Pain Control: Acute and Chronic Conditions

Pain Control: Acute and Chronic Conditions

اسلاید 1: Pain Control: Acute and Chronic ConditionsFrank C. Nacario MD DPBAAssociate ProfessorAnesthesiology & Pain MedicinePalliative CareUERMMMCI

اسلاید 2: Hippocratic precepts:“ the first duty of medicine is to heal- if it can, to relieve often, to comfort always”

اسلاید 3: Definition of painAcute vs Chronic painPhysiology of painEffects of painPain scores in different surgical proceduresPain assessmentPain control in the postoperative period

اسلاید 4: Pain “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, 1979

اسلاید 5: “Pain is whatever the experiencing person says it is; existing whenever he or she says it does.” McCaffrey, 1980“Pain is now recognized as a complex experience with at least four main componentsnociceptionsensationsuffering or distressbehaviourChampagne and Weisse,1994

اسلاید 6: Pain threshold refers to the point when stimulation is felt as painful. Pain tolerance refers to “how much” one can bear the pain experience; varies between individuals and cultures.i.e. females vs males pain as a form of punishment pain as a vital experience

اسلاید 7: Two categories of pain Acute: primarily due to nociceptionshort-lived and reversible;less than six months organic disease or injury is presentChronic: may be due to nociception but in which psychological and behavioral factors often play a major rolebehavior state, initiated by a real injurysix months or longer; that it has itself become the disease

اسلاید 8: Acute Pain

اسلاید 9: ACUTE PAIN

اسلاید 10: Chronic Pain

اسلاید 11: Chronic Pain

اسلاید 12: Two Types of PainPhysiologic or nociceptive painIncludes acute, subacute, chronic, and inflammatory painResults from noxious stimuli and inflammation in an otherwise intact tissuePain system is functioning as nature intends it toPathologic or neuropathic painAssociated with frank injury to neural tissue Reflects abnormal functioning of the pain system

اسلاید 13: Nociceptors: special sense receptors in the skin or internal organsreceptors receive noxious (painful) stimuli produced by intense heat, extreme pressure, pricks and cuts, surgery or ischemia Noxious sensation: two components

اسلاید 14: Peripheral Nociceptor SystemSomatic structuresCutaneous nociceptors: pain receptors at the termination of free-nerve endings in the skin(1) A-δ high- threshold mechanoreceptors (HTM) activated by mechanical noxious stimuli (2) A-δ myelinated mechanothermal nociceptors activated by noxious mechanical stimuli and noxious heat(3) C polymodal nociceptors activated by mechanical, thermal, and chemical noxious stimuli(4) miscellaneous C mechanical nociceptors and cold nociceptors

اسلاید 15: Deep nociceptors: also supplied by A-δ and C fibersLess sensitive to noxious stimuli than cutaneous nociceptorsEasily sensitized by inflammation; dull and poorly-localizedMuscle, fascia, tendons, and other deeper somatic structures

اسلاید 16: Visceral structuresSupplied by C afferents and some A-δ fibersActivated by disease, inflammation, contraction under isometric conditions, ischemia, rapid distention, and other adequate visceral nociceptive stimuli and endogenous algogenic substances

اسلاید 17: Sensitization following Tissue InjuryPeripheral Sensitizationdirect effect: injury > release of algogens - (activate and sensitize nociceptors); indirect effect: (release of a complex soup of inflammatory substances further sensitizing injured tissue and surrounding tissues) - make the nociceptors more sensitive to the painful stimulus, more prone to activation by:- weak touch- thermal stimuli- during movement lowered threshold to stimulation, and prolonged and enhanced response

اسلاید 18: Primary hyperalgesiaSensitization at the site of injuryCharacterized by lowered pain threshold, increased sensitivity to suprathreshold stimuli, and spontaneous pain – peripheral sensitizationSecondary hyperalgesiaRefers to the pain and tenderness felt at the area adjacent to the site of the initial injury including the area without inflammation – central sensitization

اسلاید 19: Central Sensitization - abnormal degree of amplification of the incoming sensory signal in the CNS- amplifies the signal of nociceptors, and amplifies the signal of low-threshold A-β sensory fibers (touch-sensitive & vibration) which previously are subliminal- A-β touch input is perceived as painful- key involvement of glutamate neurotransmitter and its NMDA receptor

اسلاید 20: Burn – produce tenderness in the burnt area (primary hyperalgesia); due to sensitized nociceptors (peripheral sensitization) also produce tenderness in a substantial zone of intact skin (secondary hyperalgesia)- due to spinal amplification of otherwise normal touch input (central sensitization)

اسلاید 21: Lloyd/Hunt SystemDiameter(m)Letter SystemConduction Velocity (m/s)MyelinReceptor /Ending TypesI-a12-20-70-120+Muscle spindle primary endingsI-b12-20-70-120+Golgi tendon organs-12-20A- 70-120+Muscle efferents (extrafusal)II6-12+A-30-70+Encapsulated endings-2-10A-10-50+Muscle efferents (intrafusal)III1-6A-5-30+A- specific nociceptors/ polymodal receptors, cold, most hair, some visceral receptor-<3B3-15+Preganglionic autonomicIV<1.5C0.5-2.0NoC-nociceptors, C-polymodal receptor, warmth receptor, some mechanoreceptor, postganglionic autonomic, enteric nerve fibers

اسلاید 22: Pain Pathways

اسلاید 23: A-δ fibersC fibersRelease of neurotransLateral system:nSTTMedial system:pSTT, SMT,SRTSynapse: release of neurotrans: Glutamate-aspartate, sP, FRAP, VIP CCKGRP, ENK,DYN = depolarization

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اسلاید 25: Endogenous Opiate SystemEnkephalinsOpiate-binding sites in the dorsal horn, periaqueductal gray (PAG), nucleus raphe magnus, globus pallidus and other areas involved with the pain pathwayNeurons containing serotonin (5HT) also contain enkephalins DynorphinsHypothalamus, PAG, reticular formation, medulla, dorsal horn of the SC in laminae I, VΒ-endorphinsBasal hypothalamus, limbic system, 3rd ventricle, midbrain, locus ceruleus

اسلاید 26: Opioid Receptors & Ligands

اسلاید 27: Non-opiate Descending Inhibitory SystemSerotoninThe cell bodies of 5HT originate in the nucleus raphe, medulla and ponsTheir axons terminate in laminae I, IIo, IV and V of the spinal dorsal horn and near the central canal; others in the ventral horn the analgesic action of systemic opiates can be blocked by depletion of 5HT

اسلاید 28: Non-opiate Descending Inhibitory SystemNE (norepinephrine) descending systemAxons descend in all of the laminae of the spinal cordMediates analgesia and dorsal horn inhibitionAppears to be critical for opiate-induced analgesiaHyperpolarizes 1st order neuron, internuncial neurons , and wide-dynamic range neurons in the STT

اسلاید 29: Peripheral Nociceptor SystemSomatic structuresCutaneous nociceptors: on free-nerve endings 1) A-δ high- threshold mechanoreceptors (HTM) activated by mechanical noxious stimuli (2) A-δ myelinated mechanothermal nociceptors activated by noxious mechanical stimuli and noxious heat(3) C polymodal nociceptors activated by mechanical, thermal, and chemical noxious stimuli(4) miscellaneous C mechanical nociceptors and cold nociceptorsDeep nociceptors: supplied by A-δ and C fibersLess sensitive to noxious stimuli than cutaneous nociceptorsEasily sensitized by inflammation; dull and poorly-localized Muscle, fascia, tendons, and other deeper somatic structures

اسلاید 30: Visceral structuresSupplied by C afferents and some A-δ fibersActivated by disease, inflammation, contraction under isometric conditions, ischemia, rapid distention, and other adequate visceral nociceptive stimuli and endogenous algogenic substances

اسلاید 31: Peripheral Nociceptor system

اسلاید 32: Peripheral tissuesPrimary afferent neuron(DRG)Second order neuron(dorsal horn)ThirdOrder neuron(thalamic)

اسلاید 33: noxious stimuliperipheral stimuli (temperature change or vibration)2 competing pain mechanisms which influence gate controlAβGate Control TheoryAδ, (C)input Rubbing the injured area makes it better“Transcutaneous electrical nerve stimulation, hot and cold therapies and other skin stimulation therapies are thought to be effectiveActivation of large afferent epicritic fibers inhibits WDR neuron and STT activityPain in one part of the body inhibits pain in other parts

اسلاید 34: Effects of PainComponents of the Stress Response Neuro-endocrineCardiovascularRespiratoryGastrointestinalGenitourinaryImmunologic/ CoagulationGeneral Well BeingACTH:protein catabolism cortisol:lipolysis glucagon: hyperglycemia epinephrine↓Insulin, ↓ protein anabolism↓ testosterone  aldosterone: salt and H2O retention ADH cortisol: congestive heart failure catecholamines: vasoconstriction,  myocardial contractility  heart rate angiotensin IImyocardial work- dysrhythmias- angina- MI- CHFDec FRCImpaired diaphragmatic Function(reflex inhibition of phrenic nerve)= Atelectasis= Pneumonia↑sphincteric tone↓smooth muscle tone═ Ileus↑sphincteric tone↓ smooth muscle tone ═ urinary retention↑platelet adhesiveness↓ fibrinolysisActivation of coagulation cascade═ incidence of thromboembolic phenomenaImmobilityInsomniaAnxietyHelplessness═ Fear

اسلاید 35: Pain Scores: Common procedures Appendectomy:5-7Cholecystectomy: 7Cesarian section: 4-7Thoracic surgery: 7-8Bowel surgery: 7-9Gynecologic surgery:7-8Hemorrhoidectomy: 9Opthalmologic procedures: 1-6Liposuction: 4-6Nephrectomy: 10

اسلاید 36: Pain AssessmentSelf-Report:Visual Analog ScaleNumeric Rating Scale

اسلاید 37: Visual Analogue Scale (VAS): 0 10 No pain Worst imaginable pain

اسلاید 38: Numeric Rating Scale0 1 2 3 4 5 6 7 8 9 10No pain Worst pain

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اسلاید 40: The Whaley & Wong Faces Rating Scale

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اسلاید 42: Pain Faces Scale

اسلاید 43: “Pain as the Fifth Vital Sign”“We need to train doctors and nurses to treat pain as a vital sign. Quality care means that pain is measured and treated” James Campbell, MD Presidential Address, American Pain Society November 11, 1996

اسلاید 44: Pain InterventionsNon-opioid and Opioid drug therapyvia the OralTransdermalTransmucosal Parenteral Intramuscular Intravenous intermittent Intravenous continuous

اسلاید 45: PhospholipidsPhospholipase A2Arachidonic acidCOXPGI2Vasodilator,hyperalgesic,inhib pl. aggrTXA2Pl. aggr, vasoconstricPGF2Bronchoconstr, myomet contracPGE2Vasodil,hyperalgPGD2Inh. Plt aggreg, vasodil5-lipoxygenase5- HPETELeukotrienesCyclooxygenase pathway

اسلاید 46: Involvement of COX

اسلاید 47: Non-opioid drugsAspirin: non-selective COX inhibitorCOX 1 & 3 inhibitorAcetaminophen: COX 3 inhibitorNSAIDs:Non selective COX inhibitorKetorolac (Toradol): IVKetoprofen (Orudis): IV, IMMefenamic acid (Ponstan): oralDiclofenac (Voltaren, Diclowal): IM, oral, topicalIbuprofen (Alaxan, Advil): oralCOX2 inhibitorsEtoricoxib, Celecoxib - oral Parecoxib- IV(Rofecoxib, Valdecoxib, Nimesulide)

اسلاید 48: Non opioid drugsMechanism of ActionInhibition of PG-mediated amplification of chemical and mechanical irritants on the sensory pathway.Inhibits COX (prostaglandin synthetase)Blocks response to inflammatory substances, bradykinins, acetylcholine, serotonin ═ mediation of peripheral inflammatoryresponse

اسلاید 49: OpioidsAgonist on the opioid receptors Periaqueductal greyPeriventricular grayNucleus reticularisGigantocellularisMedial thalamusReticular formationLateral hypothalamusSpinal cord

اسلاید 50: Opioid ReceptorsMu1Mu2DeltaKappaSigmaSupraspinal analg nvResp depression, dependenceSpinal analgesia nvSpinal analgesia, sedationDysphoria

اسلاید 51: OpioidsAgonists: Mu receptorMorphine: oral, IV, IM, intrathecal, epiduralFentanyl: transdermal, transmucosal, IVOxycodone: oralHydromorphone: oralWeak Agonists :MuTramadol: oral, IV, transmucosalMeperidine: IV, IM, epiduralAgonist-antagonists: kappa, sigma/ no activity on Mu; potential to reverse effect of agonistNalbuphine: IM, IVButorphanol: IM, IV

اسلاید 52: Central neuraxial analgesiaIntrathecal: spinal opioid receptors (SG)addresses the shortcomings of IV and IMsingle dose 12 to 24hours pain reliefpotential for both acute and delayed respiratory depression (rostral spread)Epiduralreduced incidence of side effects: pruritus, respiratory depressioncatheter may be inserted for intermittent 12 to 24 hour interval doses or continuous infusionPCA with background infusion achieves better analgesia

اسلاید 53: Undesirable Effects of OpioidsSedation - kNausea and Vomiting - mSuppression of cough reflex - mPsychological and Physical dependenceToleranceConstipation – most common - kRespiratory depression - m

اسلاید 54: PCA – Patient-controlled AnalgesiaBackground infusion with PCA bolusesIV or epiduralBetter maintenance of therapeutic levelsBetter patient satisfactionNot dependent on care giver (no delay in meds)Patient has control over own pain concernsUsually, patients gives only to maintain tolerable pain level – less drug use

اسلاید 55: Other interventionsTranscutaneous Electrical Nerve StimulationPsychological Intervention for Post op Analgesia

اسلاید 56: AdministrationRound the clock vs prnRTC : maintain blood level decreases total opioid requirementprn: intermittent, peaks and troughsPCA – patient-controlled analgesiaIV or epiduralBetter maintenance of therapeutic levelsBetter patient satisfactionNot dependent on care giver (no delay in meds)Patient has control over own pain control needsUsually, patients demand only to maintain tolerable pain level – less drug use

اسلاید 57: Ideal pain management RESCUE MEDICATIONSRTC MEDICATIONPERSISTENT PAINTIMEBREAKTHROUGH PAINS

اسلاید 58: Adjuvant drugs: Antidepressant Anxiolytic Steroids AntiemeticManagement of drug related side effects Antacids Laxatives/stool softeners

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اسلاید 60: WHO Analgesic LadderThree step sequence for pain controlPAINIf pain persist or increasesIf pain persist or increasesSTEP - 1STEP - 2STEP - 3Non opioidsWeak opioidsStrong opioidsAnalgesics should be administered by the mouth, by the clock, by the ladderThe three basic analgesics are: Aspirin, Codeine and Morphine“Approaching this helps prevent the Doctor Kangarooing from Analgesics-analgesics in a desperate search for some drug that will suit the patient better”.

اسلاید 61: Multimodal Pain ControlInflammation & AnalgesiaNSAIDAnalgesiaOpioidAdjuvantsNon-pharmacologic therapyPsychological supportTENS

اسلاید 62: PharmacotherapyNMDA receptor inhibitorsCounter-irritation

اسلاید 63: Triad of PainImpaired sleep Impaired ADLPain Depression Anxiety

اسلاید 64: Control pain 24/7

اسلاید 65: Medicines for severe pain

اسلاید 66: “Pain is perfect misery, the worst of evils, and excessive overturns all patience.” John Milton, Paradise Lost

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اسلاید 68: Pain free Day!!!