Apex Unit 8 Regional Flashcards
Order the spinal ligaments from superficial to deep.
(1 is superficial, and 4 is deep)
Interspinous ligament + 1
Ligamentum flavum + 2
Posterior longitudinal ligament + 3
Anterior longitudinal ligament + 4
Which statements about the epidural space are true? (Select 2.)
It neighbors the pia mater.
It ends at the sacrococcygeal ligament.
Batson’s plexus passes through the lateral region.
Its volume is increased in the third stage of pregnancy.
It ends at the sacrococcygeal ligament
Batson’s plexus passes through the lateral region
The epidural space neighbors the dura (not the pia) mater, and it terminates at the sacrococcygeal ligament.
Any condition that increases intra-abdominal pressure (obesity, pregnancy, etc.), puts backpressure on the epidural veins. This increases the volume of blood contained within, thereby reducing (not increasing) the volume of the epidural space.
Batson’s plexus is the network of epidural veins that drain the spinal cord and the meninges. It typically passes through the lateral and anterior regions of the epidural space.
In the adult, which anatomic structure correlates with the termination of the dural sac?
Superior iliac spines
Tuffier’s line
L1 vertebra
Sacral cornua
Superior iliac spines
Know these landmarks:
Conus medullaris = L1
Tuffier’s line = L4-L5 interspace (correlates with the iliac crests)
Dural sac ends =S2 (correlates with the superior iliac spines)
Sacral hiatus and sacrococcygeal ligament = S5
Transection of the C6 posterior nerve root will cause:
motor deficit of the middle finger.
impaired sympathetic outflow to the C6 distribution.
sensory block of the thumb.
diaphragmatic paralysis.
Sensory block of the thumb
Transection of the C6 posterior nerve root will cause a sensory block in the ipsilateral thumb.
The best way to approach this question is to think of the modalities carried by the anterior and posterior nerve roots. Remember that the posterior roots are sensory and the anterior roots are motor and autonomic. Knowing this would’ve helped you eliminate all the other answer choices! If you didn’t know this, you’d have to know about the dermatomes and their distributions. And yes, you’ll need to know these for the NCE!
Diaphragmatic paralysis occurs with injury to C3-5. We injured the C6 sensory nerve root, so this answer was wrong for two reasons.
Match each nerve fiber type with its degree of myelination.
A alpha + Heavy
A gamma + Moderate
B + Light
C + None
How does neuraxial anesthesia affect respiratory mechanics?
Impaired inspiration
Impaired expiration
Impaired inspiration and expiration
No impairment
Impaired inspiration and expiration
Accessory muscle function is reduced by neuraxial blockade.
Impairment of the intercostal muscles (inspiration and expiration) as well as the abdominal muscles (ability to cough and clear secretions) will decrease pulmonary reserve. This is particularly important for the patient with severe COPD.
What factor is an absolute contraindication to spinal anesthesia?
Multiple sclerosis
Patient refusal
Peripheral neuropathy of lower extremity
Mitral stenosis
Patient refusal
This is the kind of question that should ruffle your feathers a bit. When confronted with several “right” answers, you need to learn how to select the answer that is most correct.
Patient refusal is always an absolute contraindication to neuraxial anesthesia.
The other answer choices are relative contraindications to neuraxial anesthesia. The textbooks offer conflicting guidelines in these areas, but they agree that the decision to proceed with a neuraxial technique should be made on a case-by-case basis.
Identify the MOST appropriate techniques for a subarachnoid block in a patient scheduled for hemorrhoidectomy. (Select 2.)
Lidocaine 5% in 7.5% dextrose and the sitting position
Bupivacaine 0.3% in water and the jackknife position
Tetracaine 0.2% in water and the sitting position
Procaine 10% in water and the jackknife position
Lidocaine 5 percent in 7.5 percent dextrose and the sitting position
Bupivacaine 0.3 percent in water and the jackknife position
There are two ways to approach this patient. We can use a hyperbaric solution (lidocaine 5 percent in 7.5 percent dextrose) and place the block in the sitting position or we can use a hypobaric solution (bupivacaine 0.3 percent in water) and place the block in the jackknife position.
Why are the other answers wrong?
If we chose a hyperbaric solution (procaine 10 percent in water) and the jackknife position, the local anesthetic will concentrate in the lumbar region.
If we chose a hypobaric solution (tetracaine 0.2 percent in water) and the sitting position, the local anesthetic will rise in a cephalad direction, failing to adequately anesthetize the sacral nerve roots.
A 22-pound child requires a caudal anesthetic. How many milliliters of 0.2% ropivacaine should be administered to achieve a T10 sensory blockade?
(Round your answer to the nearest whole number)
10
For a T10 sensory block, you need to administer 1 mL/kg. Here’s how to perform the calculation:
Convert pounds to kilograms: 22 lbs / 2.2 kg = 10 kg
Multiply the patient’s weight by the formula: 10 kg x 1 mL/kg = 10 mL
When compared to intrathecal fentanyl, which findings are MORE likely with intrathecal morphine? (Select 3.)
Late respiratory depression Sympathectomy Faster onset Wider band of analgesia Increased risk of nausea Higher plasma concentration
Wider band of analgesia
Late respiratory depression
Increased risk of nausea
The correct answers describe a drug that is more hydrophilic. When we compare the two drugs in the question, we should recognize that morphine is more hydrophilic than fentanyl. Therefore, morphine causes late respiratory depression, will provide a wider band of analgesia, and increases the risk of nausea.
The wrong answers describe a drug that is more lipophilic. Lipophilic drugs tend to have a faster onset and achieve a higher plasma concentration.
Neuraxial opioids do not cause sympathectomy. This was a bit of trick, because neither fentanyl nor morphine cause sympathetic denervation.
Identify the MOST common side effect of neuraxial opioid administration.
Pruritus
Respiratory depression
Urinary retention
Nausea and vomiting
Pruritus
When it comes to the side effects of neuraxial opioids, you must know the big four:
Pruritus (most common)
Respiration depression
Urinary retention
Nausea and vomiting
Which factors increase the risk of postdural puncture headache? (Select 3.)
Old age
Needle perpendicular to long axis of meninges
Early ambulation
Air for loss of resistance during epidural placement
Continuous spinal catheter
Pitkin needle
Pitkin needle
Needle perpendicular to long axis of meninges
Air for loss of resistance during epidural placement
The risk of PDPH is increased by the type of needle (cutting tip is worse than pencil point tip) and needle orientation (perpendicular is worse than parallel).
Using air or saline for epidural placement does not affect the risk of incurring a dural puncture, however if this complication was to occur, then injecting air into the CSF will create a pneumocephalus and increase the risk of PDPH.
Things that don’t increase the risk of PDPH include: early ambulation, old age, and use of a continuous spinal catheter.
You are called to remove an epidural catheter from a patient receiving enoxaparin for DVT prophylaxis. According to the Consensus Statement from the American Society for Regional Anesthesia and Pain Medicine, what is the MOST appropriate course of action?
Hold enoxaparin for six hours, pull catheter, then restart enoxaparin one hour later.
Hold enoxaparin for 12 hours, pull catheter, then restart enoxaparin two hours later.
Hold enoxaparin for 24 hours, pull catheter, then restart enoxaparin six hours later.
Order a hematology consult.
Hold enoxaparin for 12 hours, pull catheter, then restart enoxaparin two hours later
The risk of epidural hematoma is similar during block placement and catheter removal, therefore you must know the ASRA guidelines for both circumstances.
The most appropriate action is to hold enoxaparin for 12 hours, pull the catheter, then restart enoxaparin two hours later.
If you know these guidelines, you won’t need to consult.
Following the resolution of a subarachnoid block, the patient complains of severe pain in the buttocks that radiates through her legs. She has normal motor function. What should be said to the patient?
Most patients will experience pain for one month.
Ibuprofen will help your pain.
Avoid bupivacaine if you have another spinal anesthetic in the future.
This was due to the use of a micro spinal catheter.
Ibuprofen will help your pain
This patient is experiencing transient neurologic symptoms. This type of pain will respond to NSAIDs, opioids, and trigger point injections.
Why are the other answers wrong?
TNS typically persists for 1 - 7 days (not a month).
Lidocaine is the most common cause of TNS (not bupivacaine).
Micro spinal catheters increase the risk of cauda equina syndrome (not TNS).
Beginning at the nerve roots, order the components of the brachial plexus from medial to lateral.
(1 is most medial, and 4 is most lateral)
Trunks + 1
Divisions + 2
Cords + 3
Branches + 4
The brachial plexus has 5 components. Beginning at the spinal cord and working outward: roots, trunks, divisions, cords, and branches.
Mnemonic: Reach To Drink Cold Beer
Thirty minutes after an interscalene block, the patient complains of dyspnea. His SpO2 is 93 percent on 40 percent FiO2 via facemask. He is otherwise stable. What is the BEST intervention at this time?
Midazolam
Noninvasive positive pressure ventilation.
Verbal reassurance
Chest x-ray
Chest x-ray
There are two causes of respiratory distress in this patient that should immediately come to mind: phrenic nerve blockade and pneumothorax.
The phrenic nerve is blocked nearly 100 percent of the time with an interscalene approach to the brachial plexus. This is usually only an issue in the patient with a reduced pulmonary reserve - think COPD.
The cupola of the lung is just medial to the first rib - it’s higher on the right side, and it is at risk of needle puncture during the interscalene or supraclavicular approach to the brachial plexus. A chest x-ray should be ordered to rule out pneumothorax in this patient.
Why are the other answers wrong?
Noninvasive positive pressure ventilation is useful if the patient can’t compensate for phrenic nerve paralysis. Positive pressure of any kind can convert a pneumothorax to a tension pneumothorax.
Midazolam might further impair this patient’s respiratory distress. In some contexts, it may be useful if the patient is overly anxious. Either way, it’s not the best answer here.
Verbal reassurance is appropriate, but it does not treat the cause of respiratory distress.
Select the BEST landmark for a supraclavicular block using a nerve stimulation technique.
First rib
Divisions of brachial plexus
Pectoralis major
Subclavian artery
Subclavian artery
Of the answer choices provided, the subclavian artery is the best landmark for a supraclavicular block using a nerve stimulation technique.
Why are the other answers wrong?
Although the supraclavicular is a trunks/divisions level block, this structure is not a landmark.
The pectoralis major is an important structure for the infraclavicular approach.
You can’t see the first rib, so it’s not a landmark.
Which artery is MOST likely to be injected with local anesthetic during supraclavicular block placement?
Axillary
Vertebral
Subclavian
Carotid
Subclavian
If you know the landmarks and surrounding anatomy for each nerve block, you’ll be able to reason out the associated complications.
Interscalene block = vertebral artery
Supraclavicular block = subclavian artery
Infraclavicular block = subclavian artery or axillary artery (depends on block level)
During an infraclavicular block using a nerve simulator technique, which patient response indicates proper needle placement?
Finger flexion
Arm abduction
Elbow flexion
Arm adduction
Finger flexion
Acceptable motor responses include finger flexion/extension when nerve stimulation is decreased from 1 mA to 0.5 mA.
Why are the other answers wrong?
The axillary nerve exits the sheath at a variable level, so it may be stimulated outside of the sheath. If you observe a deltoid response, withdraw the needle to the skin and redirect superiorly.
The musculocutaneous nerve also exits the sheath at a variable level, so it may be stimulated outside of the sheath. If you observe a biceps response, withdraw the needle to the skin and redirect caudally.
The needle must transverse the pectoralis major and minor before reaching the brachial plexus. Pectoralis stimulation means the needle is too shallow, and you should continue advancing the needle.
When compared to the supraclavicular approach to the brachial plexus, the infraclavicular approach has a higher risk of: (Select 2.)
respiratory compromise.
patient discomfort.
intravascular injection.
pneumothorax.
Patient discomfort
Intravascular injection
The supraclavicular approach has a higher risk of pneumothorax and phrenic nerve inhibition. Either can potentially cause respiratory compromise.
The infraclavicular approach has a higher risk of intravascular injection and patient discomfort (piercing the pec major and minor with the needle).
Which region is MOST likely to be inadequately anesthetized following an axillary block with a transarterial technique?
Lateral forearm
First digit
Medial forearm
Fifth digit
Lateral forearm
The musculocutaneous n. usually exits the brachial plexus proximal to the location of this block. Therefore, this nerve must be blocked separately (in the coracobrachialis muscle).
In the patient who receives intravenous regional anesthesia for a carpel tunnel release, what is the MINIMUM amount of time that the tourniquet must remain inflated following injection of the local anesthetic?
(Enter your answer in minutes)
20 minutes
Toxicity is the most significant risk of the Bier block.
The tourniquet must remain inflated for a minimum of 20 minutes following local anesthetic injection. This allows enough time for the LA to absorb into the tissue. If the cuff is deflated too soon (or if it fails), then the local anesthetic is washed into the systemic circulation where it can produce seizures or cardiovascular collapse.
Which nerves arise from the lumbar plexus? (Select 3.)
Posterior femoral cutaneous Femoral Lateral femoral cutaneous Obturator Pudendal Sciatic
Femoral
Obturator
Lateral femoral cutaneous
The lumbar plexus arises from the anterior (ventral) rami of L1-L4. It gives rise to 6 nerves:
Iliohypogastric Ilioinguinal Genitofemoral Lateral femoral cutaneous Obturator Femoral The sacral plexus gives rise to the sciatic and posterior femoral cutaneous nerves.
The coccygeal plexus gives rise to the pudendal nerve.
Match each nerve with its corresponding nerve roots.
Lateral femoral cutaneous + L2-L3
Femoral + L2-L4
Sciatic + L4-S3
Posterior femoral cutaneous + S1-S3
The psoas compartment block anesthetizes all of the following nerves EXCEPT the:
obturator.
sciatic.
lateral femoral cutaneous.
saphenous.
Sciatic
This one was a bit tricky, but it emphasizes the point that you need to understand how the nerves divide after leaving the plexus.
The lumbar plexus gives rise to three key nerves for lower extremity anesthesia:
Lateral femoral cutaneous Obturator Femoral Although the femoral nerve wasn't an answer choice, you know that the saphenous nerve is a division of the femoral nerve. Anesthesia of the femoral nerve will also anesthetize the saphenous nerve.
The sciatic nerve comes from the sacral plexus. This plexus is not anesthetized by the posterior approach to the lumbar plexus (psoas compartment block).
Pick the statements that BEST describe the proper technique for performing a fascia iliaca compartment block. (Select 2.)
Local anesthetic should be deposited between the fascia iliaca and fascia lata.
Ultrasound is required.
Local anesthetic is deposited anterior to the iliopsoas muscle.
Two pops should be felt before injecting local anesthetic.
Two pops should be felt before injecting local anesthetic
Local anesthetic is deposited anterior to the iliopsoas muscle
This block is easily performed with landmarks and feel; a nerve stimulator or ultrasound aren’t required.
You should feel two pops as you insert the needle. These are felt as the needle penetrates the fascia lata and then the fascia iliaca.
Which peripheral nerve block can be combined with a sciatic nerve block to enhance tolerance of a lower leg tourniquet?
Posterior tibial
Sural
Saphenous
Common peroneal
Saphenous
The combination of a sciatic (or popliteal) and saphenous block provides complete anesthesia to the lower leg, ankle, and foot. Therefore, if a patient has a sciatic nerve block, then anesthetizing the saphenous nerve would enhance tolerance of a lower leg tourniquet. Recall that the saphenous nerve is a continuation of the posterior branch of the femoral nerve.
Increasing tolerance of an upper leg tourniquet would require a sciatic nerve block and a psoas compartment block or a 3-in-1 block (femoral, obturator, lateral femoral cutaneous).
