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Pain Management (General concepts and primary discussions)

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"Pain Management in Chronic Wound" workshop for nurses

Publicado en: Salud y medicina
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Pain Management (General concepts and primary discussions)

  1. 1. Pain Medicine Saeid Safari, MD Anesthesiologist, Iran University of Medical Sciences
  2. 2. Sir William Osler, the eminent 19th-century clinician
  3. 3. What is the Pain?
  4. 4. Medical Definition: “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage.” International Association for the Study of Pain, 1979 “An unpleasant sensation induced by noxious stimuli and generally received by specialized nerve endings.” CancerWEB, 2011
  5. 5. Operative Definition: “Pain is whatever the experiencing person says it is, existing whenever he/she says it does.” Margo McCaffery, 1999
  6. 6. Epidemiology
  7. 7. Epidemiology • 50 million people are partially or totally disabled due to pain • 70 to 90% of patients with advanced disease from cancer have significant pain that requires the use of opioid drugs. • Severe, unrelenting pain interferes with patients' quality of life, including their activities of daily living, their sleep, and their social interactions.
  8. 8. Epidemiology • 80% of elderly patients have chronic pain. • 66% have pain in the last month of life • ~ ½ of hospitalized patients with pain are under-medicated. • Up to 50% of patients who are taking pain medication do not experience adequate relief
  9. 9. Economics • Chronic pain causes 700 million lost work days/year in the U.S. • > $ 9 billion per year on OTC pain products. • Estimated cost of pain is $150 billion per year
  10. 10. Physiologic Effects of Pain • Immune System • Developmental • Future Pain • Quality of Life • Endocrine & Metabolic • Musculoskeletal • Cardiovascular • GI/GU
  11. 11. Psychiatric Disorders in Chronic Pain
  12. 12. • Chronic pain is often comorbid with psychiatric disorders. • The typical finding is an increased occurrence of psychiatric disorders among persons with a specific pain condition when compared with persons with no pain. • Depression is the most commonly studied psychiatric disorder in the context of chronic pain.
  13. 13. • A higher occurrence of major depressive disorder among persons with chronic pain. • The association of pain with anxiety disorders • A higher level of disability is often associated with comorbid depression and anxiety disorders
  14. 14. • Other than depression and anxiety, somatoform disorders, substance use disorders, and personality disorders have all been found to be more common among patients with chronic pain compared with those without chronic pain • Posttraumatic stress disorder (PTSD) has received particular attention in the literature.
  15. 15. Pain Behaviors
  16. 16. Reactions to Pain 1. Somatic Motor Reactions 2. Autonomic Reactions 3. Emotional and Psychogenic Reactions 4. Hyperalgesia
  17. 17. 1) Somatic Motor Reactions • Excess neuromuscular excitability throughout the body. • Withdrawal Reflexes. • Immobilization Reaction. • Guarding Reaction.
  18. 18. 2) Autonomic Reactions • Mild Cutaneous pain • a pressor reaction = rise of blood pressure and heart rate, mediated by sympathetic stimulation. • Sever cutaneous, deep and visceral pain • a depressor reaction associated with hypotension, bradycardia, and nausea, due to parasympathetic stimulation. • Such pain is often described as sickening pain and may be accompanied by vomiting.
  19. 19. Autonomic Response to Pain • Grimacing • Restlessness • Guarding • Increased respirations • Increased heart rate • Increased blood pressure • Diaphoresis
  20. 20. 3) Emotional and Psychogenic Reactions • Anxiety, fear, crying, depression, as well as the feeling of being hurt may be felt by the pained person. • These reactions vary: - From person to person on exposure to similar pain stimuli - in the same person according to his emotional state
  21. 21. 3) Emotional and Psychogenic Reactions 1. Worry about the cause of pain augment the feeling of pain. • Thus, Patients suffer than healthy subject to the same degree of pain. 2. Strong emotional excitement & sever physical exertion may block the feeling of pain. • Thus, seriously wounded soldiers in a battlefield suffer little or no pain till the battle is over.
  22. 22. Four Types of Pain Behaviors • Facial/audible expression of distress • Distorted ambulation or posture • Negative affect • Avoidance of activity
  23. 23. Emotions, Coping, and Pain • Higher levels of 1. 2. Anxiety and Stress, 3. Fear, 4. Sadness, 5. • Depression Anger Fewer observable outward physical changes/signs.
  24. 24. 4) Cutaneous Hyperalgesia Increased skin sensitivity to pain. 1- Primary Hyperalgesia 2- Secondary Hyperalgesia - Develop 30-60 min. after injury. Develops later. - Lasts for several hours or days. - Shorter duration than 1ry. - In the area of redness. - Non-painful stimuli (as touch) becomes painful. - In healthy skin surrounding red area. - Pain is felt more sever than normal. Mechanism: Central sensitization explained by Decreased pain threshold due to local convergence-facilitation theory. axon reflex releasing substance P
  25. 25. Pain Terminology, Classifications, and Pathophysiology
  26. 26. Definitions • An unpleasant sensory and emotional experience associated with actual or potential tissue damage and modified by individual memory, expectations and emotions. • Pain is whatever the experiencing person says it is. • Highly subjective, leading to under treatment
  27. 27. Types of Pain 1. Acute (<6 months) 2. Chronic (6 months <)
  28. 28. Acute pain: • lasts less than 6 months, subsides once the healing process is accomplished.
  29. 29. Presentation of Pain Acute Chronic • • Often obvious distress • Can be sharp, dull, shock-like, tingling, shooting, radiation, fluctuating in intensity, and varying in location (occur in timely relationship to noxious stimuli) • • Comorbid conditions usually present Can appear to have noticeable suffering • Can be sharp, dull, shock-like, tingling, shooting, radiation, fluctuating in intensity, and varying in location (do NOT occur in timely relationship to noxious stimuli) • Symptoms may change over time • Usually NO obvious signs not May see HTN, increased HR, diaphoresis, pallor… no
  30. 30. Acute Pain (Nociceptive) • Somatic • Superficial (nociceptors of skin) • Deep [body wall (muscle, bone)] • Visceral (sympathetic system; may refer to superficial structures of same spinal nerve)
  31. 31. Acute Pain • Travels into the spinal cord along the appropriate nerve root. • Nerve root splits into a front division and a back division and carries pain sensation to the CNS (spinal cord and brain). • Passed to a short tract of nerve cells (interneurons), which in turn synapse with a nerve tract that runs to the brain .
  32. 32. Acute Pain • Sent out to the rest of the brain, connecting with thinking and emotional centers. • A modifier pathway from the brain modifies pain at the synapses in the back part of the spinal cord (acute pain is decreased rapidly after tissue injury).
  33. 33. Chronic pain: • Complex processes & pathology. • Usually altered anatomy & neural pathways. • Constant & prolonged, > 6 months, sometimes for life. • “Lasting longer than expected time frame”
  34. 34. Altered Neural Structure • Chronic pain accompanied by: • Cortical Reorganization • Brain Atrophy
  35. 35. Chronic Pain 1. Malignant (cancer) 2. Nonmalignant • Neuropathic (nerve injury) • Inflammatory (musculoskeletal) • Mixed or unspecified • Psychogenic
  36. 36. Peripheral Nerve Fibers Involved in Pain Perception • A-delta fibers–small, myelinated fibers that transmit sharp pain • C-fibers–small unmyelinated nerve fibers that transmit dull or aching pain.
  37. 37. Chronic Pain • Neuropathic: • Severe pain disorder that results from damage to the central and peripheral nervous systems. • Centrally generated • Peripherally generated • Inflammatory: • Results from the effects of inflammatory mediators.
  38. 38. Chronic Pain Conditions • Neuralgia • an extremely painful condition consisting of recurrent episodes of intense shooting or stabbing pain along the course of the nerve. • Causalgia • recurrent episodes of severe burning pain. • Phantom limb pain • feelings of pain in a limb that is no longer there and has no functioning nerves.
  39. 39. • Schematic of cortical areas involved with pain processing and fMRI
  40. 40. Major Categories of Pain 1. Nociceptive pain (stimuli from somatic and visceral structures) 2. Neuropathic pain (stimuli abnormally processed by the nervous system)
  41. 41. Nociceptive Pain • Visceral Pain: Associated with internal organs. • Nature: Crampy, pressure, deep, dull to sharp, diffuse, referred. • Somatic pain : Soft tissues/ myalgic. • Nature: Dull to sharp, throbbing, achy, localized
  42. 42. Neuropathic Pain • Abnormal neural processing by the peripheral or central nervous system. • Signals are amplified or distorted; Synapse receptor numbers are altered; pathways not originally involved become involved • Patient Description of Neuropathic Pain: • Burning, electric, searing, tingling, and migrating or traveling.
  43. 43. Tracking the Path of Pain • Peripheral receptors • Neural pathways • Spinal Cord mechanisms & long tracts • Brainstem, thalamus, cortex & other areas. • Descending pathways.
  44. 44. Pain Gate Control 3 The sites of synapses along the pain pathway are considered as gates through which pain transmission can be facilitated (if the gate is open) or blocked (if the gate is closed). 2 The main pain gates are: 1- Spinal gate: at the SGR. 2- Brain stem gate: at the nuclei of reticular formation. 3- Thalamic gate: At neurons of PVLNT & intalaminar thalamic nuclei. 1
  45. 45. Pain Pathways: 1. Painful Stimuli or tissue damage activate specialized nerve cells (nociceptors), which in turn send pain signals to the spinal cord. 2. Pain signals enter the dorsal horn of the spinal cord, where some are increased or decreased by the interneuron before continuing up to the brain. 3. Thoughts, feelings and beliefs change the pain signals into the individual’s experience of “PAIN". 4. Certain parts of the brain generate signals that travel back down the spinal cord to reduce or increase pain signals at the interneuron.
  46. 46. Sites of Action Peripherally (at the nociceptor) Peripherally Local anesthetics, Medications Cannabinoids, NSAIDs, Opioids, Tramadol, Vanilloid receptor antagonists(i.e., capsaicin) Anticonvulsants (except the gabapentinoids) (along the nociceptive nerve) Centrally (various parts of the brain) Acetaminophen Anticonvulsants (except the gabapentinoids), Cannabinoids. Opioids, Tramadol Descending Inhibitory pathway in the spinal cord Cannabinoids, Opioids, Tramadol, Tricyclic antidepressants, SHRIs Dorsal horn of the spinal cord Anticonvulsants, Cannabinoids, Gabapentinoids, NMDA receptor antagonists, Opioids,. Tramadol, Tricyclic antidepressants, SNRIs
  47. 47. Pain Assessment and Management
  48. 48. Let’s try an experiment….  Have students take pen and place over nail bed and push. Describe sensation to neighbour. All the same?  Now try counting backwards from 10 while holding pressure on nail bed. Is the pain as bad?
  49. 49. Patient Assessment • Assess and reassess • Use methods appropriate to cognitive status and context • Assess intensity, relief, mood, and side effects • Use verbal report whenever possible • Document in a visible place • Expect accountability • Include the family • Include past physician(s) • Get old records • Check for addictive personality
  50. 50. Patient Pain History • Site(s) • What makes it better/worse • Quality • Impact on sleep, mood, • Severity • Date of onset • Duration activity • Effectiveness of previous medication
  51. 51. PQRST mnemonic: • P: Precipitating and palliating factors • Q: Quality • R: Region and radiation • S: Severity • T: Time
  52. 52. Instruments • Single-dimension • Visual analog scale • Verbal numerical scale • Verbal rating scale • Multidimensional • Assesses the pain as well as the emotional and behavioral effects of the pain.
  53. 53. One type has faces—(Whaley & Wong, 198)
  54. 54. Other pain scales are just numeric
  55. 55. Single-dimension Instruments Verbal rating scale • No pain = 0 • Mild pain = 1-3 • Moderate pain = 4-6 • Severe pain = 7-9 • Worst ever = 10
  56. 56. Can pain-intensity scales be used ? • Yes- but, limited by cognitive changes, impaired vision, physical limitation • no specific scale more “user friendly” • 83% of nursing home residents could complete a pain scale
  57. 57. Why have a pain scale? • Sometimes hard to put words to pain • Pain is multi-faceted (How long? Where? How intense? What kind feeling? • Visual scales help us understand where pain located. • Faces help us understand how pain makes patient feel. • Numeric scales help quantify pain using numbers.
  58. 58. Pain Management
  59. 59. Pain Management Pharmacological & nonpharmacological management
  60. 60. Principles of Treatment • Reduction of Pain: • Behavioral, Meds, Blocks, Surgery, Complementary • There is no magic bullet, no single cure • Rehabilitation: • Reconditioning & Prevention • Coping: • Management of Residual Pain
  61. 61. Treatment Objectives • Decrease the frequency and / or severity of the pain • General sense of feeling better • Increased level of activity • Return to work • Decreased health care utilization • Elimination or reduction in medication usage
  62. 62. Treatment of Pain 1. Non-pharmacologic 2. Medications • Nonsteroidal anti-inflammatory drugs (NSAIDs) • Acetaminophen • Antidepressants & anticonvulsants • Adjuvants • Narcotics 1. Invasive procedures Copyright © 2003 American Society of Anesthesiologists. All rights reserved
  63. 63. Nonpharmacological Management
  64. 64. Non-pharmacologic Pain Management • Neurostimulation • TENS • Acupuncture • Anesthesiology • Nerve block • Surgery • Physical therapy • Exercise • Heat/cold • Psychological approaches • Cognitive therapies (relaxation, imagery, hypnosis) • Biofeedback • Behavior therapy • Psychotherapy • Complementary tx • Massage therapy • Art therapy • Music therapy • Aroma therapy
  65. 65. Non-Pharmacologic  Cognitive Behavioral Therapy: Yes, ‘A’, Cochrane “Cortical plasticity related to chronic pain can be modified by behavioral interventions that provide feedback to the brain areas that were altered by somatosensory pain memories.” H. Flor, 2002 & 03 “Individuals can gain voluntary control over … specific brain region… these effects were powerful enough to impact severe, chronic clinical pain.” de Charms, 2005, Nat’l Acad Sci
  66. 66. Non-Pharmacologic  Meditation: Yes, ‘A’, Cochrane  Strong evidence for the use of relaxation & hypnosis in reducing pain in a variety of medical conditions  Music Therapy: Yes, ‘A’, Cochrane
  67. 67. Non-Pharmacologic • Pre-Op counseling: Yes, ‘B’, Cochrane • Ice: Yes, “B”, Cochrane • Chiropractic: No, ‘B’, Cochrane • Massage: Yes for cancer, low back & OA pain, ‘B’, Cochrane • Exercise : Yes; ‘B’, Cochrane
  68. 68. Non-Pharmacologic • Magnets: Don’t Know ‘I’, Cochrane • Spinal Cord Stimulation: Don’t know, ‘I’, Cochrane • Acupuncture: Don’t Know, ‘I’, Cochrane • TENS: Don’t Know, ‘I’, Cochrane
  69. 69. Acupuncture • Acupuncture has been practiced in China for more than 4000 years as a method for pain relief. Mechanism: 1- needles in appropriate body regions are thought to excite certain sensory neural pathways which feed into the brain stem centers (such as the PAG) involved in the pain control system, with release of endogenous opioid peptides. 2- simultaneous suppression of pain transmission at the spinal pain-gate by acupuncture
  70. 70. APA offers the following tips on coping with chronic pain: • Manage your stress. • Talk to yourself constructively. • Become active and engaged. • Find support. • Consult a professional.
  71. 71. Manage your stress. • Emotional and physical pain are closely related, and persistent pain can lead to increased levels of stress. Learning how to deal with your stress in healthy ways can position you to cope more effectively with your chronic pain. Eating well, getting plenty of sleep and engaging in approved physical activity are all positive ways for you to handle your stress and pain.
  72. 72. Talk to yourself constructively. • Positive thinking is a powerful tool. By focusing on the improvements you are making (i.e., the pain is less today than yesterday or you feel better than you did a week ago) you can make a difference in your perceived comfort level. For example, instead of considering yourself powerless and thinking that you absolutely cannot deal with the pain, remind yourself that you are uncomfortable, but that you are working toward finding a healthy way to deal with it and living a productive and fulfilling life.
  73. 73. Become active and engaged. • Distracting yourself from your pain by engaging in activities you enjoy will help you highlight the positive aspects of your life. Isolating yourself from others fosters a negative attitude and may increase your perception of your pain. Consider finding a hobby or a pastime that makes you feel good and helps you connect with family, friends or other people via your local community groups or the Internet.
  74. 74. Find support. • Going through the daily struggle of your pain can be extremely trying, especially if you’re doing it alone. Reach out to other people who are in your same position and who can share and understand your highs and lows. Search the internet or your local community for support groups, which can reduce your burden by helping you understand that you’re not alone.
  75. 75. Consult a professional. • If you continue to feel overwhelmed by chronic pain at a level that keeps you from performing your daily routine, you may want to talk with a mental health professional, such as a psychologist, who can help you handle the physical and psychological repercussions of your condition.
  76. 76. Using psychological factors in clinical practice
  77. 77. Vigilance to pain • Patients are distorted by the pain and are urged to react. Pain patients will have impaired concentration as they are being interrupted constantly by an aversive stimulus. Keep all communications clear and brief. Repeat key points often. Expect patients to talk about the pain often, as it is being brought repeatedly into attentional focus for them. This is not a sign of a somatization disorder or hypochondria.
  78. 78. Avoidance • Patients will naturally avoid pain and painful procedures. Be aware that this will occur and plan for it. Painful treatments will be avoided and patients will compensate for any disability caused by avoidance (e.g. shifted body weight distribution. ¡f a habitual pattern of avoidance develops, this may lead to chronic pain. Patients must be given an understanding that pain does not necessarily equal damage. A credible medical authority must deliver this message.
  79. 79. Anger • Patients with pain may shout at you, abuse you and generally be hostile to you. If they are hostile to you they have probably been hostile to everyone. Most often this will have nothing to do with you. and you will need to understand that anger normally means extreme frustration, distress and possibly depression. Anger functions to push people away and isolate a person. The angry pain patient is therefore less likely to have received or heard any information about their problems and be more confused than the non-angry patient.
  80. 80. Involve the patient • First, assess the patient’s normal way of coping with pain by simply asking how he or she has coped with predictable pain, such as a visit to the dentist. Secondly, match your strategy to the patient’s preference. ¡f the patient needs information, inform them how much pain they may expect to feel, what it may feel like and, critically, for how long (if this information is known). Always slightly overestimate the time rather than underestimate it. Finally, if possible. involve the patient in the delivery of any pain management strategy.
  81. 81. Make sense of the pain • Always ask the patient what they know and fear about the cause of the pain, the meaning of the pain and the time course of the pain. Expect the unexpected. What makes sense to one person is nonsense to another. What matters is that it is their understanding, not yours, that will inform their behaviour. Uncertain diagnoses or unknown diagnoses will lead to increased vigilance to pain and increased symptom reporting.
  82. 82. Consistency • Develop a consistent approach to clinical information, patient instruction and patient involvement within pain management. Practice should be consistent for each patient and from each member of the pain team, over time.
  83. 83. Pharmacological management:
  84. 84. Using Pharmacological Options Safely • Pharmacokinetics • Pharmacodynamics • Compliance • Cost • Polypharmacy
  85. 85. Modified WHO 3- Step Analgesic Ladder Quality of Life Proposed 4th Step Invasive treatments Pain Severity Opioid Delivery Pain persisting or increasing Step 3 Opioid for moderate to severe pain ± Nonopioid ± Adjuvant 8 -10 Pain persisting or increasing The WHO Ladder Step 2 Opioid for mild to moderate pain ± Nonopioid ± Adjuvant 4-7 Pain persisting or increasing Step 1 ± Nonopioid ± Adjuvant Pain Deer, et al., 1999 1-3
  86. 86. • Step 1: non-opioid analgesics • (COX-2, Aspirin, Acetaminophen, Diclofenac, Ibuprofen, Tenoxicam, Panadeine, Nurofen. • Pain rating 1-2-3) Step 2: mild opioid is added (not substituted) to step 1 • (Codeine, Propoxyphene, Tramadol, Sevredol, DHC Continus, Dihydrocodeine tartate. • Pain rating: 4-5-6) Step 3: Opioid for moderate to severe pain is used and titrated to effect • Oxycodone, Morphine, Fentanyl, Pethidine, Ketamine Pain rating 7-10
  87. 87. Remember basic principles: • Use WHO pain ladder • Take a careful drug history • Know the pharmacology of the Rx • “Start low, go slow” • Regularly review the regimen • Remember that drugs may cause illness
  88. 88. Pharmacological management: • Selection of appropriate drug, dose, route and interval • Aggressive titration of drug dose • Prevention of pain and relief of breakthrough pain • Use of coanalgesic medications • Prevention and management of side effects
  89. 89. Patient Controlled Analgesia (PCA)
  90. 90. Pharmacology of Nociception Four Steps: 1. Transduction • NSAIDs, Local Anesthetics & Anticonvulsants 2. Transmission • Opioids, NMDA Antagonists 3. Perception • Distraction, Relaxation, Imagery 4. Modulation • Tricyclic Antidepressants, Opioids, GABA Agonists
  91. 91. Manage side-effects opiates: • Constipation • Tolerance to nausea and sedation develops in 3-7 days. • Use adjuvant (coanalgesic) agents with opioid: • Tricyclic antidepressants • Corticosteroids • Anticonvulsants • Muscle relaxants • Stimulants
  92. 92. Physical Dependence • A process of neuro-adaptation • Abrupt withdrawal may → abstinence syndrome • If dose reduction required, reduce by 25-50% q 2–3 days; avoid antagonists.
  93. 93. Tolerance • Reduced effectiveness to a given dose over time. • If dose is increasing • suspect opioid tolerance • disease progression • psychological/spiritual pain
  94. 94. Addiction • Acceleration of abuse patterns onto a primary illness. • Characteristics: • Psychological dependence • Compulsive use • Loss of control over amount and frequency of use • Loss of interest in pleasurable activities • Continued use of drugs in spite of harm
  95. 95. Pseudoaddiction • Drug seeking behavior associated with a person’s need to relieve pain and suffering, not an obsession with the mood altering affects of medication. Wesson et al, 1993
  96. 96. Chronic Pain Medical Issues • Physical Exam • History documenting prescribing rationale • Pain assessment documentation
  97. 97. Legal Issues • Accurate prescription records • Controlled substance laws • Schedule • Emergency Telephone Prescriptions • Nursing Home Patients Fax prescriptions
  98. 98. Skilled Prescribing • Patient –Physician Partnership • Pain management expectations • Medication responsibilities • One physician • One pharmacy
  99. 99. Role of Invasive Procedures • Optimal pharmacologic management can achieve adequate pain control in 80-85% of patients • The need for more invasive modalities should be infrequent • When indicated, results may be gratifying
  100. 100. Role of Invasive (“Anesthetic”) Procedures • Intractable pain* • Intractable side effects* *Symptoms that persists despite carefully individualized patient management
  101. 101. What about the 20% who do not get relief from the WHO ladder • Has a true pain assessment been accomplished? • Have you examined the patient? • Is the pain neuropathic? • Is the patient receiving their medication? • Is the medication schedule and route appropriate? • Have the opioids been titrated aggressively? • Have invasive techniques been employed?
  102. 102. What about the 20% who do not get relief from the WHO ladder • Lastly, • Cosider checking a vitamin D level : • There is an association between Vitamin D levels & chronic pain in women. • Women with levels of 75 – 99 nmol/L had less pain. • Ann Rheum Dis. August 12, 2008.
  103. 103. Importance of Teamwork • Complex chronic pain, especially if caused by life-threatening disease, is best treated by a team. • The diverse talents of physician, nurse, social worker, chaplain, working together offers comprehensive control of physical, emotional, and spiritual pain. • Palliative care is for ALL patients who are suffering.
  104. 104. So, what about “Pain Clinics” • Depends on where you live and of what they consist. • “Most” are not teams, but 1 or more anesthesiologists. • Most • Want to do invasive procedures • Prefer not to manage chronic medications • Do NOT have practitioners Psychologists nor alternative medical