Spinal, Epidural, and Caudal Anesthesia

Miller Anesthesia, Chapter 46

1. You are asked to provide anesthesia for an urgent cesarean section for a 20 year old gravida 1 para 0000 with a history of hemoglobin E beta Thalassemia. She is being sectioned for a breech presentation. She has a history of a DVT during this pregnancy and is on subcutaneous heparin (2000 units bid). She has had no symptoms of coagulopathy. She reports that since an MVA 1 year ago she has had severely diminished sensation and dysesthesia in her right foot, and a "foot drop". She frequently takes aspirin for her leg pain. She has symptoms and signs of moderate preeclampsia. Will you do a regional anesthetic for this section? Why/why not?

2. Assume the patient in # 1 is an otherwise healthy primip with a malpresentation in need of an urgent cesarean section. She has moderate preeclampsia with a platelet count of 234,000 and a normal bleeding time. You explain the potential risks and benefits of general and regional anesthesia and recommend that her operation take place under epidural anesthesia. She is very reluctant to "be awake during surgery." Will you attempt to persuade her to have a regional anesthetic? Insist that she comply with your recommendations or refuse to perform her anesthetic? Give her bicitra and proceed with a rapid sequence induction of general anesthesia as soon as she is prepped, draped and the surgeons are ready to make an incision?

3. The distal spinal cord in an infant terminates at ?

4. The distal spinal cord in an adult terminates at ?

5. In an infant, the distal termination of the subarachnoid space is at ?

6. In an adult, the distal termination of the subarachnoid space is at?

7. The dural sac extends from to .

8. The epidural space extends from to .

9. True or false: The ligamentum flavum extends from the foramen magnum to S2.

10. List the contents of the subarachnoid space.

11. The patient from #2 agrees to have an epidural for C-section. You place the catheter in the usual fashion. Aspiration of the catheter is negative for blood or CSF. You inject 10 cc of 2% lidocaine with 1:200,000 epinephrine. The patient rapidly becomes bradycardic, hypotensive, apneic and has bilateral mydriasis. Can you explain the likely etiology of this "total spinal".

12. List the contents of the epidural space.

13. Which of the following patients would be LEAST likely to develop a decrease in heart rate with high (C8) placement of spinal anesthesia?

• A 15 year old with history of Wolff-Parkinson-White syndrome
• A 73 year old with glaucoma treated with pilocarpine eye drops
• A 33 year old with T6 paraplegia
• A 45 year old diabetic with a history of orthostatic hypotension
• A 47 year old who had a myocardial infarction 1 month ago, now taking procainamide

14. You have placed a labor epidural for a 24 year old P1001 in early labor on pitocin. All went exceptionally well with placement of the epidural and you feel quite confident until she reports that she has a numb, weak, left leg with normal sensation and strength in the right leg. Further, she reports unaltered contraction pain which seems mostly right sided. Thermal sensory testing suggests that she has a unilateral (left sided) block. She indicates that she had similar problems with an epidural for her previous labor. What steps can you take to improve her analgesia? Is there an anatomic explanation for the one sided block which may make it impossible for you to provide adequate (symmetric) epidural analgesia.

15. True or false? The sympathectomy associated with spinal and epidural anesthesia extends two to six dermatomes above the sensory level.

16. As part of a combined anesthetic technique for repair of an abdominal aortic aneurysm, you place a high lumbar epidural and dose it to obtain a T5-6 sensory level. As part of the patient's pre-op "tune" he has had a PA catheter placed and you are interested to discover, as you shoot a set of outputs, that his cardiac output is unchanged, his peripheral resistance has fallen from 1380 to 1100, and his CVP is measurably reduced from its original level. Can you explain these changes?

17. You have placed a spinal block for TURP in a 74 year old patient with a history of smoking and chronic hypertension. His initial blood pressure is 170/90 with a heart rate of 86 and a respiratory rate of 15. You test the height of the block shortly after placement and note a T5 level. His vitals are BP=125/65, HR=100, RR=18. Will you treat his blood pressure at this time? Why/Why not? What treatment would you employ if you elected to support his blood pressure. If the patient mentioned that he felt like his left arm was weak and "clumsy" would you be concerned or would you simply reassure him that as long as he had a strong grip with each hand he would be able to breath well?

18. True or false? Mean arterial pressure is changed more gradually and to a lesser degree by epidural anesthesia than by spinal anesthesia.

19. There are 7 anatomical structures/planes traversed by a spinal needle during placement of a subarachnoid block. Name them in sequence from insertion of the needle to return of CSF.

20. Discuss the changes in tidal volume and vital capacity that occur with a T1 spinal.

21. After prehydration with 1500cc of crystalloid you perform a spinal anesthetic for C-section (failure to progress) on an otherwise healthy 21 year old P0000. All goes very well with placement of the block. You move the patient quickly from the left lateral decubitus position to supine, maintaining left uterine displacement. Her initial sensory level is tested to T5. Her blood pressure is only slightly decreased (< 10%) after placement of the block. She complains of significant nausea and asks for an emesis basin. The med student wonders aloud why your patient is nauseated when her blood pressure is so stable. What is your explanation, and how might you treat this problem?

23. A patient presents in ambulatory surgery for hemorrhoidectomy. His surgeon rarely takes more than 45 minutes to perform this procedure. The patient is interested in a regional anesthetic; a brief history and exam reveal no contraindications. Discuss your anesthetic plan, including preparation, positioning, choice of agent, and dose.

24. True or false? Epinephrine significantly prolongs the clinical effects of bupivacaine and increases the toxic dose level.

25. The following factors play a major role in determining the height of a spinal block (k-type question):

• Position of the patient
• Baricity of the agent
• Total anesthetic dose
• Patient height

26. You are asked to speak to a patient about a labor epidural. When you arrive at the patient's room you discover that she is an exceedingly pleasant 31 year old primipara who is overjoyed at the prospect of having a baby in the next 12 -24 hours as she and her husband of 10 years have finally reached this blessed moment after 2 years of infertility treatment. There are absolutely no contraindications to placement of the epidural. Indeed, you are looking forward to it as the patient is a 5'10" former distance runner who has gained exactly 30 lbs during her pregnancy, all of which appears to be baby, and her spinal landmarks look like a textbook photo. She acknowledges that she is having some discomfort with labor and, because she trusts you implicitly, suggests you go ahead, since she knows there won't be any complications. Her very involved and supportive husband nods his concurrence. You pinch yourself to be certain you are awake and in the right place. As you assemble your equipment, your patient's spouse asks casually, "What are the problems that might possibly occur on occasion when some doctors do this procedure?" How do you answer?

27. The incidence of postdural puncture headache is increased in which of the following situations (k-type):

• Pregnancy
• Young age
• Use of large-bore spinal needle
• Use of paramedian instead of midline approach

28. Which of the following would hasten the onset and increase the clinical duration of action of a local anesthetic, and provide the greatest depth of motor and sensory blockade when used for epidural anesthesia?

• Addition of 1:200,000 epinephrine
• Increasing the volume of local anesthetic
• Increasing the concentration of local anesthetic
• Increasing the dose
• Placing the patient in the head-down position

29. How much local anesthetic should be administered per spinal segment to patients between 20 and 40 years of age receiving epidural anesthesia?

• 0.3-0.5 ml
• 0.5-1.0 ml
• 1-1.5 ml
• 1.5-2 ml
• 2-2.5 ml

30. Which of the following local anesthetics would produce the lowest concentration in the fetus relative to maternal serum concentration during continuous lumbar epidural?

• Etidocaine
• Bupivacaine
• Lidocaine
• Chloroprocaine
• Mepivacaine

31. A 68 year old woman is to undergo foot surgery under spinal anesthesia. Which of the following statements concerning the immediate physiologic response to surgery is true?

• The cardiovascular response to stress will be blocked, but the adrenergic response will not
• The adrenergic response to stress will be blocked, but the cardiovascular response will not
• Both adrenergic and cardiovascular responses will be blocked
• The cardiovascular response will be blocked but the adrenergic response will be augmented

32. Transient respiratory arrest following unintentional high spinal anesthesia is caused by:

• Direct depression of medullary neurons by a high concentration of local anesthetic in the CSF
• Paralysis of the intercostal and abdominal muscles
• Phrenic nerve paralysis
• Hypoperfusion of the respiratory center of the brainstem secondary to hypotension
• None of the above

33. You are PAR dog (never fear, there is an end) and are asked to evaluate a patient for discharge. He is a 72 year old s/p TURP under spinal who is hemodynamically stable and quite comfortable. He is oriented and alert. His initial block level according to the anesthesia record was T4; you check and find it is currently T8. Is he ready for discharge?