Pain

Psychogenic Pain

Experienced in the absence of any diagnosed physiologic cause or event. Involves a long history of severe pain.

Other Types of Pain

Intractable, psychogenic, total, cancer

Mechanical

- trauma to tissues (e.g. surgery); edema; tumor; blockage of a duct; muscle spasm

Chemical

- lactic acid; bradykinins, enzymes

Radiating pain

- perceived at the source of pain and extends to nearby tissues e.g. cardiac pain - felt in chest but also (L) shoulder and arm

Phantom pain

- perceived in a body part that is missing (e.g. amputated leg)

Referred pain

-perceived in an area distant from the site of stimuli - commonly occurs with visceral pain

Prevalence of Pain in Canada

According to the 2011/2012 Canadian Community Health Survery (CCHS), when asked "Are you usually free of pain and discomfort?" chronic pain affected approx. 22% (6 million) aged 18 or older (Statistics Canada, 2015). http://www.statcan.gc.ca/pub/82-003-x/2015001/article/14130-eng.htm "One in five Canadians suffers from daily pain that is often unmanageable." (Lynn Cooper, pain sufferer & president of the Canadian Pain Coalition, 2010)

2. Transmission

Action potential continues from: site of injury to spinal cord Spinal cord to brainstem & thalamus thalamus to cortex for processing

Segment 1: Transmission to spinal cord

2 types of peripheral nerve fibers are responsible for the transmission of pain impulses from the site of transduction to the spinal cord 1) A delta fibers - small, myelinated Transmit impulses rapidly. Produce sharp, localized pain (e.g. cuts, electric shock, blunt trauma). Associated with acute pain. 2) C fibers - large, unmyelinated Transmit impulses more slowly. Produce dull, aching, burning pain from deeper structures such as muscles & viscera. Associated with persistent pain. Therapies that ↓ the movement of ions across the cell membrane such as local anesthetics and anticonvulsants (Tegretol) prevent transmission via this type of mechanism.

Baseline Assessment

A person who has screened positive for the presence, or risk of, any type of pain requires a further comprehensive and systemic pain assessment addressing; Previous pain history Sensory characteristics of pain (severity, quality, onset and duration, location, and what makes the pain better or worse) Impact of pain on usual everyday activities (ability to work, sleep, experience enjoyment) Psychosocial impacts on person or others (depression, financial) Past interventions that were effective

The Pain Experience

A person's pain experience is influenced by a number of dimensions & factors that may: increase or decrease the person's perception of pain increase or decrease the ability to withstand pain affect responses to pain

Persistent Pain

A survey (2008) of 600 moderate to severe Canadian pain sufferers revealed that chronic pain patients report the lowest health-related quality of life when compared to others with chronic illnesses such as emphysema, kidney failure & heart disease. (Canadian Pain Coalition,

1. Transduction

A) Noxious stimuli causes cell damage with the release of sensitizing chemicals (Prostaglandins, Bradykinin, Serotonin, Substance P, Histamine B) These substances activate nociceptors and lead to generation of action potential

The Pain Experience

Affects a person's physical health, emotional health & well-being Can be the primary problem or associated with a specific diagnosis, treatment or procedure

Reasons for under-treatment

Among clients: Attitudes toward pain and opioids play a major role in clients underreporting their pain Fears of addiction and side effects often make clients reluctant to report pain or take opioids Many clients believe that pain is inevitable and also do not want to complain

Reasons for under-treatment

Among health care professionals: lack of knowledge and skills to assess and treat pain inaccurate and inadequate information re. addiction, tolerance, respiratory depression and other side effects of opioids Nurses tend to routinely administer the smallest prescribed analgesic dose when a range of doses is prescribed

4. Modulation

Neurons originating in the brainstem descend to the spinal cord & release substances (endogenous opioids that inhibit nociceptive impulses)

Multidimensional Tools

Are also available for the assessment of chronic pain, cancer pain or complex pain conditions Two commonly used scales are the McGill Pain Questionnaire (MPQ) and the Brief Pain Inventory (BPI). Both use a combination of indicators that measure pain intensity, mood, pain location (body diagram), verbal descriptors & questions about the effectiveness of medications. Most often used for research purposes or for patients being treated over an extended period

Assessment of Pain in Children

Assessment needs to be suited to the child's developmental level & personality and also to the situation It is very important to know the word the child uses for pain (e.g. hurt, boo boo) A parent's assessment of their child's pain should not outweigh the child's report. But if the child is unwilling or unable to provide a self-report then the family's reports of pain should be incorporated into the assessment A change in behavior, appearance, & activity level are all important to note as they may indicate a change in pain intensity

What to do if someone cannot report their pain

Attempt to have the person self-report - e.g. a simple yes or no answer or behavioural cues such as nodding or pointing to the assessment tool to indicate presence or absence of pain Rely on behavioural indicators - several different behavioural pain assessment tools are available for use in neonates & infants; children; adults, nonverbal, critically ill adults, and use in older adults with cognitive impairment Obtain proxy reporting from family or caregivers about potential behaviour that may indicate pain. Important to combine proxy pain assessments (could be inaccurate with other evidence such as direct observation with behavioral pain scales, the person's diagnosis, findings from health history & physical exam Do not place emphasis on vital signs (heart rate, blood pressure, respiratory rate) as they may increase, decrease or remain stable during painful procedures and should not be the sole source of information on the presence of pain Remember, validated behavioural tools are only 1 component of a comprehensive pain assessment. If a person is unable to self-report , the interpretation of a person's observed behaviour & proxy reporting from family & caregivers still may not provide information on the presence, quality and intensity of pain.

Preverbal & Nonverbal children

Behavioral measures can reliably & validly indicate that infants are experiencing pain. These measures include: Crying Facial expressions Motor responses Body posture Activity Unusual quietness Restlessness Appearance

Culture

Behaviors vary greatly within a culture and from generation to generation. The nurse needs to observe each client carefully, taking the time to ask the following questions: What does this pain mean to the client? Are there culturally or socially based stigmas related to this pain? Are traditional pain-relief remedies used? What is the role of stoicism? Are there culturally or socially determined ways of expressing & communicating pain? Does the client have any fears about the pain? Has the client seen or does the client want to see a traditional healer?

Duration: Acute vs. Persistent Pain

Can be acute or persistent (chronic) or both at the same time. Acute: defined as temporary, short-term pain (minutes to several weeks) but generally less than twelve weeks duration. Pain lasts only through the expected recovery period from illness, injury or surgery. Goes away when healing occurs. Usually sharp & localized although it may radiate

International Association for the Study of Pain (IASP)

Defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" Makes clear that one can experience pain in the absence of identifiable tissue damage

Pain in Canada Fact Sheet Highlights (2014)

Canadians are left in pain following surgery - only 30% of ordered medication is given; 50% are left in mod-severe pain Acute post-op pain is followed by persistent pain in 10-50% after common surgical procedures (groin hernia repair; breast & thoracic; hip & knee replacements, etc..)10% will be left with post-surgical nerve damage from nerves and tissues cut during surgery Severity of initial post-op pain correlates with development of persistent pain 50% waiting for care at Canadian pain clinics have mod-severe levels of depression & 34% report thinking about suicide Chronic pain associated with worst quality of life as compared with other chronic illnesses such as COPD or heart disease Veterinarians receive 5 times more training in pain Pain research grossly underfunded 0.25% of total funding for health research Need to have a national pain strategy

3. Perception

Conscious experience of pain

Impact of Pain

Consequences of untreated pain include unnecessary suffering, physical dysfunction, anxiety and/or depression, impaired recovery from acute illness and surgery & sleep disturbances Pain can occupy all of a person's thinking, force changes in the ability to function each day & produce major changes in a person's life Poorly managed or unrelieved pain places a burden on the person living with pain as well as the health care system & society (Lynch, 2011). It is estimated that the cost to the Canadian economy is $56-60 billion a year (Canadian Pain Society, 2014). Can affect quality of life, interactions with family & friends, sense of well being & financial resources Double the risk of suicide as compared with people without pain (Canadian Pain Coalition, 2014) Pain is still considered to be just a symptom of an underlying illness rather than being recognized as an illness on its own

Environmental Factors

Depending on the person's surroundings, the sensation of pain may be blocked by the individual intensely concentrating on the task at hand (e.g. during sports activities - may finish the game with a severe injury or soldiers who have been severely injured on the battlefield know they will now be leaving this intense environment.)

Neuropathic

Difficult to diagnose because there are no obvious signs of disease More difficult to treat than nociceptive pain e.g. burning pain of shingles or phantom limb pain Triggered by nerve damage or malfunction of peripheral & central nervous systems resulting in abnormal signaling (burning, tingling, numbness or piercing quality; or sharp, shooting episodes as well). Approximately 8% of Canadians (2.5 million) have neuropathic pain sometimes in combination with other types of pain e.g. fibromyalgia, osteoarthritis, migraine headaches

The Sociocultural Dimension

Each person's response to pain is strongly influenced by family, community & culture. Sociocultural influences affect the way in which a person tolerates pain, interprets the meaning of pain, and reacts verbally & nonverbally to pain. Refers to factors such as demographics (age, gender, education, socioeconomic status), support systems, social roles & culture. Nurses need to be aware of their own values & beliefs related to pain. Nurses may place a higher value on silent suffering or self-control in response to pain. Therefore it is important to identify your own personal attitudes about pain in order to provide culturally competent care for clients in pain.

Client's Right

Effective pain management has been established as a client's right and therefore requires that health care professionals assess and manage pain, and attend to the subjective quality of pain in order to successfully provide effective pain relief. The International Association for the Study of Pain (IASP) focuses on a specific type of pain each year in order to increase the knowledge of health care providers

Factors Influencing Pain

Factors that influence the individual's perception of and reaction to pain include: Developmental stage Gender Environmental factors

Complexities of Assessing Pain

Failure of health care professionals to ask clients about their pain and to accept and act on clients' reports of pain is probably the most common cause of unrelieved pain. Basic pain assessment is a simple but often overlooked task. Even when appropriate assessments are made, health care professionals may not accept the findings & therefore take appropriate action. Nurses must be aware that a comprehensive pain assessment is influenced by factors including the person's illness or level of disability (pain in multiple areas), age, developmental stage, education level or cognitive status, ability to communicate, culture, ethnicity, biology, previous experiences with pain & reluctance to report pain. Spirituality may also influence a person's beliefs & behaviour around pain. These factors could influence how a person reports pain and whether they would seek help for it.

Other Factors

Fatigue, lack of sleep also are related to pain experiences. Can ↓ pain tolerance. Previous experiences with pain are likely to influence the person's response to a current pain episode The responses of health care providers to the person in pain can influence the person's response during the next pain episode. If providers were empathetic & utilized effective strategies the client will be more comfortable during following pain episodes. If it was a negative experience, anxiety may set the client up for a more painful episode

Gender

Gender differences in pain do exist. Conditions such as fibromyalgia, migraines irritable bowel syndrome and tempromanidibular joint pain (TMJ) are more common in women as compared to men (IASP, 2007). Girls may be permitted to express pain more openly than boys. If a person has been raised to believe that males should not cry and must tolerate pain then the male client may appear withdrawn and refuse pain meds.

Most relevant definition (Margo McCaffery)

In 1968, McCaffery defined pain as "Whatever the person experiencing it says it is, and existing whenever the person says it does." This is a broad definition of pain among the many definitions and descriptors of pain and the one most nurses find relevant to practice.

The 5th vital sign?

In 2000, The Joint Commission on Accreditation of Healthcare Organizations in the U.S. advocated assessment of pain as the 5th vital sign. This approach soon became endorsed internationally as it was believed pain was more likely to be undertreated than overtreated. In 2016, Physicians at the American Academy of Family Physicians (AAFP) Congress of Delegates voted to eliminate pain scores as the "fifth vital sign," partly in reaction to being seen as a scapegoat for the nation's opioid overdose epidemic.

Pain reaction

Includes autonomic nervous system (ANS) & behavioral (BEH) responses to pain ANS (e.g. automatic reaction that protects individual from further injury - remove hand from hot object) BEH (e.g. learned response used as method of coping with pain)

Pattern

Indicates that individuals will respond in a different manner to a similar stimulus. Implies the pattern of the stimulus is more important than the specific stimulus. Again does not take into account the psychosocial component of pain

Deep somatic pain

Involves stimulation found in muscle, bone joints & ligaments May be aching, dull & more diffuse e.g. an ankle sprain is an example of deep somatic pain

D) Modulation

Involves the activation of descending pathways that exert inhibitory or facilitatory effects on pain transmission Depending on the type & degree of modulation, the nociceptive stimuli may or may not be perceived as pain Modulation can occur at the periphery, spinal cord, brainstem & cerebral cortex Chemicals such as serotonin, norepinephrine & endogenous opioids (endorphins & enkephalins- morphine like neurotransmitters produced within the body) may be released than can inhibit pain transmission

Superficial somatic pain

Is confined to nociceptors found in the skin. May also be referred to as cutaneous pain. May be sharp, burning - well localized. Usually felt very quickly & diminishes as time goes on.

Physiological Dimension of Pain A) Transduction

Is the conversion of a mechanical, thermal or chemical stimulus into a neuronal action potential. Examples of each include:

Timing/Treatment

Is the pain constant? Does it come and go? Is it worse at any particular time? What medications and treatments are you currently using? How effective are these? Do you have any side effects from the medications and treatments?

Reassessment & Ongoing Assessment of Pain

It is essential that pain is reassessed on a regular basis according to the types & intensity of pain & treatment plan Pain is reassessed: At each new report of pain & new procedure, when intensity ↑, & when pain is not relieved by previously effective strategies After the intervention has reached peak effect (15-30 mins after parenteral drug therapy, 1 hr after oral admin, 1 hr after immediate release analgesic, 4 hrs after sustained release analgesic or transdermal patch, 30 mins after complementary/alternative therapies Acute post-op pain should be regularly assessed depending on the operation & severity of pain, with each new report of pain & after each analgesic according to peak effect.

Persistent pain

It is estimated that 1.5 million Canadians aged 12 to 44 report persistent pain (Ramage-Morin & Gilmour, 2010). Prevalence of persistent pain has been shown to increase with age & has been identified in approx. 65% of older adults living in long-term care (Lynch, 2011)

Avoiding Stereotyping

It is extremely important to provide individualized care rather than assuming that a patient of a particular background will exhibit more or less pain. It is important to realize that stereotypes exist and become sensitive to how stereotypes negatively affect care.

Understanding pain

It is important to understand thoroughly the multiple dimensions of pain in order to effectively assess and manage pain. Many health care professionals are involved in pain management - Nurses have a central role in assessment & management

Experience of Pain

It is the rare individual that does not experience pain at some point during their lives. For some, it is a minor inconvenience while for others it is a major problem that causes suffering & reduces overall quality of life Although pain is uncomfortable and unwelcome it does also serve as a protective role (warning of potentially health-threatening conditions)

TRUTH

It would be impossible to think that we will be able to determine the cause of all pain clients report Symptomatic relief of pain should be provided while the cause of pain is being investigated Even with severe pain, periods of physiologic & behavioral adaptation occur, leading to periods of minimal or no signs of pain. Lack of pain expression does not mean lack of pain Anxiety is often associated with pain but it is not clear that anxiety necessarily makes pain more intense When an appropriate scale is used and the client is given time to process information and respond, many can use a pain rating scale

Older Adults

Make up a large percentage of the individuals within the health care system It is important to recognize that pain is not an expected consequence of aging. The prevalence of pain is generally ↑ due to both acute & chronic health conditions. Pain threshold does not appear to change with aging, although the effect of analgesics may ↑ due to physiological changes related to drug metabolism & excretion.

Cancer pain

May be acute or persistent Most cancer pain is a direct result of tumour involvement Pain can also be associated with treatment (surgery or radiation) or not associated with cancer (trauma, arthritis, etc.)

Older adults

May be reluctant to report pain Sensory & cognitive impairment may make communication more difficult

One dimensional tools

Measure one element of the pain experience - intensity. Assist health care providers to identify the effects of administered medications or nonpharm interventions on pain intensity. There is no right or wrong number for clients to report. They are using a very objective tool to report a subjective experience. Believe the pain rating the client reports. Again remember that client self report is the gold standard for assessment. Some clients prefer to use words over numbers.

Criticism of expansion of GCT (1996)

Melzack suggested that in the absence of modulating inputs from a missing limb, the active neuromatrix produces a neurosignature pattern perceived as pain. Emphasizes the role of the brain in sustaining the pain experience. Critics have argued Melzack's theory does not contribute to the understanding of how psychological factors influence pain.

Nociceptive

Most common type of persistent pain constant stimulation of pain receptors & signals tissue damage in the skin, bone, joints or viscera (aching, throbbing quality) e.g. arthritis pain & fibromyalgia

People who are unable to self-report may include:

Neonates, infants & preverbal children; Older adults with cognitive impairment (such as dementia); Persons with intellectual disability; Critically ill or unconscious persons; Persons who are terminally ill

Neuropathic pain

Neuropathic pain is caused by a lesion or disease of the somatosensory nervous system

Perception of Pain

No two people experience pain in the same manner. Everyone has his or her own perception of pain An individual's perception of pain is influenced by variety of factors including age, gender, culture & previous experience with pain

Nociceptive pain

Nociceptive pain is considered a warning signal that results from actual or threatened damage to non-neural tissue resulting in the activation of nociceptors. Nociceptive pain occurs with a normally functioning nervous system versus abnormal functioning in neuropathic pain.

Types of Pain

Nociceptive, neuropathic, Visceral,

One dimensional Validated Self-Report Tools for Children, Adolescents & Adults - NRS, DRS, face

Numerical Rating Scale (NRS) Simple assessment tool rates pain intensity & relief on a scale of 0-10. Descriptive Rating Scales Words are on a line that describe pain from no pain to the worst pain Faces Scale Choose face that represents how they feel. Intended for use in children 5-12 yrs old but has been used in children aged 4-18 years.

Nursing's role

Nurses are the health professionals who spend the most time with clients who are experiencing pain. Key nursing roles include: Assessing pain and the client's response to it Providing pain-relief interventions & assessing the client's response Documenting & communicating this info to other members of the health care team Monitoring for adverse effects, Being an advocate for the client when pain-relieving strategies need to be changed Teaching the client & family how to manage pain at home

Role of Nursing

Nurses have an important role in screening for pain as we have the most contact with people receiving health care. When screening for the presence, or risk of any type of pain it is important to ask directly about pain rather than assuming the person or their family or caregivers will voluntarily discuss it.

A) Transduction

Occurs at the level of peripheral nerves, in particular, free nerve endings called nociceptors -respond only to intense, potentially damaging stimuli (can be from mechanical, thermal & chemical sources) Noxious stimuli from any of the 3 sources cause the release of numerous chemicals into the area around the peripheral afferent nociceptor (PAN)

C) Perception

Occurs when pain is recognized, defined & responded to by the individual experiencing the pain In the brain - nociceptive input is perceived as pain. No single, precise location where pain perception occurs. Involves several brain structures. Reticular activating system (RAS) - responsible for the autonomic response of warning the individual to attend to the pain (e.g. remove hand from hot object) Somatosensory system - localization & characterization of pain Limbic system - emotional & behavioral responses to pain Cortical structures - meaning of pain

Segment 2: Dorsal horn processing

Once the nociceptive signal arrives in the central nervous system (CNS) it is processed within the dorsal horn of the spinal column. This processing includes the release of neurotransmitters such as substance P. Some produce activation, while others inhibit activation of nearby cells. These nearby cells release other neurotransmitters.

Pain Assessment Acronym-OPQRSTUV

Onset Provoking/Palliative Quality Region/Radiation Severity Timing/treatment Understanding/impact Values

Pain Characteristics

Pain can be also be described according to specific characteristics such as: Location: body area(s) involved or body system(s) involved (somatic, visceral) Duration (acute, persistent) Frequency: how often the pain is experienced in a given time period Intensity (severity) Type of sensations (e.g. stabbing, throbbing) Cause/diagnosis (if known)

Total Pain

Pain can be understood as having physical, psychological, social, emotional & spiritual components (multidimensional).

The Pain Process

Pain is a complex process involving physiological & sensory dimensions Sensory dimensions - the perception of pain by the individual including location, intensity, pattern & quality How pain is transmitted & perceived is not completely understood

Subjective Experience

Pain is subjective, therefore it is extremely important to screen all persons for the presence, or risk of, any type of pain: On admission or visit with a health-care professional; After a change in medical status (especially with chronic health conditions such as cancer, persistent non-cancer pain, osteoarthritis, fibromyalgia or advancing age) Prior to, during and after a procedure

Location

Pain may be described according to where it is experienced in the body Radiating pain - perceived at the source of pain and extends to nearby tissues e.g. cardiac pain - felt in chest but also (L) shoulder and arm Referred pain -perceived in an area distant from the site of stimuli - commonly occurs with visceral pain Phantom pain - perceived in a body part that is missing (e.g. amputated leg)

The pain experience

Primary reason that clients access health care in Canada (Lander & Adams, 2010) & accounts for 78% of visits to ER (Canadian Pain Coalition, 2014) Can occur at any time to anyone [1 in 5 children have weekly or more frequent chronic pain; 65% of seniors living in community & 80% living in LTC] (Canadian Pain Coalition, 2014) May be the result of injury or surgery, but for others has no identifiable cause

Gate control (Melzack & Wall, 1965)

Probably the most familiar pain theory Proposes that peripheral nerve fibers that carry pain impulses to the spinal cord can have their input modified at the spinal cord level before transmission to the brain. Proposes that a gating mechanism exists at the spinal cord level where nerve transmission may be blocked by competing impulses. Synapses in the dorsal horns act as gates that close to keep impulses from reaching the brain, or open to permit impulses to ascend to the brain.

Gate-control theory (GCT)

Proposes that pain perception results from the interaction of 2 systems: 1) the substantia gelatinosa in the dorsal horns of the spinal cord 2) inhibitory system within the brain stem

Behavioral Dimension

Purposeless body movements can also indicate pain (tossing & turning in bed, flinging arms, reflexive jerking away from a painful stimulus) Rhythmic body movements (rocking back & forth or rubbing may indicate pain) It is important for the nurse to be aware that behavioural responses can be controlled, therefore they may not be very revealing. When pain is persistent there are rarely overt behavioral responses

The Cognitive Dimension

Refers to beliefs, attitudes, memories and meaning related to the pain. The meaning of pain can be particularly important. A woman in labor may experience severe pain but can manage it without analgesics because it is associated with a joyful event and also knowing that the pain will come to an end at some point. This dimension also includes pain-related beliefs and the cognitive coping strategies that people use. For example, some people cope by distracting themselves whereas others convince themselves that the pain is permanent, untreatable & overwhelming. Factors that affect cognition such as sedation, dementia, delirium and mental disability alter the pain experience and responses to pain.

The Affective Dimension

Refers to the emotional responses to the pain experience These affective responses may include anger, fear, depression & anxiety Negative emotions can impair the client's quality of life Negative emotions can become part of a vicious cycle in which pain can lead to depression which can intensify pain perception leading to further depression & impaired function. Nurses need to recognize this cycle and intervene quickly & effectively to stop it.

The Behavioral Dimension

Refers to the observable actions used to express or control the pain Facial expressions such as clenched teeth, tightly shut eyes, open somber eyes, biting of the lower lip and other facial grimacing may indicate pain or discomfort. Posturing may be used to decrease pain associated with certain movements (e.g. a client with chest pain may hold their arm across their chest or a person with abd. pain may often assume a fetal position)

Documentation of Pain Assessment

Remember that documentation of the assessment/reassessment of pain on a regular basis is essential! This may be accomplished by the nurse or by teaching the person and family/care providers to self report/report & document the findings Assess the client & family's understanding & accurate use of the selected tool & provide education on use of the tool.

Children with persistent pain

Require a more detailed pain history which includes: A description of the pain, Associated symptoms, Temporal (chronological) or seasonal variations, Impact on daily living (school, sport, play, self-care), Pain relief measures used

Assessing frail elderly, non-verbal or non-cognizant persons

Screen for the following: States he/she has pain Experiences change in condition Diagnosed with chronic painful disease Has history of chronic unexpected pain Taking pain related meds. for > 72 hrs. Has distress related behaviors or facial grimacing Indicates that pain is present through family/staff/volunteer observation

Pain Assessment Tools for Elders with Cognitive Impairment

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Categorization of Pain - Origin/Location

Somatic pain - arises from musculoskeletal system (skin, ligaments, tendons, bones) - may be sharp and well-localized or dull & diffuse

Transduction

Some of these chemicals (bradykinin, serotonin, histamine, potassium, norepinephrine, acetycholine, substance P) activate or sensitize the PAN. If the PAN is activated or excited, it will fire an action potential to the spinal cord an action potential is necessary to convert the pain stimulus to an impulse & move from periphery to spinal cord Prostaglandins are chemical substances that ↑ the sensitivity of pain receptors by enhancing the pain effect of bradykinin. Can cause vasodilation & increased vascular permeability resulting in redness, warmth & swelling of the injured area.

Pain Theories - Specifc

Specific Describes the complexity of pain. This theory demonstrates that pain neurons are as specific and unique as other specific neurons (taste, smell) in the body. The pain neurons transport the sensation to the brain to be interpreted. The transport occurs in a straight line to the brain making the pain equal to the injury. This theory does not include reference to the psychological component of pain

C) Perception

Strategies such as music, distraction, relaxation & imagery are effective pain-reducing interventions for many people. By directing attention away from the pain sensation, clients can reduce the sensory & affective components of pain. Important to consider the unconscious client who may not respond behaviorally to noxious stimuli but this does not indicate that the person lacks pain perception

Types of somatic pain

Superficial somatic pain and deep somatic pain

Other Tools for Children; oucher, poker chip, APPT

The Oucher- poster with 2 scales: numerical to 100 & photo scale (ages 3-12) Poker chip tool - 4 poker chips are used - each represents hurt (1 - little; 4 pain as bad as it can be) The adolescent and pediatric pain tool (APPT) - Measures location, quality & intensity (ages 8-17)

Persistent Pain

The Report on Pain released January, 2011 revealed that 21% of Canadians who experience chronic pain stated they had to wait more than 2 years for a diagnosis for their condition while only 54% of those who have a diagnosis have a treatment plan

Segment 2: Dorsal horn processing

The dorsal horn of the spinal cord contains specialized cells called wide dynamic range (WDR) neurons. Receive input from noxious as well as non-noxious stimuli from distant areas which may provide a neural explanation for referred pain. When the message is transmitted to the brain, the originating area of the body is poorly localized e.g. pain from liver disease is located in the RUQ of the abd. but is frequently referred to anterior & posterior neck region & posterior flank area.

Segment 2: Dorsal horn processing

The effect of this complex neurotransmitter release can facilitate or inhibit transmission of nociceptive stimuli. In this area, endogenous (within the body) and exogenous opioids play an important role by binding to opioid receptors and blocking the release of neurotransmitters (substance P) which stops pain at the spinal level

Environmental Factors

The external environment includes a variety of sources for pain Sources such as restrictive clothing, poor fitting shoes, furniture at work or at home that causes pressure, strain, discomfort or pain A different environment such as a hospital with the strange noises, lights and activity can ↑ pain.

Developmental Factors

The field of pain management for infants & children has expanded significantly. It is now accepted that anatomical, physiological & biochemical aspects that are necessary for pain transmission are present in newborns.

Screening for Pain

The following questions can be adapted to any population and can be used in persons who are able to self-report pain: Are you feeling any aching or soreness now? Do you hurt anywhere? Are you having any discomfort? Have you taken any medications for pain? Have you any aching or soreness that kept you up at night? Have you had trouble with any of your usual day-to-day activities? How intense is your pain?

GCT - pain perception #2

The second system described by GCT, the inhibitory system, is thought to be located in the brain stem. It is believed that cells in the midbrain, activated by a variety of stimuli such as opiates, psychological factors, or even simply the presence of pain itself, signal receptors in the medulla. These receptors in turn stimulate nerve fibers in the spinal cord to block the transmission if impulses from pain fibers. 1st theory to suggest that psychological factors play a role in pain perception. Helps to explain how interventions such as distraction & music provide pain relief.

GCT pain perception - #1

The substantia gelatinosa in the dorsal horns of the spinal cord - regulates impulses entering or leaving the spinal cord. In the substantia gelatinosa, impulses encounter a "gate" thought to be opened or closed by the domination of either the large-diameter fibers or the small-diameter fibers. If impulses along the small-diameter fibers outnumber impulses along the large diameter fibers, the gate is open and pain impulses travel to the brain. If impulses from the large fibers predominate, they will close the gate and pain impulses will be "turned away" at the gate. This explains why light stimulation such as massaging a stubbed toe can reduce the intensity and duration of pain.

Transduction

Therapies directed at altering the PAN environment or sensitivity are used to prevent the transduction & initiation of an action potential Decreasing the effects of chemicals released at the periphery is the basis of several pharmacological approaches to pain relief e.g. non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen (Advil, Motrin) & naproxen (Naprosyn, Aleve) which exert their analgesic effects by blocking pain-producing chemicals.

MISBELIEFS

There is no reason for clients to hurt when no physical cause for pain can be found Clients should not receive analgesics until the cause of pain is diagnosed Visible signs, either physiologic or behavioral, accompany pain and can be used to verify its existence & severity Anxiety makes pain worse Cognitively impaired elderly clients are unable to use pain rating scales

The neural mechanism by which pain is perceived consists of 4 major processes:

Transduction Transmission Perception Modulation

Segment 3 - Transmission to thalamus & cortex

Transmission of signals between the thalamus & the cerebral cortex - where the perception of pain is believed to occur.

IASP Definition

Unfortunately, this definition does not refer to persons who cannot verbalize their pain e.g. young children, cognitively impaired and unconscious clients.

Pain Assessment Tools

Using a reliable & valid pain assessment can help provide subjective criteria for pain management Important to use tools that can easily be understood by the person and their family or caregivers Choice of scale should be based on person's preferences, age, ability to verbalize, clinical condition, cognitive or developmental level, culture & ethnicity Same scale should be used each time pain is assessed & during the same level of activity It is important to understand the terminology used by the person to describe pain e.g. "ache", "discomfort". May never use the actual word "pain" as a descriptor.

Origin/Location- Visceral

Visceral pain - arises from body organs (abdominal cavity, thorax & cranium) - dull and poorly localized due to low number of nociceptors -often feels like deep somatic pain - often radiates or is referred. May be associated with nausea & vomiting, hypotension & restlessness Frequently caused by stretching of tissues, ischemia or muscle spasms (e.g. obstructed bowel)

Provoking/Palliative

What brings it on? What makes it better? What makes it worse?

Understanding/Impact on you

What do you believe is causing the pain? Are there any other symptoms with this pain? How is this pain impacting you and your family?

Quality

What does it feel like? Can you describe it? Allow to describe in his/her own words and document the same

Severity

What is the intensity of the pain? (on a scale of 0 to 10 with 0 being none and 10 being the worst possible) Right now? At best? At worst? On average? (Some people have difficulty using rating scales so ask if the pain is mild, moderate or severe.)

Values

What is your goal for this pain? What is your comfort goal or acceptable level for this pain? (on a scale of 0 to 10 with 0 being none and 10 being worst possible)? Are there any other views or feelings about this pain that is important to you or your family? Is there anything else you would like to say about your pain that has not been discussed or asked?

Onset

When did it begin? How long does it last? How often does it occur?

Region/Radiation

Where is it? (ask to point to painful area(s) Does it spread anywhere

Pain threshold

amount of pain stimulation an individual requires to feel pain. Can change - same stimuli that had caused mild pain can produce intense pain

Hyperalgesia

an increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves

Acute pain

defined as temporary, short-term pain (minutes to several weeks) but generally less than twelve weeks duration.

Thermal

extreme heat or cold

McCaffery's definition continued

has helped to change practice by focusing health care professionals' attention on the subjectivity of pain acknowledges the individual as the only person who can accurately define & describe his or her pain and serves as the basis for nursing assessment and management of persons in pain If the person says he or she has pain, the person is in pain. It is as simple as that...all pain is real! However we still need to be aware of clients who do not admit to having pain or use the word "pain"

Self-report

is the most valid source of assessment (gold standard) if the person is able to communicate

B) Transmission

is the movement of pain impulses from the site of transduction to the brain 3 segments are involved in nociceptive signal transmission Transmission along the nociceptor fibers to the spinal cord Dorsal horn processing Transmission to the thalamus & cortex

Pain sensation

same as pain threshold

Pain History for Children with Acute Pain

slide 19

Validated Pain Assessment Tools for Neonates and children

slide 22 and 23

Validated Behavioural Pain Assessment Tool for Adults

slide 25

Pain tolerance

the maximum level of pain that a person is able to tolerate

What is Pain?

universal experience; complex, multidimensional experience; personal & subjective sensation that cannot be shared with others

Intractable Pain

very hard to find relief e.g. pain from advanced malignancy. Nurses are challenged to use a number of methods to provide pain relief