Complications of Neuraxial Blockade Dr. Proper

Complications of Neuraxial Blockade Jacqueline Proper, M.D. Neurological Complications of Neuraxial Blockade • Neurological complications – Direct result of regional technique – Unrelated to technique, but temporal correlation • Risk factors – Traumatic injury to cord or nerve roots – Local anesthetic solution – Spinal cord ischemia – Infection Incidence of Neurological Complications • Rate of persistent peripheral neuropathy extremely low: 0 – 0.08% • Combined series >50,000 spinals: – 1 cauda equina – LE weakness, impotence – 1 paraplegia – pt w spinal cord tumor – 3 meningitis • Combined series >50,000 epidurals: – 3 with persistent LE weakness Incidence of Neurological Complications • Prospective study – 103,730 regional anesthetics – 5 month period – 34 patients with neurologic injury • 21 with pain or paresthesia during injection/puncture • 29 recovered within 3 months – Needle trauma and L.A. toxicity etiology of neurological complications • Significantly higher incidence of cardiac arrest and neurological complications with spinal anesthesia Auroy, Y. et al. Anesthesiology 1997; 87:479-486 Nerve Injury from Needle and Catheter Placement • Permanent neurological injury rare • Prospective study: 2/3 pt with neurological complications had pain during procedure Auroy et al Anesthesiology Vol 87 479-86 • Paresthesia and post-op neuro deficit higher with CSA vs. single shot spinal – Single shot: 13% paresthesia, 0. 13% deficit – CSA: 30% paresthesia, 0.66% deficit Dripps, RD. NY State J Med 1950; 50:1595-1599 Local Anesthetic Toxicity • Risk factors: prolonged exposure, high dose, high concentration at spinal root • Higher risk with lidocaine, tetracaine • Auroy et al: 75% of neurological complications with atraumatic spinal in patients receiving hyperbaric lidocaine • With lidocaine spinal injection avoid: – dose> 80mg – Epinephrine addition – Hyperbaric solution Local Anesthetic Toxicity • 2-chloroprocaine: low toxicity, rapid onset, rapidly hydrolyzed • 1980’s cases following unintentional intrathecal injection of large volume – LE paralysis, perineal anesthesia and loss of sphincter function lasting 6-12 weeks – Large volume, low pH, antioxidant 0.2% sodium bisulfite • 1987 Astra changed preservative to EDTA “Those who cannot remember the past are condemned to repeat it.” George Santayana • EDTA  prolonged LBP at injection site • 1996 EDTA removed from ASTRA NesacaineMPF • Abbott - 3% chloroprocaine, pH 3.1, .18% sodium metabisulfite • Recent case of permanent cauda equina syndrome following 3% chloroprocaine epidural Winnie, A et al. Reg Anesth and Pain Med, 2001 Vol 26, p.558 Transient Neurologic Symptoms • TNS: pain in the legs or buttocks occurring after resolution of spinal anesthesia • Risk factors – lithotomy position – knees/hips flexed – L.A. – lidocaine > tetracaine > bupivicaine – Obesity • Etiology unlikely to be neurotoxicity – Lack of concentration, dose effect – SSEP’s, EMG, nerve conduction studies nl Anterior Spinal Artery Syndrome • Spinal cord ischemia resulting in flaccid paralysis of the lower extremities • Large distances between radicular arteries • Risk factors: – Systemic hypotension – Localized vascular insufficiency – Vasoconstrictor addition to LA in neuraxial blockade NOT identified as risk factor Spinal Hematoma • Neurologic dysfunction from hemorrhagic complications associated with neuraxial block: epidural-0.00066% spinal-.00045% • Hemostatic abnormality risk • Coagulation status at time of epidural catheter removal is critical • Return of neurological function possible if pt undergoes laminectomy within 8 h Oral Anticoagulation and Neuraxial Block • Chronic use of warfarin: – DC and measure INR; Takes 3-5 d to normalize – Use of ASA and NSAIDS can increase risk of bleeding without affecting PT, INR • If 1st dose of warfarin given 24h prior to surgery, measure INR before neuraxial block placement Oral Anticoagulation and Neuraxial Block • 192 Knee arthroscopies/ low dose warfarin therapy / post op epidural— no symptomatic spinal hematoma Horlocker et al, Anesth Analg 79: 89-93 1994 • 459 ortho surgeries under spinal or epidural/ 412 post-op epidural/ anticoagualated with warfarin --no spinal hematoma Wu and Perkins, Reg Anesth 21: 517-524 • • • Routine motor/sensory neuro checks Catheter removal INR< 1.5 Low dose warfarin (5mg/d) epidural usually safe; Requires careful monitoring of INR/PT Antiplatelet agents and Neuraxial Block • Four classes: – – – – ASA and cyclo-oxygenase inhibitors Ticlopidine and selective ADP inhibitors Direct thrombin inhibitors (hirudin) Selective IIb (GP IIbIIIa) • Use of antiplatelet drugs alone – no added signficant risk for development of spinal hematoma with epidural or spinal anesthesia • 1906-1994: 4/61 cases spinal hematoma with epidural or spinal anesthesia associated with antiplatelet med use Vandermulen, Anesth and Analg 1994, 79:11651177 Antiplatelet agents and Neuraxial Block • Prospective 1000 surgical/OB pt – pre-op antiplatelet medication – trauma incurred during needle /catheter placement not increased /sustained Horlocker et al, Anesth and Analg 1990; 70:631-634 • Increased risk if combined with anticoagulant • Currently no recommendations for timing neuraxial anesthesia in relation to dosing of NSAIDS IV and Subcutaneous Heparin • Safety well documented – 4000 pt, indwelling spinal or epidural catheter during vascular surgery with heparinization Roa and El-Etr, Anesth 1981: 55:618-620 – 5000 pt , subQ heparin in combination with spinal or epidural anesthesia – no spinal hematoma • Risk factors for spinal hematoma: • Traumatic needle placement • Lumbar puncture or catheter removal <1 hr before start or < 24hr after DC IV heparin • Concomitant ASA therapy Low Molecular Weight Heparin • No reported cases of spinal hematoma in Europe during 1st 10 years of use • During 1st five years after release of LMWH for use in US, 40 cases reported – Intraop or early post-op administration – Concomitant antiplatelet medication – Dosing in Europe of 40mg q24h vs in US 30mg q12h Horlocker and Wedel, Reg Anesth 2000 Vol 25 83-98 LMWH • Needle placement/catheter removal should be delayed 10-12 hr following dose of LMWH • If high dose (1mg/kg) dosing, delay for 24h • If intraop epidural, delay postop administration of LMWH for 24h Risk of Infection • Bacterial infection: spinal abscess or meningitis – contaminated equipment or medication – seeding from patient or physician • Risks: – underlying sepsis – diabetes – depressed immune status, steroid treatment – long term catheter maintainance Meningitis after Dural Puncture • ? Risk from LP/bacteremia: study at military installation during meningitis outbreak • LP during E.Coli bacteremia in rats – – – – Bacteremic rat / LP  meningitis Bacteremic rats /no LP  no meningitis Healthy rats / LP no meningitis Antibiotic treatment of bacteremic rats before LP  no meningitis Carp and Bailey, Anesthesiology 1992;76:739-742 Epidural Abscess following Epidural Anesthesia • Superficial abscess – local tissue swelling, erythema, drainage, fever – Drainage and IV antibiotic treatment • Deep abscess – severe back pain, local tenderness, fever, neurologic deficit – Surgical intervention within 12 h for best possible outcome Epidural Abscess • 293 women with chorioamnionitis/ epidural anesthesia Bader et al Reg Anesth 1992;17:84-86 – 43 received antibiotics before needle placement – no incidence of infectious complication • Chronic epidural catheterization in cancer patients is risk for infection DuPen et al Anesthesiology 1990;73:905-909 – 19/350 pt with tunneled catheters developed deep track infection – Rate of 1/1703 d of catheter use – All infections resolved with antibiotics and removal of catheter Epidural Abscess • Actual risk of placement in pt with chronic localized infection unknown • Maintain vigilance so if infection occurs, it is recognized early and treated appropriately HSV • HSV-2 is recurrent incurable viral infection • Active HSV-2 infection at time of delivery requires cesearean section – 110/169 HSV-2 parturients received spinal or epidural – 1/110 developed transient unitlateral leg weakness after bupivicaine spinal anesthesia Bader et al Reg Anesth 1990 15:261-263 HIV • Risk of complications from neuraxial block unknown • 40% of patients with HIV have clinical signs of neuropathy; At autopsy 70-80% have neuropathic change • 18 infected parturients underwent neuraxial block without complication Hughes, Anesth 1995;82 • 9 HIV+ patients underwent epidural blood patch without complication tom et al Anesth 1992;76 Management of Infected or Febrile Patient • Neuraxial block : NOT if untreated bacteremia – single shot spinal anesthesia probably safe, indwelling catheter not recommended • Bacterial meningitis is a medical emergency – Fever, severe HA, altered LOC, meningismus – Mortality 30% – Dx confirmed with LP Management of Infected or Febrile Patient • Epidural abscess – Presents with spinal ache and root pain – Progression to weakness, bowel bladder symptoms, then paralysis • Diagnosis with MRI • Antibiotics and surgical drainage • Recovery dependent on duration of deficit and severity of impairment before treatment Preexisting Neurologic Disorders and Neuraxial Block • Preexisting deficits theoretically places patients at increased risk for further neurologic injury • No controlled studies assessing risk • Difficult ? surgical vs anesthetic etiology • Imperative: document preop neuro exam, discuss possible progression of deficit Multiple Sclerosis • MS : disorder of CNS -- peripheral blocks preferred • Fatigue, stress, surgery implicated in exacerbation of symptoms • Epidural and spinal anesthesia associated with relapse • Direct local anesthetic toxicity as likely mechanism Diabetes • Risk for nerve injury increased in diabetics – Subclinical neuropathy without pain, paresthesia, sensory loss – Microangiopathy of nerve blood vessels decreases absorption rate of LA • Diabetic: lower dose of LA for anesthesia, decreased risk of nerve injury Performance of Neuraxial Block in Patients Under Anesthesia • Risk of morbidity theoretically increased • Pediatric prospective study: Giaufre et al, Anesth and Analg 83: 897-900 – 89% of 24,409 regional blocks – 15,013 caudal blocks, 2396 epidurals (135 thoracic) – 506 spinals (75% premature infants) – 23 complications, .015%; None with long-term sequelae Performance of Neuraxial Block in Patients Under Anesthesia • No prospective studies in adults • Retrospective review 4392 patients, upper abdominal or thoracic surgery Abel et al Reg Anesth, 1998;23S:3 – Opioid only infusion in 98% – No documented neurologic complications • Review of 478 patients, transphenoidal surgery, intraop spinal drainage Grady et al, Anesth Analg 1999; 88 – No neurologic deficits Conclusion • Major complications after neuraxial techniques rare, but devastating • Preoperative evaluation and discussion • Consider peripheral regional and general for patients at higher risk • Careful patient positioning and postoperative follow-up important