In regional anesthesia local anaesthetics alone provide analgesia for not more than 4-8 hours. Increasing the duration of local anaesthetic action is often desirable because it prolongs surgical anaesthesia and analgesia. Different additives have been used to prolong regional blockade. Vasoconstrictors can be used to constrict vessels, thereby reducing vascular absorption of the local anaesthetic. Additives like opioids, clonidine and verapamil were added to local anaesthetics, but the results are either inconclusive or associated with side effects. Steroids when used intrathecally are reported to cause arachnoiditis, but there is no evidence suggesting any neuritis when steroids are used in low concentration in peripheral nerve blocks.

Steroids have powerful anti-inflammatory as well as analgesic properties. Perineural injection of steroids is reported to influence postoperative analgesia. They relieve pain by reducing inflammation, and blocking transmission of nociceptive C-fibres and by suppressing ectopic neural discharge. The addition of 5 mg of dexamethasone to 10 ml of 0.5% levobupivacaine in interscalene brachial plexus block showed improvement of postoperative analgesia for arthroscopic shoulder operation without any specific complications.

The objective of this study is to compare the effects of combining of dexamethasone and bupivacaine versus bupivacaine alone in combined femoral and sciatic nerve block in patients undergoing lower limb vascular surgeries. The effects will be studied in terms of:

• Onset of sensory blockade and motor blockade
• Duration of analgesia / first request for analgesic
• Duration of motor blockade

Inclusion Criteria:

• Age ranging from 18 to 70 years
• American Society of Anesthesiologists (ASA) physical status I, II and III
• Patients scheduled for lower limb vascular surgeries

Exclusion Criteria:

• Patient refusal for the procedure
• Any bleeding disorder or patients on anticoagulant therapy
• Neurological deficits involving lumbar or sacral plexuses
• Patients with allergy to local anaesthetics
• Local infection at the injection site
• Patients on any sedative or antipsychotic drugs
• Body mass index > 35