Comparison of Levobupivacaine and dexmedetomidine versus Ropivacaine and dexmedetomidine for ultrasound guided supraclavicular brachial plexus block: a randomised control trial.

Background

Supraclavicular brachial plexus block is popular and widely used nerve block technique for anaesthesia and analgesia for upper limb surgeries. Lidocaine and bupivacaine are most often used local anaesthetic agents. Newer drugs are safe and have less systemic side effects. The purpose of the present study is to to find a local anaesthetic agent with maximum efficacy and minimum side effects for upper extremity blocks.

Research Question

Is Levobupivacaine with dexmedetomidine better than Ropivacaine with dexmedetomidine for peripheral nerve blocks?

Objectives

Primary objectives 1. To compare the onset and duration of sensory and motor block between levobupivacaine with dexmedetomidine and ropivacaine with dexmedetomidine 2. To compare post operative analgesia between levobupivacaine with dexmedetomidine and ropivacaine with dexmedetomidine Secondary objectives 1. To compare the Ramsay sedation score between the two groups 2. To compare the hemodynamic parameters between two groups

Hypothesis

Null hypothesis (H0): There is no difference between the two drugs (levobupivacaine with dexmedetomidine and ropivacaine with dexmedetomidine) for onset of action, duration of action and postoperative analgesia.

Alternate hypothesis (H1): Levobupivacaine with dexmedetomidine is better than ropivacaine with dexmedetomidine for onset of action, duration of action and postoperative analgesia.

Methodology

Inclusion criteria

1. American society of Anaesthesiology Grade (ASA) - I, II

2. Age between 18 years and 65 years

3. Elective upper limb surgery lasting more than 30 mins

Exclusion criteria

1. Uncontrolled hypertension, diabetes mellitus, arrhythmias,

2. Heart failure, renal failure, liver failure

3. Seizure disorder

4. Bleeding/ coagulation disorder

5. Pre-existing peripheral neuropathy

6. Known hypersensitivity to local anaesthetics.

7. BMI >30

8. Local skin infection

9. Pregnancy and lactating mothers

10. Bradycardia (heart rate <50 /min)

Procedure standardization

Patients will be randomized using simple lottery (sealed envelope) technique. Once patients received in preoperative area, patients will be divided into two groups; Group L and Group R based on envelope selected by them. Envelopes would contain drug details and dosage to be prepared by OT technicians.

The drugs will be prepared as follows: Group L: Levobupivacaine 0.5% (24 ml) with dexmedetomidine 50 mcg (1 ml) Group R: Ropivacaine 0.5% (24 ml) with dexmedetomidine 50 mcg (1 ml) Total volume of the drug will be 25ml for all patients.

Patient will be taken to the operation theatre; vitals will be monitored, and supraclavicular block performed under all aseptic precautions under ultrasound guidance by an anaesthesiologist who will be unaware of the drug composition. Once the study drug is delivered, following parameters will be assessed and noted. 1. Time of onset of sensory and motor block 2. Time when complete sensory and motor block is achieved After achieving complete sensory and motor block patient is proceeded for surgery. Only successful block cases will be taken for study. Throughout intraoperative period vitals are monitored .Degree of sedation will be monitored at all intervals as that of vital parameters. On arrival in the postanaesthetic care unit, pain scoring will be assessed using Numeric Rating Scale (NRS) on movement of operated arm. NRS on movement will be assessed hourly following surgery till the request of first analgesic. Postoperative vitals will be assessed every hour till the regression of block. Any side effects such as nausea, vomiting, and sedation will be noted. Postoperative sedation score will be assessed hourly till the regression of block.

Data analysis

The data will be tabulated and analysed using Microsoft© Excel© 2013 and IBM© SPSS©-21 software. The categorical data will be analysed using χ2 and Fisher Exact test and continuous data using student t-test and ANOVA.