Presentation on intravenous regional anaesthesia

Detailed presentation regarding Intravenous regional anesthesia

1. INTRAVENOUS REGIONAL ANAESTHESIA Moderator: Dr. D. JAYADHEER BABU (Professor) Dr. B.J. PRAVEENA (Assistant professor) Speaker: Dr. K. GEETHIKA (3rd yr Postgraduate)

2. The technique of IVRA or Bier block was first introduced in 1908 by German Surgoen August Bier . Bier block :- Injecting local anaesthetic into venous system of upper or lower extremity that has been exsanguinated by compression or gravity and that has been isolated from central circulation by means of torniquet.

3. AUGUST KARL GUSTAV BIER Born in Helsen, Germany in 1861; Graduated in 1889 at Kiel. He became familiar with the technique “ Lumbar Puncture ,” a safe investigation in routine neurological examination. In 1898, he gave the first deliberate spinal anaesthetic by injecting 2ml of 1% Cocaine solution into his own theca with the help of his assistant. He invented the method of treating chronic inflammation by the method of passive hyperaemia with Esmarch’s bandage. He pioneered intravenous Procaine analgesia. He introduced the “ Tin Helmet ,” into the German army in the 1st World War. He died at the age of 88yr.

4. Conditions 1.Surgical procedures involving the arm below the elbow. 2.Surgical procedures involving the leg below the knee.

5. MECHANISM OF ACTION The mechanism of action is felt to be via diffusion of the local anesthetic extravascularly to block distal peripheral branches of nerves - PERIPHERAL BLOCK The local anesthetic,diffuses into small veins sorrounding the nerves and into vasa nervorum and ciliary plexus of nerves leading to centrifugal conduction in the nerves involved - CONDUCTION BLOCK

6. Torniquet produces ischemia,which contibutes analgesic action of local anaesthetic by blocking nerve conduction and motor end plate function. Diffusion of local anesthetic into the surrounding tissues also plays a role. Ischemia and compression of the peripheral nerves at the level of the inflated cuff is probably another contributory component of the mechanism of IVRA . The onset of anesthesia is usually within 5 minutes

7. INDICATIONS Reduction and fixation of fractures , Burns debridement Ganglionectomy, carpal tunnel release, Dupuytren’s contracture surgery Mass excision, Digital Nerve repair, Phalangeal dislocation, Accessory Navicular excision Inj. Botulinum Toxin A for treatment of Hyperhidrosis Complex Regional Pain Syndrome type I Limited surgical procedures < 45min duration Upper extremity IVRA can be used for longer procedures (>1hr) with a mandatory torniquet deflation period of atleast 1min prior to re-establishing the anesthetic state.

8. EQUIPMENTS Local Anesthetic agents - Lidocaine (0.25% - 1%), Prilocaine 0.5% One 20- or 22-gauge intravenous catheter One Esmarch bandage ( 60 inch length and 4 inch width) One 500-1000ml bag of IV solution connected to an infusion set ASA monitors Rescuscitation equipment ( IV catheter, crystalloids, infusion set for contralateral upper extremity) Double pneumatic cuff tourniquet 30 ml or 50ml Leur lock syringe Sterile skin preparatory set Graduated measuring cup ( preferably 100ml capacity) for solution mixing Adhesive tape

9. PATIENT PREPARATION Patient lies in dorsal recumbent position For surgery on the elbow, the needle will be placed in the forearm or antecubital fossa. For procedures on the hand or forearm, a vein in the dorsum of the hand is best selected. For lower extremity procedures, a vein on the foot, ankle, or lower leg is chosen.

10. After obtaining intravenous access in a nonoperated extremity, a full complement of ASA monitors is applied, and baseline vital signs are assessed. If the patient is in severe pain, small aliquots of intravenous analgesics may be administered (ie, fentanyl 1–2 μg/kg) to facilitate the exsanguination process. For anxiolysis, Benzodiazepines like Inj. Midazolam 15-25mcg /kg can be given.

11. TECHNIQUE A small IV intravenous catheter (e.g, 22-gauge) is introduced in the dorsum of the patient's hand of the arm to be anesthetized under strict aseptic conditions. A double-pneumatic tourniquet is placed on the proximal cuff high on the upper arm. The entire arm is elevated to allow passive exsanguination and a rubber Esmarch bandage is wound around the arm spirally from the fingertips of the hand to the distal cuff of the double tourniquet to exsanguinate the arm .

12. This study compared forearm tourniquet placement (n = 28) with 8 mL of 2% lidocaine and 10 mg ketorolac and upper arm tourniquet placement (n = 28) with 15 mL of 2% lidocaine and 20 mg ketorolac found that patients in the forearm tourniquet group experienced less discomfort, fewer sedation interventions , and a greater likelihood of bypassing the postanesthesia care unit (PACU ) when compared with the group with the upper arm tourniquet

13. The axillary artery is digitally occluded, and while pressure is maintained on it, the proximal pneumatic cuff is inflated to 50–100 mm Hg above the systolic arterial blood pressure, after which the Esmarch bandage is removed. The axillary artery is digitally occluded, and while pressure is maintained on it, the proximal pneumatic cuff is inflated to 50–100 mm Hg above the systolic arterial blood pressure, after which the Esmarch bandage is removed.

14. Following inflation of the proximal cuff and removal of the Esmarch bandage, 30–50 mL of 0.5% lidocaine are injected via the indwelling plastic catheter, depending on the size of the arm being anesthetized. The forearm discolors, and the patient perceives a transient “pins and needles” sensation and warmth as anesthesia ensues over the following 5 minutes. The intravenous cannula in the surgical extremity is then withdrawn, and pressure is quickly applied over the site using sterile gauze.

15. About 25–30 minutes after the onset of anesthesia or when the patient complains of tourniquet pain, the distal cuff is inflated and the proximal cuff is deflated to minimize the development of tourniquet pain. LOWER EXTREMITY IVRA : The only significant difference is requirement of relatively larger volumes of Local anesthetic needed. (50-100ml)

16. DRUGS 1.PRILOCAINE The drug of choice as it is least toxic largest therapeutic index. 40ml of 0.5% Prilocaine is recommended Maximum dose for a 70kg adult = 400mg (approx. 6mg/kg) which equates 80ml of 0.5% solution. Onset 2 - 15minute and duration 1 – 4hours. 2.BUPIVACAINE Unsuitable due to its cardiotoxic profile

17. 3.LIGNOCAINE On average, 40ml of 0.5% of Lignocaine recommended. Maximum dosage = 250ml for a 70kg adult (approx. 3mg/kg) which equates 50ml of 0.5% solution. onset 1.5 - 5minute and duration 1 – 4hours . * Only plain solution of Prilocaine and Lignocaine should be used without Adrenaline.

18. ADJUVANTS TO LOCAL ANESTHETICS a 2 AGONIST - Clonidine, Dexmedetomedine OPIOIDS - Fentanyl TRAMADOL MUSCLE RELAXANTS NEOSTIGMINE NSAID’s - Ketorolac, Tenoxicam, Lornoxicam, Dexketoprofen STEROIDS ACETAMINOPHEN NITROGLYCERIN MIDAZOLAM KETAMINE

19. Drug related: Lidocaine – excessive plasma concentration of lidocaine associated with large IV boluses result in peripheral vasodilation, decreased cardiac contractility causing hypotension. 2. Prilocaine – rarely methhemoglobinemia. ( Prilocaine is metabolized to o-toluidine derivatives, which converts hemoglobin to methemoglobin, of concern when exceeds 600mg) COMPLICATIONS

20. 3. Opioids- when administered in combination with L.A occasional side effects are nausea , vomiting and mild sedation. * Lowest dose of Local Anesthetic with a Seizure was 1.4mg/kg for lidocaine, 4mg/kg for Prilocaine, 1.3mg/kg for Bupivacaine.

21. EQUIPMENT RELATED : Cuff failure Sudden increase in Pressure ( higher than the cuff pressure) An intact interosseous circulation NERVE INJURY : Rarely, damage to Median Nerve, Ulnar Nerve, Musculocutaneous Nerve.

22. TORNIQUET : Unintentional deflation of cuff Ischemic pain and discomfort Systemic Hypertension from inflation is sustained When surgery is less than 30 min duration, intermittent cuff deflation and inflation may effectively prolong the time to achieve peak arterial concentration of LA but may not be entirely reliable in minimising toxicity due to release of LA into circulation.

23. COMPARTMENT SYNDROME : Occurs rarely especially when IVRA is used for reduction of long-bone lower extremity fractures, and may be due both to the large volume of local anesthetic injected to effect analgesia and to inadequate or incomplete exsanguination of the limb prior to performing the block.

24. LOCAL ANESTHETIC SYSTEMIC TOXICITY LAST is due to excess plasma concentrations of the Local Anesthetic Plasma concentrations of L.A are determined by rate of drug entrance into the systemic circulation relative to the redistribution and clearance. CNS effects: Perioral numbness, restlessness, vertigo, tinnitus, slurred speech, skeletal muscle twitching, seizures, coma CVS effects: profound hypotension , decreased cardiac output, arrhythmias, asystole.

25. LIPID RESCUSCITATION THERAPY : Scavenging effect ( Lipid Sink) - Lipid emulsions have ability to take up lipophilic modifies and transfer them around blood to sites of storage and detoxification. This provides LIPID SHUTTLE EFFECT. Direct Cardiotonic effect - Increases cardiac output through a combination of volume and direct cardiotonic effects to improve cardiac output once the cardiac concentration of drug drops below ion channel–blocking thresholds.

26. A 1000ml of 20% intralipid solution is composed of 200g of Soyabean oil, 12g of Egg phospholipids, 22mg of anhydrous glycerol with omega 3 and 6 fatty acids. Maximum of upto 10ml/kg over 30min is recommended as upper limit for initial dosing. Side effects: Allergy, Nausea and Vomiting Dyspnea, Chest pain Bronchospasm Bacterial contamination Hepatospleenomegaly

27. CAUTION : PROPOFOL is not a substitute for a lipid emulsion as there is insufficient lipid content in standard sedating or antiseizure doses of propofol to exert a benefit ; can also compromise CV stability. Avoid Vasopressin, CCB’s, Beta blockers

28. PREVENTION : Do not Deflate until atleast 30 min have elapsed after injecting local anesthetic. Monitor continuously for atleast 15min following torniquet deflation. CYCLICAL DEFLATING/ RE-INFLATING : The cuff is deflated → Immediately reinflated. The patient is observed or questioned carefully If there are no such signs or symptoms after about 1 minute, the cuff is once again deflated and again immediately reinflated for a period of about 1 to 2 minutes, with the patient being observed and queried for systemic local anesthetic toxicity.

29. If none appears by this time, the tourniquet may be safely deflated and removed from the extremity. The safety of such cycled deflating/reinflating is that, with each deflation, only a small fraction of the administered (and unbound) local anesthetic is allowed to enter the systemic circulation, minimizing the possibility of a sudden, sustained increase in the blood level of the local aneshtetic.

30. SEVERE METHEMOGLOBINEMIA Medical emergency Good history and high level of suspicion is required First line of treatment : METHYLENE BLUE INFUSION DEXTROSE should be given because it is the major source of NADH in the red blood cells is the catabolism of sugar through glycolysis. Dextrose is also necessary to form NADPH through the HMP shunt, which is necessary for MB to be effective.

31. METHYLENE BLUE : The dose of MB is 1 to 2 mg/kg IV over 5 minutes (total dose should not exceed 7–8 mg/kg). MB can cause dyspnea, chest pain, or hemolysis. MB provides an artificial electron transporter for the reduction of MetHb via the NADPH dependent pathway. The response is rapid; the dose may be repeated in 1 hour if the level of MetHb is still high 1 hour after the initial infusion. Rebound methemoglobinemia may occur up to 18 hours after MB administration due to prolonged absorption of lipophilic agents (benzocaine) from adipose tissue.

32. It is reasonable to perform serial measurements of MetHb levels following treatment with MB. MB should not be administered to patients with G6PD deficiency because the reduction of MetHb by MB is dependent on NADPH generated by G6PD (hemolysis). An alternative treatment for these patients is ASCORBIC ACID (2 mg/kg). Blood transfusion or exchange transfusion may be helpful in patients who are in shock. Hyperbaric oxygen has been used with anecdotal success in severe cases.

33. CONTRAINDICATIONS ABSOLUTE - Patient refusal RELATIVE : Reynaud’s disease Homozygous sickle cell disease Young children Shock Multiple trauma (crush injuries of relevant limb) Hypersensitivity to Prilocaine or lidocaine Seizure disorder Inability to locate peripheral veins Local skin infection, Cellulitis

34. ADVANTAGES OF THE BIER BLOCK Easy to administer Low incidence of block failure Safe technique when used appropriately Rapid onset and recovery Patient is awake during procedure. Controllable extent of anesthesia.

35. DISADVANTAGES OF THE BIER BLOCK Should be used for only short procedures Patient may experience tourniquet pain after 20-30 minutes Sudden cardiovascular collapse or seizures may occur if local anesthetic is released into the circulation too early. Rapid recovery may lead to postoperative pain. Difficulty in providing a bloodless field.

36. REFERENCES : HADZIC’s TEXTBOOK OF REGIONAL ANESTHESIA BARASCH Clinical Anesthesia Article on INTRAVENOUS REGIONAL ANAESTHESIA - BIER’S BLOCK - Dr Natasha Clark, Royal Devon & Exeter Single-cuff forearm tourniquet in intravenous regional anaesthesia results in less pain and fewer sedation requirements than upper arm tourniquet. F. B. Chiao, J. Chen, J. B. Lesser, F. Resta-Flarer, H. Bennett BJA, Volume 111, Issue 2, August 2013

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