Acute Pain: Mechanisms, Management, And Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

ACUTE PAIN IT WILL BE POTENTIAL TO KILL YOUR PATIENTS Mulyono Soedirman FK UNHAS / RSPAD GATOT SOEBROTO JAKARTA

Acute Pain: Mechanisms, Management, and Treatment Options

Overview Pain: Definition and Features Physiologic Consequences of Acute Pain JCAHO and Pain Management Characteristics of Acute, Chronic, Peripheral Neuropathic Pain Assessment of Pain and Pain Relief Pain Mechanisms Role of Prostanoids in Pain Treatment Options for Acute Pain Other Approaches Acute Pain Services

Acute Pain: Mechanisms, Management, and Treatment Options

Pain Definition and Features

Acute Pain: Mechanisms, Management, and Treatment Options

Definition “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.”

International Association for the Study of Pain. Pain. 1979;6:249.

Acute Pain: Mechanisms, Management, and Treatment Options

Features of Acute Pain • Onset • Intensity • Somatic vs visceral • May be referred

Siddall PJ, Cousins MJ. In: Cousins MJ, Bridenbaugh PO, eds. Neural Blockade in Clinical Anesthesia and Management of Pain. 3rd ed; 1998:675–713.

Acute Pain: Mechanisms, Management, and Treatment Options

Physiologic Consequences of Acute Pain

Acute Pain: Mechanisms, Management, and Treatment Options

Physiologic Consequences of Acute Pain • • • • •

General stress response/neuroendocrine Respiratory Cardiovascular Gastrointestinal/urinary Musculoskeletal

Bonica JJ. The Management of Pain. 2nd ed. Vol. 1; 1990.

Acute Pain: Mechanisms, Management, and Treatment Options

General Stress Response Endocrine/Metabolic • ↑ ACTH, cortison, catecholamines, interleukin-1 • ↓ insulin Water/Electrolyte Flux • H2O, Na+ retention

ACTH = adrenocorticotropic horrmone Kehlet H. Reg Anesth.1996;21(6S):35–37. Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Respiratory Effects Acute Pain

↓ Tidal volume

↓ Vital capacity

↓ FRC

↓ Alveolar ventilation

↓ Mobility

Atelectasis Hypostatic pneumonia V/Q inequality FRC = functional residual capacity; V/Q = ratio ventilation:perfusion of the lung Craig DB. Anesth Analg. 1981;60:46. Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Respiratory Effects (Cont’d) Acute Pain Muscle spasm Impaired ventilation

Muscle splinting

Cough suppression Lobular collapse

Hypoxemia

Infection/pneumonia Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Cardiovascular Effects Acute Pain

Coronary vasoconstriction ↑ Anxiety, pain

• Ischemia

Sympathetic overactivity ↑ HR, ↑ PVR, ↑ BP, ↑ cardiac output

• Angina • MI

Ischemia

MI = myocardial infarction; HR = heart rate; PVR = peripheral vascular resistance; BP = blood pressure Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491. Bowler DB, et al. In: Cousins MJ, Phillips GD, eds. Acute Pain Management; 1986:187–236.

Acute Pain: Mechanisms, Management, and Treatment Options

Effects on Peripheral Circulation Acute Pain ↓ Limb blood flow1 ↓ Venous emptying2 ↑ Venous thrombosis/embolism3

1. Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491. 2. Modig J, et al. Acta Anaesth Scand. 1980;24:305–309. 3. Modig J, et al. Anesth Analg. 1983;62:174–180.

Acute Pain: Mechanisms, Management, and Treatment Options

Gastrointestinal and Urinary Effects

Gastrointestinal

Acute Pain

Urinary

↑ Intestinal secretions ↑ Smooth muscle sphincter tone

Sympathetic overactivity

↑ Urinary sphincter activity

↓ Intestinal motility Urinary retention

Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491. Nimmo WS. Br J Anaesth. 1984.56:29–37.

Acute Pain: Mechanisms, Management, and Treatment Options

Musculoskeletal Effects Acute Pain ↑ Muscle spasm

Sympathetic overactivity

↑ Sensitivity of peripheral nociceptors

Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Musculoskeletal Effects (Cont’d) Acute Pain

↓ Mobility Reflex vasoconstriction

• Impaired muscle metabolism • Muscle atrophy • Delayed normal muscle function Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Effects on Pain-Signaling Systems Acute Pain ↑ Peripheral nociception

↑ Nerve excitability • Hyperalgesia (1° + 2°)

Prolonged pain

Chronic pain

• Allodynia

Damaged spinal pain-signaling systems

Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Psychologic Effects Acute Pain

Anxiety

Sleep deprivation

Depression Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491.

Acute Pain: Mechanisms, Management, and Treatment Options

Other Effects of Acute Pain • Wound repair • Impaired immunocompetence • Hypercoagulable state

Drucker W, et al. J Trauma. 1996;40(3):S116–122. Cousins M, Power I. In: Wall PD, Melzack R, eds. Textbook of Pain. 4th ed; 1999:447–491. Jorgensen L, et al. Br J Anaesth. 1991;66:8–12.

Acute Pain: Mechanisms, Management, and Treatment Options

Advantages of Effective Pain Management • Patient comfort and satisfaction1,2,3 • Earlier mobilization4 • ↓ hospital stay3,4 • ↓ costs4

1. Eisenach JC, et al. Anesthesiology. 1988;68:444–448. 2. Harrison DM, et al. Anesthesiology. 1988;68:454–457. 3. Miaskowski C, et al. Pain. 1999;80:23–29. 4. Finley RJ, et al. Pain. 1984;2:S397.

Acute Pain: Mechanisms, Management, and Treatment Options

JCAHO and Pain Management

Acute Pain: Mechanisms, Management, and Treatment Options

Joint Commission on Accreditation of Healthcare Organizations • New standards in 2000–2001; scoring begins in 2001 • Record pain as the 5th vital sign • Interdisciplinary management with needs assessment • Patient’s right to pain assessment • Monitor pain intervention responses • Provide pain management education Joint Commission on Accreditation of Healthcare Organizations. Jt Comm Perspect. 1999;19(5):6–8. Sklar DP. Ann Emerg Med. 1996;27:412–413.

Acute Pain: Mechanisms, Management, and Treatment Options

Pain: The Fifth Vital Sign • Pain should be considered the “fifth vital sign” • Patients should be assessed for pain every time pulse, blood pressure, core temperature, and respiration are measured • Healthcare professionals should recognize a report of unrelieved pain as a “red flag”

American Pain Society Quality Improvement Committee. JAMA. 1995;1847–1880.

Acute Pain: Mechanisms, Management, and Treatment Options

JCAHO Revised Standards: The Patient’s Rights • Patients have the right to appropriate assessment and management of pain • The patient’s right to pain management is respected and supported • Patients are involved in all aspects of their care, including pain management

Joint Commission on Accreditation of Healthcare Organizations. Jt Comm Perspect. 1999;19(5):6–8.

Acute Pain: Mechanisms, Management, and Treatment Options

A Team Approach to Implementing the JCAHO Revised Standards for Pain Management Others

Nursing

Medical

Pharmacy

Managers

Dietetic Rehabilitation

Joint Commission on Accreditation of Healthcare Organizations. Jt Comm Perspect. 1999;19(5):6–8.

Acute Pain: Mechanisms, Management, and Treatment Options

Characteristics of Acute, Chronic, and Peripheral Neuropathic Pain

Acute Pain: Mechanisms, Management, and Treatment Options

Characteristics of Acute Pain • Sudden, sharp, intense, localized • Usually self-limited • May be associated with physiologic changes, eg, sweating, ↑ HR, ↑ BP

Siddall PJ, et al. In: Cousins MJ, Bridenbaugh PO, eds. Neural Blockade in Clinical Anesthesia and Management of Pain; 1998:675–713.

Acute Pain: Mechanisms, Management, and Treatment Options

Characteristics of Chronic Pain • Gnawing, aching, diffuse • No definite beginning or end • Varies in intensity; may remit briefly • Associated with psychological and social difficulties • Acute pain may be superimposed

Siddall PJ, et al. In: Cousins MJ, Bridenbaugh PO, eds. Neural Blockade in Clinical Anesthesia and Management of Pain; 1998:675–713.

Acute Pain: Mechanisms, Management, and Treatment Options

Characteristics of Peripheral Neuropathic Pain • Caused by pathologic changes in peripheral nerves • Spontaneous pain • Burning, tingling, numbness • Allodynia, hyperalgesia

Rathmell JP. Katz JA. In: Benzon H, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:288–294.

Acute Pain: Mechanisms, Management, and Treatment Options

Assessment of Pain and Pain Relief

Acute Pain: Mechanisms, Management, and Treatment Options

Patient’s Perception of Pain Pain is subjective and may be influenced by: • Age1,2 • Gender1 • Culture2 • Communication/language skills • Previous experience 1. Burns JW, et al. Anaesthesia. 1989;44:2–6. 2. Preble L, Sinatra R. In: Sinatra RS, et al, eds. Acute Pain Mechanisms and Management. St. Louis: Mosby-Year Book; 1992:140–150.

Acute Pain: Mechanisms, Management, and Treatment Options

Benefits of Patient Preparation

• Less postoperative pain1 • Fewer postoperative analgesic medications • Reduced hospitalization2

1. Croog SH, et al. J Am Dent Assoc. 1994;125:1353–1359. 2. Boeke S, et al. Pain. 1991;45:293–297.

Acute Pain: Mechanisms, Management, and Treatment Options

Example of Measurement Tool for Assessing Pain Visual Analog Scale (VAS)

No pain Pain as bad

as it could

Carr DB, et al. AHCPR Pub. No. 92–0032. 1992.

possibly be

Acute Pain: Mechanisms, Management, and Treatment Options

Frequency of Pain Assessment and Documentation • Preoperatively • Routinely at regular intervals postoperatively • With each new report of pain • At suitable intervals after each analgesic intervention

Carr DB, et al. AHCPR Pub. No. 92-0032. 1992.

Acute Pain: Mechanisms, Management, and Treatment Options

Pain Mechanisms

Acute Pain: Mechanisms, Management, and Treatment Options

The Somatosensory System Frontal cortex

Somatosensory cortex Thalamus Hypothalamus

Descending pathway Periaqueductal gray matter

Ascending tracts Midbrain

Medulla

Dorsal horn area Noxious stimuli activate receptors in periphery

Spinal cord

Acute Pain: Mechanisms, Management, and Treatment Options

Peripheral Sensitization Cell Damage

Inflammation

Sympathetic Terminals

Release of pain and inflammatory mediators eg, bradykinin, H+, prostaglandins

High Threshold

Nociceptor

• Central sensitization • Hyperalgesia • Allodynia

Low Threshold Spinal cord

Acute Pain: Mechanisms, Management, and Treatment Options

Central Sensitization Peripheral Sensitization

Tissue Injury

• • • • Spinal cord

↑ C-fiber output Hyperalgesia (1°, 2°) Allodynia Activation of NMDA receptors

Acute Pain: Mechanisms, Management, and Treatment Options

Hyperalgesia Primary • Sensitization of primary neurons → ↓ threshold to noxious stimuli within site of injury • May include response to innocuous stimuli • ↑ pain from suprathreshold stimuli • Spontaneous pain Secondary • Sensitization of primary neurons in surrounding uninjured areas • May involve: – Peripheral sensitization – Central sensitization

Raja SN, et al. In: Wall PB, Melzack R, eds. Textbook of Pain. 4th ed; 1999:11–57.

Acute Pain: Mechanisms, Management, and Treatment Options

Allodynia • Pain evoked by innocuous stimuli • Central sensitization → pain produced by Aβ fibers1 • Possibly mediated by spinal NMDA receptors2

1. Woolf CJ. Drugs. 1994;47(suppl 5):1–9. 2. Dolan S, Nolan AM. Neuroreport. 1999;10(3):449–452.

Acute Pain: Mechanisms, Management, and Treatment Options

Pain Mediators Cell Damage

Aa

K+

BK

Brain

PG Nociceptor Spinal cord HISTAMINE Peptides, eg, SUBSTANCE P

Mast Cell SEROTONIN

Aa = arachidonic acid; BK = bradykinin; PG = prostaglandin

Platelet

Acute Pain: Mechanisms, Management, and Treatment Options

Role of Neurotransmitters Excitatory • Glutamate, aspartate, ATP • Mediate afferent synaptic transmission Inhibitory • GABA, glycine, norepinephrine, 5-HT, adenosine, Ach • Analgesia at spinal and higher levels • Altered function → hyperalgesia, neuropathic or chronic pain GABA = γ -aminobutyric acid; 5-HT = 5-hydroxytryptamine (serotonin); Ach = acetylcholine Dougherty PM, Raja SN. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:7–9.

Acute Pain: Mechanisms, Management, and Treatment Options

Role of Neuropeptides Excitatory • Substance P, neurokinin A • ↑ Ca2+, induce sensitization, hyperalgesia • Transsynaptic transmitters Inhibitory • Somatostatin, enkephalins, endorphins, dynorphins (?) • Modulate intracellular cAMP, K+ • Act at µ , δ , κ opioid receptors cAMP = cyclic adenosine monophosphate Dougherty PM, Raja SN. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:7–9.

Acute Pain: Mechanisms, Management, and Treatment Options

Role of Prostanoids in Pain

Acute Pain: Mechanisms, Management, and Treatment Options

Prostanoid Production by Cyclooxygenase (COX) Arachidonic acid Cyclooxygenase activity of COX PGG2 Peroxidase activity of COX

PGH2 PGD2

PGF2

PGE2

α

PG = prostaglandin; TX = thromboxane

PGI2

TXA2

Acute Pain: Mechanisms, Management, and Treatment Options

Prostanoids and Their Physiologic Activities Prostanoid PGE2

Activities/Properties • Produced in many organs, (eg, kidney, intestinal tract) • GI mucosal protection/repair • Vasodilates • Diuresis and natriuresis • Inhibits inflammatory/ allergic cells

Thromboxane A2

• ↑ platelet activation • ↑ intravascular platelet aggregation • ↑ smooth muscle contraction in arteries and bronchi • ↓ platelet aggregation • Vasodilates • ↑ renin release in kidney

Prostacyclin (PGI2)

Acute Pain: Mechanisms, Management, and Treatment Options

Treatment Options for Acute Pain

Acute Pain: Mechanisms, Management, and Treatment Options

WHO Analgesic Ladder Fre ed Op can om fr ioid om ce to s for m r pain ± N evere oder a ± Aon-op pain te dju ioid van t Pa in or pers Op inc i ioid rea sting for sin mo m g i d l ± N erat d to e ± Aon-o pain p dj u i oi d van Pa t in p or e inc rsis rea tin sin g g No ± n-op Ad i juv oid an t

2

1 World Health Organization, 1990. Used with permission.

3

Acute Pain: Mechanisms, Management, and Treatment Options

Analgesic Options for Acute Pain Management • Opioid analgesics • Nonopioid analgesics – acetaminophen – tramadol – anti-inflammatory agents • Combination analgesic products • Local anesthetics, nerve, neuraxial blocks

Acute Pain: Mechanisms, Management, and Treatment Options

Opioid Analgesics • Binding at µ , δ , κ receptors • Highly efficacious • May be combined with anti-inflammatory agents • Effects may be reversed • Side effects common • Pain recurrence

Fishman SM, Borsook D. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:51–54.

Acute Pain: Mechanisms, Management, and Treatment Options

Adverse Effects of Opioids • CNS depression, sedation • Respiratory depression • ↓ GI motility, nausea, vomiting • Urinary retention • Pruritus

Acute Pain: Mechanisms, Management, and Treatment Options

Nonopioid Analgesics Acetaminophen

Tramadol

Mechanism of action

↑ pain threshold

• µ -receptor binding • inhibits re-uptake of norepinephrine and serotonin (5-HT3)

Adverse effects

Hepatotoxic

Opioid-like effects

Sisson CB. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:59–62.

Acute Pain: Mechanisms, Management, and Treatment Options

Anti-inflammatory Agents • Inhibit cyclooxygenase (COX), key enzyme in prostaglandin synthesis • Conventional anti-inflammatory analgesics inhibit both COX1 and COX-2 isoenzymes • COX-1 inhibition → gastrotoxicity, ↓ platelet aggregation • Some newer agents target COX-2 but do not inhibit COX-1 at full therapeutic doses (specific cox-2 inhibitor, the COXIBS, e.g. Celecoxib, the savest anti inflamatory agents in this decade, that effective also as pain killer).

Acute Pain: Mechanisms, Management, and Treatment Options

Combination Analgesic Products • Usually two or more agents with different yet complementary mechanisms of action • Severity of dose-related side effects may be reduced, since lower doses of each agent are utilized • Range of side effects increased

Acute Pain: Mechanisms, Management, and Treatment Options

Local Anesthetics, Nerve, Neuraxial Blocks • Na+ channel blockade • Possible interaction at pre- and postsynaptic junctions • Tachyphylaxis • Dose-related CNS, cardiovascular toxicity

Acute Pain: Mechanisms, Management, and Treatment Options

Nonpharmacologic Treatment Options for Pain Cognitive-Behavioral • Relaxation • Preparatory information • Imagery • Hypnosis • Biofeedback Physical Agents • Application of superficial heat and cold • Massage • Exercise • Immobilization (eg, to provide rest and maintain alignment after musculoskeletal procedures) • Electroanalgesia (eg, TENS) • Chiropractic • Acupuncture

Carr DB, et al. AHCPR Pub. No. 92-0032. 1992.

Acute Pain: Mechanisms, Management, and Treatment Options

Other Approaches

Acute Pain: Mechanisms, Management, and Treatment Options

Multimodal Analgesia An Example Morphine

• Reduced doses of each analgesic

Potentiation

NSAID, acetaminophen, nerve blocks

Kehlet H, Dahl JB. Anesth Analg. 1993;77:1048–1056.

• Improved antinociception due to synergistic/additive effects • May reduce severity of side effects of each drug

Acute Pain: Mechanisms, Management, and Treatment Options

New Approaches to Treatment of Acute Pain • Bradykinin receptor antagonist • COX-2 specific inhibition • Cytokine suppressive anti-inflammatory agents (CSAIDs) • Neuropeptide inhibitors • Epibatidine analogues

Rang HP, Urban L. Br J Anaesth. 1995;75(2):145–156.

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain Services

Acute Pain: Mechanisms, Management, and Treatment Options

Management of Surgical Pain The Unmet Needs • Pain is undertreated • Inadequate knowledge of pain management • Inadequate pain assessment

Rawal N. Anesth Pain Med. 1999;24(1):68–73. Sinatra R. In: Cousins MJ, Bridenbaugh PO. Neural Blockade in Clinical Anesthesia and Management of Pain; 1998:793–835. American Pain Society Quality Improvement Committee. JAMA. 1995;1847–1880.

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain Services Goals • Improve management of surgical pain • Promote continuing education and training of healthcare providers • Increase awareness of importance of effective pain management • Serve as clinical research center

Chin ML. In: Ashburn MA, Rice LJ, eds. The Management of Pain; 1998:537–545.

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options

Acute Pain: Mechanisms, Management, and Treatment Options