w10 Flashcards
what is pain?
pain is an unpleasant, subjective sensory and emotional experience associated w/ actual or potential tissue damage, or described in terms of such damage
what is nociceptive pain?
experience of pain that occurs in response to tissue injury. it involves the neural processing of noxious stimuli that occurs when nociceptors (pain-sensing nerves) are activated by tissues damage or inflammation
what is neuropathic pain?
involves the abnormal processing of stimuli due to a lesion or disease in the peripheral or central nervous system
what are the four processes of nociception?
transduction, transmission, perception, and modulation
what is transduction?
- first process of nociception
- when tissues cells are damaged by thermal stimuli, (burn) mechanical stimuli, (cut) or chemical stimuli (chemo) the damaged cells release pain-sensitizing inflammatory substances including prostaglandins, bradykinin, histamine, serotonin and substance P
- generates electrical activity in the peripheral terminals (action potential)
what is transmission?
-second process
-pain-sensitizing and inflammatory substances around the pain nerve fibres in the extracellular fluid, creating the spread of pain message via the afferent peripheral nerve fibres to the dorsal horn of the spinal cord.
w/in the dorsal horn of the spinal cord, a synaptic transmission from the afferent (sensory) peripheral nerve to the spinothalamic tract nerves occur through a complex neurophysiologicall and neurochemical mechanisms =signalling to various higher brain centers
what are the two types of afferent peripheral nerve fibres?
fast, myelinated A-delta fibres, and the small, slow, unmyelinated C fibres
what are the A fibres?
- myelinated
- send sharp, localized and distinct sensations that focus the source of the pain and detect its intensity
- think of more acute pain like stepping on a nail
what are the c-fibres
slow and unmyelinated fibres
-that are poorly localized, burning, and persistent
think of chronic pain
what is perception?
- third nociceptive process
- conscious awareness of pain
- once a pain stimulus reaches the cerebral cortex, the brain interprets the intensity, quality, and character of the pain, and information from past experiences
- the somatosensory cortex identifies the location and intensity of the pain, and the association cortex determines how we feel about the pain
- limbic system plays a role in processing the emotional reaction to pain, and the memory of pain experience
- perception gives awareness and meaning to pain so that a person can reaction
true or false- a humans ability to remember pain depends on cognitive ability (explicitly memory)
false
-infants can even remember pain and even those born prematurely
what is modulation?
- final nociceptive phase and refers to the increase or decrease in pain signal intensity that can occur before, during, or after the pain is perceived
- once the brain perceives pain, inhibitory neurotransmitters are released- including endogenous opioids (endorphins and enkephalins) serotonin, norepinephrine, and gamma aminobutyric acid, which work to hinder the transmission of pain and help produce an analgesic effect
what pain threshold?
minimal intensity of a stimulus that is perceived as painful
autonomic nervous system vs parasympathetic nervous system w/ pain
- ANS-pain impulses ascend the spinal cord toward the brain stem and thalamus, the ANS becomes stimulated as a part of the stress response
- if pain is continuous, severe, deep, to involved the visceral organs the parasympathetic nervous system is triggered (i.e. gallbladder stones, MI)
nonverbal or behavioural indicators of pain may include:
body movements, facial expressions, and vocalizations
-bracing, splitting, protecting the painful part, rocking, body stiffening, jaw clenching, grimacing, frowning, crying, moaning, or screaming
affective responses to pain include:
social w/drawl, changes in eating or sleep patterns, stoicism, fear, anxiety, anger, or feelings of hopelessness
what is acute pain?
- usually has an identifiable cause–> either somatic, visceral, or nociceptive
- short duration (less than 6months)
- has a predictable ending (healing) and eventually resolves w/ or w/out treatment after a damaged area heals
what is chronic pain?
- defined as pain that persists past the normal time of healing
- can be intermittent or persistent
- pt may have sleep disturbances, depression, anxiety and anger
- major cause of psychological and physical disability–> leading to job loss, inability to perform ADL’s, sexual dysfunction, and social isolation
what is cancer pain
may be acute, chronic or both
- may be nociceptive, neuropathic or both
- it can be sensed at the actual site of the tumour or distant to the site
what is referred pain?
when pain is sensed at a site that is distant to the area of tissue damage
nociceptive pain is subdivided into _ and _
somatic (musculoskeletal) and visceral (internal organ)
what is breakthrough pain?
-some pts experience occasional, transitory exacerbations of their baseline pain- the pain “breaks through” the regular pain medication or treatment that adequately controls the baseline pain
what is incident pain?
when breakthrough pain is brief and precipitated by an activity-related action, such as movement, sneezing or coughing
what is idiopathic pain?
- another subtype of breakthrough pain
- not associated w/ identifiable cause and has longer duration than that of incident pain
what is somatic pain?
arises from bone, joint, muscle, skin, or connective tissues
-usually aching or throbbing and is well localized
what is visceral pain?
- arises from visceral organs, such as the GI tract, pancreas etc.
- can be subdivided:
- tumour involviert of the organ capsule, which causes aching and fairly well-localized pain
- obstruction of hollow viscus, which causes intermittent cramping and poorly localized pain
what is centrally generated pain?
deafferentation pain. Injury to either the peripheral or central nervous system. Examples:
Phantom pain may reflect injury to the peripheral nervous system; burning pain below the level of a spinal cord lesion reflects injury to the central nervous system.
what is painful polyneuropathies- peripheral pain
Pain is felt along the distribution of many peripheral nerves.
Examples: Diabetic neuropathy, alcohol-nutritional neuropathy, and those associated with
Guillain-Barré syndrome.
what is painful mononeuropathies.- peripheral pain
Usually associated with a known peripheral nerve injury, and
pain is felt at least partly along the distribution of the damaged nerve. Examples: Nerve root compression, nerve entrapment, trigeminal neuralgia.
what are the subtypes of breakthrough pain?
- Incident pain: Cause of pain is generally identifiable but occurrence may be unpredictable.
a. Predictable incident pain: Something identifiable, such as movement,
predictably causes the pain.
b. Unpredictable incident pain: Occurrence of pain is unpredictable and
may be caused by events such as bladder spasm. This pain occurs
spontaneously. - Idiopathic pain: Cause is not readily identifiable.
- End-of-dose pain: An increase in baseline pain that occurs prior to a scheduled dose of around-the-clock analgesic. Onset is usually gradual, and duration may be longer than that of incident or idiopathic pain.
what is pain tolerance
the greatest level of pain an individual is prepared to endure in a given situation
what should pain assessment include?
- obtain pain intensity
- determining pain location
- pain descriptors
- effect of pain on function/mood of pt
what dose OPQRSTV mean
- onset/origin-when/where did it start?
- palliation/provocation- what makes the pain better/worse?
- quality-what dose the pain feel like?
- region/radiation-where is your pain and dose it radiate?
- severity- score of pain (0-10)
- timing-when did pain start/how long does it last?
- understanding-what do you believe is causing this symptom? how dose it affect your life
- value-are there any other views or feelings about this symptom that are important to you or your family?
pain management goals should be _
smart
- specific, measurable, achievable, and realistic
- should have a time frame associated with them
onset of pain
- when did the pain start
- how long has it lasted
- dose it occur at the same time each day
- how often dose it recur
- is there frequent breakthrough pain or prolonged pain recovery
provocation/pain pattern
- ask pt to describe activities that cause or increase pain- specific actions that trigger it
- asking pt if the pain is worse at certain times of day, if it is intermittent, constant, or a combination of both
what is palliation/relief measure
- ask what pain-relief measure he/she uses and which measures are found to be most effective
- heat, ice, exercise, stretching, massage, imagery, relaxation, distraction, music etc
quality
-is the pain crushing, throbbing, sharp or dull, burning, shooting etc
radiation/location
-ask pt to point to painful area using their body as a guide
-when documenting pain be specific
“pt is localized in the upper right abdominal quadrant” is better than “pt states pain is in the abdomen”
severity/intensity
- we have different types of pain scales
- visual analogus scale (VAS), verbal descriptor scale (VDS), numerical rating scale (NRS)
- face scales can be used w/ children age 3-4, or those who don’t understand numbers -the Wong-baker FACES
what is radiating pain
sensation of pain extending from initial site of injury to another body pain- pain feels as though it travels down or along the body part
a rating of _ or more on a 0-to-10 scale__
5
-requires immediate attention
what is superficial or cutaneous pain
pain resulting from stimulation of skin
-pain is localized and short duration- usually sharp sensation like a needle-stick injury
what is relaxation
mental and physical freedom from tension or stress
- provides pts’ with self-control and can be used at any phase of health or illness
- includes mediation, yoga, guided imagery, and progressive relaxation exercises
guided imagery
-pt creates and image in his/her mind, concentrates on the imagine gradually becomes less aware of pain
distraction
- boredom or isolation may cause pts to focus on pain and perceive it more acutely
- distraction works best for short, intense pain lasting a few mins
biofeedback
- behavioural therapy that involves giving individuals information about physiological responses and ways to exercise voluntary control over those responses
- used to produce deep relaxation
what is acupuncture
- may help reduce chronic and acute pain
- natural Chinese medicine
- involves the insertion of acupuncture needles into specific “acupuncture points” on the pt’s body followed by the twisting of the needle up and down by hand
- acupuncture activates endogenous opioid mechanisms and may stimulate gene expression of neuropeptides
what is cutaneous stimulation (touch healing)
- stimulation of the skin to relieve pain
- a massage, warm bath, ice bag, and transcutaneous electrical nerve stimulation are simple ways to reduce pain perception
- benefits- can be done at home
therapeutic touch (TT) and Reiki
classified as boiled, training-specific therapies, the medical use of subtle energy fields and around the body for positive health effects
-involves the practitioners use of hands to help strengthen the body’s ability to heal
what is transcutaneous electrical nerve stimulation (TENS)
involves stimulation of the skin w/ a mild electrical current passed through external electrodes
- requires a physicians order
- tingling sensation can be applied until pain relief occurs
- effective for post-surgical pain
herbal supplement ginkgo biloba
may decrease the ability for blood to clot after surgery
- so increase risk of bleeding esp in pt taking anticoagulants
- needs to be discontinued at least 36 hours pre-op
how does the TENS machine work?
- it’s a battery-powered transmitter, lead wires, and electrodes
- electrodes are placed directly over or near the pain site
- hair/skin preparations should be removed before attaching the electrodes
- when pt feels pain, the transmitter is turned on and a buzzing or tingling sensation is created
what is the max dose for acetaminophen over 24hours for an adult
4grams or 4000mg -same dose limitation as aspirin (adults only)
how do we treat an overdose of acetaminophen
-acetylcysteine (Mucomyst)
NSAIDS (aspirin or ibuprofen)
provide relief for mild to moderate acute pain resulting from trauma or an inflammatory process
- NSAIDS are believed to act by inhibiting the synthesis of prostaglandins
- most NSAIDS act on peripheral nerve receptors to reduce transmission of pain stimuli
- do not depress the CNS, and do not interfere w/ bowel or bladder function
why do we avoid salicylates or aspirin in peds?
they can contribute to the development of Reye’s syndrome, caused by failure of the mitochondria, which can cause agitation, delirium and confusion
acetaminophen (Tylenol)
- has no anti-inflammatory effects and works peripherally and centrally
- adverse effect is hepatotoxicity
- dose not affect platelet function and has minimal impact on the GI tract
- for post-op/severe pain it is often combined w/ opioids b/c it reduces the dose of opioid needed to achieve successful pain control
celecoxib cannot be used with patient’s with what allergy
sulpha allergy
what is a prodrug?
a prodrug is a drug that must undergo chemical and enzymatic conversion to morphine to have an analgesic effects
ex. , codeine
- genetic variations exist on how the isoenzyme CYP2D6 converts codeine to morphone- some ppl are ultrafast metabolizers–> risk for respiratory depression=death
what is the opioid antagonist?
naloxone
adjuvants or co-analgesics
are drugs that were originally developed to treat conditions other than pain but have been show to have angelic properties
ex., amitriptyline for neuropathic pain
patient-controlled analgesia (PCA pump)
safe method for pain management that allows pt to self- administer opioid doses (morphine, hydromorphone, fentanyl) on demand w/ minimal risk of overdose
- goal is to maintain a constant plasma level of analgesic so that the problems of pre dosing are avoided
- lockouts every 6-8 minutes
PCA pumps can deliver though which sites?
IV administration, subcut, epidural, intrathecal, and transdermal route
how is PCA dosing measure?
based on weight
-any peds patient over 50kg is based on adult dosing
medication on demand (MOD)
device allows pt to access their own oral prn meds including opioids and other analgesic, antiemetics, and anxiolytics at the bedside
sucrose
oral sucrose is an effective way to reduce pain while procedures are carried out in infants-
-sweet taste is thought to trigger a release of endogenous opioids
local anaesthia
-medication to induce loss of sensation to a localized body part -can be a topical cream, or injection through the subcut or intradermal rote to the anaesthetize body part
adverse effects of local anaesthesia
itching or burning of the skin or localized rash is common after topical applications
-application to the vascular mucous membranes increase the chance of systemic effects such as a change in heart rate
regional anaesthesia
the injection of a local anaesthetic to block a group of sensory nerve fibres
-ex epidural anaesthesia, nerve blocks, and spinal anaesthesia
epidural analgesia
permits control or reduction of severe pain w/out the more serious sedative effects of parenteral or oral narcotics
-commonly used for post-op pain, labour and delivery and chronic pain esp associated w/ cancer
common symptoms from receiving anaesthesia
numbness, tingling, and coldness are common
what is the pt most at risk for after receiving anesthesia?
- injury
- never use ice/heat
- teach pt to avoid using limb until full motor function returns
physical dependence
a state of adoption that is manifested by a class-specific drug w/drawl syndrome that can be procured by abrupt cessation, rapid dose reduction, decreasing blood level of the drug or administration of an antagonist
-not the same as addicaiton
drug tolerance
a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug’s effects over time.
-not the same as addiction
addiction
- a neurobiological disease that has genetic, psychosocial, and environmental factors influencing its development and manifestations
- characterized by behaviours that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving
pseudoaddiction
patient drug-seeking behaviours that may occur when the pain is undertreated
st john’s worts
-may prolong the effect of anaesthetic agents, potentiate opioids and cause electrolyte imbalance
