Lippincott's Anesthesia Review: 1001 Questions and Answers

Chapter 7. Spinal and Epidural Anesthesia

Thomas Halaszynski

    1.   A spinal neuraxial anesthetic was given 20 minutes earlier to a 28-year-old G3P2 parturient scheduled for repeat cesarean section. Alcohol swab exam revealed that she has lost temperature sensation up to T2 level. At what level do you anticipate the block will reach to provide adequate pain control?

          A.   T2

          B.   T3

          C.   T4

          D.   T5

    2.   You have just administered a bolus of 2% lidocaine (25 mL) through an epidural catheter that has been working well for labor analgesia in preparation for emergency cesarean section for fetal distress in an otherwise-healthy 35-year-old woman. Shortly after administration of lidocaine, the patient complains of nausea, and you notice that her heart rate has decreased from 99 to 38 bpm. The most likely cause is

          A.   Anaphylactic reaction to lidocaine

          B.   Pneumothorax

          C.   Epidural level is higher than T4

          D.   Amniotic fluid embolus

    3.   Contraindication(s) for neuraxial blockade include(s)

          A.   Severe aortic stenosis

          B.   Severe bleeding tendency

          C.   Existing severe hypotension

          D.   All of the above

    4.   During epidural placement using a midline approach, the epidural needle penetrates all the following anatomical layers, except

          A.   Ligamentum flavum

          B.   Subarachnoid membrane

          C.   Supraspinous ligament

          D.   Intraspinous ligament

    5.   Major benefits of a neuraxial block in a Whipple procedure include all the following, except

          A.   Decreases the incidence of atelectasis

          B.   Leads to earlier return of GI function

          C.   Decreases the risk of urinary retention

          D.   Reduces the risk of pulmonary embolism or deep-vein thrombosis

    6.   The correct statement for human neuraxial anatomy is

          A.   Adult spinal cord ends at L2

          B.   Spinal cord in children ends at L3

          C.   The dural sac and subarachnoid space in adults end at S1

          D.   The dural sac and subarachnoid space in children end at S2

    7.   Blood supply to the human spinal cord includes all of the following, except

          A.   Blood supply to the spinal cord is from a single anterior spinal artery and two posterior spinal arteries

          B.   The anterior spinal artery supplies the anterior two-thirds of the spinal cord, and the posterior spinal arteries supply the posterior one-third

          C.   Anterior spinal artery originates from the vertebral artery

          D.   Posterior spinal artery originates from the posterior cerebral artery

    8.   The principal site of action of local anesthetics placed into the epidural space is the

          A.   Spinal cord

          B.   Nerve roots

          C.   Epidural space

          D.   Subarachnoid space

    9.   Lidocaine and epinephrine are commonly used together when testing epidural anesthesia because

          A.   Lidocaine injection (3 mL of 1.5%) intravascularly will induce local anesthetic toxicity such as perioral numbness

          B.   Intrathecal injection of epinephrine will result in a high spinal

          C.   Intrathecal injection of lidocaine can cause a low-level spinal anesthesia with some degree of motor block

          D.   Intravascular injection of epinephrine (typically 15 μg/3 mL) can cause hypertension more than tachycardia

  10.   As an adjuvant in epidural anesthesia, epinephrine can

          A.   Prolong duration of blockade

          B.   Improve the quality of blockade

          C.   Decrease the peak plasma levels of local anesthetic concentration

          D.   All of above

  11.   Factors that can affect the level of an epidural anesthetic include

          A.   Patient weight, amount of local anesthetic injected, patient position

          B.   Patient height, amount of local anesthetic injected, patient position

          C.   Patient age, amount of local anesthetic injected, patient position

          D.   B and C

  12.   Addition of sodium bicarbonate to epidural local anesthetics may accelerate the onset of blockade with all of the local anesthetics, except

          A.   Lidocaine

          B.   Chloroprocaine

          C.   Mepivacaine

          D.   Bupivacaine

  13.   Factors influencing the level of spinal anesthesia achieved include all of the following, except

          A.   Baricity of anesthetic solution

          B.   Patient age

          C.   Volume of anesthetic solution injected

          D.   Patient gender

  14.   All of the following factors may influence the spinal level achieved during spinal anesthesia, except

          A.   Drug dose

          B.   Needle direction

          C.   Patient position at the time and immediately following injection

          D.   Patient weight

  15.   Complications from neuraxial blockade may include all of the following, except

          A.   Radiculopathy

          B.   Anterior spinal artery syndrome

          C.   Arachnoiditis

          D.   Constipation

  16.   Neuraxial block complications using local anesthetics alone include all of the following, except

          A.   Post–dural puncture headache

          B.   Urinary retention

          C.   Postoperative cognitive dysfunction

          D.   High spinal anesthesia

  17.   Spinal anesthesia was performed on a 25-year-old healthy male for ureter stent placement. A total of 1.5 mL of 5% preservative-free lidocaine in 7.5% dextrose was injected intrathecally after being mixed with CSF. There was evidence of free CSF flow before and after injection. The surgery was performed in the lithotomy position and was uneventful, but the patient complained of severe buttock pain in the post–anesthesia care unit. A neuro exam was negative for sensory and motor deficits. The most likely diagnosis is

          A.   Spinal hematoma

          B.   Spinal abscess

          C.   Transient neurological symptoms

          D.   Radiculopathy

  18.   You are consulted as to when a patient would be an appropriate candidate for a neuraxial block following administration of the following anticoagulant medications (patient does not have any other coagulopathies, and does not take other medications that could influence coagulation). The most correct statement is

          A.   Last dose of ticlopidine (Ticlid) 7 days ago

          B.   Last dose of clopidogrel (Plavix) this morning

          C.   Last dose of abciximab (ReoPro) 24 hours ago

          D.   Last dose of eptifibatide (Integrilin) 12 hours ago

  19.   You performed an epidural anesthetic for an elective open–abdominal aneurysm repair. You are asked to advise the surgeon when it would be considered safe to administer intraoperative intravenous heparin:

          A.   Not at all

          B.   One hour after epidural placement

          C.   Two hours after epidural placement

          D.   Four hours after epidural placement

  20.   A higher-than-expected spinal level achieved or greater dermatomal spread of local anesthetic can be associated with all of the following clinical situations, except

          A.   Pregnancy

          B.   Ascites

          C.   Elderly

          D.   Female gender

  21.   Commonly used spinal anesthesia adjuvants include all the following, except

          A.   Morphine

          B.   Clonidine

          C.   Dexmedetomidine

          D.   Ephedrine

  22.   A 75-year-old female with ovarian cancer is scheduled for total abdominal hysterectomy/bilateral salpingo oophorectomy and tumor debulking. A thoracic epidural anesthesia was performed using a test dose of 1.5% lidocaine with 1:200,000 epinephrine injected through the epidural Tuohy needle that resulted in no evidence of adverse sequelae. An epidural catheter was then threaded through the needle followed by evidence of negative aspiration through the catheter. A total of 10 mL 0.5% bupivacaine was administered through the epidural catheter. Thirty seconds later, the patient became agitated and complained of lightheadedness, tinnitus, and feeling faint, but still able to move all of her extremities. Her BP decreased from 150/70 to 100/45 mm Hg and her HR decreased from 85 to 55 bpm. The patient maintained spontaneous breathing throughout with an oxygen saturation (SpO2) of 95%. The most likely diagnosis is

          A.   Local anesthetic systemic toxicity (LAST)

          B.   High epidural anesthesia

          C.   Total spinal anesthesia

          D.   Anaphylactic reaction

  23.   All of the following local anesthetic systemic toxicity (LAST) treatment measures should be performed when caring for a patient who may be experiencing toxicity, except

          A.   Stop epidural medication administration

          B.   Support the airway with 100% oxygen

          C.   Administer intravenous epinephrine according to ACLS protocols

          D.   Administer an intralipid bolus and continuous infusion

  24.   You have just placed a lumbar epidural for labor analgesia at L3–L4 interspace in a 34-year-old G2P1 woman of 39 weeks’ gestation. The patient is 6-feet tall and weighs 300 pounds. Two hours later, you are called for an emergency cesarean section on the woman. The minimum amount of 2% lidocaine you would need to administer through the epidural catheter in order to achieve a T4 level is

          A.   5 mL

          B.   10 mL

          C.   20 mL

          D.   30 mL

  25.   The correct statement regarding caudal anesthesia is

          A.   Caudal anesthesia is essentially sacral epidural anesthesia

          B.   Caudal anesthesia can only be performed in pediatric population

          C.   A caudal anesthesia catheter should be positioned without penetrating the sacrococcygeal ligament

          D.   The younger the child, the less likely you are to experience an intrathecal injection

  26.   You just placed a thoracic epidural in a morbidly obese female (5’1” and 350 lb). You quickly administer a total of 20 mL 0.5% bupivacaine through the epidural catheter. As you reposition the patient from the sitting to the supine position, the patient complains of shortness of breath, bilateral arm weakness, and nausea. Her HR has decreased from a baseline of 98 to 41 bpm, and her systolic blood pressure has decreased from a baseline of 140s to 70s mm Hg. The most likely cause is

          A.   Accidental intravascular injection of local anesthetic

          B.   Local anesthetic systemic toxicity

          C.   A high epidural block

          D.   Anaphylactic reaction to local anesthetic or latex

  27.   The most likely reason for dyspnea in a patient experiencing the effects of a high neuraxial blockade is

          A.   Phrenic nerve palsy when the neuraxial level reaches T3–T5

          B.   Patient is experiencing an anxiety attack

          C.   Medullary hypoperfusion

          D.   Congestive heart failure

  28.   In the situation of a high spinal anesthetic, which of the following drug is pharmacodynamically considered the least useful in controlling hypotension

          A.   Ephedrine

          B.   Atropine

          C.   Phenylephrine

          D.   Epinephrine

  29.   During performance of lumbar epidural anesthesia for labor analgesia, you experience free-flowing cerebrospinal fluid (CSF) from the advancing 17G Tuohy epidural needle. The epidural needle is removed and a second attempt is successfully performed with an epidural catheter placed at a different level. Which of the following you would not recommend for the patient to practice in the next 72 hours?

          A.   Bed rest

          B.   Fluid restriction

          C.   Increase caffeine intake

          D.   Continue with daily stool softener

  30.   You are consulted by an emergency room (ER) physician to evaluate a patient experiencing a severe and bilateral retro-orbital headache, described as constant, along with diplopia. The ER physician also indicated that the patient presented to the ER 2 days prior with fever, chills, and photophobia when a diagnostic lumbar puncture was performed with a 20G needle. The CSF study proved negative for meningitis, but now the patient has returned to the ER with complaints of a severe headache that has failed therapies of bed rest, caffeine, nonsteroidal anti-inflammatory drugs, and increased fluid intake. The next method of treatment you would suggest is

          A.   Repeat the CSF study as one set of negative results is not definitive

          B.   Recommend opioids for treatment of the headache

          C.   Recommend performing an epidural blood patch

          D.   Continue with conservative therapy as it will eventually prevail

  31.   Incorrect statement regarding neuraxial blockade is

          A.   Dermatome level of anesthesia achieved with a spinal anesthetic is often more predictable than following an epidural blockade

          B.   Spinal anesthesia can more rapidly and consistently produce denser motor blockade than epidural anesthesia

          C.   Local anesthetics administered during epidural anesthesia are typically more volume-dependent, and during spinal anesthesia are more concentration-dependent

          D.   Thoracic epidural anesthesia has an increased risk of urinary retention compared to lumbar epidural anesthesia when the same volume of local anesthetic is administered

  32.   Following performance of spinal anesthesia at the L4–L5 level with 3 mL of 5% lidocaine, you suspect a potential injury to the conus medullaris. Which of the following symptoms is least likely to be associated with cauda equina syndrome?

          A.   Urinary incontinence

          B.   Saddle anesthesia

          C.   Quadriceps weakness

          D.   Biceps femoris weakness

  33.   You are called to see a 76-year-old female who had a L3–L4 lumbar epidural placed 3 days prior for postoperative analgesia for a colectomy. The epidural placement was traumatic on the first attempt (at L4–L5 level) with evidence of positive blood aspiration. The patient is now complaining of new onset back pain with radiation to the right lower extremity and right knee weakness that was confirmed by physical exam. The most likely diagnosis and optimal management is

          A.   Breakthrough pain in a patient who is confused, treat with additional pain medications

          B.   Stat MRI of the back to rule out neuraxial hematoma

          C.   Surgical complication, consult orthopedics

          D.   Symptomatic spinal stenosis, consult neurology for suggestions

CHAPTER 7 ANSWERS

    1.   C.   In spinal and epidural anesthesia, differential blockade is frequently reported to observe the “two segments rule,” namely, sympathetic block is two segments higher than sensory block, and sensory block is two segments higher than motor block. In this spinal block, alcohol swab tested the level of sensory/sympathetic blockade.

    2.   C.   A large local anesthetic bolus to a parturient with an anticipated epidural space reduced in size secondary to engorged epidural veins and enlarged uterus can cause a higher level of epidural blockade than anticipated. If the block level reaches higher than T4 and influences T1–T4 (cardiac accelerator fibers), patients may have bradycardia, hypotension, anxiety on physical exam and report symptoms such as nausea, vomiting, and headache, and even paresthesia in the upper extremities.

    3.   D.   Neuraxial block is a great alternative to general anesthesia for many surgical procedures below the diaphragm and an excellent choice for postoperative pain control. However, there are conditions where neuraxial block needs to be used with caution. Neuraxial blocks are associated with a sympathectomy and can therefore worsen existing hypotension and hypovolemia. Hypotension in combination with aortic and/or mitral valve stenosis may not be very well tolerated. Although spinal/epidural hematoma is rare yet possible, the risk of bleeding is significantly higher in patients with a known coagulopathy.

    4.   B.   To perform an epidural block, the needle passes through several layers, including skin, subcutaneous tissue, supraspinous ligament, intraspinous ligament, and ligament flavum. To perform a spinal anesthesia, the needle goes deeper to penetrate the dura and frequently the subarachnoid membrane.

    5.   C.   Neuraxial blocks in upper abdominal and thoracic procedures offer advantages of decreased pulmonary and cardiac complications in high-risk patient populations, promote peristalsis, and reduce conditions for a hypercoagulation state perioperatively. However, urinary retention is one of the potential major side effects associated with neuraxial blockade.

    6.   B.   The spinal cord typically ends around L1 in adults, and around L3 in children. This is the reason why neuraxial blocks are performed below these levels and carry a lower risk of direct spinal cord injury. The dural sac and subarachnoid spaces end at S2 in adults and S3 in children.

    7.   D.   Blood supply to the spinal cord is by one anterior spinal artery and two posterior spinal arteries. The anterior spinal artery supplies the anterior two-thirds of the spinal cord, and the posterior spinal arteries supply the posterior one-third. The anterior spinal artery is branched from the vertebral artery, and the posterior spinal artery arises from the posterior inferior cerebellar artery.

    8.   B.   Major site of action of neuraxial blockade takes place on the nerve roots. Local anesthetics act on nerve roots in the subarachnoid space in the case of a spinal blockade and on the nerve roots in the epidural space in the case of epidural anesthesia.

    9.   C.   A total of 3 mL of 1.5% lidocaine with 1:200,000 epinephrine is commonly used when testing for epidural anesthesia to rule out intrathecal (lidocaine can result in spinal blockade) and/or intravascular injection. Intravascular injection of epinephrine (15 μg) can result in a transient increase in heart rate of 20% or higher, within 30 seconds of injection and without evidence of a BP change.

  10.   D.   During epidural anesthesia, epinephrine in the dose of 5 μg/mL will improve the quality of an epidural anesthetic. Additionally, epinephrine can also prolong blockade duration, delays local anesthetic intravascular absorption, and decreases peak plasma local anesthetic concentration(s).

  11.   D.   It is currently believed that body weight alone does not influence the level of an epidural block (although extreme obesity may). Patient height (vertebral levels covered decrease with height) and age (vertebral levels covered increase with age) along with local anesthetic volume (about 1 to 2 mL local anesthetic medication per segment) and patient position (theory of gravity) can play significant roles.

  12.   D.   Addition of a base with acidic local anesthetic medications will increase the amount of uncharged local anesthetic molecules injected and can therefore increase diffusion of local anesthetic molecules through the lipid layer of the cell membrane. However, sodium bicarbonate is not used with bupivacaine as it can precipitate in solutions of a pH above 6.8.

  13.   D.   Major factors influencing the level of spinal anesthesia includes baricity of local anesthetic solution, patient position immediately following spinal block placement, drug dose used, site of injection, patient age and spine anatomy, pH of the CSF, drug volume used, needle orifice direction, patient height, and patients being pregnant.

  14.   D.   Major factors influencing the level of spinal anesthesia includes baricity of local anesthetic solution, patient position immediately following spinal block placement, drug dose used, site of injection, patient age and spine anatomy, pH of the CSF, drug volume used, needle orifice direction, patient height, and patients being pregnant.

  15.   D.   Complications from neuraxial blockade can be diverse and range from death, cardiac arrest, seizures, paraplegia, radiculopathy, anterior spinal artery syndrome, high/total spinal anesthesia, arachnoiditis, post–dural puncture headache, back pain, epidural hematoma, epidural abscess, and urinary retention. However, the complication rates are typically low and may even improve bowel function and decrease constipation.

  16.   C.   Potential complications of neuraxial blockade can be diverse and range from death, cardiac arrest, seizures, paraplegia, radiculopathy, anterior spinal artery syndrome, high/total spinal anesthesia, arachnoiditis, post–dural puncture headache, back pain, epidural hematoma, and epidural abscess. However, complication rates are low and patients do not typically experience delirium unless systemic opioid analgesics have been used.

  17.   C.   Although transient neurological symptoms are usually self-limiting, it can be bothersome to patients. The etiology is mostly likely due to the high concentration of lidocaine; therefore, 5% lidocaine is now avoided in spinal anesthesia when possible.

  18.   D.   According to the ASRA guidelines, waiting period for the commonly used antiplatelet agents are as follows: ticlopidine (Ticlid) 14 days, clopidogrel (Plavix) 7 days, abciximab (ReoPro) 48 hours, and eptifibatide (Integrilin) 8 hours.

  19.   B.   Subcutaneous heparin prophylaxis at once or twice daily is not a contraindication to neuraxial anesthesia placement or prior to epidural catheter removal. Systemic heparin administration can be considered safe if given 1 hour or longer following neuraxial blockade according to the ASRA guidelines.

  20.   D.   Factors associated with a decreased CSF volume include pregnancy, large abdominal tumor, ascites, and the elderly, and can be associated with an exaggerated spread of neuraxial local anesthetic (volume and amount of local anesthetic injected remain constant).

  21.   D.   Adjuvants added to neuraxial local anesthetics may improve quality and/or prolong the duration of spinal anesthesia. Some commonly used agents include the following: opioids such as morphine and fentanyl, α1 agonist such as epinephrine and α2 agonists such as clonidine/dexmedetomidine. Indirect-acting vasopressors added to local anesthetic mixtures have not been shown to be effective.

  22.   A.   According to ASA closed-claims database, LAST is more common than what is being formally reported. Performing a test dose with epinephrine and aspiration is not always 100% effective. Small and incremental dosing of epidural medications should always be considered as another safety measure to decrease the risk.

  23.   C.   In LAST management, steps taken toward advanced life support still need to be followed despite evidence that intralipid administration is the definitive treatment. Administration of epinephrine as well vasopressin in the treatment of LAST should be avoided as it has not been shown to be associated with improved patient outcomes.

  24.   B.   Initial vertebral level achieved with epidural anesthesia can be variable and is not as predictable as spinal anesthesia. The generally accepted rule is that 1 to 2 mL of an appropriately selected local anesthetic should be administered for each vertebral level of anesthesia desired in adults.

  25.   A.   Caudal anesthesia is a type of epidural anesthesia performed in the sacral region just as lumbar epidural anesthesia is performed in the lumbar region. Caudal anesthesia can also be used in adults, but may be more difficult to perform due to calcification of the sacrococcygeal ligament. Caudal anesthesia needle/catheter placement must penetrate the sacrococcygeal ligament in order to enter the caudal space. Within the sacral canal, the dural sac stops at the first sacral vertebra in adults and approximately around the third sacral vertebra in infants; therefore, the risk of spinal anesthesia is higher in younger children.

  26.   C.   Rapid injection of large volumes of local anesthetics either epidurally or intrathecally, especially in short and obese patients can predispose them to higher-than-anticipated levels of neuraxial anesthesia. In this particular situation, the cardiac accelerator fibers were affected, and therefore, the patient experienced bradycardia and hypotension.

  27.   C.   Although phrenic nerve palsy may contribute to patient’s experiences of shortness of breath and apnea, the most likely reason for dyspnea following a high neuraxial blockade is persistent hypotension-induced brain-stem hypoperfusion. Therefore, airway support is needed and aggressive control of hypotension is important in the management of high neuraxial blockade effects.

  28.   C.   Hypotension associated with a high spinal may be worsened as a result of effects on the cardiac accelerator fibers at the T1–T4 levels. Therefore, a vasopressor that can simultaneously increase both HR and BP would be the most ideal medication to administer. All of the above drugs, except phenylephrine, can be used to treat severe bradycardia in the management of a high neuraxial block associated with a decreasing heart rate.

  29.   B.   In patients who may experience a “wet tap” during placement of an epidural, conservative therapy should include bed rest and plenty of fluid intake, including caffeine; food diet low in fiber and stool softeners are encouraged to prevent straining.

  30.   C.   Initially, a post–dural puncture headache is typically treated conservatively. If there is insufficient or no evidence of symptomatic improvement after 24 to 48 hours, most clinicians may choose to perform an epidural blood patch (if no contraindications) with 15 to 20 mL of autologous blood.

  31.   D.   During neuraxial blockade, urinary retention is most often due to the local anesthetic effects on the S2–S4 nerve roots. Opioids can also adversely affect bladder function. Therefore, a lumbar epidural anesthetic has a higher risk of bladder reflex inhibition and urinary retention than a thoracic epidural.

  32.   C.   Cauda equina syndrome is usually secondary to neurotoxic effects from local anesthetics on the sacral nerve roots. All of above symptoms, with the exception of the quadriceps muscles, could be explained by the cauda equina syndrome (innervated by the sacral plexus). Quadriceps muscles are innervated by lumbar plexus and lumbar nerve roots and are rarely involved in the cauda equine syndrome.

  33.   B.   Epidural hematoma may present with back pain, focal neurological deficits, and bowel and bladder dysfunction. If a neuraxial hematoma is suspected, emergent intervention needs to be taken to confirm diagnosis and then to perform an emergency decompression as soon as possible to avoid permanent spinal cord/nerve roots injury.