Pain

Question 1

What is pain?

Answer 1

An unpleasant sensory and emotional experience associated with actual or potential tissue damage

Question 2

What are the general problems with pain

Answer 2

1. It’s often under-treated
2. Uncontrolled pain produces detrimental SE that we don’t want
3. The treatment of pain carry risks and/or side effects
4. Many patients and providers have misconceptions about the treatment of pain
   
   • _{fear of addiction}
   • _{fear of side effects (ex: constipation)}
5. Pain increases the patient’s stay in PACU, ICU, and the hospital in general

Question 3

What is acute pain?

Answer 3

• Pain caused by a noxious stimulus d/t injury, trauma, acute disease process, or abnormal function of muscle or viscera
• almost always nociceptive pain
• results in neuroendocrine response
  
  • _{​stress response with HPA and SNS activation}

Question 4

Endocrine and CV response to pain

Answer 4

Endocrine

1. Increased catecholamines
2. Increased cortisol
3. Increased aldosterone and ADH, renin, and angiotensin II
4. Immune system suppression

CV

1. Increased HR, BP, SVR, CO, contractility
2. Enhanced myocardial irritability
3. Vasoconstriction, including coronary artery constriction
4. Increased myocardial O2 consumption with decreased myocardial O2 supply (think ischemia)
5. Increased plasma viscosity
6. Increased water retention
7. Vasoconstriction and fluid retention increase the workload of the heart

Question 5

Pulmonary Effects of Pain

Answer 5

Decreased lung volumes (VC, TV,FRC) Phrenic nerve dysfunction Inadequate cough (don’t want to agitate the pain) Inadequate ventilation (will decrease TV, VC, and FRC –> FRC may approach closing volume and cause atelectasis and VQ mismatch) May have limited movement of respiratory muscles due to spasm of muscles Decreased ability to clear airway secretions Susceptible to pneumonias Increased total body O2 consumption which increases respiratory workload Increased CO2 production

Question 6

Heme Effects of Pain

Answer 6

1) Hypercoagulability - Natural anticoagulants decrease and natural procoagulants increase. - Inhibition of fibrinolysis - Increased platelet reactivity/ adhesiveness - Increased plasma viscosity - Increased risk of DVTs and vascular grafting failure, poor wound healing, MI risk 2) Immunosuppression - Potentiates postoperative immunosuppression (poor wound healing) - Depressed lymphocyte response - Decreased cell mediated immunity - Alterations in balance of T-helper cells - Increased interleukins and cytokines

Question 7

GI/GU Effects of Pain

Answer 7

GI - Hypersecretion of gastric acid - Slowed GI motility (risk of aspiration and paralytic ileus) GU: - Urinary retention

Question 8

Neurendocrine Response to Pain

Answer 8

Basically reacting as if the body is in stress: Increased catecholamines Increased catabolic hormones Decreased anabolic hormones Increased ADH, Aldosterone, renin, and angiotensin II Increased cortisol Increased glucagon Decreased insulin Sodium and water retention Increase blood glucose Free fatty acids Ketone bodies Lactate

Question 9

What is chronic pain?

Answer 9

• Pain that serves no purpose
• Pain that persists beyond the usual coarse of an acute disease after a reasonable amount of time for healing to occur
• Poorly controlled acute pain can transition to chronic pain
  
  • Intensity of acute pain is significant predictor of chronic pain

Question 10

Chronic Pain may occur after these procedures

Answer 10

1. Limb amputations (30-83%)
2. Thoracotomy (22-67%)
3. Sternotomy (28%)
4. Breast surgery
5. Gallbladder surgery

Question 11

Chronic pain is associated with an imbalance in _____

Answer 11

Neuromodulation controls

• Attenuated neuroendocrine response (unlike acute pain) →
• Exhausted supplies of endorphins and serotonin →
• Predominance of C-fiber stimulation

Question 12

Chronic pain is associated with ____ in the periphery

Answer 12

chronic inflammation

1. Continuous release of inflammatory mediators in the periphery sensitizes functional nociceptors and activates dormant nociceptors
   
   • There is sensitization of nociceptors and hyper excitability
2. Functional changes occur in the dorsal horn of the spinal cord (neuroplasicity)
3. Dormant nociceptors are activated
4. Recruitment of additional nerve fibers and pathway tracts
5. Pain is perceived as more painful
6. Reflexes can create excessive muscle tension, with actual disruption of microcirculation

Question 13

Cancer pain

Answer 13

Pain caused by:

1. tumor invasion of the bone
2. tumor compression of peripheral nerves
3. Treatments of cancer (chemo and radiation)
   
   • mostly d/t tissue destruction

Question 14

Physical and psych components of cancer pain

Answer 14

Physical

• worse due to loss of sleep, appetite, nausea & vomiting

Psychological

• heightened anxiety
• feelings of loss
• low self-esteem
• changes in life goals
• disfigurement

Question 15

What is allodynia?

Answer 15

Pain in response to a stimulus that shouldn’t normally cause pain

Question 16

Pain Preop Evaluation

Answer 16

1. Evaluate pain
   
   • Pain history
   • Physical exam
   • Self report measurement scales
   • Medications for pain
   • Document
2. Preparation
   
   • Adjustments and/or continuation of meds
3. Develop plan

Question 17

Benefits of adequate post-op pain control

Answer 17

1. Reduction of the stress response
2. Shorter times to extubation
3. shorter ICU stay
4. early discharge
5. Improved respiratory function
6. Earlier return of bowel function
7. Earlier enteral nutritional intake
8. Early mobilization
9. decreased risk DVTs
10. Reduction in:
    
    • sensitization
    • neuroplasticity
    • wind-up phenomenon and
    • transition to chronic pain
11. Increased patient satisfaction

Question 18

When does post-op pain control begin?

Answer 18

Pre-operatively!!

Goal is to prevent pain before it happens.

Question 19

Who requires that we do a pain assessment of our patients?

Answer 19

JCHO

Question 20

Respiratory and routes of opioid administration

Answer 20

Incidence of respiratory depression does not vary across routes. You get depression despite whatever route you choose.

Question 21

Preferred routes of opioid administration

Answer 21

IV

Then sublingual or rectal (avoid first pass effect)

Question 22

Opioids exert their effects via these receptors

Answer 22

Mu and Kappa

Question 23

Is there an analgesic ceiling with opioids?

Answer 23

No

The dose is only usually limited by tolerance or SE.

Question 24

Most common drugs for PCA use

Answer 24

Morphine and hydromorphone

Question 25

NSAIDs work by inhibiting \_\_\_\_

Answer 25

COX

Question 26

By using NSAIDs with opioids, the pain response is attenuated in both these locations

Answer 26

The spinal cord (opioids) and in the periphery (NSAIDs)

Question 27

Using NSAIDs can decrease opioid requirement by \_\_\_%

Answer 27

50%

Question 28

SE of NSAIDs

Answer 28

1. Decreased hemostasis * Platelet dysfunction * Inhibition of thyromboxane A2 2. Renal dysfunction 3. GI hemorrhage 4. Liver dysfunction 5. Effects on bone healing/ osteogenesis

Question 29

Ketamine as an adjuvant drug

Answer 29

Small doses to act as adjunct to LAs and opioids. Enhances the analgesic effect and reduces SE.

Question 30

These drugs may be used as adjuvants

Answer 30

1. Ketamine 2. Tramadol (Ultram) 3. Nalbuphine (Nubain) 4. Methadone 5. Acetaminophen

Question 31

Tramadol as an adjuvant

Answer 31

* Weak PO opioid that induces serotonin release and inhibits NE re-uptake * Contraindicated in those on MAOIs and those with seizures

Question 32

Nalbuphine as an adjuvant

Answer 32

Agonist-antagonist (fewer SE) Really only used in OB.

Question 33

Methadone as an adjuvant

Answer 33

Very long 1/2 life (15-29 hours) Can be given IV for nice post-op pain control (20mg IV)

Question 34

What provides better analgesia: Regional blocks or systemic opioids?

Answer 34

Regional blocks

Question 35

Benefits of neuraxial analgesia

Answer 35

1. Better analgesia than systemic opioids 2. Reduced stress response 3. Facilitates return of GI motility 4. Fewer pulmonary complications (less chance of resp depression) 5. Less incidence of coagulation-related adverse effects * less complications d/t bleeding (ex- from NSAIDs)

Question 36

Hydrophilic Opioids used in Neuraxial Blocks

Answer 36

Morphine and Dilaudid 1. Tend to stay in the CSF 2. Extensive CNS spread 3. Delayed onset of action (unable to penetrate the neuron) 4. Longer DOA (not taken up by fat quickly) 5. High incidence of SE (d/t cephalad spread of the opioid)

Question 37

Lipophilic Opioids used in Neuraxial Blocks

Answer 37

Fentanyl and Sufentanil 1. Rapid onset 2. short DOA (systemic uptake) 3. Minimal spread * d/t segmental analgesic effect) 4. fewer SE

Question 38

These opioids may be given in neuraxial blocks

Answer 38

1. Fentanyl 2. Sufentanil 3. Morphine 4. Hydromorphone 5. Meperidine (Demerol)

Question 39

Can epidurals be connected to a PCA?

Answer 39

Yes Benefits : 1. Allows for individualization 2. Lower drug use 3. Increased patient satisfaction 4. Side effects similar to continuous epidural infusions 5. Background infusion with demand dose common

Question 40

What needs to be considered in continuous epidural analgesia?

Answer 40

1. Choice and dose of the agent used 2. Location of catheter placement 3. Onset and duration of periop use 4. SE and risks 5. Will pain management personnel be around to manage the catheter if issues arise?

Question 41

Options for what agents to place in an epidural

Answer 41

1. LA only * _{High failure rate} * _{High chance of motor blockade} * _{Hypotension is common} 2. Opioid only 1. _{Avoids motos block} 2. _{Less hypotension} 3. _{Has other SE ex: respiratory depression and pruritis} 3. LA + Opioid 1. _{Better choice} 2. _{Limits regression of sensory block} 3. _{Decreases the total dose of LA needed (avoids toxicity)} 4. _{Able to give low concentration of LA and low dose of opioid} 5. _{Work synergistically by working on two separate MOAs} 6. _{Less motor block} * _{allows for earlier ambulation} 7. _{Good choice for thoracic, abdominal, pelvic, and orthopedic lower extremity procedures}

Question 42

Adjuvant neuraxial drugs

Answer 42

1. Clonidine * A2 agonist * Prolongs duration of block * SE: Hypotension, bradycardia, sedation * these limit the use of clonidine 2. Epi and phenylephrine * Prolongs duration of block * Increases intensity of block

Question 43

Where to place an epidural catheter what are the advantages?

Answer 43

Location **congruent to the incisional dermatome** _{it results in optimal postoperative analgesia by infusing analgesic agents to the appropriate incisional dermatomes} Advantages 1. provides superior analgesia 2. utilizes less drug 3. minimizes side effects 4. decreases morbidity

Question 44

Recommended epidural catheter levels for various surgeries

Answer 44

* Thoracic sx = T4-8 * Upper Abdominal or cholecystectomy = T6-8 * Nephrectomy = T7-10 * Lower abdominal = T8-11 * Lower Extremities = L1-4

Question 45

SE of neuraxial blockade

Answer 45

Medication related + sympathectomy and possible motor blockade * Resp depression * N/V * Pruritis * Urinary retention * Hypotension * Motor blockade

Question 46

Risks of epidural block

Answer 46

1. Complications with the placement * Epidural hematoma * Abcess * Neurologic/Cord injury 2. Misplacement of injection * IV, subarachnoid, or subcutaneous injection 3. Complications r/t anticoagulatnts: * pt may need to be started on them post-op (r/t surgery type) or given intra-op

Question 47

Non-pharmacologic adjuncts to pain management

Answer 47

1. Ice 2. Extremity elevation 3. TENS (transcutaneous nerve stimulator) 4. Acupuncture 5. Phych approaches * hypnosis * imagery * distraction * music 6. Surgical * local infiltration * intra-articular analgesia * pain pumps (ex: onQ)

Question 48

Considerations for ambulatory patients

Answer 48

1. Severe post-op pain will prolong hospital stay 2. Common to have pain after discharge 3. N/V common * may interfere with ability to take PO analgesics 4. Best to do a multimodal approach to pain management (opioid, non-opioid, LA, ice, etc)

Question 49

Considerations for elderly patients

Answer 49

1. Old people have lots of changes: in their 1. physiology * _{less N/V than other populations} * _{more co-morbidities} * _{may have dementia or communication issues that serve as barriers to pain management} * _{decreased physiologic reserves} 2. pharmacodynamics 3. kinetics 4. processing of pain information * _{increased pain threshold} * _{decreased pain tolerance} * _{decreased pain perception} 2. Titrate drugs slowly 3. Regional may be a better option * preserves cognitive function * earlier ambulation * return of GI function, etc.

Question 50

Considerations for opioid-tolerant patients (not addicted, just tolerant)

Answer 50

1. Higher doses to relieve pain 2. They are often worried about risk of addiction or medication-related SE 3. Goals 1. _{Provide their baseline opioid requirement (maybe some SR meds)} 2. _{Anticipate that they will need higher doses than normal post-op} 3. _{Maximize the use of adjunct drugs and techniques (consider regional anesthesia)}

Question 51

Considerations for pediatric patients

Answer 51

* Myth - Kids don't experience pain the same as an adult or won't remember it. Because of this myth, there are issues with **pain being undertreated.** * Assessing the level of a child's pain can be difficult. * RA and PCAs are encouraged. * Avoid IM (duh, why would you do this?) * Preferred routes are IV, PO, and rectal.

Question 52

Considerations for obesity and OSA patients

Answer 52

* High risk for pulmonary complications and respiratory arrest * Goals * Avoid resp depressants * Consider epidurals w/o opioids * NSAIDs * Will probably need CPAP post-op

Question 53

TCAs for chronic pain

Answer 53

* Elevates mood and helps with sleep * Use smaller doses than used for depression * Blocks the reuptake of serotonin and NE * Potentiates opioids * Use smaller doses than indicated for depression * NEED to monitor drug levels * Has anticholinergic SE * _{dry mouth} * _sedation * _fatigue * _hypotension * _arrhythmias

Question 54

Anticonvulsants for chronic pain

Answer 54

* Alters ion channels along the nerve fiber, blocking pain transmission * Treats neuropathic pain from lesions of the peripheral NS (herpes, DM, etc) or CNS (stroke) * Drugs used: * _{Carbamazepine (Tegratol)} * _{Phenytoin (Dilantin)} * _{Gabapentin (Neurontin)} * _{Clonazepam (Klonipin)} * SE * Sedation * dizziness * ataxia.

Question 55

Corticosteroids for chronic pain

Answer 55

* Reduces inflammatory mediators * prevents the release of prostaglandins and stimulate appetite * Dexamethasone - most commpnly used for pain

Question 56

Chronic pain adjuvants

Answer 56

1. Muscle relaxants * Baclofen, flexeril, etc. * Reduces muscle spasms 2. NMDA receptor antagonists * Ketamine and dextromethorphan 3. A2 Agonists * Clonidine & Dexmedetomidine * work pre and post-synaptically in the dorsal horn to inhibit neuron firing * Precedex also works by inhibiting substance P release\* 4. GABA receptor agonists * Baclofen * Inhibitory NT that works in the cord - prevents release of excitatory NT 5. LAs * PO mexiletine and tocainide * high 1^st pass effects - are not as effective

Question 57

Nerve Blocks for Chronic Pain

Answer 57

1. Myofascial pain * Treat with trigger point injections * Use LA of botulinum toxin * TENS 2. Lower back pain * Epidural steroid injections * Reduces swelling at the nerve root and stabilizes nerve membranes 3. Sympathetic Nerve Blocks 4. Somatic Nerve Blocks * Normal PNB blocks we think of but more localized to the source of pain

Question 58

What is a Neurolytic Block for Chronic Pain?

Answer 58

Permanent destruction of the nerve causing chronic pain using alcohol and phenol.

Question 59

What are the most common neurolytic blocks?

Answer 59

1. Lumbar sympathetic chain 2. Celiac plexus 3. Hypogastric plexus 4. Ganglion impar 5. Intercostal blocks

Question 60

Spinal Cord Stimulation for Chronic Pain

Answer 60

* Stimulating electrodes are placed in the epidural space around the entry level of noxious stimuli into the spinal cord * This activates the descending modulatory system and inhibits sympathetic outflow * electric current that drown out the pathway * Treats phantom limb pain, PVD, and spinal cord lesions.

Question 61

TENS

Answer 61

Transcutaneous electrical nerve stimulation 1. Hyperstimulation of the nervous system - drowns out the pain signals 2. Good for: * myofascial pain * peripheral nerve injuries * phantom limb pain * stump pain

Question 62

Radiofrequency Ablation (RFA)

Answer 62

Dysfunctional tissue is ablated using heat (microwaves) Nerves can also be ablated with cold (cryoneurolysis)

Question 63

\_\_\_-\_\_\_% of cancer pain can be treated well with pharmacotherapy alone. However, \_\_\_-\_\_\_% of patients with cancer pain do not receive enough pain control.

Answer 63

70-90% 40-50%

Question 64

Why is cancer pain often inadequate?

Answer 64

1. Poor pain assessment and treatment plans * ​r/t so many ppl involved in their care 2. Lack of knowledge about available analgesics 3. Fear of addiction 4. Fear of respiratory depression * CA patients & prescribers fear that it will hasten their demise

Question 65

Ladder of cancer pain

Answer 65

1. Step One (mild pain) * Non-opioid analgesics * ASA, tylenol, NSAIDs 2. Step 2 Mild (Moderate Pain) * Weak oral opioids * Codeine, oxycodone, hydrocodone 3. Step 3 (Moderate-Severe Pain) * Potent IV opioids * Morphine - Hydromorphone (Dilaudid) - Fentanyl 4. Step 4 (Intractable Pain) * Invasive therapy * Regional blocks - Neurolytic blocks

Question 66

Chronic Pain Continuum

Answer 66

1. Diagnosis 2. Level 1 Therapies * _{Cognitive & Behavioral modification} * _{Over the Counter meds} * _NSAIDs * _TENS * _Rehab * _Exercise 3. Level 2 Therapies 1. _{Systemic opioids} 2. _{Nerve blocks and neyrolysis} 3. _{Thermal procedures} 4. Level 3 Therapies 1. _Surgery 2. _{Neuroablation} 3. _{Implantable drug pumps (onQ)} 4. _{Spinal cord stimulation}

Question 67

Organization that developed **clinical** practice **guidelines** and pain management **standards**

Answer 67

JCAHO ## Footnote Joint Commission on Accreditation of Healthcare Organizations

Question 68

Organization that developed **national** practice **guidelines** for management of acute pain

Answer 68

AHRQ Agency for Healthcare Research and Quality

Question 69

Organization that defined pain

Answer 69

WHO World Health Organization

Question 70

Organization that _develops_ pain management _standards_

Answer 70

APS American Pain Society

Question 71

Causalgia

Answer 71

1. syndrome of sustained * burning pain * allodynia, and * hyperpathia * after a traumatic nerve lesion 2. often combined with vasomotor and motor dysfunction 3. later can lead to trophic changes.

Question 72

Hyperesthesia

Answer 72

Increased *sensitivity* to stimulation, excluding the special senses

Question 73

Hyperalgesia

Answer 73

Increased *pain* from a stimulus that normally provokes pain

Question 74

Neuralgia

Answer 74

Pain in the distribution of a nerve or nerves

Question 75

Preemptive Analgesia What is it? What are the benefits?

Answer 75

What? 1. Pain management before pain occurs 2. Blockade of noxious stimuli response with the extension of this blockade into the postoperative period * takes the whole peri-operative period in consideration Benefits 1. Reduces postoperative pain 2. Accelerates recovery 3. Attenuates (stops) peripheral and central sensitization and hyperexcitability to pain * therefore, stops the development of chronic pain

Question 76

Pain - Multimodal Approach ## Footnote What is it? Why do it? How to do it? Issues?

Answer 76

What? * An extension of “clinical pathways” into effective postoperative rehabilitation pathways Why? 1. to control postoperative pain 2. to attenuate the perioperative stress response How? * through the use of * regional anesthetic techniques and a combination of analgesic agents (multimodal analgesia) Issues: * more complex * can have synergistic effects

Question 77

Opioids ## Footnote What are they (in relationship to pain management)? how they work Advantages Disadvantages

Answer 77

* Gold standard in pain management * Exert their analgesic effect through mu and kappa opioid-receptors in the CNS * No analgesic ceiling * Disadvantages * side effects * _{esp. respiratory depression} * _hypotension * _{nausea/ vomiting} * _sedation * _pruritus * _{urinary retention} * variability * tolerance

Question 78

sxs of intra-op pain

Answer 78

* increased HR * increased BP * fast & shallow breathing * pupil dilation * sweating ## Footnote _{think SNS activation}

Question 79

PCA ## Footnote What is it Most common drugs used Advantages

Answer 79

Pain management option with * Reservoir and Infusion controller * Button pushed by patient * Demand (bolus) * Lockout interval * Continuous background * infusion Most Common used drugs: * Morphine Sulfate * Hydromorphone Advantages * Cost-effective * Higher degree of patient satisfaction * Total drug consumption is less * Harder to over medicate self * Prevents the “pain/ no pain” cycle

Question 80

Continuous Epidural Analgesia Benefits

Answer 80

1. Superior analgesia to systemic drugs 2. Faster patient recovery 3. Attenuates stress response to surgery 4. Lessens pulmonary complications

Question 81

Cancer Pain Management Adjuncts

Answer 81

1. `Corticosteroids * Prevent release of prostaglandins and stimulate appetite 2. Non-invasive analgesics * psychotherapy, guided-imagery, hypnosis, PT 3. Antidepressants * Elevate mood, help with sleep, block reuptake of serotonin, potentiate opioid analgesics 4. ​Regional analgesia * Disadvantage—short term relief 5. Neurolytic blocks * Disadvantage—motor loss 6. Hospice