1. INTRODUCTION:
Brachial plexus block has proved to be a good alternative to general anaesthesia (GA) for upper limb surgeries. Brachial plexus block is given by various approaches viz. supraclavicular, inter scalene, infraclavicular and axillary routes, using either ultrasound or peripheral nerve stimulator (PNS). Supraclavicular block helps in achieving good anaesthesia along with complete muscle relaxation while providing hemodynamic stability and excellent post-operative analgesia. The supraclavicular level is an ideal site to achieve anesthesia of the entire upper extremity just distal to the shoulder as the plexus remains relatively tightly packed at this level, resulting in a rapid and high-quality block.
Among the local anaesthetics, either bupivacaine or Levobupivacaine is being used. Here, I am using levobupivacaine which is the S(-) enantiomer of racemic bupivacaine. having pharmacology and duration of anaesthesia are like those of bupivacaine but is less cardio toxic compared to bupivacaine.
With a local anesthetic solution, various adjuvants like epinephrine, bicarbonate, opioids, clonidine, neostigmine, dexmedetomidine, midazolam have been injected concomitantly as it achieves quicker onset, improve the analgesic profile, prolong the duration of blockade. It also reduces the dose of local anaesthetics used thus minimizing the risk of local anaesthetic toxicity. Each drug has advantages and disadvantages, so efforts were made to combine the adjuvant with local anesthetics to improve patient and surgeon satisfaction. Fentanyl is being used since long time to improve the quality of nerve blocks. Addition of fentanyl to local anesthetics injected during brachial plexus block has been shown to shorten the onset time of sensory as well as motor blockade and prolongs the duration of blockade. It also decreases the post operative systemic analgesic requirements.
Magnesium is the fourth most common cation in the body, has postsynaptic N-methyl D-aspartate calcium channel blocker properties. The anti-nociceptive action of Magnesium sulfate has been used to augment quality and duration of analgesia in supraclavicular brachial plexus block. Magnesium sulfate has been studied less frequently for nerve blocks. A previous clinical study demonstrated that adding magnesium sulfate to supraclavicular brachial plexus block may increase the sensory and motor block duration and time to first analgesic use, and decrease total analgesic needs, with no side effects.
Here, we are evaluating Magnesium sulfate as an adjuvant to Levobupivacaine for supraclavicular brachial plexus block and compare it with Fentanyl added to Levobupivacaine for supraclavicular brachial plexus block.
2. STUDY HYPOTHESIS
Our study may find both adjuvants effective when added to levobupivacaine but magnesium sulfate may be a better adjuvant than fentanyl in terms of extended the motor and sensory block durations and better analgesic profile.
3. AIMS AND OBJECTIVES
The primary aim of this clinical study is to evaluate and compare the effects of adjuvants - Magnesium sulfate and Fentanyl added to levobupivacaine in ultrasound guided supraclavicular brachial plexus block.
OBJECTIVES
I. Primary objective:
To assess sensory blockade and motor blockade
II. Secondary objectives:
To assess analgesia profile
Duration of postoperative analgesia
Number of rescue analgesia required in first 24 hours.
To observe hemodynamic parameters like heart rate, MAP, SpO2
To observe complications, if any
1. STUDY DESIGN
Study Site: Orthopedic Operation theatre, B. J. Medical College, Civil Hospital, Ahmedabad
Study Type: A prospective randomized controlled study
Sample Size: The sample size calculation was done using Epi info software. The parameter duration of sensory blockade has been taken from the reference study, considering probability of alpha error 0.05 and power of the study 90%, a sample size of 11 patients in each group came. Considering rate of 10% dropout a total of 20 patients per group will be taken. So, total 40 patients will be studied.
6. PATIENT SELECTION
INCLUSION CRITERIA:
Age: 18-60 years.
Gender: Both.
ASA physical status I, II.
Patient undergoing upper limb surgeries below shoulder.
EXCLUSION CRITERIA:
ASA physical status III, IV, V.
Unwilling patient.
Having head injury
Patient having distal neuro-vascular deficit
Had a history of hypersensitivity to the any of the study drug.
Known allergy to LA
Patient already received either fentanyl or magnesium sulfate.
Pregnant patient.
H/o cardiac, hepatic, or renal disease.
On treatment with calcium channel blockers.
7. MATERIAL AND METHOD
After obtaining approval from institutional ethical committee, written informed consent will be taken. Total 40 patients will be randomly allocated into two groups (n=20 in each group) using computer generated random numbers. Patients having American society of Anesthesiologist (ASA) physical status up to II of both the genders undergoing upper limb surgeries under supraclavicular block will be enrolled in the study. A total of 40 will be randomly divided in to two groups and their allocation will be sealed in opaque envelope.
Group F: Injection Levobupivacaine 0.5% 25 ml + Injection Fentanyl 50 µg diluted in 5 ml normal saline (NS).
Group M: Injection Levobupivacaine 0.5% 25 ml + Injection Magnesium Sulfate 250 mg diluted in 5 ml normal saline (NS).
DRUGS
Study drugs are fentanyl, magnesium sulfate and levobupivacaine, which are available in government supply if not available then I will purchase on my own and no cost will be bear by patient.
METHOD:
Pre -operative evaluation will be carried out a day before surgery. A thorough history will be taken and detailed examination will be carried out.
Patient will be subjected to routine and relevant investigations like hemoglobin, renal function tests, serum electrolytes, random blood sugar, coagulation profile, chest X-ray PA view and ECG and other special tests needed according to procedure.
All the patients will be kept nil by mouth as per ASA guidelines.
On the day of surgery informed, written consent will be taken and prior to operation after explaining about the visual analogue scale score and the procedure to be done and doubts will be cleared.
Patient will be taken on O.T table and all standard monitors including non-invasive blood pressure (NIBP), pulse oximetry (SpO2), electrocardiogram (ECG) will be attached.
After establishing intravenous access IV fluids will be started and pre-operative vital parameters will be recorded.
ULTRASOUND-GUIDED SUPRACLAVICULAR BRACHIAL PLEXUS BLOCK:
The patient will be positioned supine with the head turned gently to the contralateral side, and a pillow placed under the head and shoulders. Ultrasound imaging will be performed. Under complete aseptic technique, the ultrasound probe will be positioned in the supraclavicular fossa to visualize the subclavian artery and brachial plexus in the transverse sectional view (i.e., at approximately 90°). The brachial plexus, a cluster of hypo echoic nodules, is often found lateral to the round pulsating hypo-echoic subclavian artery lying on top of the hyper-echoic first rib. After local skin infiltration with 3 mL xylocaine 2%, a 22-gauge 50 mm insulated block needle will be placed on the outer (lateral) end of the probe and advanced along the long axis of the probe and in the same plane as the ultrasound beam. Needle movement will be observed in real time. Once the needle reached the brachial plexus cluster, the LA solution will be injected incrementally over 3–5 min after negative aspiration. LA spread within plexus sheath at the time of injection will be observed in real time. If spread did not reach some parts of the brachial plexus, the needle will be repositioned once before depositing the remaining half of the LA dose.
After that, Patients will be evaluated every 2 minutes for 10 minutes and then every five minute up to 30 minutes after the end of LA injection by the anesthesiologist.
OBSERVATION
Sensory block will be assessed by a pinprick test using a three-point scale in the ulnar, median, radial, and musculocutaneous nerve dermatome distribution and compared with the contralateral arm as a reference:
0 = normal sensation
1 = loss of sensation of pinprick (analgesia)
2 = loss of sensation to touch (anesthesia)
Onset of sensory block(seconds) is defined as the time from completion of injection (time 0) to the time sensory block began to be detected (Score 1) in the distribution of any one of the major nerves.
Complete sensory block(seconds) is defined as the time from completion of injection (time 0) to the time score 2 has been achieved in all nerve dermatomes.
Total duration of sensory block is defined as the duration from the end of local anesthetic administration to complete resolution of anesthesia from distribution of all four nerves, i.e., Score 0.
Motor block will be evaluated by the ability to flex the elbow and hand against gravity as the following;
Grade 0: no block (normal motor function with full flexion and extension of the elbow, wrist, and fingers)
Grade 1: decreased motor strength with ability to flex or extend only the fingers
Grade 2: compete motor blockade with inability move fingers.
Onset of motor block is defined as the time from completion of injection of study drug to detection of a motor block of Score ≥1.
Complete motor block is defined as time from completion of injection of study drug to detection of a motor block of Score =2.
Total duration of motor block will be defined as time interval between the end of local anesthetic administration and the recovery of complete motor function of the hand and fingers, i.e., Score 0.
A successful block defined as complete sensory and motor block in all nerve dermatome assessed within 30 min of local anesthetic injection.
In case of failed block after 30 mins, general anesthesia will be administered and the patient will then be excluded from data analysis.
Patient satisfaction score will be measured with point scale: 1 = very satisfied; 2= satisfied; 3= undecided; 4 = dissatisfied; 5 = very dissatisfied.
INTRA OPERATIVE COMPLICATIONS
Patients will be observed for any systemic side effects like bradycardia (PR < 52/min), hypotension (BP < 90/60 mmHg), nausea, vomiting, respiratory depression (RR < 8/min), hypoxia (SpO2< 90%), any significant ECG changes etc.
Post operative analgesia will be assessed using visual analogue scale. Patients will be assessed for duration of postoperative analgesia and number of rescue analgesia required in first 24 hours. Injection tramadol 50 mg intravenously will be given as a rescue analgesic when VAS ≥4 or on patient demand.
8. DATA ANALYSIS
All observations will be recorded, and results will be analyzed statistically. Data will be entered in Microsoft excel and analyzed using student’s T-test. Numerical data will be expressed as mean ± SD. P value < 0.05 will be interpreted as clinically significant.
9. STUDY END POINTS:
We will observe the patient for 24 hours for post operative analgesia and till pre-defined sample size is achieved.