Brachial plexus block new

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Brachial plexus block new

  1. 1. BRACHIAL PLEXUS BLOCK A REVIEW Dr.P.NARASIMHA REDDY M.D D.A PROFESSOR & H.O.D DEPT. OF ANAESTHESIOLOGY KURNOOL MEDICAL COLLEGE KURNOOL
  2. 2. Brachial plexus- a review <ul><li>1)Introduction </li></ul><ul><li>2)Brief history </li></ul><ul><li>3)Applied anatomy </li></ul><ul><li>4)Approaches to brachial plexus </li></ul><ul><li>5)Techniques of brachial plexus block </li></ul><ul><li>6)Some relevant facts </li></ul><ul><li>7)Complications </li></ul><ul><li>8)Future research </li></ul>
  3. 3. Introduction <ul><li>The word plexus means to twine. It implies a network of nerves or vessels. </li></ul><ul><li>“ Man uses his arms and hands constantly.. </li></ul><ul><li>As a result he exposes his arms and hands to injury constantly.. </li></ul><ul><li>Man also eats constantly… </li></ul><ul><li>Man’s stomach is never really empty.. </li></ul><ul><li>The combination of man’s prehensibility and his unflagging appetite keeps a steady flow of patients with injured hands and full stomachs streaming into hospital emergency rooms . </li></ul><ul><li>DAVID LITTLE 1963 . </li></ul>
  4. 4. Introduction <ul><li>To give a successful block One must have </li></ul><ul><li>1) Perfect anatomical knowledge of nerves and dermatomal distribution. </li></ul><ul><li>2) Perfect knowledge about local anaesthetic agents, complications and side effects. </li></ul><ul><li>3) Perfect technical skill which is gained by experience . </li></ul>
  5. 5. HISTORY <ul><li>1884 – Karl koller used cocaine in clinical practice. </li></ul><ul><li>1859 – 1922 – Karl ludwig used infiltration anaesthesia. </li></ul><ul><li>1884 – Halstead </li></ul><ul><li>Matas </li></ul><ul><li>Crile injected local anaesthetic directly into the nerves. </li></ul><ul><li>- Hirschel injected brachial plexus blindly. </li></ul><ul><li>1912 – Kulen Kampff after experimenting on himself used supraclavicular technique. </li></ul>
  6. 6. History <ul><li>1922 – Gaston Labott used axillary block. </li></ul><ul><li>1940 – MacIntosh and Mushin modified Kulen Kampff block and wrote a monogram on supraclavicular block. </li></ul><ul><li>1964 – Alon P Winnie described pervascular sheath and block. </li></ul>
  7. 7. APPLIED ANATOMY <ul><li>Except for cutaneous supply to upper medial aspect of the arm and uppermost aspect of shoulder entire supply to the arm is by brachial plexus. </li></ul><ul><li>Anterior primary divisions(or roots) of C5-8 to T1(C4- prefixed, T2 – postfixed). </li></ul><ul><li>Roots unite to form three trunks. </li></ul><ul><li>Trunks converge on to the first rib and divide into anterior and posterior divisions. </li></ul><ul><li>These divisions unite in the axilla to form cords. </li></ul><ul><li>The plexus gives rise to 21 nerves, 9 above the clavicle. </li></ul>
  8. 8. Applied Anatomy <ul><li>Name peripheral S.branches </li></ul><ul><li>Axillary upper lat. Cut. N. of arm </li></ul><ul><li>lower lat. cut. N. of arm </li></ul><ul><li>Radial post. Cut N. of arm </li></ul><ul><li> Post. Cut. N. of forearm </li></ul><ul><li> Cut. To dorsum of hand </li></ul><ul><li>Ulnar Cut. To dorsum of hand and palm </li></ul><ul><li>Median Cut. To dorsum of hand and palm </li></ul><ul><li>Musculo cut. Nerve Lat. Cut. N. of forearm </li></ul><ul><li>Medial cutaneous nerve of arm and forearm araise directly from medial cord. </li></ul><ul><li>with interscalene approach c8 and t1 are likely to be missed and in axillary block musc. Cut. And radial nerves are likely to be missed. </li></ul><ul><li>In such situations brachial block with selective nerve blocks will give good results and prolonged post operative pain relief. </li></ul>
  9. 10. Applied Anatomy <ul><ul><ul><ul><ul><li>Rule of 3 and 5 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>roots 5 C5-TI </li></ul></ul></ul></ul></ul><ul><li>Trunks 3 superior(C5-C6) </li></ul><ul><li>Middle (C7) </li></ul><ul><li>Inferior (C8-T1) </li></ul><ul><li>DIVISONS 3 Anterior </li></ul><ul><li> 3 Posterior </li></ul><ul><li>Cords 3 Lateral </li></ul><ul><li> medial </li></ul><ul><li> posterior </li></ul><ul><li>Terminal nerves 5 Median(lat and med. Cords) </li></ul><ul><li>Musculo c.N. (Lat. Cord) </li></ul><ul><li>ulnar (Med. Cord) </li></ul><ul><li> Axillary (Post. Cord) </li></ul><ul><li>Radial(Post. Cord) </li></ul>
  10. 11. Applied Anatomy <ul><li>Peripheral nerves : </li></ul><ul><li>Both sensory and motor supply of upper limb from infraclavicular part of B.P. </li></ul><ul><li>Because of interconnection of 5 nerve roots there is overlapping and difference between dermatomal, myotomal and sclerotomal distribution of individual nerves. </li></ul><ul><li>Seven major configurations of B.P are noted.in 61% there is left to right asymmetry. </li></ul>
  11. 12. Applied Anatomy <ul><li>Relationships: </li></ul><ul><li>vertebral A. travels cephalaud and enters bony canal ar C6. </li></ul><ul><li>Cervical roots are just post. To vertebral A. </li></ul><ul><li>Ext. Jugular vein overlies the interscalene groove at C6. </li></ul><ul><li>Over the first rib the divisions of B.P lie post., cephalaud and lat. To subclavain A. </li></ul><ul><li>Axillary A. lies ant. To radial N., Postero medial to median nerve, Posterolateral to ulnar N. </li></ul>
  12. 13. Applied Anatomy <ul><li>Non brachial plexus anatomy : </li></ul><ul><li>1) supraclavicular nerve (c3-4) provides sensory supply to ‘cape area’ </li></ul><ul><li>2) suprascapula r nerves (C5-6) sensory fibers to the posterior aspect of the shoulder capsule, acro. Cla. Jt., cut. Supply to proximal third of arm in the axilla. </li></ul><ul><li>3) Intercostobrachial nerve (T2) with medial cut. N. innervates upper half of the post. And medial side of skin of the arm. </li></ul>
  13. 15. Applied Anatomy <ul><li>Sensory innervation of the arm: It is to determine </li></ul><ul><li>which cut. N. distribution is with in the surgical field, </li></ul><ul><li>which terminal nerves require supplementation in partial block and </li></ul><ul><li>Determine pre and post operative neurological deficits . </li></ul>
  14. 16. Applied Anatomy <ul><li>Motor innervation of the arm: It is important when we are using PNS to elicit end point. </li></ul><ul><li>Sup. Trunk stimulation at ISC groove- shoulder elevation. </li></ul><ul><li>Median nerve stimulation – forearm pronation, wrist flexion and thumb opposition. </li></ul><ul><li>Ulnar nerve stimulation – ulnar deviation of wrist, finger flexion and thumb adduction. </li></ul><ul><li>Radial nerve stimulation – extension of wrist and fingers. </li></ul><ul><li>Assessment of efficiency of block can be done by evaluating the function of each individual nerve. </li></ul>
  15. 17. Applied Anatomy <ul><li>Rule of 4 P’s: </li></ul><ul><li>1) Patient is asked to push the arm by extending the forearm at the elbow (radial nerve). </li></ul><ul><li>2) To pull the forearm at the elbow(Musc. Cut.N.). </li></ul><ul><li>3) Ability to distinguish a Pinch at the palmar base of index finger (Medain N). </li></ul><ul><li>4) Ability to distinguish a pinch at the palmar base of little finger(Ulnar N). </li></ul><ul><li>. </li></ul>
  16. 18. Choice of approach <ul><li>Depends on </li></ul><ul><li>1) site of surgery </li></ul><ul><li>2) duration of surgery </li></ul><ul><li>3) surgeon </li></ul><ul><li>4) anaesthetist </li></ul><ul><li>5) Patient. </li></ul>
  17. 19. Approaches to brachial plexus <ul><li>Inter scalene block(ISB): </li></ul><ul><li>Surgery on the shoulder </li></ul><ul><li>can spare C8-T1(ulnar in 50%) </li></ul><ul><li>Poor for arm and hand surgery </li></ul><ul><li>10-15ml of L.A </li></ul><ul><li>Central neuraxial blockade </li></ul><ul><li>vagal or phrenic nerve blockade </li></ul><ul><li>Pneumothorax rare </li></ul><ul><li>Intravascular injection a possibility </li></ul>
  18. 20. INTERSCALENE BLOCK
  19. 21. Approaches- contd. <ul><li>Supraclavicular block : </li></ul><ul><li>Provides anaesthesia for entire extremity </li></ul><ul><li>“ No parasthesia- No Anaesthesia” an aphorism by- Dr. Moore is more appropriate </li></ul><ul><li>BID success rate is more than 95% </li></ul><ul><li>It is modified by Macintosch </li></ul><ul><li>Vertical method “Plumb-Bob” method </li></ul>
  20. 24. SUPRACLAVICULAR BLOCK
  21. 25. Approaches contd . <ul><li>Inter sternocledomastoid block: </li></ul><ul><li>For hand and arm surgery </li></ul><ul><li>Needle is directed laterally placed in between the two heads of the sterno-mastoid muscle </li></ul><ul><li>Catheter insertion is easy and safe </li></ul><ul><li>Less risk of pneumothorax </li></ul><ul><li>15% failure in ulnar distribution </li></ul>
  22. 26. CONTINOUS INTERSCALENE BLOCK
  23. 27. Approaches contd . <ul><li>Infraclavicular block ( coracoid approach): </li></ul><ul><li>For surgery on arm and hand </li></ul><ul><li>More consistent anaesthesia for axillary and MUSC. Cut.N. </li></ul><ul><li>Latency more </li></ul><ul><li>No changes in pulmonary function </li></ul><ul><li>Catheter fixation is easy </li></ul>
  24. 28. INFRACLAVICULAR BLOCK
  25. 29. INFRACLAVICULAR BLOCK
  26. 30. Approaches contd . <ul><li>Axillary block(AXB ): </li></ul><ul><li>For hand surgery </li></ul><ul><li>All techniques work at terminal branches level </li></ul><ul><li>Success rate 60-100% </li></ul><ul><li>Anaesthesia of MCN is done by a separate injection into the belly of coracobrachialis </li></ul>
  27. 31. AXILLARY BLOCK
  28. 32. Approaches contd . <ul><li>Mid humeral block 1994 By Dupre </li></ul><ul><li>Each individual nerve is located at the junction of upper one third to the lower two thirds of the humerus in the humeral canal. </li></ul><ul><li>Success rate is very high </li></ul><ul><li>Latency less </li></ul><ul><li>Low volume of L.A. </li></ul><ul><li>Time consuming </li></ul>
  29. 33. TECHNIQUES FOR BP BLOCK <ul><li>Fascial clicks : </li></ul><ul><li>Mostly we depend on fascial clicks </li></ul><ul><li>Well appreciated with short beveled needles </li></ul><ul><li>Many studies gave mixed results </li></ul><ul><li>Paraesthesias : </li></ul><ul><li>An abnormal sensation </li></ul><ul><li>Indicate that the needle tip is near the nerve </li></ul><ul><li>They also indicate nerve injury </li></ul><ul><li>Repeated or exaggerated parasthesias are undiserable </li></ul><ul><li>Success rate – 70 to 90% </li></ul>
  30. 34. Techniques Cont …. <ul><li>PNS: </li></ul><ul><li>Is popularised by Raj. P in peripheral nerve blocks </li></ul><ul><li>Success rates are high </li></ul><ul><li>Latency is very less </li></ul><ul><li>Nerve injuries are less </li></ul><ul><li>Motor response with ≤ 0.5mA gives successful blocks </li></ul><ul><li>Pitfalls are: Correct polarity of the needle </li></ul>
  31. 35. Techniques Cont …. <ul><li>PNS Cont … </li></ul><ul><li>Pitfalls are : Correct polarity of the needle is important </li></ul><ul><li>Positive electrode should be secured to the patient </li></ul><ul><li>Loose connections and flat batteries to be avoided </li></ul><ul><li>Motor response should be in the distal group of muscles </li></ul><ul><li>Nerve damage can occur </li></ul><ul><li>Compartmental syndrome can occur </li></ul>
  32. 36. Techniques Cont .. <ul><li>Transarterial : </li></ul><ul><li>Penetration of artery is a good indication of needle in the axillary sheath </li></ul><ul><li>Stan et al. – showed that it is very safe with minimal complications and high success rate </li></ul><ul><li>Cocking’s – A single injection of large volume. Success rate – 99% </li></ul><ul><li>Perivascular: </li></ul><ul><li>BP is enveloped by fibrous sheath from cervical spine to midportion of forearm </li></ul><ul><li>A.P Winnie suggested large volume of single injection into the sheath will suffice </li></ul>
  33. 37. TRANSARTERIAL TECHNIQUE AXILLARY BLOCK
  34. 38. Techniques Cont …. <ul><li>Perivascular Cont </li></ul><ul><li>It was challenged by Thompson. He said each nerve is in separate sheath </li></ul><ul><li>Rorie described septae in neurovascular bundle, demonstrated compartmentalization of dye. This explains profound/partial block </li></ul><ul><li>Patridge, Katz and Benirschke demonstrated septae but they are very thin and incomplete </li></ul><ul><li>Communication exist in between septae </li></ul><ul><li>Touch and feel is the main guiding principle </li></ul>
  35. 39. Techniques Cont …. <ul><li>Imaging techniques : </li></ul><ul><li>Fluroscopy and ultrasound </li></ul><ul><li>U /s of blood vessels used to assist BP Block </li></ul><ul><li>Recently u /s nerves described </li></ul><ul><li>This is the future promise for the </li></ul><ul><li>Anaesthetists </li></ul><ul><li>Drawbacks : 1.Interpretation 2.Size of the probe 3.2/3 dimensional views 4.No functional end point </li></ul>
  36. 40. Techniques Cont ….. <ul><li>P.E.G (Percutaneous Electrical Guidance): </li></ul><ul><li>By W. Urmey. F </li></ul><ul><li>This is a new technique </li></ul><ul><li>Involves indentation of skin and transcutaneous stimulation with cylindrical smooth tipped electrode probe to locate desired and later to guide a block needle to the nerve </li></ul><ul><li>Grossi proposed concept of anaesthetic line. </li></ul><ul><li>P.E.G. concept works well with anaesthetic line </li></ul>
  37. 41. Techniques Cont….. <ul><li>Single versus multiple injections : </li></ul><ul><li>Still it is not clear which one superior </li></ul><ul><li>AXB using 2,3 and 4 injections reported high success rate </li></ul><ul><li>More complete block, less anaesthetic agent and shorter latency </li></ul><ul><li>Incidence of neuropraxia is 1.7% </li></ul><ul><li>Time consuming </li></ul>
  38. 42. Techniques Cont ….. <ul><li>Continuous techniques : </li></ul><ul><li>Exiting and evolving areas of block </li></ul><ul><li>Particular approaches are useful </li></ul><ul><li>Catheter fixation is difficult </li></ul><ul><li>Migration of catheter </li></ul><ul><li>Use of large bore needles and prolong searching for nerves </li></ul><ul><li>Injection any solution </li></ul>
  39. 43. SOME GUIDING PRINCIPLES FOR BP BLOCK <ul><li>SEDATIVE DRUGS : </li></ul><ul><li>Titration is very important </li></ul><ul><li>No drug absolutely prevents drug toxicity </li></ul><ul><li>Patient should not be unconcious </li></ul><ul><li>LOCAL ANAESTHETIC AGENTS : </li></ul><ul><li>Higher concentrations not necessary </li></ul><ul><li>Mixing is not very useful </li></ul><ul><li>Alkalnization gives useful results </li></ul><ul><li>Rate of convulsions per 1000 blocks: (A)1.2-epidural (B)1-2.8 axillary (C)7-8 interscelene/supraclavicular </li></ul>
  40. 44. Guiding principles cont….. <ul><li>LA Cont …… </li></ul>2-4 0.25-0.5 8-10 Ropivacaine 2-3 0.25-0.5 8-12 Bupivacaine 7mg with adrenaline 0.5-1 4-7 Lidocaine Dose (mg / kg) Concentr-- ation (%) Duration (hrs) Drugs
  41. 45. Guiding principles cont…. <ul><li>Vasoconstrictors: </li></ul><ul><li>Epinephrine is the drug. 1:2,00,000 is appropriate </li></ul><ul><li>Freshly made solution </li></ul><ul><li>Equipment and needles: </li></ul><ul><li>Nondisposable syringes </li></ul><ul><li>Sterility </li></ul><ul><li>Short bevel needles are best </li></ul>
  42. 46. Guiding principles cont …. <ul><li>Additives: </li></ul><ul><li>Many drugs to LA to potentiate and to prolong the block </li></ul><ul><li>Ketamine </li></ul><ul><li>Buprenorphine </li></ul><ul><li>Clonidine </li></ul><ul><li>Tramadol </li></ul><ul><li>Neostigmine </li></ul>
  43. 47. Guiding principles cont …. <ul><li>Measuring success of block : </li></ul><ul><li>Difficult to measure </li></ul><ul><li>Always some legal, political, social, educational and personal reasons to use additive drugs </li></ul><ul><li>Not an excuse for sloppy technique or inappropriate dosing </li></ul>
  44. 48. COMPLICATIONS <ul><li>Incidence: Extremely rare </li></ul><ul><li>France study of 21,278 blocks cardiac arrest – 0.01% </li></ul><ul><li>death – 0.005% </li></ul><ul><li>seizures – 0.8% </li></ul><ul><li>radiculopathy – 0.02% </li></ul><ul><li>ARNI(Anaesthesia Related Nerve Injuries) </li></ul><ul><li>16% of ASA claims </li></ul><ul><li>Out of these 8% ulnar, 20%BP </li></ul><ul><li>RA did not increase the risk of neuropathy in patients with preexisting neuropathy </li></ul>
  45. 49. Complications cont … <ul><li>Peripheral nerve injuries : </li></ul><ul><li>Residual paraesthesia, hypoasthesia and rarely permanent paresis </li></ul><ul><li>Early onset indicates extra or intra neural haematoma or injection or edema </li></ul><ul><li>Late onset suggests tissue reaction or scar formation </li></ul>
  46. 50. Complications cont …. <ul><li>Factors contributing to nerve injuries : </li></ul>Needle or catheter trauma, vasoconstrictors, perineural edema, LA toxicity Anaesthesia factors Surgical trauma, strech of nerves, tourniquet ischemia, vascular compromise, peri op. imflamation, post op. infection, hematoma, cast compression, pt. position Surgical factors Preexisting neurological disorders Male, old age,extemes of body habitus, DM Patient factors Pre op. risk factors Categories
  47. 51. Complications cont …. <ul><li>Factors that contribute directly to ARNI include : </li></ul><ul><li>Mechanical trauma </li></ul><ul><li>Ischemic injury and </li></ul><ul><li>Chemical injury </li></ul>
  48. 52. Complications <ul><li>MECHANICAL TRAUMA : </li></ul><ul><li>Needle : </li></ul><ul><li>Trauma depends on type of needle and elicitation of parasthesias </li></ul><ul><li>Selander et al. examined 24hr histological changes in rabbit sciatic nerve </li></ul><ul><li>injury more with long bevel needles(14 ° vs 45°short bevel) </li></ul><ul><li>severity of injury more with short bevel needles </li></ul><ul><li>Rice Mc Mahan – observed parallel insertion of needle – less injury than transverse insertion </li></ul>
  49. 53. Complications cont…. <ul><li>Mechanical trauma cont …. </li></ul><ul><li>Parasthesias: </li></ul><ul><li>Whether elicitation of parasthesias cause </li></ul><ul><li>direct needle trauma there by increasing the risk of nerve injury is unknown </li></ul><ul><li>Selander reported higher incidence of ARNI when parasthesias are sought in AXB with perivascular technique (2.8% vs 0.8%) </li></ul><ul><li>Auroy et al. noted cases of radiculopathy associated with parasthesias are pain during injections </li></ul>
  50. 54. Complications cont …. <ul><li>Parasthesias cont … </li></ul><ul><li>Winchell and Wolfe reported 0.36% of ARNI despite 98% of patients experiencing parasthesias. </li></ul><ul><li>Moore’s contension was mechanical parasthesias during RA are persae not an indication of nerve injury </li></ul><ul><li>Pain during injection increases the risk </li></ul><ul><li>Supplimental injection after a failed block or under GA increases the risk </li></ul>
  51. 55. <ul><li>ISCHEMIC INJURY </li></ul><ul><li>Functional integrity of nerve depends on its micro circulation </li></ul><ul><li>Intrinsic supply of exchange vessels within the endoneurinium </li></ul><ul><li>Extrinsic supply of larger nutritive vessels which are under control of sympathetic system and responds with epinephrine containing solutions </li></ul><ul><li>NBF(Neural Blood Flow ): Plain 2% lidocaine reduces NBF by 39%. By adding adrenaline 1:2,00,000 NBF reduced by 78%. </li></ul>complications
  52. 56. Complication cont …. <ul><li>Ischemic injury cont… </li></ul><ul><li>Epinephrine : Adrenaline is safe when added to nerve bundles in appropriate concentrations with intact barrier mechanisms ( blood neural barrier ) </li></ul><ul><li>Epinephrine may increase the risk with disrupted barrier mechanism or by decreasing the NBF as in intraneural injection or chemotherapy related neurotoxicity, DM neuropathy or atherosclerosis </li></ul>
  53. 57. Complications cont … <ul><li>Ischemic injury cont … </li></ul><ul><li>Neural edema : Can occur after intraneural injection of LA </li></ul><ul><li>Intraneural pressure may go upto 100mm of Hg for up to 15min after injection </li></ul><ul><li>Increased pressure interferes with microcirculation or alter the permeability of BNB </li></ul><ul><li>Results in degeneration and dystrophy of axons. Fibroblasts proliferation causes late changes, increasing perineural thickening and endoneural fibrosis </li></ul>
  54. 58. Complications . <ul><li>CHEMICAL INJURY </li></ul><ul><li>In clinical concentrations LA are safe to the nerves </li></ul><ul><li>Higher concentrations, prolonged exposure and intraneural injection cause damage </li></ul><ul><li>Both long acting, short acting with or without adrenaline can cause changes depending on the concentration </li></ul><ul><li>Continuous catheters – more incidence of injuries </li></ul><ul><li>Most of the time the injury may be single or combined. </li></ul>
  55. 59. Complications cont … <ul><li>VASCULAR INJURIES : </li></ul><ul><li>Rare but potentially dangerous </li></ul><ul><li>In anticoagulated patients definite guidelines not available. Benefits must be weighed against the risks </li></ul><ul><li>Transient vascular insufficiency: Reported in AXB, may be due to intra-arterial puncture. Incidence 1% </li></ul><ul><li>Hematoma: 0.001-0.02%. May or may not be associated with post operative nerve problems </li></ul><ul><li>Pseudo-aneurysm and axillary artery dissection is reported </li></ul>
  56. 60. Complications cont …. <ul><li>MUSCLE INJURIES : </li></ul><ul><li>Necrosis can occur at the site of injection </li></ul><ul><li>More so with bupivacaine </li></ul><ul><li>Depends on dose, time of exposure and calcium levels in muscles </li></ul><ul><li>Hemidiaphramatic paralysis(HDP ): </li></ul><ul><li>ISB – 90 to 100%, mild dyspnoea, 25 – 30% reduction in RS function, ropivacaine is not protective, abnormal RS function persists for 24hrs in 50% of patients </li></ul>
  57. 61. Complications <ul><li>PNEUMOTHORAX : </li></ul><ul><li>Common in SCB </li></ul><ul><li>Also occurs in ISB and ISCB </li></ul><ul><li>Plumb-bob technique reduces the incidence </li></ul><ul><li>Careful with tall, thin and emphysematous patients </li></ul><ul><li>Symptoms occur after 6 – 12hrs after injection </li></ul><ul><li>Immediate symptoms if patients is on IPPV </li></ul>
  58. 62. Complications <ul><li>LA REACHING UNINTENDED PLACES : </li></ul><ul><li>Intravascular injection : </li></ul><ul><li>0.2% in transarterial </li></ul><ul><li>Can occur in ISB and SCB </li></ul><ul><li>Direct injection or retrograde flow via subclavian artery </li></ul><ul><li>Convulsive dose of bupivacaine is 3.6mg, lidocaine is 14.4mg </li></ul><ul><li>Safety margin </li></ul><ul><li>bupivacaine:l-bupivacaine/ropivacaine:lidocaine </li></ul><ul><li>1 : 2 : 9 </li></ul>
  59. 63. Complications <ul><li>LA Reaching unintended places cont… </li></ul><ul><li>Subarachnoid/epidural space : </li></ul><ul><li>Common in ISB </li></ul><ul><li>Needle enters directly or via dural cuff </li></ul><ul><li>Avoided by shorter needles and directing the needle cauded </li></ul><ul><li>Slow, fractionated doses </li></ul><ul><li>Cervical sympathetic chain : </li></ul><ul><li>Horner’s syndrome – common in ISB, SCB </li></ul><ul><li>20 to 90%, no harm </li></ul><ul><li>Recurrent laryngeal nerve block : </li></ul><ul><li>Common in ISB and SCB – 1.3%. Hoarseness of voice. Treatment: Reassurance </li></ul>
  60. 64. Complications <ul><li>HYPOTENSIVE / BRADYCARDIAC EVENTS(HBE): </li></ul><ul><li>13 – 24% patients develop HBE in shoulder arthroscopy under ISB </li></ul><ul><li>Mechanisms could be </li></ul><ul><li>β -agonistic effects of epinephrine or activation of Bezold-Jarisch reflex </li></ul><ul><li>HBE is reduced by prophylactic metaprolol but not glycopyrrolate </li></ul><ul><li>Metaprolol 2.5mg increments upto 10mg or to get HR about 60/min </li></ul>
  61. 65. Complications <ul><li>TOURNIQUET EFFECTS : </li></ul><ul><li>Ischemic injury under the compressed area occurs with in 2-4hrs </li></ul><ul><li>In non compressed area occurs at about 6hr </li></ul><ul><li>40min needed re-establish normal status after deflation </li></ul><ul><li>Pain of tourniquet by complex mechanism – neural ischemia transmitted by nonmyelinated C fibres </li></ul><ul><li>Pain disappears immediately after deflation </li></ul>
  62. 66. Complications <ul><li>LIMB PROTECTON AND DISCHARGE CRITERIA: </li></ul><ul><li>No RCT data </li></ul><ul><li>Prolonged blocks can increase the risk of nerve injury </li></ul><ul><li>Can be discharged with partial sensory block with instructions to avoid thermal or pressure injuries </li></ul><ul><li>Fitted with a sling or protective device </li></ul><ul><li>Mid </li></ul><ul><li>Humeral block is best </li></ul><ul><li>Blocking the individual nerves with different agents </li></ul>
  63. 67. THANK Q

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