Chapter 37 Perioperative Pain Management
1. What factors correlate with the severity of postoperative pain?
2. What are some potential adverse physiologic effects of acute postoperative pain?
3. What are some potential benefits of the effective management of acute postoperative pain?
4. What are the principles of multimodal perioperative analgesia?
Neurophysiology of pain
7. What are nociceptors? How are they stimulated?
8. What is the neurologic pathway of afferent pain impulses?
9. Where along the neurologic pathway of afferent pain impulses can modulation of the painful stimulus occur?
10. How can the modulation of painful stimuli occur in the periphery? What pharmacologic agents may be particularly useful for the modulation of painful stimuli in the periphery?
11. How can the modulation of painful stimuli occur at the level of the spinal cord?
12. How can the modulation of painful stimuli occur above the level of the spinal cord?
13. Name some excitatory and inhibitory neurotransmitters believed to have a role in the modulation of painful stimuli.
14. What is the difference between preemptive analgesia and preventative analgesia?
Analgesia delivery systems
15. Name some routes for the administration of analgesic drugs.
16. What is the limitation of the oral administration of analgesic agents for the management of acute postoperative pain? When is this route of administration appropriate?
17. What benefit does the intramuscular administration of analgesic agents have over oral administration? What are some problems with this method of administration?
18. Does ketamine have a role in the perioperative period? What are the side effects of low dose ketamine therapy?
19. How is a patient taking oral buprenorphine managed preoperatively, intraoperatively, and postoperatively?
20. What are the advantages and disadvantages of the subcutaneous, transdermal, and transmucosal administration of opioids?
21. Describe patient-controlled analgesia (PCA). What is the lockout interval?
22. What are some of the advantages of patient-controlled analgesia?
23. How do neuraxially administered opioids exert their effect?
24. What are some of the potential benefits of neuraxial opioids for postoperative analgesia?
25. What are some of the potential adverse effects of neuraxial opioids for postoperative analgesia? What different potential adverse effects may be caused by neuraxial infusion of local anesthetics?
26. What is the early depression of ventilation that may be seen with the neuraxial administration of an opioid believed to be due to?
27. What is the delayed depression of ventilation that may be seen with the neuraxial administration of an opioid believed to be due to? Why might this effect be more pronounced with morphine than with fentanyl?
28. Which patients may be most at risk for delayed depression of ventilation from the administration of a neuraxial opioid?
29. What characteristic of an opioid administered into the intrathecal space determines its time of onset and its duration of action?
30. What are the disadvantages of a single-dose administration of opioid in the intrathecal space for the management of acute postoperative pain?
31. What may be the reason for the clinical impression that the incidence of side effects associated with intrathecally administered opioid is higher than the incidence of side effects associated with the epidural administration of opioid for postoperative analgesia?
32. Why does the epidural administration of opioid require more drug than the intrathecal administration of the same opioid? What dose of epidural opioid is equipotent to the same opioid administered in the intrathecal space?
33. Why is it believed that fentanyl produces a more segmental band of anesthesia than morphine when administered in the epidural space?
34. How do the resulting plasma concentrations of fentanyl compare when the same dose of fentanyl is administered intravenously versus epidurally?
35. Why might a local anesthetic be added to the opioid for administration in the epidural space for the management of postoperative pain?
36. What is the concern regarding the concurrent use of neuraxial analgesia and anticoagulants? What are some general concepts regarding this issue covered in the American Society of Regional Anesthesia guidelines?
37. What factors increase the risk of postoperative epidural abscess associated with epidural analgesia?
Alternative approaches to management of Acute postoperative pain
38. What is an advantage and a disadvantage of peripheral nerve blocks for the management of acute postoperative pain?
39. What are the advantages and disadvantages of the intraarticular administration of analgesics?
40. Are there any unique benefits of the paravertebral blockade technique?
41. What are the advantages of perioperative continuous perineural catheters in both upper and lower extremity surgeries?
42. What is the role of clonidine as an adjuvant in peripheral nerve blockade?
43. How is intrapleural regional analgesia achieved? What is an advantage and a disadvantage of this technique for the management of acute postoperative pain?
44. What are the indications for a transverse abdominis plane block? What advantages does this peripheral block offer?
Answers*
1. Factors that positively correlate with severity of postoperative pain include preoperative opioid intake, anxiety, depression, pain level, and the duration of surgery. Factors that are negatively correlated include the patient’s age and the level of the surgeon’s operative experience. A perioperative plan should be developed that encompasses these factors to lessen the severity of the patient’s postoperative pain. (650)
2. Potential adverse physiologic effects of acute postoperative pain include hypoventilation, atelectasis, ventilation-to-perfusion mismatching in the lungs, hypercapnia, pneumonia, systemic hypertension, tachycardia, cardiac dysrhythmias, myocardial ischemia, deep vein thrombosis, decreased immune function, ileus, nausea and vomiting, urinary retention, hyperglycemia, sodium and water retention, insomnia, fear, and anxiety. Poorly controlled postoperative pain may also be a factor in developing chronic postsurgical pain. (650-651, Table 40-1)
3. Some potential benefits of the effective management of acute postoperative pain include improvement in patient comfort, a decrease in perioperative morbidity, enhanced postoperative rehabilitation, and a possible decrease in chronic postsurgical pain. It may also reduce cost by shortening the time spent in postanesthesia care units, intensive care units, and hospitals. (650)
4. The goals of multimodal analgesia include sufficient diminution of the patient’s pain to instill a sense of control over their pain, enable early mobilization, allow early enteral nutrition, and attenuate the perioperative stress response. The secondary goal of this approach is to maximize the benefit (analgesia) while minimizing the risk (side effects of the medication being used). (653-654)
5. The goals of an acute pain management service are to evaluate and treat postoperative pain to minimize the period of recuperation, decrease duration of hospital stay, improve patient satisfaction, and to inhibit the development of chronic (persistent) pain through early intervention. (653-654)
Neurophysiology of pain
6. Nociception is used to describe the recognition and transmission of painful stimuli. Pain is described as an unpleasant sensory and emotional experience caused by actual or potential tissue damage. (652)
7. Nociceptors are the free nerve endings of afferent myelinated A-delta and unmyelinated C nerve fibers. Nociceptors are stimulated by thermal, mechanical, or chemical tissue damage. (652)
