spinal anesthesia distributed into two groups each comprising 30 patients group(D) (dexmedetomidine group): received intrathecal 15mg hyperbaric bupivacaine 0.5% plus 5μg dexmedetomidine (total volume of 3.5ml), Group (F) (fentanyl group):received intrathecal 15mg hyperbaric bupivacaine 0.5% plus 25μg fentanyl (total volume of 3.5ml).
A comparison was made between two groups as regards motor and sensory block, duration and quality of postoperative analgesia,
hemodynamic and respiratory variables as well as side effects during lower abdominal surgery under spinal anesthesia.
There was no statically significant difference between two groups in age, sex, weight and in operative duration and type.
Initially there was a statistically significant reduction of MAP at 1st hour following the block in group (F) compared with group
(D),(P<0.05).
Regarding heart rate changes in both groups, there was a statistically significant reduction of HR at 1st hour following the block in group (D) compared with group (F),(P<0.05). However there was a statistically significant rise of HR at 4 and 12 hours following the block in group (F) compared with group (D),(P<0.05).
Intrathecal 15mg heavy bupivacaine supplemented with 5 μg dexmedetomidine significantly shortened the onset time of both sensory and motor block, shortened time to reach T10 dermatome as well as time to reach peak sensory level. Also, it significantly prolonged time to two segment regression, complete sensory resolution time and regression of motor block to Bromage 0 with prolonged analgesic effects of spinal hyperbaric bupivacaine evident by decreased postoperative pain scores(VAS), total analgesic consumption and prolongation of time to first request analgesia, compared with intrathecal 25μg fentanyl and heavy bupivacaine in patients undergoing lower abdominal surgery. There was no serious postoperative complication in both groups.
Also, there was insignificant sedation in both groups.
According to our result, both 5 μg dexmedetomidine and 25ug fentanyl prolonged both sensory and motor block, prolonged time to 1st analgesic request and diminished the risk of supplementation of general anesthesia. Also, 5ug dexmedetomidineis better alternative to 25μg fentanyl as an adjuvant to spinal bupivacaine in surgical procedures. It provides good quality of intraoperative analgesia, hemodynamically stable conditions, lower side effects, and excellent quality of postoperative analgesia.