Study: NCT03606902

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Group f : Epidural catheter insertion
Description: Infiltrate the skin with local anesthetic lidocaine approximately 1 cm lateral to the inferior aspect of the targeted spinous process , epidural needle tip is midline at the junction of the lamina and spinous process . The needle is withdrawn and advanced with the same medial angle but in small increments cephalad to the same depth. Either bone or ligamentum flavum is contacted. If bone is contacted, the needle is redirected cephalad and advanced. If bone is no longer contacted and the depth exceeds the depth previously noted, the epidural needle stilette is removed. loss-of-resistance syringe is attached to the needle Once attained, stabilize the epidural needle and thread the catheter. Secure the catheter using a sterile locking device and adherent dressings.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Group F: Continous epidural infusion of bupivacaine plus fentanyl
Description: Epidural injection of bolus of 15 ml total Volume of 0.0625%bupivacaine with 1 µg /Kg Fentanyl initial bolus, then from the 1st hour continuous epidural infusion of 0.0625% bupivacaine with µ/Kg/h Fentanyl fixed for the next 5 hour during operation and in the recovery room after recovery of general anesthesia then stop epidural infusion. (Total infusion time 6 hours=maximum hours needed for nephrectomy surgery)

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Group LF :Continous epidural infusion of decreasing doses of fentanyl plus pubivacaine
Description: Epidural injection of bolus of 15 ml total Volume of 0.0625%bupivacaine with 1 µg/Kg Fentanyl initial bolus, then continuous IV infusion of 0.0625%bupivacaine with 1 µg/Kg/h Fentanyl for the 1st hour then continuous epidural infusion of 0.0625%bupivacaine with 0.5 µg/Kg/h Fentanyl during the 2nd hour, then 0.0625%bupivacaine with 0.25 µ g/Kg/h Fentanyl for the 3rd hour then continue the same infusion volume and dose (0.0625%bupivacaine with 0.25Mg/Kg/h Fentanyl) for the next 3 hours during operation and in the recovery room after recovery of general anesthesia then stop epidural infusion. (Total infusion time 6 hours=maximum hours needed for nephrectomy surgery)

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Group L f : Epidural catheter insertion
Description: Infiltrate the skin with local anesthetic lidocaine approximately 1 cm lateral to the inferior aspect of the targeted spinous process , epidural needle tip is midline at the junction of the lamina and spinous process . The needle is withdrawn and advanced with the same medial angle but in small increments cephalad to the same depth. Either bone or ligamentum flavum is contacted. If bone is contacted, the needle is redirected cephalad and advanced. If bone is no longer contacted and the depth exceeds the depth previously noted, the epidural needle stilette is removed. loss-of-resistance syringe is attached to the needle Once attained, stabilize the epidural needle and thread the catheter. Secure the catheter using a sterile locking device and adherent dressings.