E2 Pain Flashcards
Acute pain is ____
protective –> promotes withdrawal from painful stimuli, allows injured parts to heal, and teaches avoidance
What are the 3 parts of the nervous system involved in the sensation, perception, and response to pain?
- Afferent pathway: begin in PNS, travels to CNS (Sensation)
- Interpretive centers: Cortical and subcortical areas of brain- Brain stem, midbrain, cerebral cortex (Interpret sensation)
- Efferent Pathway: CNS back to PNS
(elicit physical and mental response to pain)
Define Nociception
Process of feeling pain or sensation
Decine Nociceptors
Pain receptors
Free nerve endings in afferent PNS that when stimulated calls nociceptive pain
We target these pain receptors when we give pain meds
Nociceptive stimuli
stimuli of a certain intensity that cause or are close to causing tissue injury
Sharp objects, electric current, heat, coldness, chemical stimuli (pain meds)
With low intensity may not be activated (prick finger)
Where are nociceptive receptors located?
skin, dental pulp, periosteum, meninges, some internal organs
None or very few in brain, alveoli, deep tissues
Neurotransmitter modulate control related to the _____ of pain impulses and can be _____
transmission
inhibitory or excitatory
Endorphins
Natural neurochemicals or endogenous opioids that aid in inhibiting the pain response
-Produced in brain
-Produce sense of exhilaration that dulls or inhibits pain
What are the 4 steps in the physiology of pain (nociception)?
- Transduction
- Transmission
- Perception
- Modulation
Transduction
Painful stimuli concerted to action potentials at the sensory receptor: occurs at A-DELTA fibers and C FIBERS
-Substances/chemical mediators released as a result of a direct injury and inflammation (prostaglandin)
Define prostaglandin
important mediator that when activated lowers the pain threshold
A delta
-Small diameter
-Less of these
-Myelinated: rapid transmission of pain
-Pain is sharp, stinging, cutting, pinching
-Localized
C Fibers
-Small diameter
-More of these
-Unmyelinated: slow transmission of pain
-Dull, burning, aching
-Poorly localized
A alpha and A beta
Large diameter
Don’t transmit pain signals
Transmission
Process where action potentials move from peripheral receptors to the spinal cord and then the brain
-A delta and C-fibers are responsible for this transmission
Perception
Brain then receives these signals adn interprets them as painful
What are the factors that influence perception of pain
-Attention
-Distraction
-Anxiety
-Fear
-Fatigue
-Previous experiences
-Genetics
-Age
-Cultural impact
-level of health
Pain tolerance
-Greatest intensity of pain a person can handle
-Varies greatly overtime
-Childbirth: Tolerance is way up
-Increase: Alcohol, persistant opioid use, hypnosis, distracting, strong faith
-Decrease: fatigue, anger, bordem, sleep deprivation, apprehension
Pain threshold
-Lowest intensity of pain that a person can recognize
-Perceptual dominance occurs
-Intense pain at one location may increase threshold in another location
-Increase threshold: stress, sex, exercise, physical exertion, acupuncture
Opioid tolerance
state of adaptation in which exposure to a drug causes changes in drug receptors that result in reduced drug effects overtime
Modulation
Synaptic transmission of pain signals in altered
-Can be amplified or dampened
-endorphins mediate pre-synaptic transmission
-Morphine mimics the effect of endorphins
What is the gate control theory
Theory that if we can block the pain before it gets to the thalamus/cortex we can stop or lower pain perception (stimulate A delta and C-fibers)
Touch, rubbing skin, massage, distraction, acupuncture, getting active
Signs and symptoms of inflammation are produced by
chemical mediators
What are the S/S of chemical mediators
pain, swelling, redness, heat, immobility
Chemical mediators begin to be present in the plasma and activated by _______
tissue injury
What are 2 examples of chemical mediators?
Histamine & Arachidonic Acid Metabolites (prostaglandins & leukotrienes)
What do prostaglandins do?
Promote inflammation, pain, and fever
COX-1 & COX-2
-Protect the lining of the stomach from the effects of acid
-Promote blood clotting by activating platelets
-Affect kidney function–> dilate blood vessels that lead to the kidneys
How long does acute pain last?
Transient, can last seconds to months (no longer than 3 months)
Pain stops when chemical mediator or injury is gone
How long does chronic pain last?
more than 3-6 months
Acute pain stimulates the ___ causing
ANS
physcial response to pain such as Increased HR & BP, diaphoresis, dilated pupils, anxiety
Chronic pain serves no _____ and has no ____ response
No purpose
No ANS response
Acute pain is mostly ____ while chronic pain is mostly _____
Tissue input
Emotions
Chronic pain stimulas is ____ the CNS
within
Nociceptive pain: Cutaneous/somatic pain
Involves? Complaints? Location?
Involves MS system
Complaints: constant and achy
Location: Well-Localized (muscles, blood vessels, connective tissue)
Delta fiber (mostly)
C-fibers (some)
Nociceptive pain: Visceral Pain
Involves? Complaints? Location?
Involves Organs & inflammation sometimes present
Complaints: cramping, splitting, N/V, Diaphoresis
Location: Poorly-localized (internal organs, diffuse, deep)
C fibers
Neuropathic pain: Neuropathic pain
Involves? Complaints? Location?
Involves Nerves
Complaints: shooting, burning, electric shock, sharp, numb, motor weakness
Location: Poorly localized (peripheral nerves, spinal cord, brain)
Referred pain:
Pain is felt at a distance from the actual pathology
Common in Visceral pain
Ex. MI pain felt in chest/jaw/left arm
Ex. Pancreatitis –> shoulder pain
Phantom pain:
Sensation of pain that originates from an amputated part
-Constant (Chronic)
Who should not take tramadol?
If Seizure hx
If taking CNS depressants (SSRIs & MAOIs)
What pain med can only be partially reversed by narcan?
Gabapentin
Gabapentin is used specifically for
neuropathic pain
NSAIDs
Non-steroidal anti-inflammatory drugs
Nonselective COX inhibitors and Selective COX inhibitors
What NSAID is not a true NSAID
Acetaminophen/ Tylenol
What NSAID do people take to reduce formation of thromboxane?
Aspirin (reduces platelet activation)
Which type of NSAIDs has serious cardiovascular thrombotic events and has a 87% chance of developing a long-term ulcer?
Selective COX-2 inhibitors
What are the 2 black box warnings for NSAIDS?
Increased risk of Cardiovascular thrombotic events such as stroke or heart attack
Increased risk of GI adverse effects (Elderly at great risk)
Salicylate poisoning/ toxicity
Aspirin side effect if taken too long or overdose
Acute: N/V, Seizures, cerebral edema
Chronic: N/V, tinnitus, hearing loss
Reye’s syndrome
-Aspirin Side effect
-NO aspirin for Kids
-Can cause severe brain/liver damage, high mortality rate
What is the most potent NSAID?
Ketorolac (IV or IM)
Used 5 days or less
What are the limitations of acetaminophen (Tylenol)?
-Ceiling effect (won’t feel above 1000mg)
-No anti-inflammatory properties (choose other NSAID if inflammation)
What is the adult dose restriction of acetaminophen?
4grams/ 24 hours
What is the acute ingestion antidote for acetaminophen?
acetylcysteine- may cause vomiting
Chronic alcohol users should limit acetaminophen (tylenol) use to ____
<2 g/ 24 hrs
Avoid taking acetaminophen in patients who have
hepatitis or liver dysfunction
When do you use IV tylenol (ofirmev)
-Acute pain/ post op pain
-Usually in combination with opioids
-Sometimes first dose given at the time of incision or in pre-op and continued post off
What are the opioids?
-Morphine
-Hydromorphine
-Fentanyl
-Meperdine
-Codeine
-Oxycodone
-Hydrocodone
All opioids are
High Alert Drugs
What do you need to assess prior to giving an opioid?
LOC, BP, HR, RR
If RR <10/min, assess level of sedation (Don’t give)
What are the interactions for morphine?
Alcohol & CNS depressants (like benedryl)
Nursing considerations for Opioids
-May impair mental or physical abilities required for operating machinery or car
-PO dose is higher than IV dose
Common and serious adverse reactions of opioids
CONSTIPSATION
Drowsiness/ fatigue
Confusion, dry mouth, itching
Respiratory depression
CNS depression
What opioid do opioid abusers want?
Hydromorphone (dilaudid)
What opioid is EXTREMELY potent?
Fentanyl
0.1mg IV fentanyl = 10mg IV morphine
What opioid is not given often but is given usually in ED for migrane or shivering?
merperidine
What are important things to known about merperidine?
-Lots of drug/drug interactions
-With repeated doses it breaks down to toxic metabolite
-Can cause seizures
What opioid do alot of people say they are allergic to due to GI problems?
Codeine
Which opioid is a cough suppressant?
Hydrocodone
What is the opioid of choice for detoxification treatment in opioid addiction?
Methadone
Longer half-life (1 or 2 x a day)
What are the adverse effects of naloxone?
-Abrupt reversal of opioid effects with recurrent pain
-Increased BP
Strength of Opioids from lowest to highest
LOWEST strength
Codeine
Hydrocodone
Oxycodone
Merperidine
Morphine
Hydromorphone
Fentanyl
HIGHEST
