NURS 2500 - Week 5: Pain

What is pain?

• an unpleasant sensory + emotional experience associated with actual/potential tissue damage

What is pain the result of? (3)

• a response to tissue injury

• a symptom of pathology associated with a disease process

• an altercation of the somatosensory system (how your body interprets pain)

What is the purpose of pain?

• a protective response

What are the components of the nature of pain? (5)

• physiological (transmission of nociceptive pain)

• affective - emotions/suffering

• behaviour - behavioural responses

• cognitive - beliefs, attitudes, evaluations, goals

• sensory - pain perception

What does unrelieved pain impact?

• decreased personal autonomy

• increased perception of vulnerability

• dignity of human person is undermined

What is the pain pathway? (4)

• transduction

• transmission

• perception

• modulation

What is transduction? (1.1)

• harmful stimuli causes cell damage with the release of sensitizing chemicals

  • these substances activate nociceptors = generation of action potential

What are the sensitizing chemicals released after noxious stimuli? (5)

• prostaglandins

• bradykinin

• serotonin

• substance P

• histamine

What occurs after noxious stimuli stimulates nociceptors? (2)

• chemical mediators release from site of injury - attach to nociceptor

• after attachment - signals Na/K channels to open = action potential

What is transmission?

• AP moves from site of injury → spinal cord → brainstem + thalamus → cortex for processing

What type of pain sensations do the different pain receptors transmit? (3)

• c - dull ache/throbbing

  • non-mylinated

• delta - fast sharp

• beta - all other non-pain processing stimuli

What is the pathway of transmission for pain? (1.1)

• sensory/stimuli → grey matter → white matter → brain

  • dorsal horn → thalamus (sorts stimuli) → midbrain (evaluates signals to see how much pain)

What is perception?

• conscious experience of pain

What is modulation? (2)

• sending the signal from the brain → spinal cord → back down

• = releases substances that inhibit nociceptive impulses

What are enkephalins?

• endogenous opioids

What are the types of pain? (2)

• acute

• chronic

What is acute pain? (1.1)

• abrupt sudden onset pain; time limited

  • a SNS response

What is chronic pain? (1.1)

• ongoing pain; >3 months or years

  • altered SNS response from over-activation

What are the classifications of pain? (4)

• nociceptive pain

• neuropathic pain

• nociplastic pain

• mixed

What is nociceptive pain?

• normal pain - warns of actual/potential injury + starts SNS response

What are the types of nociceptive pain? (3)

• somatic

• visceral

• referred

What is somatic pain?

• pain from nerve receptors in skin/close to surface

  • sharp + well localized or dull and diffused

What is visceral pain?

• from organs

What is referred pain? (1.1)

• pain perceived in a distant area

  • common with visceral pain

What is neuropathic pain?

• abnormal processing of sensory input as result of injury of peripheral or CNS

What are the types of neuropathic pain? (2)

• centrally generated pain

• peripherally generated pain

What is centrally generated pain?

• deafferentation pain - injury to peripheral or CNS

  • sympathetically maintained pain association with dysregulation of ANS

What is peripherally generated pain? (2)

• painful polyneuropathies - pain felt along peripheral nerves

• painful mononeuropathies - associated w/ peripheral nerve injury

What is nociplastic pain?

• pain from altered pain processing in nervous system without clear evidence of tissue/nerve damage - we dont know why it’s happening

What is mixed pain?

• combination of nociceptive + neuropathic pain

What are dermatones?

• area of skin supplied by a single nerve root

What is the goal of a pain assessment? (2)

• describe patients sensory, affective, behavioural, and sociocultural response to pain

• identify patient goals for therapy, resources, and strategies for self management

What is the primary role of the nurse in relation to pain?

• advocate for patient by accepting reports of pain + acting quickly to relieve it while respecting values

What are the types of descriptive pain assessment tools? (3)

• faces pain scale revised

• pain assessment tool

• wong-baker faces pain rating scale

What are potential challenges in assessing pain? (7)

• critically ill

• comatose/LOC

• sedated

• imminently dying

• language/communication

• developmental age

• cognitively impaired

How do you observe the pt in relation to pain? (6)

• position of comfort

• guarding area of pain

• facial expression

• movement/gestures

• behaviour

• vital signs

What are patient related barriers to adequate pain management? (9)

• fear of addiction

• fear of tolerance

• concerns about adverse effects

• fear of injections

• desire to be a good patient

• forgetting to take analgesics

• concern that pain = worsening disease

• medication not working

• don’t want to bother HC team

What are the assessment considerations for acute pain? (1.4 + 1.4)

subjective findings:

• pain 4+

• mild-moderate severity

• should be able to identify how much they can tolerate

• assess nausea, vomiting, pruritus

objective:

• elevated vitals

• respiratory changes

• physical changes

• gastrointestinal changes

What are assessment considerations for neuropathic pain? (1.2 + 1.3)

subjective

• altered sensation

• nocturnal flare ups

objective

• skin + tissue inspection

• trophic changes

• secondary complications

What are the goals of care for chronic pain? (3)

• controlled symptoms

• functional independence

• active support systems

What are the steps in the WHO step ladder? (1.4 + 1.6 + 1.6)

• 1 - mild (1-3) non-opioids

  • ASA

  • acetaminophen

  • NSAIDS

  • +adjuvants

• 2 - moderate (4-6) moderate opioids

  • A/codeine

  • A/hydrocodone

  • A/oxycodone

  • A/dihydrocodeine

  • tramadol

  • + adjuvants

• 3 - severe (7-10) strong opioides

  • morphine

  • hydromorphone

  • methadone

  • levorphanol

  • fentanyl

  • oxycodone

What are pharmacological interventions for pain? (1.4)

• analgesics

  • non-opioids

  • opioids

  • adjuvant analgesics

  • atypical analgesics

What are types of NSAIDS? (4.1)

• acetylsalicylic acid

• ibuprofen

• naproxen

• celecoxib

  • never take 2 together

What are NSAIDS not good for? (1.7)

• the entire body

  • kidney problems

  • bleeding disorders

  • GI issues

  • asthma

  • CV

  • ASA not safe for kids

  • not safe for pregnancy

What is the MOA for NSAIDS?

• Cox 1 and Cox 2 inhibition

What is the function of cox 1?

• prostaglandin production

What do cox 1 prostaglandins help with? (3)

• gastric mucosa protection

• renal blood flow

• platelet aggregation (clotting)

What do cox 2 prostaglandins help with? (3)

• mediates inflammation (swelling/vasodilation)

• sensitizes pain receptors

• induces fever

What is the MOA for ibuprofen?

• inhibits prostaglandin synthesis by blocking cox 1 + 2 = decreased inflammation

What are the indications of ibuprofen? (3)

• inflammation

• mild/moderate pain

• fever reduction

What are the contraindications for ibuprofen? (4)

• allergy to NSAIDS

• renal or liver dysfunction

• peptic ulcer

• thrombotic events

What are the side effects of ibuprofen? (1.4 + 1.5 + 1.2 + 1)

• CVS -

  • MI/stroke

  • HTN

  • edema

  • nephrotoxicity with high doses

• GI

  • nausea

  • dyspepsia

  • GI pain

  • constipation

  • diarrhea

• Hema

  • bleeding

  • platelet inhibition

• steven johnson syndrome

What are the nursing considerations for ibuprofen? (3)

• assess for S+S of Gi bleed, renal + liver function

• use drug only as suggested

• report - sore throat, fever, rash, itching, swelling, changes in vision, black/tarry stool

What is the MOA of acetylsalicylic acid?

• inhibits the synthesis of prostaglandins - inhibits platelet aggregation

What are the indications of acetylsalicylic acid? (4)

• mild to moderate pain

• fever

• reduced risk of recurrent stroke in males

• MI prophylaxis

What are the contraindications for acetylsalicylic acid? (4)

• allergy to salicylates, NSAIDS

• conditions that increase the risk of bleeding, clotting, or deficiencies

• surgery scheduled within a week

• severe hepatic disease

What are the side effects of acetylsalicylic acid? (4)

• irritation of GI tract

• hepatotoxicity

• hypersensitivity

• tinnitus

What are the nursing conditions for acetylsalicylic acid?

• assess: history, allergies, physical condition related to liver, kidneys,

• reported ringing in ears, dizziness, confusion, abdominal pain, nausea, vomiting, bloody stool

What are the therapeutic effects of acetylsalicylic acid? (3)

• reduction in pain

• reduction in fever

• reduces risk of heart attack + stroke (anti-platelet action via COX 1 inhibition

What is the MOA of acetaminophen? (2.1)

• reduces fever by acting directly on hypothalamic heat regulating centre

• analgesic mechanism: through inhibition of prostaglandins in CNS

  • not an inflammatory agent

What is the max dosage of acetaminophen in adults + geriatrics? (2)

• 4000 mg - adults

• 3000 mg - geriatric

What are the indications for acetaminophen? (2)

• treatment of mild-moderate pain

• reduction in fever

What are the therapeutic effects for acetaminophen? (2)

• reduced pain

• reduced fever

What are the contraindications for acetaminophen? (2)

• allergy to acetaminophen

• use cautiously with impaired hepatic function, chronic alcoholism

What are the side effects of acetaminophen? (3)

• hypersensitivity; rash, fever

• hepatotoxicity

• renal damage

What are the nursing considerations for acetaminophen? (3)

• assess history + physical condition related to liver + kidneys

• monitor LFTs if concerned

• avoid using multiple preparations with acetaminophen (scheduled + PRN)

What are the opioid strengths? (2)

• hydromorphone 5x stronger than morphine

• fentanyl 10x stronger than hydromorphone

Why are opioid analgesics used?

• manges moderate-severe nociceptive pain

How do opioid analgesics produce effects?

• interacts with opioid receptor sites throughout body ; binds to receptor sites to produce analgesia + unwanted side effects

What are facts about moderate opioid analgesics? (7)

• second on the pain ladder

• most effective + primary drugs for moderate to severe pain

• they’re weak opioids with acetaminophen

• can cause sedation, euphoria, constipation, respiratory distress, urinary retention

• tolerance can develop

• ceiling effect

• can result in physical dependence

What is the MOA for codeine phosphate? (2)

• binds to opioid receptors in CNS + alters perception + response to painful stimuli while depressing CNS

• codeine metabolized to morphine = lots of the analgesic effect

What are the therapeutic effects of codeine phosphate? (3)

• relieves mild-moderate pain

• suppresses cough

• mild antidiarrheal effect

What are the indications for codeine phosphate? (3)

• relief of mild-moderate acute + chronic pain

• antitussive for nonproductive cough

• sometimes used for diarrhea

What are the contraindications for codeine phosphate? (6)

• hypersensitivity to codeine/other opioids

• respiratory depression

• acute/severe asthma

• paralytic ileus

• children <12 years - risk of fatal respiratory depression

• breastfeeding

What are the side effects of codeine phosphate? (7.3)

• CNS depression (drowsiness, sedation, dizziness)

• respiratory depression

• constipation

• nausea

• vomiting

• sweating, pruritus

• potentially fatal:

  • severe respiratory depression

  • collapse

  • anaphylaxis

What are the nursing considerations for codeine phosphate? (6)

• assess pain, respiratory rate, level of sedation before + during therapy

• keep naloxone available

• encourage fluids, fiber, and possible stool softeners

• educate pt on not driving + operating machinery

• avoid alcohol + other CNS depressants

• monitor for signs of misuse or dependence

What are strong opioid analgesics?

• pure opioid agonists

What are characteristics about strong opioid analgesics? (2)

• no ceiling effect - increased dose = increased relief

• can adjust on pain severity

What is the MOA for strong opioid analgesics? (2)

• binds to mu-type opioid receptors in CNS = altered perception + response to painful stimuli

• also produces generalized CNS depression

What are the potencies for morphine, hydromorphone, and fentanyl? (3)

• morphine - 1x (standard)

• hydromorphone - 4-7x more potent vs morphine

• fentanyl - 100x more potent vs morphine

What are the dosing units for morphine, hydromorphone, and fentanyl? (3)

• morphine - mg

• hydromorphone - mg

• fentanyl - mcg

What are the indications for morphine? (4)

• moderate-severe pain relief

• MI chest pain

• acute pulmonary edema

• palliative dyspnea

What are the indications for hydromorphone? (3)

• moderate-severe pain relief

• severe breakthrough pain

• palliative dyspnea

What are the indications for fentanyl? (4)

• severe chronic/cancer pain

• surgical anesthesia

• procedural sedation

• acute pain

What is the relation between morphine + renal impairment?

• use with caution/avoid because causes accumulation of active metabolites = neurotoxicity/sedation

What is the relation between hydromorphone + renal impairment?

• preferred over morphine - fewer metabolites = safer in moderate renal dysfunction

What is the relation between fentanyl + renal impairment?

• safest choice in severe renal impairment/dialysis - no active neurotoxic metabolites

What are the nursing responsibilities when administering strong opioid analgesics? (3)

• monitor baseline + ongoing pain rating, spO2, sedation score

• monitor for hypotension

• keep naloxone nearby

What are the adverse effects of strong opioid analgesics? (7)

• sedation

• constipation

• nausea/vomiting

• urinary retention

• respiratory depression

• dizziness

• itching

What are the contraindications for strong opioid analgesics? (7)

• severe acute respiratory depression

• acute/severe asthma

• COPD exacerbation

• paralytic ileus

• severe head injury

• increased intracranial pressure

• acute alcoholism

What is the adjuvant therapy for those on the 2nd step of the WHO ladder?

• acetaminophen

• anti-inflammatory meds

• both

What is the adjuvant therapy for those with chronic pain? (5)

• anticonvulsants

• antidepressants

• benzodiazepines

• other opioids

• cannabinoids

How do cannabinoids affect the body?

• affects all cell receptors in the body

What is multimodal therapy?

• using 2+ classes of analgesics or interventions to target different pain mechanisms in PNS or CNS

• purposeful combination of pain meds to maximize relief + prevent gaps in treatment

Where do opioid antagonists work?

• at mu and kappa receptors

What is tolerance?

• effect where prolonged use requires a higher dose to produce an effect

What is physical dependence?

• needing a medication to maintain function

What is addiction?

• intense cravings, loss of control, and compulsive behaviour to obtain the substance

What are non-pharmacological interventions? (8)

• heat/ice

• massage

• TENS

• physiotherapy

• imagery

• distraction

• deep breathing

• cultural practices

What is the gate-control theory? (1.1)

• non-pain sensations override/alter the pain response from pain stimuli

  • large nerve A-beta fibers excite inhibitory neurons = closes gate to block pain signals