1. 1. By Mohamed El-Sadany, MD
2. 2. What to learn? General principles Systemic complications with local anesthetics Complications of Peripheral nerve block Toxic effect of LA on nerve and surrounding structures Complications of neuroaxial blocks
3. 3. Statement No matter how skillful an anesthesiologist may be, adverse peri- operative events are inevitable in anesthesia practice.
4. 4. General principles Safe regional anesthesia begins with: 1. A thorough preoperative assessment of the patient. 2. Skilled intra-operative sedation and monitoring. 3. Regional anesthesia area in the OR where equipment, monitoring, resuscitation drugs and assistance are readily available. 4. Early identification and intervention are of the utmost importance in preventing neurologic injury.
5. 5. Standard of Care During Regional Anesthesia Preoperative patient selection Informed consent Appropriate use of equipment and technique Monitoring regional anaesthesia practice Accurate and meticulous anaesthesia documentation Physicianpatient communication Appropriate and timely postoperative follow-up
6. 6. Patient Selection Inappropriate patient selection: Some patients are not psychologically suitable for regional anesthesia. Patients with severe mental illness. Neuraxial techniques in hemodynamic unstable. Patients with pre-existing neurologic disease. Patient refusal (explain in detail)
7. 7. Consent Potentially serious complications associated with regional anesthesia should be disclosed to patients, including convulsions and the risk of cardiac toxicity from systemic injections of local anesthetics, spinal cord/nerve injury leading to paralysis or neurologic deficit, pneumothorax, hematoma, infection, cardiac arrest, and death. A recent study revealed that fewer than half of anesthetists disclose the risks of seizures, respiratory failure, and cardiac arrest before the administration of either neuraxial blocks or peripheral nerve blocks.
8. 8. Appropriate Equipment and Technique For years, percutaneously insertion of needles toward neural targets relying on anatomy and techniques of paresthesia and the loss of resistance (LOR). Nerve stimulation was an important advance providing some evidence that the needle tip is close to the neural target. Ultrasonography allows real-time visualization of anatomical structures and offers the potential to guide needle and catheter placement in regional anesthesia. To minimize risks combine ultrasound and nerve stimulation techniques.
9. 9. Monitoring Regional Anesthesia Standard ECG and pulse oximetry are essential monitors. A baseline blood pressure reading should be obtained and Once the regional anesthesia procedure is complete, the monitors should remain attached. In conscious patients, Et CO2 monitoring may not be used. Evidence of regressing blockade and stable vital signs must be present to fulfill the criteria for discharge Patients receiving local anesthetic infusions should be visited regularly by a qualified physician postoperatively.
10. 10. Documentation Detailed documentation of patient consent and the clinical procedure is very important. Open and honest communication with the patient is essential for providing good quality patient care.
11. 11. PhysicianPatient Communication Patients may report anxiety, and appropriate preoperative education for the patient can help mitigate this. Patients undergoing supraclavicular blocks should be warned about the risk of pneumothorax. Caution patients about the risk of burns (ie, from radiators) if sensory anaesthesia continues after discharge. Warn patients about lying on paralyzed extremities for any length of time or letting them become dependent. Patients should receive written instructions when to seek medical attention before discharge from the hospital.
12. 12. What to learn? General principles Systemic complications with local anesthetics Complications of Peripheral nerve block Toxic effect of LA on nerve and surrounding structures Complications of neuroaxial blocks
13. 13. Systemic complications of local anesthetics ALLERGIC REACTIONS Signs and symptoms are almost always associated with amino ester preparations or preservatives. Nazir and Holdcroft found 797 from 331 from 96. SYSTEMIC TOXIC REACTIONS Systemic toxic reactions to local anesthetic drugs occur as a result of unintentional intravascular injection and rarely follow the injection of an excessive quantity of local anesthetic into an appropriate site.
14. 14. Systemic complications of local anesthetics The lungs are an important eliminator for local anesthetic drugs (an accidental intra-arterial injection in the head, face, or neck region). Plasma concentrations of local anesthetics are influenced by the (CO2) and the pH. An elevated arterial CO2 tension increases cerebral blood flow, and an acidotic state increases intracellular ion trapping and the amount of free drug available. This combination of factors has a synergistic effect on the seizure threshold.
15. 15. Systemic complications of local anesthetics Rapid absorption;intercostal, epidural, brachial plexus, lower extremity, and subcutaneous tissue. The addition of epinephrine to local anaesthetic drugs. Local anesthetics affect both electrical and mechanical cardiac activity. Tachycardia and hypertension are early signs of cardiac toxicity, and with increasing doses patients develop bradycardia and hypotension.
16. 16. Systemic complications of local anesthetics Prevention The administration of epinephrine and isoproterenol with the local anesthetic can aid in ruling out an intravascular injection. Increased heart rate (>10 beats/min) and systolic blood pressure (>15 mmHg) in addition to T-wave changes (>25% decrease in Amplitude) are considered sensitive and specific end points in response to an intravascular injection of a test dose containing 15 ug epinephrine.
17. 17. Systemic complications of local anesthetics Management (ABC) Medications: Lipid emulsion (administer early): Bolus of 1.5 mL kg1 iv over one minute Infusion of 0.25 mL kg1 iv min1 Repeat bolus q3-5 min to a total of 3 mL kg1 Bronchospasm/edema antihistamines, corticosteroids, bronchodilators Hypotension fluid, epinephrine. Seizures midazolam (0.05-0.1 mg kg1), propofol (0.5-1.5 mg kg1), barbiturates (thiopentone [1-2 mg kg1]) Ventricular arrythmias amiodorone (300 mg initially, followed by repeat 150-mg bolus 3-5 min later)
18. 18. What to learn? General principles Systemic complications with local anesthetics Complications of Peripheral nerve block Toxic effect of LA on nerve and surrounding structures Complications of neuroaxial blocks
19. 19. Complications of Peripheral nerve block DIRECT NEEDLE TRAUMA TO THE NERVE Typically neurapraxia injuries are observed postoperatively when patients complain of persistent numbness in the distribution of a peripheral nerve. Numbness gradually regresses over a period of weeks and is rarely observed beyond 3 months. Regional anesthesia-related injuries may be the result of needle trauma, injection pressure, or the toxic effects of local anesthetics or additives.
20. 20. Complications of Peripheral nerve block Prevention Some suggest that most neural injuries are associated with either paresthesia or pain on injection. Needle damage or pressure generated during injection of local anesthetics account for most of these injuries. Nerve damage occurred by both mechanical and chemical injury during intraneural injections of neurotoxic substances (ie, local anesthetics). Chemically induced damage is also possible from high concentrations of local anesthetics, vasoconstrictors, preservatives, and other additives.
21. 21. Complications of Peripheral nerve block Sterilizing agents, skin-cleansing substances, detergents, and certain preservatives (eg, metabisulfite) all cause neurotoxicity and should be carefully avoided when introduced into perineural spaces. Because most regional anesthesia procedures involve the percutaneous insertion of needles toward nerves, the burden often lies with the anesthesiologist to prove that damage was not caused as a result of improper technique and unsafe practice.
22. 22. Complications of Peripheral nerve block Anesthesiologists have more information concerning preoperative and intraoperative events than do most neurologists. Symptoms and signs of compression of the spinal cord must be dealt with urgently (within 6-8h). The anesthesiologist, neurologist, neurosurgeon, and radiologist must work as a team to reach diagnosis before serious permanent injury occurs. Electrodiagnostic and imaging techniques can often help.
23. 23. Surgical causes 1. Surgical retractors, a scalpel blade, or tension within the surgical site may not have been mentioned to the anesthesiologist. 2. Long-acting local anesthetics may have been injected by the surgeon. 3. Compartment syndrome resulting from edema, or bleeding around the wound caused by dressings or casts, can compromise neural function. 4. Vascular injury during the surgery could result in nerve injury. 5. Patient positioning must be reviewed to rule out direct pressure otherwise attributed to a regional anaesthetic mishap.
24. 24. Anaesthetic causes 1. The details of anaesthesia management should be thoroughly reviewed, especially if portions of the anesthetic care were delivered by other anaesthesiologists. 2. Drug choice, dose, and last time of administration should be recorded. 3. Duration of nerve blockade should be noted; a long duration of blockade can result in neural injury. 4. High concentrations of agents probably increase the risk of neural complications.
25. 25. Complications of Peripheral nerve block 5. Multiple nerve-blocking attempts can increase the risk of injury. 6. The presence of paresthesia during needle insertion and the subsequent injection of local anaesthetic can be a warning sign indicating neural injury. 7. The level of sedation must be appropriated without compromising the ability to observe a paresthesia.
26. 26. Complications of Peripheral nerve block Diagnosis CT is best suited for evaluating bony abnormalities. MRI is ideally suited for the examination of soft-tissue abnormalities, especially the spinal cord. For peripheral nerve, nerve plexus, and peripheral nerve complications, imaging is less likely to be useful for the demonstration of nerve injury. MRI may demonstrate the accumulation of blood and edema fluid, which can lead to compartment syndrome.
27. 27. Complications of Peripheral nerve block Nerve conduction studies test the function of large sensory and motor nerve fibers. Evaluating nerve conduction can reveal axonal loss or demyelination of the nerve; however, nerve conduction is less useful in timing lesions when the injury occurs. EMG is preferentially used for evaluating smaller motor units. EMG can be useful for the diagnosis of axonal injury and is also useful for quantitating the severity of the neurologic injury and for identifying the actual site of injury. EMG studies are typically recommended 2 to 3 weeks after an injury.
28. 28. Complications of Peripheral nerve block NEEDLE TRAUMA TO SURROUNDING STRUCTURES Vascular injury Pneumothorax Spinal cord injury Prevention of spinal cord injury 1. Perform it while awake. 2. Use of ultrasound 3. Use remote insertion sites. 4. Small gauge short needles
29. 29. Complications of Peripheral nerve block Prevention of Pneumothorax 1. Extra care in tall, thin patients. 2. Right Pneumothorax for elevated cupola. 3. Avoid in severe impairment of pulmonary function. 4. Blocks should never be performed bilaterally.
30. 30. What to learn? General principles Systemic complications with local anesthetics Complications of Peripheral nerve block Toxic effect of LA on nerve and surrounding structures Complications of neuroaxial blocks
31. 31. Toxic effect of LA on nerve and surrounding structures NEURAL TOXICITY High concentrations of local anesthetics can permanently damage neural tissue in some instances. Preservatives in local anesthetic drugs may also damage nerves and other surrounding tissues. 5% hyperbaric lidocaine for spinal anesthesia is linked to the syndrome transient neurologic symptoms (TNS)
32. 32. Toxic effect of LA on nerve and surrounding structures Myotoxicity Myotoxicity is a recognized complication of intramuscular injections of local anesthetics. Local anesthetics are proposed to cause a pathologic efflux of Ca++ from the sarcoplasmic reticulum, resulting in contracture, cell destruction, and necrosis. In clinical practice, myotoxicity is largely unnoticed except in ophthalmic regional anesthesia, as Diplopia has been reported after retrobulbar blocks.
33. 33. Toxic effect of LA on nerve and surrounding structures Phrenic nerve paresis Phrenic nerve paresis is common after supraclavicular blocks, regardless of the technique used, yet patients do not usually become symptomatic. Supraclavicular techniques may need to be avoided in patients with advanced pulmonary disease. Bilateral supraclavicular techniques are absolutely contraindicated.
34. 34. Toxic effect of LA on nerve and surrounding structures HORNER SYNDROME Horner syndrome (ipsilateral, miosis, ptosis, enophthalmos, loss of sweating) is frequently observed after supraclavicular approaches to the brachial plexus, although its incidence may be lower when ultrasound is used to guide the supraclavicular approach.
35. 35. Toxic effect of LA on nerve and surrounding structures HOARSENESS Hoarseness may occur if the local anesthetic spreads to the recurrent laryngeal nerve. Specific management is not required, as the symptoms will abate as the anesthetic wears off. Persistent hoarseness should urge the clinician to consider an alternative cause.
36. 36. What to learn? General principles Systemic complications with local anesthetics Complications of Peripheral nerve block Toxic effect of LA on nerve and surrounding structures Complications of neuroaxial blocks
37. 37. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) DIRECT NEEDLE TRAUMA As a needle or catheter is advanced into the epidural space, direct trauma to the spinal cord, conus medullaris, and spinal nerve roots can occur. Sensory loss and, less commonly, motor deficits occur as a result of spinal cord trauma. Three well-known syndromes are associated with damage to the spinal cord, roots, and coverings: cauda equina syndrome, adhesive arachnoiditis, and anterior spinal artery syndrome.
38. 38. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Prevention of direct needle trauma When performing an epidural in an awake, cooperative adult, needle advancement should be halted if the patient complains of pain. Pain is more commonly associated with extra-axial lesions affecting the nerve roots or blood vessels that are innervated by pain-mediating sensory neurons. In contrast, because there are no pain receptors within the spinal cord (or the brain), intra-axial trauma may be painless; this allows percutaneous cervical cordotomy to be performed in awake patients.
39. 39. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Electrical stimulation during epidural needle advancement may provide an additional warning sign. Ischemic injuries are among the rarest complications reported after regional anesthesia procedures; Hypotension. Anormal positioning. Vascular disease. Diabetes mellitus. The clamping of major vessels.
40. 40. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Management of direct needle trauma Undiagnosed preexisting neurologic disorders. Ligation of nutrient spinal cord vessels during abdominal or thoracic surgery. Injury to the femoral nerve during pelvic surgery. Injury to the lateral cutaneous nerve of the thigh during retraction close to the inguinal ligament. Pressure on the fibular head leading to neurapraxia of the lateral popliteal nerve.
41. 41. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) The lesion should be localized by taking the patients history and by performing a thorough neurologic examination. Bilateral symptoms associated with pain should alert one to the possibility of neuraxial pathology. Injury at the nerve roots affects both posterior and anterior rami. Preservation of sensation over the para-spinous muscles suggests a more distal injury.
42. 42. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Investigations should include blood cultures and coagulation studies. Immediate MRI is the standard for evaluating neuraxial lesions. EMG can be used to determine the site of injury and the degree of axonal loss, although it may take up to 3 weeks for changes to appear on the electromyogram. It may be useful to perform this immediately upon recognition of neural dysfunction to establish the possibility of a pre-existing lesion.
43. 43. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) HEMATOMA Prevention The American Society of Regional Anesthesia has released guidelines in response to this evolving shift in medical practice; it is important to follow these guidelines to minimize the risk of hematoma.
44. 44. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Management Back pain with lower-limb weakness and sensory deficit should alert the clinician to the presence of a central compressing lesion. Bowel and bladder incontinence can be an associated finding. Problem may be masked by the administration of local anesthetic via an epidural catheter and the presence of a urinary catheter. If MRI confirms the diagnosis, then rapid surgical intervention within 6 to 8 hours is recommended.
45. 45. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) INFECTION Epidural abscess presentation can be variable, but the cardinal symptoms and signs involve back pain with localized tenderness and fever that often develop days after the puncture. Leukocytosis may occur several days or months after needle and catheter insertion. Weakness may develop paraplegia if untreated. Meningitis may develop if the patient has endured a lumbar puncture in this setting.
46. 46. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Prevention of infection Sound aseptic technique, monitoring of the infection site, antibiotic prophylaxis, and bacterial filter use all contribute to a lower incidence of epidural space infections. Although both lidocaine and bupivacaine are bactericidal in high concentration, this property is likely not clinically significant at the concentrations used in practice. The performance of neuraxial block should be avoided where local infection exists at the needle entry site.
47. 47. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Management of Infection Prompt removal of the catheter is essential when erythema and local discharge are present. Carefully assess any symptoms or signs of back pain. If any neural dysfunction occurs, a diagnosis must be immediately made in order to evaluate infective causes. Once a diagnosis of epidural abscess is made, a combination of medical (antibiotic) and surgical (incision and drainage) treatment may be needed.
48. 48. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) TOTAL SPINAL ANESTHESIA Prevention The subsequent use of small, incremental doses of local anesthetics may reduce the risk of this complication. Management Resuscitation with endotracheal intubation, mechanical ventilation, and vasopressor therapy is frequently required, and recovery may take between 30 minutes and 6 hours.
49. 49. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) SUBDURAL INJECTIONS OF LOCAL ANESTHETIC DRUGS Clinically, the subdural injection of local anesthetic drugs should be suspected when motor or sensory changes do not follow the expected pattern. Subdural injections result in a very slow onset of motor and sensory anesthesia and extensive and/or patchy sensory blocking.
50. 50. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) SYSTEMIC AND LOCAL TOXICITY POSTDURAL PUNCTURE HEADACHE Bevel orientation is the most important factor. Needle gauge less than 25 . Blunt needles should be used for spinal anaesthesia. Management Intrathecal placement of the epidural catheters after accidental dural puncture in the obstetric setting is common practice in some centers.
51. 51. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Conservative measures, including bed rest and oral hydration, remain popular therapies for PDPH, despite no evidence to support them. Obstetric patients should be encouraged to mobilize soon after delivery, so that PDPH, if present, can be diagnosed and treated while yet in the hospital. A single oral dose of caffeine but prohibited in pregnancy-induced hypertension. Sumatriptan is a serotonin type 1-d receptor agonist and has been used for cluster headaches and migraine and has been suggested as a treatment of PDPH.
52. 52. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Cosyntropin, the synthetic form of ACTH hormone, has been used to treat PDPH; this pharmaceutical is thought to work by stimulating CSF production and - endorphin output. The epidural blood patch The epidural blood patch (EBP) was introduced by Gormley in 1960 and is known to be the most effective treatment for PDPH. The success rate for a first epidural blood patch is 85%, rising to 98% after a second patch.
53. 53. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) An assistant draws 15 to 20 mL of autologous blood aseptically. The administration of blood should be done at a rate of 1 mL/3 s. The end point of injection occurs when the patient complains of back, neck, or buttock pain.
54. 54. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Alternatives to the Epidural Blood Patch Epidural saline treatment has been used for PDPH, but it is significantly less effective than EBP. Successful use of prolonged saline infusion has been reported in patients with failed EBP. Fibrin glue, a pooled plasma product, has been used to treat CSF leak in cancer patients and in PDPH cases after spinal anesthesia where 2 EBPs had failed. Dextran-40 has also been used to treat PDPH as it undergoes delayed absorption from the epidural space because of its high viscosity and molecular weight.
55. 55. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) FAILURE OF SPINAL/EPIDURAL ANESTHESIA Easiness of pass of catheter into the epidural space. Catheters may become occluded with blood, or the catheter may kink, take a unilateral course, break, or become knotted, all of which can contribute to the complete failure of epidural anesthesia. When epidural local anesthetic dosing for anesthesia approaches the maximum safe limit without noticeable analgesia, a failed epidural must be considered and should prompt the clinician to pursue an alternative course of anesthesia.
56. 56. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) HYPOTENSION Significant hypotension may occur in obstetric patients but it is uncommon in pediatric patients after the proper administration of epidural analgesia. A high sympathetic single-shot caudal block to T6 caused no significant changes in heart rate, cardiac index, or blood pressure in children. RESPIRATORY COMPLICATIONS End-tidal Pco2 and the tidal excursion of the abdomen remained unchanged, whereas hypercapnic ventilatory response decreased significantly. Lumbar and high thoracic regioninduced epidurals do not interfere with the ventilatory response to hypoxemia.
57. 57. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Prevention of respiratory complications, do the following: Avoid the use of high doses of opioids. Limit opioid dosages, especially in the intrathecal space. Avoid the concomitant use of parenteral opioids or sedatives. Avoid or limit doses in the patient with advanced age (>60 years of age), sleep apnea, and other coexisting diseases. Use hydrophilic drugs (eg, morphine) with caution.
58. 58. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) Management of respiratory complications: Treat mild respiratory depression with oxygen. If an infusion is used, then reduce the rate. Depending on the severity of respiratory complications, consider ventilatory support, the administration of narcotic antagonists, and the discontinuation of the opioid infusion.
59. 59. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) NAUSEA AND PRURITUS To prevent and/or manage PONV and pruritus: Reduce the dose of neuraxial opioid. Use antihistamines, opioid antagonists (naloxone and nalbuphine), propofol, nonsteroidal antiinflammatory drugs (NSAIDs), and 5-HT3 receptor antagonists as both preventative and therapeutic measures. Investigation into acupressure point P6 for the prevention of PONV has revealed inconsistent findings.
60. 60. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) POSTOPERATIVE URINARY RETENTION Epidural use for postoperative pain management is usually reserved for patients undergoing major surgery, where urinary catheter placement may be performed for reasons other than anticipated postoperative urinary retention. A threshold of 600 mL has been suggested as a diagnostic threshold.
61. 61. COMPLICATIONS OF NEURAXIAL BLOCKS (EPIDURAL/SPINAL) BACKACHE Prevention/Management Backache after epidural placement Backache should not be ignored, as it can be a cardinal symptom of a space-occupying lesion within the spinal canal. Complications such as an epidural hematoma and abscess, although rare, can have catastrophic outcomes if unrecognized and untreated.