Pain Flashcards
What is pain?
It’s subjective; it’s whatever the person experiencing it says it is occurring whenever he/she says it does.
An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.
What is the purpose of pain?
Warns us of imminent / actual tissue damage.
Elicits coordinated reflex and behavioural respes to keep injury to a minimumons.
As a nurse, what’s your role in pain assessment and management? (4)
Assess pain & document
Ensure delivery of effective pain relief measures
Evaluate the effectiveness of these interventions
Monitory the ongoing effectiveness
of pain management strategies.
How do we feel pain?
Nociception
- A number of neurotransmitters are released into the body; Na&K channels open & close. Peripheral nerves fire & send to spinal cord
- Peripheral nerve message goes to spinal cord then to brain. Pain is processed before it goes down the spinal cord to the motor nerves at the area w/ pain
What are the classifications of pain?
Acute pain: physiological response; sudden onset, avoids potential/actual tissue damage; tissue injury; few secs to many weeks; predictable outcome (ex: sprained ankle -> nociceptive)
Chronic pain: persistent pain that lasts long; no biological advantage (ex: amputation, arthritis, diabetes, shingles)
What is the prevalence of acute pain? Chronic pain?
Acute pain
- After surgery (moderate to severe pain weeks later); ER (78% have pain 8/10); primary care visit: family doctor (pain after surgery, new back pain, pain in throat, sprain/strain)
Chronic pain
- W/o any known injury/disease (fibromyalgia)
- 60% say it interferes w/ their daily life
What is the difference b/w allodynia and hyperalgesia?
Allodynia: pain due to a stimulus that does not normally provoke pain.
Hyperalgesia: increased pain from a stimulus that normally provokes pain.
What is nociceptive pain? What are the characteristics?
Caused by direct stimulation of peripheral nociceptors
Usually associated with tissue damage as well as inflammatory processes
Characteristics:
- Well-localized
- More diffuse if deeper structures or if viscera involved
- Aching, sharp, dull
What is neuropathic pain? What is its prevalence? What are the characteristics?
Pain that is initiated or caused by a primary lesion or dysfunction in the nervous system
Sustained by abnormal processing of sensory input by the peripheral or central nervous system.
Characteristics:
- Burning
- Shooting
- Numb/tingling
- Electric shocks
- Allodynia
- Hyperalgesia
What is the prevalence or neuropathic pain?
Affects 2 to 3% of the population of the developed world
Affects 1 million Canadians
How often should you assess pain? (5)
- During the initial assessment
- At least once per shift for inpatients
- At least once every visit for outpatients and homecare
- Before, during and after procedures
- Following treatment of pain
What information should you gather during a comprehensive pain assessment? (11)
- Pain history & current pain experience
- Physical exam
- Medication use – past & present (addiction screening)
- Functional status
- Psychosocial impact
- Meaning of pain to pt & family
- Expectations for pain relief
- Assess ADLs (walk through a day in the patient’s life; pain diary
- Assess sleep
- Identify goals (present & future)
- Ask about how the pain interferes with lifestyle & limits daily living (Physical limitations? )Work?
What is OPQRSTUV?
- Onset
- Provocative/Palliative
- Quality
- Region/Radiating
- Severity
- Timing
- Understanding (what do they think is causing the pain?)
- Value (eg: religious/spiritual beliefs; personal/family experiences or beliefs)
What is the link b/w cultrual bias and pain?
As a HCP, don’t make stereotypical judgements based on a person’s ethnic heritage, however, do conduct a cultural assessment of the patient
What is the difference b/w how different cultures feel pain?
Ex: Chinese people may believe reporting pain is a sign of weakness so they only report it when it’s really bad. They may also be reluctant to discuss pain and believe it’s inappropriate to bother ppl w/ their problems. They may also be unwilling to take pain meds. This is not to say every Chinese person has these values, but it is something to watch out for.
When assessing for pain, what should you be looking for in your physical exam?
Review of the systems / vital signs
Physical appearance
Musculoskeletal exam and neurological exam
- Gait
- Examine the painful body locations
- Consequences (stiffness and atrophy
- Signs of neuropathic pain (hyperalgesia, allodynia, parasthesia, skin changes)
What tests should you run? (5)
- Blood tests
- X Rays
- CT/MRI
- Bone scan
- EMG
When do we need to intervene?
Pain Score of 4/10 or greater
Patient unable to do ADL’s due to pain
Patient unable to mobilize/deep breath and cough due to pain
What is the pharmacological approach to treat pain?
Non-Opioids:
- Acetaminophen
- Non-Steroidal Anti-inflammatory Drugs (NSAIDS)
Opioids
- Morphine
- Hydromorphone (dilaudid)
- Meperidine (demerol)
- Codeine
- Oxycodone (found in percocet/percodan)
- Fentanyl
- Tramadol
- Methadone
- Bupinorphine
Adjuvant drugs:
- Anticonvulsants
- Antidepressants
- Anxiolytics
How do opioid agonists work? What is the indication? What is the ceiling? What is the peak/duration?
Action:
- Bind to receptors (in the central nervous system, on nerve terminals in periphery and on cells of the gastrointestinal tract) and activate cellular changes to decrease the amount of pain transmissions to the brain
Indication:
- Useful in both nociceptive and neuropathic pain
What is the ceiling of opioid agonists? What is the peak/duration?
Ceiling:
- Dosage titration is limited by side effects
Watchful dose 90mg/day morphine equivalents
Peak/Duration:
- Oral (recommended route)
- IV
What is the pharmacokinetics of opioids?
Absorbed in the upper small bowel
Significant first pass effect
Liver metabolism
- Certain opioids have active metabolites (ex: Morphine-6-glucuronide, morphine 3-glucuronide, normeperidine)
- Usually maintained even in situations of severe liver disease
Renal excretion
- Renal dysfunction may affect metabolite clearance leading to increased toxic and analgesic effects
What are the side effects of opioids? (9)
- Nausea and Vomiting
- Sedation
- Constipation
- Pruritus
- Mental Clouding
- Hallucinations
- Urinary Retention
- Respiratory Depression
- Myoclonus
What is respiratory depression?
Less than 10 breaths/min
What kind of medication can cause resp depression?
It rarely occurs in patients who have been receiving stable doses of opioids over a period of months
What is the main sign/symptom of resp depression?
Decreased level of consciousness
How is resp depression treated?
Reverse respiratory depression with Naloxone (an opioid antagonist)
What are the pharmacogenetics of pain for pts taking codeine?
Codeine requires conversion to active metabolites (morphine, C-3-G, C-6-G) to have any analgesic effect
3-10% of the Caucasian population are poor metabolizers at the Cytochrome P-450 2D6 enzyme
Poor metabolizers will have no analgesic effects but all of the side effects when taking codeine for pain
Some people are super metabolizers and metabolize codeine into morphine too quickly