Complications of Regional Anesthesia


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Presented by Dr.Nabil El-Kassabany

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Complications of Regional Anesthesia

  1. 1. Complications of Regional Anesthesia Nabil M Elkassabany MD MSCE Assistant Professor Director; Orthopedic Anesthesia Section Department of Anesthesiology and Critical Care University of Pennsylvania Health System
  2. 2. Objectives <ul><li>1- Discuss complication that may be associated with regional anesthesia/analgesia </li></ul><ul><li>2- Discuss diagnosis /management of each </li></ul><ul><li>3- Discuss how can we avoid these complications </li></ul>
  3. 3. What Will We Be Discussing Today? <ul><li>1- Nerve injury after peripheral nerve blocks </li></ul><ul><li>2- Infection after continuous perineural catheters </li></ul><ul><li>3- Systemic Toxicity of Local Anesthetics </li></ul><ul><li>4- Brief Discussion of anticoagulation and regional anesthesia </li></ul>
  4. 4. ASRA Practice Advisory
  5. 5. Why we do not have a definitive answers as for the incidence of neurological complication? <ul><li>Rare event; do not lend itself to RCT, meta-analysis, and conventional research methods </li></ul><ul><li>Malpractice database ( ASA closed claim database) will tend to over estimate the incidence </li></ul><ul><li>Under-reporting </li></ul><ul><li>Billing and administrative database: Suffer from bias </li></ul><ul><li>Only 44-72% of academic anesthesiologist mention neurologic complication in their consent form </li></ul>
  6. 6. Peripheral nerve injury <ul><li>In the early postoperative period, mild paraesthesia may be present in up to 15% of patients that undergo peripheral nerve block. </li></ul><ul><li>Most of these symptoms resolve within days to weeks, with over 99% completely resolving by 1 year. </li></ul><ul><li>Serious neurologic injury reported in a large prospective study occurred in 2.4 per 10,000 peripheral nerve blocks. </li></ul><ul><li>ASRA Practice advisory for neurological complication </li></ul>
  7. 7. Factors that may contribute to peripheral nerve injury <ul><li>Patient specific: </li></ul><ul><li>pre-existing neurologic disorders, </li></ul><ul><li>diabetes mellitus, </li></ul><ul><li>extremes of body habitus, </li></ul><ul><li>male gender, and advanced age. </li></ul><ul><li>Surgical risk factors: </li></ul><ul><li>direct surgical trauma or stretch, </li></ul><ul><li>compressive dressings or casts, </li></ul><ul><li>tourniquet inflation, </li></ul><ul><li>hematoma or abscess formation, </li></ul><ul><li>perioperative inflammation </li></ul><ul><li>Improper patient positioning. </li></ul><ul><li>ASRA Practice advisory for neurological complication </li></ul>
  8. 8. ASA closed claim on peripheral nerve injury <ul><li>Most claims involving peripheral nerve injury were for temporary injury (56%) with half of the deficits believed to be block-related. </li></ul><ul><li>The brachial plexus > the median> ulnar> and radial nerves. </li></ul><ul><li>Lower extremity nerve injuries are rare in the Closed Claims Database, most likely reflecting the less frequent practice of lower extremity regional anesthesia </li></ul><ul><li>ASRA Practice advisory for neurological complication </li></ul>
  9. 9. Incidence of Neurologic Complications and Identification of Etiology <ul><li>RA has a inherent risk of nerve injury but remember… </li></ul><ul><li>peripheral nerve injury may be associated with either regional or general anesthesia </li></ul>
  10. 10. Hip and knee surgery <ul><li>hip replacement (performed under general anesthesia) is associated with a 0.5% to 2% incidence of sciatic nerve lesion </li></ul><ul><li>Sciatic and/or femoral nerve blocks are associated with nerve injury in 2 : 1000 anesthetic procedures (almost 10 times less common) </li></ul><ul><li>in difficult-to-diagnose cases, a surgery-induced lesion should be considered first </li></ul>
  11. 12. <ul><li>J Am Acad Orthop Surg. 1999 Mar-Apr;7(2):101-11 . </li></ul><ul><li>Nerve injuries in total hip arthroplasty . </li></ul><ul><li>DeHart MM , Riley LH Jr . </li></ul>Clin Orthop Relat Res. 1997 Nov;(344):188-206. Update on nerve palsy associated with total hip replacement. Schmalzried TP , Noordin S , Amstutz HC . J Bone Joint Surg Am. 1991 Aug;73(7):1074-80. Nerve palsy associated with total hip replacement. Risk factors and prognosis. Schmalzried TP , Amstutz HC , Dorey FJ .
  12. 13. Nerve Injury after TKA <ul><li>J Arthroplasty. 2001 Dec;16(8):1048-54 . </li></ul><ul><li>Nerve injury after primary total knee arthroplasty. </li></ul><ul><li>Schinsky MF , Macaulay W , Parks ML , Kiernan H , Nercessian OA . </li></ul><ul><li>Department of Orthopaedic Surgery, College of Physicians and Surgeons, Columbia University, New York, New York, USA . </li></ul><ul><li>J Arthroplasty. 2005 Dec;20(8):1068-73. </li></ul><ul><li>Peroneal nerve palsy after total knee arthroplasty. </li></ul><ul><li>Nercessian OA , Ugwonali OF , Park S . </li></ul><ul><li>Department of Orthopedic Surgery, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. </li></ul>
  13. 15. <ul><li>Femoral nerve block before TKA is not a harmless intervention. We recommend postoperative protocols be modified for patients who have FNB to account for decreased quadriceps function in the early postoperative period, which can lead to falls . </li></ul>
  14. 16. The effects of femoral nerve blockade in conjunction with epidural analgesia after total knee arthroplasty <ul><li>29% of patients who received FNB had buckling </li></ul><ul><li>because of decreased quadriceps strength, whereas only 3% of patients who did not receive FNB had buckling </li></ul>YaDeau JT et al, Anesth Analg. 2005 Sep;101(3):891-5
  15. 17. <ul><li>Reg Anesth Pain Med. 2007 Jan-Feb;32(1):67-72. </li></ul><ul><li>Falls associated with lower-extremity-nerve blocks: a pilot investigation of mechanisms. </li></ul><ul><li>Muraskin SI , Conrad B , Zheng N , Morey TE , Enneking FK </li></ul>Anesth Analg. 2010 Dec;111(6):1552-4. Epub 2010 Oct 1. The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Ilfeld BM , Duke KB , Donohue MC .
  16. 18. Shoulder arthroplasty <ul><li>incidence of severe neurologic injuries of 4.3% after 417 total shoulder arthroplasty procedures </li></ul><ul><li>Only 11% were related to the anesthetic technique whereas the remaining 89% were a result of the surgical procedure </li></ul>
  17. 19. J Shoulder Elbow Surg. 1996 Jan-Feb;5(1):53-61 . Neurologic complications after total shoulder arthroplasty. Lynch NM , Cofield RH , Silbert PL , Hermann RC . Department of Orthopedic Surgery, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA. Three hundred sixty-eight patients underwent 417 total shoulder arthroplasties between 1975 and 1989. Seventeen patients with 18 operated shoulders had a neurologic deficit after surgery.
  18. 20. <ul><li>results9'1&quot;9-49-66-94.' </li></ul><ul><li>Neural Injuries </li></ul><ul><li>1858 shoulders from 1975-1995 in 41 case series </li></ul><ul><li>We found reports of fourteen shoulders that had a complication involving the peripheral nerve or the brachial plexus following total shoulder-replacement arthroplasty. Most of these injuries involved a neurapraxia, and non-operative treatment yielded good results. However, in two shoulders, the mechanism of neural injury involved a laceration of the axillary nerve, which occurred in a heavily scarred operative field. While most of these complications involved the axillary nerve (six shoulders), injury of the ulnar nerve (three shoulders), the musculocutaneous nerve (two shoulders), the median nerve (one shoulder),and the brachial plexus (two shoulders) was also reported. Seven of these injuries resolved completely, two resolved incompletely, one did not resolve at all,and the status of four was not mentioned . </li></ul>
  19. 24. Mechanism of nerve injury <ul><li>Factors </li></ul><ul><li>Needle trauma </li></ul><ul><li>Intraneuronal injection </li></ul><ul><li>Neuronal ischemia </li></ul><ul><li>Toxicity of local anesthetics </li></ul><ul><li>Surgical factors </li></ul><ul><li>Positioning </li></ul><ul><li>Retractor injury </li></ul><ul><li>Ischemia </li></ul><ul><li>Hematoma </li></ul>Classification Neuropraxia Focal demyelination Partial deficits Axonotmesis Disruption of axon Intact schwann cells And Connective tissue structure Neurotmesis Complete disruption of Axon and Connective tissue structure
  20. 25. Functional histology of a nerve fiber
  21. 26. Pathophysiology of peripheral nerve injury <ul><li>. Neuropraxic lesions, which damage the myelin sheath but preserve the axon, are typically associated with compressive or stretch injuries and are perhaps more likely to resolve. </li></ul><ul><li>Conversely, if the axon is completely disrupted, recovery is slower and more likely to be incomplete. </li></ul><ul><li>The double crush theory </li></ul><ul><li>Nerve injury theory suggests that more than 1 insult is often necessary to cause damage. Peripheral nerve injury appears to require the breach of connective tissue barriers such as the perineurium that surrounds individual nerve fascicles and protects them from the external mi-lieu. Disruption of the perineurium from needle or catheter trauma is remarkably difficult to accomplish </li></ul>
  22. 27. Pathophysiology of peripheral nerve injury <ul><li>. Animal studies and experience with ultra-sound-guided nerve localization has shown that nerves tend to move away from approaching needles. When nerves are impaled, the needle may pass harmlessly into or through connective tissue, which constitutes up to 70% of a nerve's cross-sectional area. </li></ul><ul><li>However, if the fascicle is penetrated, neurons are exposed to local anesthetics that can cause time- and concentration-dependent injury. Vasoconstrictors play a role by limiting local anesthetic clearance and thereby enhancing the time-dependent component of injury. Decreased neural blood flow from edema or mass effect can also potentiate cytotoxicity. </li></ul>
  23. 30. Clinical Classification of nerve injuries <ul><li>Seddon </li></ul><ul><li>Sunderland : Proposed a five- grade classification system </li></ul>Axontomesis:. Neurotemesis Neuropraxia
  24. 31. Seddon Sunderland Structural and functional processes Neuropraxia 1 Myelin damage, conduction slowing Axonotmesis 2 Loss of axonal continuity, endoneurium intact, no conduction 3 Loss of axonal and endoneurial continuity, perineurium intact, no conduction 4 Loss of axonal and endoneurial and perineural continuity, epineurium intact, no conduction Neurotmesis 5 Entire nerve trunk separated; no conduction
  25. 32. Still with nerve injury
  26. 34. Mechanical nerve injury <ul><li>Intraneural injection </li></ul><ul><li>Inflammatory changes associated with intra-fascicular injection </li></ul>
  27. 35. Prevention of Intraneuronal injection <ul><li>Pain on injection. </li></ul><ul><li>May not be a reliable sign. </li></ul><ul><li>Fanelli et al reported paresthesias in 14% subjects. </li></ul><ul><li>Univariate analysis failed to demonstrate paresthesia as a risk factor. </li></ul><ul><li>Nerve stimulator and multiple injection technique for upper and lower limb blockade.: Failure rate, Patient acceptance, and neurologic complications. Fanelli G et al; Anesthesia Analgesia: 1999 : 88: 847-52. </li></ul><ul><li>Can pain or paresthesias be used to prevent neurologic injury . </li></ul><ul><li>Auray et al found that neurologic injuries occurred after paresthesias ensued even though the injection was stopped when pain was reported. </li></ul><ul><li>Serious complications related to regional anesthesia.: results of a prospective survey in france.Auroy Y et al; Anesthesiology. 1997: 87,479-86 </li></ul>
  28. 36. Intensity of current <ul><li>Most authors suggest a current intensity between 0.2 to 0.5 mA. </li></ul><ul><li>Current less than 0.2mA  with intraneuronal injection. </li></ul><ul><li>Currents more than 0.5mA  block failure. </li></ul><ul><li>Nerve stimulators usually provide rough approximation as nerve injuries have occurred despite using nerve stimulation. </li></ul><ul><li>Major complications of regional anesthesia in france: The SOS regional hotline service. Auroy Y et al. Anesthesiology. 2002:1274-80 </li></ul>
  29. 37. Resistance to injection <ul><li>Highly subjective and depends  needle size </li></ul><ul><li> speed of injection. </li></ul><ul><li>If an injection pressure > 20 psi  Stop the injection and check for needle patency. </li></ul><ul><li>One canine model  intrafascicular injections are associated with high pressures (>20 psi) and carried a high risk of nerve injury. </li></ul><ul><li>Neurologic and histologic outcome after intraneural injections of lidocaine in canine sciatic nerves. Kapur E at al;Acta Anaesthesiol Scand. 2007 Jan;51(1):101-7. Epub 2006 Nov 1 </li></ul>
  30. 38. Intra-fascicular injection of lidocaine 1% in the sciatic nerve in a dog model
  31. 39. Commercial Pressure monitor device
  32. 40. Needle trauma <ul><li>Selander et al  Nerve trauma is lower with a short bevel needle ( 45deg) as compared to a long bevel needle (12-15 deg). </li></ul><ul><li>Selander et al;Peripheral nerve injury due to injection needles used for regional anesthesia.Acta anesth Scand:1977:22;182-189 </li></ul><ul><li>Rice and Macmohan when placed intraneuronally short bevel needle resulted in more nerve damage </li></ul><ul><li>Rice A, Macmohan S;Peripheral nerve injury caused by injection needles used in regional anesthesia.Influence of bevel configuration studied in a rat model.British journal of anesthesia;1992:9;433-38 . </li></ul><ul><li>Needle trauma usually leads to an injury of minor magnitude. </li></ul><ul><li>But if accompanied by intraneuronal injection into a fascicle the risk of severe injury is high. </li></ul>
  33. 41. Neurotoxicity local anesthetic <ul><li>All local anesthetics are potentially neurotoxic </li></ul><ul><li>The potential for neurotoxicity with local anesthetic is a function of its potency, concentration, and the length of exposure of the neuronal tissue to the agent. </li></ul>
  34. 42. Ultrasound versus nerve stimulation <ul><li>Is there a difference in outcomes between the use of ultrasound and nerve stimulator </li></ul>
  35. 43. Ultrasound Pros and Cons <ul><li>PROS </li></ul><ul><li>1- Anatomy related benefits </li></ul><ul><li>2-time to perform the block </li></ul><ul><li>3-decreased onset time </li></ul><ul><li>4-increased success rate </li></ul><ul><li>5-increased safety </li></ul><ul><li>6- Rejuvenation of unpopular blocks </li></ul><ul><li>7- less patient discomfort </li></ul><ul><li>CONS </li></ul><ul><li>1-$$$$$ </li></ul><ul><li>2- resident teaching in university hospitals </li></ul>
  36. 45. Recommendation of the practice advisory <ul><li>NO nerve localization or monitoring technique has been shown to be clearly superior in terms of reducing the frequency of clinical injury </li></ul>
  37. 46. NS guided sciatic nerve block at the popliteal fossa followed by US results in the finding that intra-neural injection is as common as 76% of patients
  38. 47. How to avoid nerve injury <ul><li>Never inject local anesthetic when abnormal pressure on injection is present. </li></ul><ul><li>Never inject when patient complains of severe pain or has a withdrawal reaction. </li></ul><ul><li>Never inject when there is abnormal resistance. </li></ul>
  39. 48. Vasoconstructive agent Least toxic drug Recommended doses Site of injection Resuscitation equipment And drugs Monitoring Avoid forceful and Fast injections Frequent aspiration Verbal contact Slow injection Precautions
  40. 49. Evaluation of Nerve Injury after Regional Anesthesia <ul><li>History </li></ul><ul><li>Physical Examination </li></ul><ul><li>Electrophysiologic studies (EMG, nerve conduction studies) </li></ul><ul><li>Radiographic studies (MRN) </li></ul>
  41. 50. MRN
  42. 51. Infection after Continuous Perineural Catheters
  43. 52. Bacterial colonization/infection after continuous nerve catheters Findings: 1- Effective postop. analgesia 2- 57% Bacterial colonization rate 3- In 6 weeks, no complications 4- one femoral paraesthesia; completely resolved in 6 months 5-The incidence of bacterial colonization was 7.5% (**) Cuvillon P Ann Fr Anesth Reanim 1998;17:991 **
  44. 54. <ul><li>1- Para neuroaxial blocks </li></ul><ul><li>2- Precautions before removal of indwelling catheters </li></ul>
  45. 55. <ul><li>Can J Anaesth. 2011 Jan;58(1):62-7. </li></ul><ul><li>Complications of peripheral nerve catheter removal at home: case series of five ambulatory interscalene blocks. </li></ul><ul><li>Clendenen SR, Robards CB, Greengrass RA, Brull SJ. </li></ul>
  46. 56. <ul><li>Int J Shoulder Surg. 2010 Jan–Mar; 4(1): 1–7. </li></ul><ul><li>New trends in regional anesthesia for shoulder surgery: Avoiding devastating complications </li></ul><ul><li>André P. Boezaart 1,2 and Patrick Tighe 1 </li></ul>
  47. 57. <ul><li>Spine . 2010 May 1;35(10):E413-20 . </li></ul><ul><li>Postoperative spinal epidural hematoma: a systematic review. </li></ul><ul><li>Glotzbecker MP , Bono CM , Wood KB , Harris MB . </li></ul><ul><li>Harvard Combined Orthopaedic Residency Program and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. </li></ul>
  48. 58. <ul><li>Spinal and epidural hematoma:1.3-2.7/100000 neuroaxial technique </li></ul><ul><li>Neuraxial infectious complications (epidural abscess and meningitis) range from 0 infections in over 70,000 epidural and spinal anesthetics to 1 abscess per 1,930 epidural anesthetic </li></ul>
  49. 60. Toxicity of local anesthetic <ul><li>CNS toxicity </li></ul><ul><li>CVS toxicity </li></ul><ul><li>Hematologic effects </li></ul><ul><li>Allergy to local anesthetic </li></ul>
  50. 61. CNS Toxicity Perioral numbness Metallic taste Light headness Tinnitus Visual disturbances Muscle twitching and tremors Seizures Coma Respiratory arrest
  51. 62. Factors influencing CNS toxicity <ul><li>1-Plasma concentration (drug specific) </li></ul><ul><li>Lidocaine 5-10 mcg/ml </li></ul><ul><li>Bupivacaine 4-5 mcg/ml </li></ul><ul><li>2-Rate of injection </li></ul><ul><li>3-Inverse relationship between PaCO2 and local anesthetic seizure threshold </li></ul><ul><li>4-Hyperkalemia: promote depolarization </li></ul><ul><li>Treatment of LA induced seizures </li></ul>
  52. 63. Cardiovascular toxicity <ul><ul><li>Toxic doses of local anesthetic agents can cause myocardial depression and cardiac dysrhythmias. </li></ul></ul><ul><ul><li>Several anesthetics also have negative inotropic effects on cardiac muscle that lead to hypotension. Bupivacaine is especially cardiotoxic </li></ul></ul>
  53. 64. Lipid emulsion <ul><li>Weinberg et al ----- Intravenous lipid infusion in rats </li></ul><ul><li>Increased the dose of bupivacaine to produce asytole. </li></ul><ul><li>Improved survival. </li></ul><ul><li>Successfully resuscitated all dogs with lipid infusions following bupivacaine induced cardiac arrest. </li></ul><ul><li>Recommended - </li></ul><ul><li>1 ml/kg bolus of lipid emulsion 20% over 1 min. </li></ul><ul><li>The dose can be repeated every 3-5 mins upto a maximum of 3 ml/kg. </li></ul><ul><li>At conversion to sinus rhythm continue the infusion at 0.25 ml/kg/min until hemodynamic recovery. </li></ul><ul><li>Weinberg G, VadeBoncouer T, Ramaraju GA, Garcia-Amaro MF, Cwik M: Pretreatment or resuscitation with a lipid infusion shifts the dose-response to bupivacaine-induced asystole in rats. Anesthesiology 1998; 88:1071-5 </li></ul><ul><li>Rosenblatt et al reported the first case of successful resuscitation after a prolonged cardiac arrest following interscalene block. </li></ul><ul><li>Successful use of 20% lipid emulsion to resuscitate a patient after a presumed bupivacaine related cardiac arrest. Rosenblatt et al Anesthesiology July 2006 ; Volume 105( 1); 217-18 </li></ul><ul><li> </li></ul>