Pain Review 08

The Concept of

Asst. Prof. Chanell Jan C. Concepcion, RN, MHSS Reviewer

Significance of Pain A.Subjective response: only felt by the person B.Negative: discomfort C.Protective role: • warning of potential threat to health; • prompt for person to seek medical attention D.Fifth vital sign

What is Pain? video

PAIN Defined

Pain: • "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" (International Association on the Study of Pain).

Pain: • Pain has personal meaning to individual experiencing pain • All pain is real

Pain: • Response to and warning of actual or potential trauma • Difficult to measure

Dimensions of Pain

Types of Pain    

Location Duration Intensity Etiology

Referred Pain • pain perceived in area distant from stimuli • intense although there is little or no pain at the point of noxious stimuli. • eg. myocardial ischemia is not felt as pain in the heart. Rather it is felt as left arm, shoulder or jaw pain.

• Visceral – arises from body organs; dull and poorly localized; with nausea and vomiting; may radiate or is referred • Superficial (Cutaneous) – Arise from skin and subcutaneous tissues – tends to be easily localized • Somatic (Deep Somatic Pain) – Tissues of body wall, muscles, bone, periosteum, cartilage, tendons, deep facia, ligaments, joints, BV, nerves

Pain According to Duration • Acute Pain • Chronic Pain • Cancer Pain

Acute Pain • • • •

sudden onset usually sharp and localized less than 6 months significant of actual or potential injury to tissues • initiates flight or fight stress response

Chronic Pain • • • •

prolonged pain more than 6 months often dull, aching, diffuse not always associated with specific cause, often unresponsive to conventional treatment • most common is lower back pain

Characteristics of Acute and Chronic Pain CHARACTERISTI CS

ACUTE

CHRONIC

RECENT

INTERMITTENT CONTINUOUS

LESS THAN 6MONTHS

MORE THEN 6MONTHS

AUTONOMIC

Sympathetic Response

4. REPONSE PSYCHOLOGIC

ASSOCIATED ANXIETY

Absence of Autonomic Response

• ONSET 2. DURATION 3.

5. OTHER COMPONENT TYPES OF RESPONSE

WITHDRAWAL DEPRESSION Libido Appetite

The truth about Chronic Pain (Today @ NBC)

CANCER – RELATED PAIN

malignant pain is considered to have qualities of both acute and chronic pain.

Intensity 1-3 =Mild 4-6 =Moderate 7-10 = Severe (Kozier, 2008)

Etiology • Physiologic Pain – Experienced when an intact, properly functioning nervous system send signals that the tissues are damaged, requiring attention and proper care.

•

• Subcategories of Physiologic Pain – Somatic Pain – Visceral

Etiology • Neuropathic Pain

May be due to: – Experienced by people • Illness (postherpetic who have damaged or neuralgia, diabetic malfunctioning nerves. peripheral neuropathy) • Injury (e.g. phantom limb pain, spinal cord injury pain • Undetermined reasons

Injury or Damage of the Nerve • After damage of nerve  may cause continuing pain • Regeneration of nerves can lead to changes in nociceptive pathways that contribute to pathological pain. • Healing process could be accompanied by hyperalgesia ( sensitivity to pain) due to proliferation of regenerating nerve fibers • Neuroma formation – can be a constant cause/source of pain •

(Show Nerve Injury Flash)

Concepts Associated with Pain 1. Pain threshold

2. Pain tolerance

Concepts Associated with Pain 1. Pain threshold - The least amount of stimuli that is needed for a person to label a sensation as pain. 2. Pain tolerance - is the maximum amount of painful stimuli that a person is willing to withstand without seeking avoidance of the pain or relief.

Pain Threshold • the point at which an individual first acknowledge or interprets a sensation as being painful The least experience of pain which a subject can recognize. (IASP)

Pain Tolerance –the individual’s ability to endure the pain being experienced –The greatest level of pain which a subject is prepared to tolerate. (IASP)

Nociceptive vs Neuropathic Pain • Nociceptive Pain pain in which normal nerves transmit information to the CNS about trauma to tissues Pain in response to obvious stimuli

• Neuropathic Pain Does not require the presence of an identifiable noxious stimuli pain in which there are structural and/or functional nervous system Ex. post herpetic (or post-shingles) neuralgia

A. Nociception B. Pain pathway C. Chemical Mediators D. Endorphins (endogenous morphines/ opiates)

• nerve receptors for pain ends • located in numerous skin and muscles • stimulated by direct cellular damage or local release of biochemicals from cellular damage (e.g. bradykinin)

• the system involved in the transmission and perception of pain

nociceptors (nerve cell endings)

nociceptors • mechanicalinstruments, equipments • thermal – flames, hot liquids, steam • chemical - noxious substances

PROCESS OF PAIN • threatened or actual tissue damage  stimulates nociceptive neural receptors • Damage to the pain transmission system itself • Specific structures in the nervous system are involved in transforming a stimulus into a pain sensation

Neurons Involved in Pain Perception: • A-delta (αδ ) • C Fibers

A-delta (Aδ) • Transmits signals more rapidly • Delivers information on painproducing stimulus • Determine the location, severity and type of pain • Perceived as sharp, cutting or stabbing sensation

C Fibers • Conducted more slowly along pain pathway • Characterized as dull, burning sensations associated with suffering

• Transduction • Transmission • Perception • Modulation

Transduction • Cell damage causes release of sensitizing chemicals (prostaglandin,

bradykinin, serotonin, substance P, histamine)

• Stimulus is detected by nociceptive receptors • conversion of mechanical, chemical and thermal information into electrical activity in the nervous system.

Transduction • Process of Depolarization – Na enters; K exits

• Generates action potential • Electrical energy  travel to spinal cord

Transmission • Movement of pain impulse from site of transduction to the brain • Message is relayed from receptors to the CNS

Transmission • 3 segments involved in nociceptive signal transmission: • Level of spinal cord • Dorsal horn processing • Transmission to thalamus & cortex

Transmission of pain impulses

• Substance P and other neurotransmitters transfer the impulse from the nociceptors to the spinothalamic tract.

Perception • Only when the impulses reach the brain are they intellectually recognized as pain. • Brain perceives the sensation as painful

Perception • Dynamic and changing in response to many factors • May be brief (seconds or hours), prolonged (hours or weeks) or even permanent

Modulation • Adjustment • Refers to internal and external ways of reducing or increasing pain – Where does modulation occur?

Modulation • Pain modulation is determined by activity in the endorphinergic system and other pain modulating systems. • In the endorphinergic system, analgesia is mediated by – the binding of endogenous opioid compounds to special subsets of receptors: mu, delta, and kappa.

Modulation • Endorphins • other neurotransmitters that play a role in the endogenous pain modulating system include serotonin and norepinephrine, GABA

Summary of Noceceptive Processes

Drug Therapy Interrupting the Pain Pathways Pain Medication

Mechanism of Action

Transduction – NSAID Local Anesthetics Antiseizure agents Corticosteroids

-Blocks prostaglandin production -Blocks action potential initiation -Blocks action potential initiation -Blocks action potential initiation

Transmission – Opioids

-Blocks release of substance P

Perception – Opioids - conscious experience of pain NSAIDs Adjuvant (antidepressants) Modulation – Tricyclic antidepressants

- Interferes with reuptake of serotonin & norepinephrine

Pain A T H W A Y

• First, nerve endings in the finger sense the injury to the finger (sensory neurons) • and they send impulses along axons and enter the spinal cord in an area called the dorsal horn (magenta pathway). • The incoming axons form a synapse with neurons that project up to the brain. • The neurons that travel up the spinal cord then form synapses with neurons in the thalamus, which is a part of the midbrain (magenta circle). • The thalamus organizes this information and sends it to the sensory cortex (blue), • Sensory cortex interprets the information as pain and directs the nearby motor cortex (orange) to send information back to the thalamus (green pathway). • Again, the thalamus organizes this incoming information and sends signals

Pain Pathway

Ascending Pain Pathway

Other pain pathways: • Descending pathway – Pain modulation

• • • • •

The spinothalamic pathway. The spinoreticular pathway The dorsal column pathway The spinomesencephalic tract. The spinohypothalamic pathway.

1. Bradykinin – a powerful vasodilator that increases capillary permeability and constricts smooth muscles. 2. Histamine – a compound found in all cells. It is released in allergic inflammatory reactions. 3. Acetylcholine – a neurotransmitter substance widely distributed in body tissues which functions as a vasodilator and cardiac depressant

CHEMICAL MEDIATORS OF PAIN 4. Substance P – •stimulant at pain receptor sites involved in inflammatory response in local tissue •Release of plasma by increasing vascular permeability  availability of bradykinin •Contributes to prostaglandin release

CHEMICAL MEDIATORS OF PAIN • 5. Prostaglandin – chemical substance thought to increase the sensitivity of pain receptors by enhancing the pain provoking effect of bradykinin • 6. Endorphin/Enkephalin – reduce or inhibit the transmission of pain. Both are found in heavy concentrations in the CNS

INFLUENCE OF ENDOGENOUS OPIATES • Endogenous – produced by the body • Opiates – produce analgesia by direct action on the CNS • The endogenous opiates consists of naturally occurring opioids and their receptors • Opioids – (e.g. endorphines, enkephalins, dynorphin)

INFLUENCE OF ENDOGENOUS OPIATES Opioids- are morphinelike substances synthesized in many regions of the CNS (including pituitary gland)

Endorphin- (endogenous morphines) bind with opiate receptors on neuron to inhibit pain impulse transmission Enkephalins – (endogenous opiates in the “kephalus”Greek for brain) a naturally occurring analgesic thought to inhibit substance P release

Endorphins • Levels vary among individuals • People with:  endorphin levels  feel less pain  endorphin levels  feel more pain

Gate Control Theory Melzack and Wall (1965)

•holistic nature of pain. •many interventions such as imagery and distraction are used to help relieve a client’s pain. •related to the transmission of painful stimuli

The theory states that:

•

Small diameter nerve fibers conduct excitatory pain stimuli toward the brain

•

Large diameter nerve fibers appear to inhibit the transmission of pain impulses from the spinal cord to the brain

The theory states that:

3. gating mechanism that is believed by some to be located in the substantia gelatinosa cells in the dorsal horn of the spinal cord 4. The excitatory/inhibitory signals at the gate in the spinal cord determine the impulses that eventually reach the brain

The theory states that:

5. Limited amount of sensory information can be processed by the nervous system at any given moment.When too much information is sent thru, certain cells in the spinal column interrupt the signals as if closing the gate. 6. The brain also appears to influence the gating mechanism.

Gate Control Theory Con’t…

• Works on the premise that the SG (located in dorsal horn) modulates afferent nerve impulses and influence transmission of T cells. This activates a central controlling mechanism

Gate Control Theory Con’t…

• gate closes - impulses are less likely to be transmitted to the brain.

Gate Control Theory Melzack and Wall (1965)

• In Dorsal Horn of Spinal Cord Brain

. A-Beta Sensory, Proprioception, Etc

SG

A-Delta, C Fibers Pain Transmission

T *Inhibitory Synapse (Large Diameter NF) *Facilitator Synapse (Small Diameter NF)

Gate Control Theory Updates (from Black, Hawks & Keene, 2002):

• Gate control theory is correct in predicting that nociceptive information was modifiable in the dorsal horn • Researches have shown that the “Gate” conceptualization is no longer tenable. • Inhibition of pain is not limited to the SG • “This theory is out of date” • Many researches has more fully delineated the physiologic mechanism underlying pain inhibition • “Theory is incomplete and even incorrect in details” (Fields, in Hawthorn, 1999)

Responses to Pain

Responses to Pain • Physiologic • Behavioral • Other affective response

PHYSIOLOGIC REACTIONS TO PAIN • involve the activation of the sympathetic nervous system • evokes the “fight or flight” reaction • with catecholamine release from adrenal medulla.

Manifestations during the Fight-or Flight Response: 

Increased mental activity

 RR  HR

  Cardiac Output

 arterial BP  fatty acids

• Dilated pupil • Bronchial Dilation  glucose  flow to skeletal muscles

Physical Response • • • •

Moving Away Protecting painful area Restlessness Facial Expression – Grimacing, biting lips, tensing of limb and body muscles • Voluntary and involuntary protective body movements (Guarding painful area)

Psychological or Behavioral RESPONSES: • Refers to observable actions used to express or control the pain Verbal statements – praying, swearing cursing, repeating nonsensical phrases Altered responses to environment Vocal behaviors- moan, scream, sighing, crying

Psychological or Behavioral RESPONSES: • Body movements- rocking, rubbing, stretching, shifting weight, pounding, biting • Physical contact with others • Facial expression – grimace, clenched teeth, tight shutting lips, staring, wrinkling forehead, tearing

Other affective responses: • • • •

Anger Fear Depression Anxiety

Ethic and Cultural Factors Behavior related to pain is part of the socialization process

Developmental Stage Children are less able to articulate their experience or needs related to pain  puberty – emergence of pain syndrome (esp. women) * elderly – mostly affected by chronic pain

Environment & Support People Strange environment can compound pain Support network affects pain perception Other factors that affect pain perception & response: Expectations Family role

Past Experience with pain  affects the way we perceive our current pain  Negative experience with pain as children have reported greater difficulties managing pain  Impact of past experience may not be predictable  Earlier pain experience allows us to adopt coping mechanisms

Meaning of Pain Meaning of person’s pain influences his or her response to pain e.g. pain in childbirth different from pain in surgery Known vs. unknown cause of pain Meaning or experience – negative vs. positive

Expectation and the Placebo Effect Client’s expectations play a major role in a person’s pain perception and effectiveness of pain relief intervention Placebo effect – may initiate the body's endogenous opiate system activated by the expectation of relief

Nursing Process in the Care of Clients in Pain

ASSESSMENT • History and Physical Examination Intensity Location Quality Duration Pattern

COLDERR • Character: Character describe the sensation (e.g. sharp, aching, burning) • Onset: Onset when it started, how it has changed • Location: Location where it hurts (all locations) • Duration: Duration constant vs. intermittent • Exacerbation: Exacerbation factors that make it worse • Relief: Relief factors that make it better • Radiation: Radiation pattern of shooting/spreading/location of pain away from its origin

The alphabet of PAIN Protective or Palliative (Ask what provokes or worsens pain; what relieves or causes pain to subside

Quality or Quantity (Ask for quality, associated symptoms, pattern, interruption of ADL)

Region and Radiation (Location of pain and if it is radiating)

Severity (Use Pain scale; description of Intensity) Timing (Ask when pain began, onset – sudden or gradual, constant or intermittent?; time of day it occurs)

Assessment Scales • For adults, adolescents, and older children (including those with language barriers) who can say or point to a number, or who can point to a face.

• a) Numerical Scale – 0 to 10 (11-point intensity Scale) • b) Wong-Baker Faces Scale • For stoic or cognitively impaired adults, adolescents, and children: • FLACC Scale • For Neonates/Infants • a) N-PASS • b) CRIES • c) FLACC Scale

Intensity: Use PAIN SCALES

Location of Pain

Quality •Sharp- pain that is sticking in nature & intense

•Dull – pain that is not as intense or acute as sharp pain but more annoying than painful. More diffuse than sharp pain •Diffuse – pain that covers a wide area; client cannot point to a specific area without moving the hand over a large surface, eg the entire abdomen •Shifting – pain that moves from one area to another such as from the lower abdomen to the

Periodicity •Continuous – pain that does not stop •Intermittent – pain that stops and starts again •Brief or transient – pain that passes quickly

Patterns • • • • •

Precipitating Alleviating Associated Symptoms Effect on ADL Coping Resources

Nursing Diagnosis

• Primary Nursing DX:

• Alteration in Comfort: Pain related to tissue injury from incision, ischemia, tumor encroachment in organs

Nursing Management of Pain • Acknowledgement and Accepting Client’s Pain • Assisting Support Persons • Reducing misconceptions about pain • Reducing fear & anxiety • Preventing pain

Pharmacologic Interventions for Pain

• Medications: most common approach to pain management – Analgesics • Non-narcotic (Acetaminophen) • NSAIDS • Narcotic analgesic • Adjuvant analgesics (antidepressants, anticonvulsants) • Local anesthesia

WHO Analgesic Ladder

Non-narcotic or non-opioid analgesics

• For nociceptive or neuropathic pain • Effective in somatic components of nociceptive pain such as joint and muscle pain • May also reduce fever and inflammation

Non-narcotic analgesics • For mild to moderate pain • Drug types: • Acetaminiophen • Salicylates • NSAID

Non-Steroidal Anti Inflammatory (NSAIDs) • Temporary relief from mild to moderate pain • Long-term treatment for osteoarthritis and rheumatoid arthritis • Acts mainly to interfere with prostaglandin synthesis

Advantages of NSAIDs: • Taken orally • Don’t cause CNS or respiratory depression when used in therapeutic dose • Generally available without prescription

NSAIDs: Main teaching points • Act by inhibiting enzymes (prostaglandin, cyclooxygenase, etc) that normally enhance pain • Peripherally acting painkiller • Not addictive • Some potential problems with gastric side-effects • Some central S/E

Example of NSAIDs: • • • • •

Ibuprofen Mefenamic acid Naproxen Piroxicam COX-2 Inhibitors (Vioxx, Celebrex)

Narcotic analgesics • Natural or synthetic medications with morphine-like actions • Derived from opium • (e.g. morphine) or Synthetic narcotics (Oxycodone) • act within and outside CNS

Opioids • • • • • • •

Related to morphine Works at morphine receptors Physical dependence Psychological dependence Development of tolerance Withdrawal effects Long term use effects (possibly enhancing pain) • Interaction with benzodiazepines (central effect)

Examples of Opioids • Mixed or Weak Opioid – Butorphanol (Stadol) – Hydrocodone (Vicodin) – Codeine (Tylenol No. 3) – Tramadol

Strong Opioid Analgesic • Meperidine HCl (Demerol) • Morphine Sulfate (Morphine) • Methadone (Dolophine)

Common Opioids Side Effects • Constipation • N/V • Sedation – Tolerance – 3-5 days – Consider stimulants (e.g. Ritalin) – Alternative route (epidural)

Common Opioids Side Effects • Respiratory Depression – (first 12-24 hrs) – Give opioid antagonist Naloxone Hydrochloride (Narcan) – Stop, Change, Slow

• Pruritus • Urinary Retention

Adjuvant analgesics or coanalgesic • Drugs that have other primary indications but are used as analgesics in some circumstances. • Given in combination with opioids or used alone to treat chronic pain. • Examples of Adjuvant analgesics: – Antidepressants: (such as tricyclic antidepressants) promote serotonin and inhibit pain, promotes sleep – Anticonvulsants – Local and topical anesthetics

Medications to Ease Pain

1. Oral 2. Sublingual 3. Buccal administration (Actiq – oral transmucosal fentanyl citrate is a flavored lozenges on a stick) 4. Intranasal 5. Rectal 6. Transdermal (e.g. Lidocaine patches, EMLA) 7. Parenteral Route: IM, IV, SC - Patient controlled analgesic (PCA) 8. Intrathecal, , Narcotic Infusion, epidural

Patient Controlled Analgesia (PCA) Pumps • Demand analgesia • A specific type of SC, IV or intraspinal delivery system • A dose of opioid delivered when patient decides the needed dose • Infusion system • Management of acute pain, post operative pain and cancer pain.

PCA Advantages • Less nurse time • Patient reports better pain relief • Requires less total analgesic meds than patients on PRN meds • Have greater sense of Control

• Physical Cutaneous Stimulation • Transcutaneous Electrical Nerve Stimulation (TENS) • Cognitive-Behavioral Interventions

Transcutaneous Electrical Nerve (TENS) Stimulation • nerve conducts electrical current and so cannot conduct pain

Non-Pharmacologic Interventions for Pain a)Heat & Cold Application b)Guided Imagery c)Hypnosis d)Meditation e)Biofeedback f) Yoga

Non-Pharmacologic Interventions for Pain • Therapeutic touch • Cutaneous Stimulation (Massage) • Distraction • Deep Breathing and Relaxation • Music • Progressive Relaxation Training

Surgical Interventions to Manage Pain • Nerve blocks – interrupts nociceptive transmission – Chemical interruption of pain pathway – Common in dental work

Surgical Interventions to Manage Pain • Neurosurgical interventions – Implantation of drug-infusion system – Neuroablation – destroys nerves – Neuroaugmentation – electrical stimulation

Invasive Interventions to Manage Pain

Non-Pharmacologic/ Alternative Interventions for Pain Acupuncture

Alternative Therapies to Ease Pain

Evaluation & Documentation • Evaluation: utilizes client perception and pain rating scale to document changes in pain • Reassessment • Important Considerations • Documentations • (show video)

The Ten Commandments of Pain Management • • • •

Thou shalt believe the patient’s report of pain. Thou shalt assess and reassess the patient’s response to pain interventions. Thou shalt not be afraid of prescribing or administering opioid analgesics. Thou shalt not prescribe inadequate amounts of any analgesic. Cont’d

The Ten Commandments of Pain Management • Thou shalt not use the abbreviation PRN for continuous pain, but ATC. • Thou shalt reassure the patient and family that risk of opioid addiction is rare. • Thou shalt provide support for the whole family. • Thou shalt not limit thy approach simply to the use of analgesics, but also adjuvant drugs and “mind-body” techniques.

The Ten Commandments of Pain Management

• Thou shalt prevent or treat side effects of opioids. • Thou shalt not be afraid to ask colleagues’ advice. Modified from Twycross, R: Practical Palliative Care Today. Spring 2000, Vol. 2. Center for Palliative Studies at San Diego Hospice, San Diego.