الفهرس 
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Abstract
Pain is the most complex human experience. Perioperative pain is more distressing to the patient and is also much more difficult to relief adequately.
Methods of preemptive analgesia should be sought, because pain free patient is a happier one, and this helps in the speedy recovery, also pain free patient will be much more mobile and able to breathe deeply which result in reducing the incidence of post-operative pulmonary morbidity.
Regional nerve blocks can be a good alternative or used as a useful adjuvant to the systemic analgesics in patients undergoing renal surgeries who often suffer from impaired renal function. Paravertebral nerve blockade, by injecting local anesthetic solution alongside the vertebral column, produces ipsilateral analgesia and has been advocated mainly in unilateral surgeries like thoracotomy, chest wall, breast and renal surgeries.
Paravertebral block is a safe and inexpensive technique with the advantage of providing surgical analgesia and prolonged postoperative pain relief. It is also an effective treatment of operative pain, blunts autonomic, somatic and endocrine responses.
It has become a common practice to use poly-pharmaceutical approach for treatment of intra and postoperative pain, because no drug has yet been identified that specifically inhibits nociception without associated side effects.
The aim of this work was to compare the effect of adding Dexmedetomidine to Bupivacaine or adding Fentanyl to Bupivacaine in paravertebral block for perioperative analgesia in renal surgeries.
The present study was carried out on 60 adult patients of both sexes, ASA physical status class I and II, admitted to “Alexandria Main University hospital” for elective unilateral renal surgeries .
Exclusion criteria
1. Contraindications of paravertebral block
• Patient refusal
• Vertebral column anomalies
• Systemic infection or sepsis
• Coagulation disorders
2. Sensitivity to used drugs.
3. Patients on medications with α-adrenergic blocking effect
The selected patients were randomly categorized into two groups; 30 patients each:
Group F: Patients received bolus dose 20 ml of 0.25% Bupivacaine+ Fentanyl (0.3 µg/kg) before the beginning of the surgery in the paravertebral space via a catheter placed at the level of the surgical incision followed by continuous infusion of 0.25% Bupivacaine+ Fentanyl (1.5 µg/ml) at rate of 6 ml /h intraoperative and for the first 24 hours post operatively.
Group D: Patients receivedbolus dose of 20 ml (0.25% Bupivacaine + Dexmedetomidine (1µg/kg) before the beginning of the surgery in the paravertebral space via a catheter placed at the level of the surgical incision followed by continuous infusion of (0.25% Bupivacaine +Dexmedetomidine 0.25 µg/kg) at rate of 6 ml /h intraoperative and for the first 24 hours post operatively.
On the preoperative interview, full medical history was taken, full clinical examination was done and investigations including complete blood count, coagulation profile, renal and liver function tests and plain chest x-ray. Moreover all patients were taught how to express pain intensity postoperatively using visual analogue score.
When using a high-frequency linear transducer for out-of-plane needle guidance, position the patient sitting or in lateral decubitus similar to the landmark-baesd techniques. We use caution when advancing the needle past the TP to avoid pneumothorax. We will apply the transducer perpendicular to skin in a parasagittal plane approximately 2 cm lateral to the midline and oriented parallel to the spine. We will identify the TP of the vertebral bodies cephaled and cauded to T12-L1 paravertebral space, then we visualize the pleura anterior to the paravertebral space and note the depth, then we will insert the block needle perpendicular to skin next to the ultrasound transducer after injecting a local anesthetic skin wheal and advance the needle out-of-plane toward the paravertebral space. When the desired depth is achieved based on visualization of corresponding tissue movement in the target area or predetermined depth, we will inject 4 to 5 ml of local anaesthetic solution after negative aspiration for blood. Injectate spread should be confirmed within the paravertebral space under ultrasound.(19, 20)
When performing in-plane needle guidance, position the patient prone. The large low-frequency curvilinear transducer is preferred because it enables us to visualize the needle even at steeper angles. We will apply the transducer perpendicular to skin in a parasagittal plane approximately 2 cm lateral to the midline and oriented parallel to the spine, then we will identify the TP of the vertebral bodies cephaled and cauded to T12-L1 paravertebral space and the pleura anteriorly. With the large curvilinear transducer, we can visualize more than one paravertebral space. This will allow us to perform more than one PVB by simply redirecting the needle cephaled or cauded utilizing one needle insertion. A local anesthetic skin wheal will be injected cauded to the ultrasound transducer, and the block needle will be inserted through this skin wheal and directed in plane toward the paravertebral space. When the needle tip is visualized within the target paravertebral space, we will inject 4 to 5 ml of local anesthetic solution after negative aspiration for blood. Injectate spread should be confirmed within the paravertebral space under ultrasound.
Patients turned back to the supine position, and block was activated either by 20 ml of 0.25% Bupivacaine plus 0.3µg/kg Fentanyl (Group F) or by 20 ml of Bupivacaine 0.25% plus 1µg/kg Dexmedetomidine (Group D).
Induction of anesthesiawas carried out with Fentanyl citrate (1 µg/kg) i.v, Propofol 2 mg/kg i.v and endotracheal intubation was facilitated by injection of Rocuronium bromide, 0.6 mg/kg i.v.
Anesthesia was maintained with 1.2% Isoflurane in 100%O2, intermittent boluses of Rocuronium (0.1mg/kg) as indicated intravenously.
Continuous infusion starting after paravertebral block activation, patients of group F received a continuous infusion of 6 ml/h 0.25% Bupivacaine plus Fentanyl ( 1.5µg/ml), while patients of group D received a continuous infusion of 6ml/h 0.25% Bupivacaine plus Dexmedetomidine (4µg/ml) in the paravertebral space.
At the end of surgery, the patient was transferred to Post-anesthesia care unit (PACU).
In (PACU), the infusion continued in the postoperative period by rate of 6ml/h. In both groups, if visual analogue scale (VAS) was more than 3, Meperidine hydrochloride 0.5mg/kg i.vwas given.
The following measurements were carried out:
- Assessment of Heart rate, MABP, SBP and DBP was carried at skin incision, then every 20 min till the end of the surgery. Postoperative, at PACU admission, every 2 hour for the first 12 hours, then every 4 hours for the next 12 hours.
- Assessment of VAS was carried Postoperative at PACU admission, hourly for the first 12 hours, then every 2 hours for the next 12 hours.
- Post-operative sedation was assessed by Ramsay Sedation Score of 1, 2, 4, 8, 16 hours postoperatively.
- Also assessment of time to first analgesic requirement , total Meperidine hydrochloride consumption during 24 hours postoperatively and complication, such as hypotension and bradycardia.
The following results were obtained:
- VAS, in the group D (Bupivacaine + Dexmedetomidine) was significantly lower than that of the group F (Bupivacaine + Fentanyl) and the latency of starting the pre-designed analgesic regimen was delayed significantly in group D (7.13 h±4.19) than group F (4.67 h±3.45),also total consumption of Meperidine hydrochloride was significantly lower in the group D (83.75±21.46) mg than group F (69.81±24.28) mg. post-operative sedation score was better in group D than group F .
- Heart rate and MABP decreased significantly in both groups, with significant decrease in heart rate, and SBP in group D than group F and the results of DBP and MABP were comparable between both groups.
- Complications encountered were: hypotension in 4 patients in group D(13.3%) and 2 patients in group F(6.7%) and bradycardia in one patient in group D.