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. Statement No matter how skillful an anesthesiologist may be,
adverse peri- operative events are inevitable in anesthesia
practice.
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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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.