pain and pca

Question 1

origins of pain

Answer 1

treated with different drugs
nociceptive: non opioids, opioids and adjuvant therapy
neuropathic: adjuvant (anticonvulsants, antidepressants, etc)

Question 2

types of pain

Answer 2

acute, chronic malignant (cancer), chronic nonmalignant
treatment varies

Question 3

gate control theory

Answer 3

gating mechanism at dorsal horn of spinal cord
gate open = pain impulse gets through to brain and pt perceives; a alpha and a beta fiber stim (large diameter nerve fibers - rubbing, p, hot, cold)
gate closed = pain impulse cant get through and person does not perceive
decrease pain perception: distraction provides adequate sensory input at brainstem, avoid anx producing stimuli at cerebral cortex (teach to know what to expect, provide reassurance)
no brain no pain -> nurses can minimize impulse getting to brain

Question 4

two pathways for pain transmission

Answer 4

Pathway for “fast pain” is the A-delta fibers.
Pathway for “slow pain” is the C-fibers.

Question 5

pain threshold

Answer 5

least amount of pain a person can recognize. (Does not vary from person to person)

Question 6

pain tolerance

Answer 6

ability to withstand pain stimuli without demonstrating physical signs of pain. (Varies widely from person to person, and event to event)

Question 7

addiction

Answer 7

psychological
Overwhelming involvement with obtaining a drug for psychic effects.

Question 8

tolerance

Answer 8

physiological
The opioid begins to lose its effectiveness & larger doses are necessary. This would happen to everyone who was on opioids for an extended period. NOT to be confused with addiction.

Question 9

dependence

Answer 9

physiological
Withdrawal symptoms would occur if the drug were to be withdrawn abruptly. This would happen to everyone who was on opioids for an extended period. NOT to be confused with addition.

Question 10

opioids

Answer 10

morphine is drug of choice
avoid merperidine for >2days
percocet is oxycodone + acetaminophen
antidote = naloxone
opioids except for codeine do NOT have ceiling effect

Question 11

non opioids

Answer 11

NSAIDs and tylenol (no antiinflam)
ceiling effect

Question 12

adjuvant therapy

Answer 12

gabapentin
neuropathic pain

Question 13

opioids SE

Answer 13

Sedation – will develop tolerance to this (? Caffeine, if not contraindicated)
Pruritis – will develop tolerance to this (? Administer Benadryl)
Urinary retention – will develop tolerance to this (I&O cath prn)
Constipation – the only side effect that the patient will NOT develop tolerance to; the good nurse is always vigilant about the patient’s bowel patterns when he is on opioids; the constipation could get to be a bigger problem than the pain!
Resp depression is biggest fear but VERY uncommon; be most vigilant when administering an opioid to an ‘opioid naïve’ patient.

Question 14

non opioids SE

Answer 14

NSAIDS, including ASA – GI upset, increased bleeding time & possible renal problems
COX2 inhibitors – claim to fame was avoidance of the above side effects; however, several that were originally marketed were found that these drugs increase likelihood of MI & CVA in at-risk patients. (One currently on market = celecoxib)
acetaminophen (Tylenol) – minimal GI upset; people with stomach problems love this drug; has NO anti-inflammatory properties; works by inhibiting prostaglandin synthesis (prostaglandins are the ‘bad guys’); IMPORTANT: Take no more than 4 Gm of Tylenol in 24 hrs (hepatotoxic); antidote = acetylcysteine (Mucomyst).

Question 15

PCA general

Answer 15

contain opioid, also now seeing ketamine
IV, epidural, or both -> always monitor excite site (infection)
only pt pushes (too sleepy = higher risk for resp dep so no pushy)

Question 16

pca - bolus

Answer 16

amount of medication (in ml) the patient gets every time he pushes the button

Question 17

pca - lockout time

Answer 17

amount of time the pump is “locked” after a bolus is administered; typically, 6 or 10 minutes; this feature prevents the patient from overdosing

Question 18

pca - basal rate

Answer 18

Some PCA’s (particularly epidural) have a basal (or continuous) rate; so, if the patient never pushes his button in a given hour, he still gets the basal rate; very often this amount is 1 ml; most IV PCA’s don’t have a basal rate (so this number would be a zero). CAUTION: With basal, he is getting this medication even when he is not “pushing the button”; be vigilant of excessive sedation.

Question 19

pca - maximum possible dosage/hr

Answer 19

Is just what it sounds like; you can calculate this on your own; take (1) the bolus amount (usually 1), (2) take the lockout number & figure out how many doses can be given in one hour (for instance, if lockout is 6 minutes, then the maximum number of doses per hour would be 10 doses – because 6 x 10 = 60), and (3) add basal rate, if applicable. Example – bolus 1; lockout 6; basal rate 1; max possible/hr = 11.

Question 20

pca - pt hx

Answer 20

note and document q shift
attempts/hr, actual boluses received that hr
o Note: if he makes 5 attempts in 6 minutes, he will still only receive 1 bolus of medication. And - this means one of two things:
1. He is not getting enough pain medication (& the provider needs to be consulted after a thorough pain assessment is completed) – or…
2. He does not understand the lockout interval &/or know how to use the PCA machine (& patient teaching is indicated).
will determine POC, will tell story about pt pain experience

Question 21

pca assessment

Answer 21

• Change of shift, perform patient handoff. (Go visualize patient, check medication and PCA settings, document handoff on MAR.)
• Assess ability to understand PCA, the use of the PCA, and settings
• Assess pain
• Assess VS
• Continuous pulse ox monitoring and consider EtCO2 monitoring.
• Assess for side effects
  o Respiratory depression
  o Constipation
  o Altered LOC
  o Itching
  o Urinary retention
  o Nausea
• Assess pump settings/attempts/deliveries
• Assess IV site and IV line set up. Ensure anti-reflux valve/check valve in place
• Patient/family education
  o How to use it
  o Report unmanageable pain
  o Report any side effects
• Verify Narcan ordered on MAR
• Set up, make changes, and document any wastes with witness
• Ongoing education modules presented as WBTs yearly