Central Neuraxial Anesthesia Quiz

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Questions and Answers

What is the primary pharmacologic barrier in the meninges that prevents drug movement from the epidural to the subarachnoid space?

Dura mater

Subdural space

Arachnoid membrane (correct)

Pia mater

Which positioning method for spinal anesthesia is considered the most commonly used due to its advantages in enhancing patient comfort and ease of needle placement?

Prone position

Lateral position

Sitting position (correct)

Supine position

What is the most critical anatomical landmark for determining the spinal cord end in adults?

C7 vertebra

L4 vertebra

L1 vertebra

L2 vertebra (correct)

Which is NOT a reason to select the L4-L5 interspace for spinal anesthesia?

Close proximity to the conus medullaris Signup and view all the answers

Which statement about the epidural space is INCORRECT?

It is located anteriorly to the anterior longitudinal ligament. Signup and view all the answers

Which condition is considered a contraindication for the use of epidural anesthesia?

Infection at the injection site Signup and view all the answers

What mechanism of action do local anesthetics primarily use to achieve their anesthetic effect?

Blocking the transmission of action potentials in peripheral nerves Signup and view all the answers

In which scenario are the benefits of epidural opioids preferred over IV opioids?

Lower chance of sedation and respiratory depression Signup and view all the answers

Which characteristic is an advantage of epidural anesthesia over spinal anesthesia?

Better control over the intensity of sensory block Signup and view all the answers

When using a hyperbaric solution in spinal anesthesia, where is the anesthetic likely to spread when the patient is supine?

To T7 Signup and view all the answers

What is a significant contraindication for the use of epidural anesthesia?

Infection at the injection site Signup and view all the answers

Which mechanism of local anesthetics primarily affects sensory blockade?

Inactivation of sodium channels in myelinated fibers Signup and view all the answers

What benefit does epidural anesthesia offer compared to IV opioids for pain management?

Ability to titrate the dosage continuously Signup and view all the answers

Which of the following statements about spinal anesthesia is NOT correct?

It typically produces less motor block than epidural anesthesia. Signup and view all the answers

What anatomical structure provides access to the epidural space in the sacral region?

Sacral hiatus Signup and view all the answers

During spinal anesthesia, where will motor blockade typically occur in relation to the site of injection?

2 levels below the site of injection Signup and view all the answers

Which opioid is considered most hydrophilic and stays in the cerebrospinal fluid (CSF) for a longer period?

Morphine Signup and view all the answers

Which technique involves injecting local anesthetic into the CSF for rapid onset of block?

Spinal anesthesia Signup and view all the answers

What is one absolute contraindication for the use of epidural anesthesia?

Compromised skin integrity Signup and view all the answers

Which local anesthetic is known for its long duration and high protein binding properties?

Bupivacaine Signup and view all the answers

How does epidural anesthesia compare to IV opioids in terms of systemic side effects?

Lower systemic side effects with epidurals Signup and view all the answers

What adverse outcome is associated with intravascular injection of local anesthetics in epidural procedures?

Local anesthetic toxicity Signup and view all the answers

Which local anesthetic is characterized as having the shortest duration and is associated with a higher failure rate?

Procaine Signup and view all the answers

Which factor most significantly influences the level of anesthesia achieved in an epidural injection?

Volume of the drug used Signup and view all the answers

Which anatomical landmark is the preferred site for performing a paramedian technique in epidural anesthesia?

Lateral aspect of the spine Signup and view all the answers

What is a primary risk associated with using cutting tip needles during epidural procedures?

Higher risk of post-dural puncture headache (PDPH) Signup and view all the answers

Which type of epidural anesthetic is commonly used as a supplement to general anesthesia during labor?

Combined spinal epidural (CSE) Signup and view all the answers

What is the recommended wait time for patients on Ticlopidine before undergoing an epidural procedure?

10 days Signup and view all the answers

Which local anesthetic has a faster onset and shorter duration compared to others used for spinal anesthesia?

Chloroprocaine Signup and view all the answers

What is the main advantage of using epidural anesthesia over epidural opioids?

Longer duration of pain relief Signup and view all the answers

What anatomical landmark is used to identify the location of the L4 vertebral body?

Line drawn between the iliac crests Signup and view all the answers

Which condition is NOT specifically mentioned as affecting the choice of positioning for spinal anesthesia?

Cervical spine injury Signup and view all the answers

What is the primary significance of the T7-T8 interspace when performing a thoracic epidural?

Estimating needle placement Signup and view all the answers

What anatomical structure does the epidural space surround?

Dural sac Signup and view all the answers

At what vertebral level does the spinal cord end in adults?

L1-L2 Signup and view all the answers

What is the impact of selecting the L4-L5 interspace for spinal anesthesia?

Increased risk of needle failure Signup and view all the answers

Which physiological characteristic is most important when determining the effectiveness of spinal anesthetic distribution?

Spinal anatomy of the patient Signup and view all the answers

What is the primary disadvantage of using a paramedian approach compared to the midline technique for spinal procedures?

Increased risk of vascular injury Signup and view all the answers

What anatomical structure provides access to the epidural space in the sacral region?

Sacral hiatus Signup and view all the answers

What is the typical motor block level in relation to the site of injection during spinal anesthesia?

2 levels below the site of injection Signup and view all the answers

Which of the following factors most significantly influences the level of anesthesia achieved in an epidural injection?

Concentration of local anesthetic Signup and view all the answers

In which scenario would a hyperbaric solution likely spread to T7 and the sacrum when the patient is supine?

When the solution is hyperbaric Signup and view all the answers

Which statement accurately describes the advantages of spinal anesthesia over epidural anesthesia?

Provides a more intense sensory block Signup and view all the answers

What is a potential complication of using cutting tip needles during epidural procedures?

Increased risk of hematoma Signup and view all the answers

Which level of the vertebral column is most significant for identifying lordosis?

L3 Signup and view all the answers

What is the primary risk associated with intravascular injection of local anesthetics during epidural anesthesia?

Cardiovascular toxicity Signup and view all the answers

What is a typical benefit of placing a catheter for epidural anesthesia?

Improved control over the duration of the block Signup and view all the answers

Which anatomical structure cannot be accessed directly for epidural anesthesia?

Subarachnoid space Signup and view all the answers

What is the potential risk associated with using a cutting tip needle during epidural procedures?

Increased risk of post-dural puncture headache (PDPH) Signup and view all the answers

Which factor has the least influence on the spread of anesthetic in the epidural space?

Patient's weight and height Signup and view all the answers

What is a primary complication associated with the failure of an epidural nerve block?

Patchy or unilateral block Signup and view all the answers

Which local anesthetic is associated with a higher risk of methemoglobinemia when administered in large doses?

Prilocaine Signup and view all the answers

Which of the following is considered an absolute contraindication for epidural anesthesia?

Patient refusal Signup and view all the answers

What is the primary advantage of using a non-cutting tip needle for epidural anesthesia?

Lower risk of PDPH Signup and view all the answers

Which local anesthetic has the fastest onset and shortest duration for spinal anesthesia?

Chloroprocaine Signup and view all the answers

What parameter most influences the dermatomal level of anesthesia achieved with epidural injection?

Volume of the anesthetic used Signup and view all the answers

Which statement is true regarding hydrophilic and lipophilic opioids used in the epidural space?

Hydrophilic opioids have a higher risk of respiratory depression. Signup and view all the answers

What is a specific relative contraindication for the use of epidural anesthesia?

Uncooperative patient Signup and view all the answers

Which aspect of the epidural procedure can help minimize the risk of failure of the block?

Proper midline or paramedian technique Signup and view all the answers

The effectiveness of epidural anesthesia can be diminished by which of the following factors?

Patient's blood volume level Signup and view all the answers

Which of the following statements accurately reflects the differences between midline and paramedian approaches in spinal procedures?

Paramedian technique can target specific nerve roots more effectively. Signup and view all the answers

Study Notes

Central Neuraxial Anesthesia

Central neuraxial block includes spinal and epidural anesthesia.
Commonly used for both general anesthesia augmentation and as an alternative, especially in obstetrics.

Spinal Anesthesia

Involves injecting local anesthetic into the cerebrospinal fluid (CSF) within the subarachnoid space.
Layers penetrated during injection: skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, ligamentum flavum.
Advantages include quicker procedure, reduced discomfort, lower local anesthetic usage, and intense sensory and motor blocks.
Confirmation of correct placement is through CSF appearance during administration.

Epidural Anesthesia

Advantages include a lower risk of headache and hypotension compared to spinal anesthesia.
Allows for segmental sensory block and better control of block intensity.
A catheter can be placed for continuous infusion and titration of anesthesia.

Anatomy & Considerations

Key anatomical landmarks include L3 and C5 for lordosis, T7 and sacrum for kyphosis.
A patient's position affects the spread of anesthetics; hyperbaric solutions spread downwards, hypobaric upwards.
Sensory block occurs approximately 2 levels above the injection site, while motor block occurs about 2 levels below.

Vertebral Canal Anatomy

Spine structure: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae.
Sacral hiatus is present in 92% of adults; it's used for access to the sacral canal in pediatric cases.

Positioning for Anesthesia

Lateral position preferred for frail patients; sitting promotes midline recognition.
Selecting the interspace for spinal anesthesia affects anesthetic distribution, with L4-5 presenting a higher failure risk.
Spinal cord ends at L1-L2 (conus medullaris), with the cauda equina below.

Drug Characteristics & Administration

Local anesthetics can be enhanced with bicarbonate for faster onset and epinephrine for prolonged effects.
Opioids used in epidurals differ in hydrophilicity; hydrophilic via CSF for longer duration, while lipophilic produce faster effects but shorter duration.
Commonly used opioids include morphine (hydrophilic), fentanyl, and sufentanil (lipophilic).

Complications

Possible complications include failure of block, nerve injury, infection, epidural hematoma, and PDPH.
PDPH is characterized by frontal-occipital headache worsening in upright position.

Contraindications

Absolute contraindications include patient refusal, coagulopathy, increased intracranial pressure, and skin infections.
Relative contraindications include uncooperative patients, pre-existing neurologic disorders, and certain anatomical abnormalities.

Local Anesthetics Overview

Long-acting: Bupivacaine (2.5-3 hours), ropivacaine (lower motor block), and tetracaine (may last 5 hours with a vasoconstrictor).
Short-acting: Procaine (high failure rate), chloroprocaine (minimal fetal side effects), and lidocaine (risk of TNS).

Needle Types

Cutting-tip needles (e.g., Quincke) require less force but have a higher risk of PDPH.
Non-cutting-tip needles (e.g., Sprotte) are associated with lower risk of complications but require more force.

Caudal Anesthesia

Provides effective pain management for surgeries in sacral segments, utilized predominantly in pediatrics.
Performance entails easier execution in children and offers about 12 hours of analgesia with bupivacaine.
Complications similar to spinal anesthesia, including infection and intravascular injection.