Stoelting Study 12 Epidural

Front 1

2. Where is medicine deposited in spinal anesthesia? In epidural anesthesia? In caudal anesthesia?

Back 1

2. In spinal anesthesia, medicine is deposited in the subarachnoid space, most commonly at the lumbar level. In epidural anesthesia, medicine is deposited in the epidural space, most commonly at the lumbar level. In caudal anesthesia, medicine is also deposited in the epidural space but the needle used to inject the medicine approaches the epidural space via introduction through the sacral hiatus

Front 2

3. What are some advantages and disadvantages of spinal and epidural anesthesia?

Back 2

3. Some advantages of regional anesthesia include the provision of surgical anesthesia without affecting the state of consciousness of the patient, skeletal muscle relaxation, and the lack of the need to manipulate the airway or mechanically ventilate the lungs. Spinal anesthesia when compared with epidural anesthesia takes less time to perfonn and has a quicker onset, provides for intense sensory and motor anesthesia, and may be of less discomfort to the patient. Epidural anesthesia when compared with spinal anesthesia has a decreased risk of a postdural puncture headache, allows for more control over the level of anesthesia and the duration of the anesthetic if prolonged anesthetic times are desired, may lead to better control of associated hypotension due to its slower onset, and provides for an indwelling catheter that can be used for acute postoperative pain management.

Front 3

6. How effective are opioids introduced into the epidural or subarachnoid space? What is this technique often used for?

Back 3

6. Opioids introduced into the epidural or subarachnoid space have proven to be very effective in deepening the level of analgesia as well as for postoperative prun control.

Front 4

7. What is the number of each type of vertebrae in the vertebral column?

Back 4

7, The vertebral column consists of 7 cervical vertebrae, 12 thoracic vertebrae, · 5 lumbar vertebrae, as well as the 5 fused sacral and 4 fused coccygeal vertebrae.

Front 5

8. Describe the anatomic parts of a vertebra by answering the following questions: What are the two parts that make up a vertebra? From what parts of the vertebra does the transverse process arise? From what parts of the vertebra does the spinous process arise?

Back 5

8. A vertebra is made up of the vertebral body and the bony arch. The transverse process arises from the junction of the pedicle and laminae. The spinous process arises from the joining of the laminae.

Front 6

9. How is the spinous process oriented relative to the vertical axis of the upright patient in the lunbar region? In the thoracic region? What clinical implications does this have?

Back 6

9. The spinous processes in the lumbar region are oriented in a nearly horizontal pOSluon 10 the upright patient, whereas in the thoracic region the spinous processes are oriented in a position approaching vertical. Clinically, this implies what the orientation of the long axis of the needle must be to successfully transverse the illterspace at these levels to administer an epidural or spinal anesthet

Front 7

10. How are the laminae of adjacent vertebrae connected?

Back 7

10. The laminae of adjacent vertebrae are connected by the ligamentum flavum.

Front 8

· 11. How are the posterior spinous processes of adjacent vertebrae connected?

Back 8

11. The posterior spinous processes of adjacent vertebrae are connected by the interspinous ligaments.

Front 9

12. How are the tips of the spinous processes of adjacent vertebrae connected?

Back 9

12. The tips of the spinous processes of adjacent vertebrae are connected by the supraspinous ligaments.

Front 10

13. What passes through the intervertebral foramina?

Back 10

13. The spinal nerves pass through the intervertebral foramina and supply a specific dermatome.

Front 11

14. Where do the preganglionic nerves of the sympathetic nervous system originate from the spinal cord? What is their course of travel after leaving the spinal cord?

Back 11

14. Preganglionic nerves of the sympathetic nervous system originate from the spinal cord at the T1 to L2 levels. From there they travel with the spinal nerves before separating to form the sympathetic chain. (168, Fig. .

Front 12

15. Where does the sympathetic chain extend? What are some nerve plexuses and ganglions the sympathetic chain gives rise to?

Back 12

115. The sympathetic chain sits on the anterolateral aspects of the vertebral bodies along the entire length of the spinal column. The sympathetic chain gives rise to the stellate ganglion, the splanchnic nerves, and the celiac plexus.

Front 13

16. What are the contents of the spinal canal?

Back 13

16. Contents of the spinal canal induce the spinal cord, pia, arachnoid, dura mater, and cerebrospinal fluid. (1·

Front 14

17. What are the cepbalad and caudad limits of the spinal cord?

Back 14

17. The cephalad limit of the spinal cord is the foramen magnum, whereas its caudal limit is at the Ll-L2 level. (

Front 15

18. What is the cauda equina7 Where does it extend?

Back 15

18. The cauda equina is the collection of lumbar and sacral nerves that extend from the end of the spinal cord as a collection of nerves in the spinal canal · before exiting via the intervertebral foramina at their respective vertebral column levels.

Front 16

19. Where is cerebrospinal fluid? What is another term for this space?

Back 16

19. Cerebrospinal fluid is found in the spinal space between the pia and arachnoid, or subarachnoid. Another term for this space is the subarachnoid space.

Front 17

20. Where is the epidural space? What is it bound by?

Back 17

20. The epidural space is found between the connective tissue covering the vertebrae and the ligamentum ftavum posteriorly and the dura mater anteriorly. Laterally it is bound by the pedicles and the intervertebral foramina. The epidural space extends from the foramen magnum, where the dura is fused to the base of the skull, to the sacral hiatus.

Front 18

21. What is the plica mediana dorsalis? What is its clinical significance?

Back 18

21. The plica mediana dorsalis is a comective tissue band that may extend from the dura mater to the ligamentum flavum. The plica mediana dorsalis may divide the posterior epidural space into two compartments, a right and left compartrr.ent. Clinically, this is significant because it may affect the manner in which medicine deposited into the epidural space is distributed.

Front 19

22. What four things are contained in the epidural space?

Back 19

22. The epidural space, a potential space, contains connective tissue, venous plexuses, and adipose tissue. (

Front 20

23. How does a preoperative evaluation for a regional anesthetic differ from that for a general anesthetic?

Back 20

23. A preoperative evaluation of a patient scheduled to undergo a surgical procedure with a regional anesthetic is no different than the evaluation of the same patient were he or she to undergo the procedure under general anesthesia. Special consideration should be given to possible systemic infections; infections overlying the skin where the introduction of a needle may be necessary to perfonn the regional anesthetic; and any history of coagulopatby, bleeding dyscrasias, or medicines that may alter normal clotting. Any abnormalities of these special considerations may preclude proceeding with a regional anesthetic technique.

Front 21

26. How should the coagulation status of a patient be determined

Back 21

26. The coagulation status of a patient should be determined by either history or laboratory test before a:lministering a regional anesthetic. The administration of a regional anesthetic in the face of clotting abnormalities puts the patient at an increased risk of an epidural hematoma and subsequent serious neurologic symptoms that may be permanent. before administering regional anesthesia? What is the risk of administering regional anesthesia to a patient who is anticoagulated?

Front 22

27. When should a regional anesthetic be administered to a patient who is anticoagulated?

Back 22

27. A regional anesthetic should only be administered to an anticoagulated patient if the risk of the alternative outweighs the risk of the regional anesthetic technique. (1"

Front 23

28. What is the recommendation with regard to regional anesthesia for patients who are to receive heparin or enoxaparin after surgery?

Back 23

28. For patients who are to receive heparin or enoxaparin after surgery the administration of a regional anesthetic is a controversial issue. If the decision is made to proceed, and a blood vessel is disrupted during the course of placement of the regional technique, it may be prudent to delay the start of surgery for approximately 24 hours. This may allow for healing of the blood vessel to occur. Another alternative is to proceed with surgery but in the case of enoxaparin to delay its administration until 24 hours postoperatively.

Front 24

29. What are the risks of administering regional anesthesia to a patient who is septic?

Back 24

29. the administration of regional aresthesia to a septic patient is controversial because of the risk of introduction of infected blood into the epidural or subarachnoid space by the needle during the technique. The infected blood may lead to an epidural abscess or meningitis in these patients. If regional anesthesia is to be performed in these patients, appropriate antibiotic therapy must be instituted before the administration of the regional anesthetic. (170;

Front 25

30. What is the risk of administering regional anesthesia to a patient who is hypovolemic?

Back 25

30. The administration of regional anesthesia to a hypovolemic patient is of oncem because of the probable inability of the patient to tolerate the peripheral sympatheTIc nervous system blockade that accompanies the technique. This could result in hypotension that is difficult to reverse. (1'

Front 26

31. What are the goals of preoperative medication for a patient who is to undergo a regional anesthetic?

Back 26

31. Preoperative medication for the patient who is to undergo a regional anesthetic technique should make the patient comfortable and help to decrease his or her level of anxiety as necessary. This may include an opioid or a benzodiazepine as needed. Reassurance by the anesthesiologist that the patient will be kept comfortable is also a useful preoperative anxiolytic.

Front 27

32. Why should an intravenous catheter be placed prior to the administration of a regjonal anesthetic?

Back 27

32. An intravenous catheter should be placed before the administration of any regional anesthetic technique. There are at least two reasons for this. First, hydration of the patient before the administration of the regional anesthetic helps to attenuate the hypotension that often results from the peripheral sympathetic nervous system blockade that accompanies regional anesthesia. Second, intnvenous access must be obtained in the event that the emergent administration of medicines becomes necessary during the course of, or directly after, the administration of regional anesthesia

Front 28

33. How do the equipment, monitors, and drugs that the anesthesiologist has present for administering a general anesthetic differ from those present for administering · a regional anesthetic? .

Back 28

33. The eqllipment, monitors, and drugs that the anesthesiologist has present for a regional anesthetic are not different from those present during a general anesthetic. These must be present in case of the emergent need to administer a general anesthetic, as in the case of a total spinal anesthetic

Front 29

34. What are some anatomic landmarks the anesthesiologist uses to administer a spinal anesthetic?

Back 29

34. Spinal anesthetics are most commonly administered at the lumbar level. Anatomic landmarks that the anesthesiologist uses to administer a spinal anesthetic include the spinous processes and the iliac crests.

Front 30

35. What vertebral level is crossed by a line drawn across the patient's back at the level of the top of the iliac crests? What interspace is represented directly above this line? What interspace is represented directly below this line?

Back 30

35. A line drawn across the patient's back at the level of the top of the iliac crests usually crosses the vertebral column at the L4 vertebral level. The interspace palpated directly above this line is the L3-L4 interspace, and the interspace palpated directly below this line is the L4-L5 interspace.

Front 31

36. What is the anatomic value of placing a spinal anesthetic at a level below L2

Back 31

36. The anatomic value of placing a spinal anesthetic at a level below L2 is that the spinal cord ends at L2. Thus. risk of trauma to the spinal cord by the spinal needle decreases by placing the spinal anesthetic below this level.

Front 32

37. What are the two most common positions the patient is placed in for the administration of a spinal anesthetic? What are the circumstances in which each may be preferred?

Back 32

37. The two most common positions that the patient is placed in for the adrninistration of a spinal anesthetic are the seated upright and the lateral decubitus positions. The lateral decubitus position may be preferred in ill or sedated patients. The seated upright position may be preferred in patients in whom the midline is difficult to identify, there is difficulty in accessing the vertebral interspaces, or when a low level of spinal anesthesia is desired. Whichever of these two positions the patient is in, the patient is asked to round out his or her back as much as possible to facilitate access to the subarachnoid space through the vertebral interspaces.

Front 33

38. What equipment and drugs are typically prepackaged in a kit used for spinal anesthesia?

Back 33

38. Prepackaged spinal anesthesia kits typically contain a local anesthetic such as bupivacaine or tetracaine, lidocaine and a 25-gauge needle for local infiltration, a spinal needle, epinephrine, two syringes, and drapes.

Front 34

39. What preparations should be made to minimize infection when administering a spinal anesthetic?

Back 34

39. Sterility should be maintained with each spinal anesthetic. The technique should involve preparing the skin overlying the selected area with an antiseptic solution such as povidone-iodine (Betadine); the back should be sterilely draped, and sterile gloves should be worn. (172)

Front 35

40. How is the skin anesthetized before the introduction of the spinal needle?

Back 35

40. The skin should be anesthetized with local anesthetic before the introduction of the spinal needle. The local anesthetic should be administered with small-gauge needle (e.g., a 25-gauge needle), and the skin wheal created should directly overlie the interspace in which the anesthesiologist wishes to advance the spinal needle.

Front 36

41. How is the subarachnoid space located by the anesthesiologist?

Back 36

41. The subarachnoid space is located by advancing the spinal needle through the skin between two spinous processes. The spinal needle continues to be advanced traversmg the supraspinous and interspmous ligaments between two vertebrae. The advancement of the spinal needle continues through the ligamentum fiavum, where increased resistance is felt. Finally, the dura mater is traversed and the subarachnoid space is accessed. I

Front 37

42. What accounts for the "pop" the anesthesiologist may feel when advancing a spinal needle into the subarachnoid space?

Back 37

42. The anesthesiologist may feel a characteristic "pop" just before accessing the subarachnoid space as the spinal needle is being advanced. This "pop" is the spinal needle passing through the dura mater. (172; 1

Front 38

43. How is subarachnoid placement of the spinal needle confirmed?

Back 38

43. Subarachnoid placement of the spinal needle is confi:med by the appearance of cerebrospinal fluid in the hub of the spinal needle. The most common reason for the lack of cerebrospinal fluid, and erroneous placement of the needle, is off·midline placement of the needle.

Front 39

44. How should the spinal needle be handled by the anesthesiologist to stabilize the needle after proper placement into the subarachnoid space is confirmed?

Back 39

44. The spinal needle should be stabilized by the anesthesiologist after proper placement into the subarachnoid space is confirmed. This can be done by holding the hub of the spinal needle between the anesthesiologist's thumb and forefinger and resting the dorsum of the same hand on the patient's back. When the spinal needle is held in this manner, it should remain stabilized even with patient movement

Front 40

45. After the syringe containing the local anesthetic solution for administration into the subarachnoid space is attached to the spinal needle, how can continued subarachnoid placement of the spinal needle be confirmed?

Back 40

45, After the syringe containing the local anesthetic solution for administration into the subarachnoid space is attached to the spinal needle, the anesthesiologist typically aspirates back on the syringe to confirm continued subarachnoid placement of the spinal needle tip. Confirmation is made by the characteristic swirl in the syringe as cerebrospinal fluid enters the syringe and mixes with the local anesthetic solution. The local anesthetic solution can then be deposited into the subarachnoid space over a period of 3 to 5 seconds. After completion of the deposition of the local anesthetic solution into the subarachnoid space, the spin.al needle and syringe should be removed together as a single unit

Front 41

46. When blood-tinged cerebrospinal fluid initially flows from the spinal needle, should the anesthesiologist proceed?

Back 41

46. If blood-tinged cerebrospinal fluid appears in the hub of the spinal needle, the anesthesiologist should wait until the fluid clears. If blood-tinged cerebrospinal fluid continues to flow from the spinal needle, the spinal needle should be removed and reinserted at a different interspace. If blood-tinged cerebrospinal fluid is encountered in the second interspace accessed, the attempt at administration of a spinal anesthetic should be discontinued and the patient further evaluated. On the other hand, when blood-tinged fluid initially appears in the hub of the spinal needle but subsequently clears and is free flowing, the local anesthetic solution can be deposited safely into the subarachnoid space.

Front 42

47, What are some spinal needle types and sizes? What are their potential advantages and disadvantages?

Back 42

47. There are a variety of spinal needle types and sizes that are used for spinal anesthesia. Among the needle sizes used are 22-, 24-, 25-, and 27 -gauge needles. The advantage of using a smaller-gauge needle is that it may decrease the risk of a postdural puncture headache. There are two main types of spinal needles, those that cut the dura and the newer type that are designed to spread the dural fibers. The cutting needles include the Quincke-Babcock and Pitkin needles. The newer needles, also called pencil-point needles, include the Greene, Sprotte, and Whitacre needles. These newer needles are thought to decrease the risk of a postdural puncture headache by causing less disruption of the dura

Front 43

48. What are some disadvantages to using a smaller-gauge spinal needle?

Back 43

48. Although spinal needles that are 25-gauge or smaller may decrease the risk of a postdural puncture headache, there are some disadvantages associated with their use. First, they are too flexible for easy advancement through the I ligaments to access the subarachnoid space. For this reason a larger-gauge introducer needle well embedded in the interspinous ligament facilitates the advancement of the smaller-gauge spinal needle to the subarachnoid space. They also provide the anesthesiologist with poor tactile feedback as the tissue planes are penetrated. Finally, the successful entry of the subarachnoid space may not be immediately known secondary to the slow return of cerebrospinal fluid to the hub of the spinal needle. Aspiration of the needle with an attached S}'nnge hastens the return of cerebrospinal fluid through the spinal needle and provides confinnation of appropriate placement of the spinal needle.

Front 44

49. Describe the paramedian approach to a spinal anesthetic. When is this approach advantageous?

Back 44

spinal needle through the skin I em lateral to the midline and directecl meclilll and cephalad. The needle meets resistance at the ligarnentnm fbm..... nnrl .1.0 · and cephalad. The needle meets resistance at the ligamentum flavum, and the remainder of the technique is similar to that of the median approach. The I paramedian approach to a spinal anesthetic is less reliant on the patient flexing his or her back. This approach may be useful in patients who are unable to flex their backs, such as parturients. It may also be useful in patients in whom ligaments may be calcified, such as the elderly.