Acute Postoperative Pain Management Flashcards
(99 cards)
1
Q
definition of pain
A
an unpleasant sensory and emotional experience associated with actual or potential tissue damage; the 5th vital sign (acc to joint comission)
2
Q
JCAHO Identified Responsibilities of Pain Management
A
- patient has right to appropriate assessment and management of pain
- assess existence of pain, its nature, and intensity
- record assessment in a way that facilitates reassessment/follow-up
- assure staff competency in pain assessment and management
- establish policies that support appropriate prescription of pain medications
- educate patient/family about pain management
- address patient needs for symptom management and discharge
3
Q
nociception
A
detection, transduction and transmission of noxious stimuli
4
Q
acute pain
A
- primarily due to nociception
- short duration (<6 weeks)
- cause usually known
- temporary
- located in area of trauma or damage
- resolve spontaneously with healing
5
Q
chronic pain
A
- may be due to nociception but also affected by psychological/behavioral factors
- persists beyond normal duration of recovery from acute injury or disease
- cause may not be identifiable
- affects patient self image and sense of well-being
6
Q
thoracotomy incidence of chronic pain
A
5-65%
7
Q
sternotomy incidence of chronic pain
A
30-55%
8
Q
mastectomy incidence of chronic pain
A
20-50%
9
Q
hysterectomy incidence of chronic pain
A
32%
10
Q
inguinal hernia repair incidence of chronic pain
A
5-35%
11
Q
four classifications of pain pathophysiology
A
- nociceptive
- neuropathic
- idiopathic
- psychogenic
12
Q
nociceptive pain
A
- appropriate response to identifiable tissue damage
- due to activation or sensitization of peripheral nociceptors that transduce noxious stimuli
- pain consistent with degree of tissue injury
13
Q
neuropathic pain
A
- may be abnormal, unfamiliar pain, probably caused by dysfunction in the PNS or CNS
- result of injury or acquired abnormalities of peripheral or central neural structures
14
Q
idiopathic pain
A
- pain not attributed to identifiable processes
- pain in absence of identifiable physical or psychological cause
- pain perceived to be excessive for the extent of pathology
15
Q
psychogenic pain
A
- pain sustained by psychological factors
- more precisely characterized in psychiatric terminology
- patients have an effective and behavioral disturbance
16
Q
4 processes of nociceptive pain
A
- transduction
- transmission
- modulation
- perception
17
Q
transduction
A
stimuli translated into electrical energy at the site
18
Q
transmission
A
propagation of electrical pain impulse through the nervous system
19
Q
modulation
A
alteration of the stimuli that can be amplified or attenuated
20
Q
perception
A
based on psychological framework of patient
21
Q
two subtypes of nociceptive pain
A
- somatic
- visceral
22
Q
superficial somatic pain
A
-arises from skin, subQ tissues, and mucous membranes -characterized as well-localized, sharp, pricking, throbbing, or burning
23
Q
deep somatic pain
A
- arises from muscles, tendons, joints, or bones
- dull aching that is less well-localized
24
Q
visceral pain
A
- due to disease process (appendicitis or pancreatitis) or abnormal function of an internal organ
- may be localized or referred
25
two subtypes of neuropathic pain
- central generator
| - peripheral generator
26
central generator
central pain due to injury to brain or spinal cord; phantom pain
27
peripheral generator
originates in nerve root, plexus, or nerve; poly-neuropathies or mono-neuropaties
28
allodynia
perception of an ordinarily non-noxious stimulus as pain
29
analgesia
absence of pain perception
30
anesthesia
absence of all sensation
31
hyperalgesia
exaggerated response to noxious stimuli
32
neuralgia
pain in nerve distribution
33
paresthesia
abnormal sensation perceived without stimulus
34
radiculopathy
functional abnormality of one or more nerve roots
35
how are peripheral nerve afferent fibers categorized
- size
- degree of myelination
- speed of conduction
- distribution of fibers
36
three groups of peripheral nerve afferent fibers
- Class A (subtypes alpha, beta, delta, gamma)
- Class B
- Class C
37
Class A Fibers
- large, myelinated fibers
- low threshold for activation
- 1-20 micrometers in diameter
38
Class A delta
- mediates pain sensation
- transmits fast or first pain sensation
- sharp, stinging, pricking type pain
- conduction speed of 5-25 m/s
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Class A alpha
- transmits motor and proprioceptive impulses
| - conduction speed of 60-120 m/s
40
Class A beta
- cutaneous touch and pressure
| - conduction speed of 60-120 m/s
41
Class A gamma
- cutaneous touch and pressure
| - conduction speed of 15-35 m/s
42
Class B Fibers
- medium-sized myelinated fibers
- conduction speed 3-14 m/s
- diameter less than 3 micrometers
- higher threshold (i.e., lower excitability) than Class A fibers
- lower threshold than class C
- postganglionic sympathetic and visceral afferents
43
Class C Fibers
- unmyelinated or thinly myelinated
- conduction speed 0.5-2 m/s
- diameter 0.4-1.2 micrometers
- preganglionic autonomic fibers and pain fibers
- slow or second pain
- burning, persistent, aching, throbbing pain
44
pain conducting fibers
- A-delta fibers
| - C fibers
45
A delta fiber pain pathway
- myelinated
- diameter 1-4 micrometers
- first or fast pain
- well localized - sharp, stinging, pricking
- duration of pain coincides with painful stimulus
- pain from parietal peritoneum carried here
- major NT glutamate binds to NMDA and AMPA receptors on postsynaptic membrane
46
C fiber pain pathway
- un-myelinated
- diameter 0.4-1.2 micrometers
- second or slow pain
- diffuse and persistent - aching, burning, throbbing
- duration exceeds stimulus
- pain from viscera carried here
- major NT substance P binds to NK-1 receptors on the postsynaptic membrane
47
pain pathway
- Release of NT/hormones into the blood from the destroyed cell and diffuse to primary afferent neuron (Histamine, Serotonin, Substance P, CGRP)
- Activate the primary afferent neuron by influx of Na into the cell
- AP propagated from the site of damage, through the DRG
- Primary afferent neuron synapses on the interneuron or secondary neuron in the (laminae 1, 2, 5)
- Secondary afferent neuron decussates to the spinothalamic tract on the dorsal (or posterior) portion of the spinal cord
- Secondary neuron traverses up the spinothalamic tract to the thalamus of the brain
- In the thalamus, secondary neuron synapses on tertiary neuron
- Tertiary neuron brings the afferent information to the somatosensory cortex in the brain
48
substances released from damaged cells that activate pain pathway
- bradykinin
- cations
- free radicals
- histamine
- prostanoids
- purines
- serotonin
- tachykinins
49
where is pain modulated?
descending dorsolateral spinal tract
50
supraspinal analgesia
- refers to the fact that IV opioids act primarily at other sites in the brain including the limbic system, hypothalamus, and thalamus
- mediated by Mu1 receptors
51
spinal analgesia
- refers to the fact that IV opioids can also produce effects by working in the periventricular area and periaquaductal gray
- stimulation of Mu2 receptors
52
spinal anesthesia
- neuraxial opioids work at the same receptor site as enkephalin
- MOA = decrease the release of substance P by binding to Mu2 receptors
53
CV effects of surgical stress response
- HTN
- tachycardia
- enhanced myocardial irritability
- increased SVR (ANG II)
- CO increase except in patient with compromised LV function
- increased MVO2 --> ischemia
54
respiratory effects of surgical stress response
- increased in O2 consumption + CO2 production causes increased minute ventilation
- increased WOB
- pain may decrease chest expansion (splinting), resultant atelectasis, shunting, hypoxemia, and hypoventilation
- increase in skeletal muscle tension that results from pain may lead to V/Q mismatch
55
endocrine effects of surgical stress response
- hyperglycemia secondary to increased glucagon + epi and decreased insulin
- vasoconstriction, increased myocardial contractility, and tachycardia secondary to increased cortisol + catecholamines and activation of RAAS
- salt and water retention due to increased aldosterone and ADH, may lead to CHF
56
GI effects of surgical stress response
- increased sphincter tone with decreased smooth muscle tone may lead to formation of ileus and lead to PONV
- decreased oral intake associated with septic complications and delayed wound healing
- hypersecretion of gastric acid promotes ulcers
- abdominal distention further aggravates loss of lung volume and pulmonary dysfunction
57
immunological effects of surgical stress response
stress response produces leukocytosis with lymphopenia and depresses the reticuloendothelial system predisposing patients to infection
58
hematological effects of surgical stress response
increased platelet adhesiveness and diminished fibrinolysis promote a hypercoagulable state; immobility exacerbates this problem
59
general anesthesia influence on surgical stress response
not effective in attenuating the response except with high dose narcotic techniques
60
regional anesthesia influence on surgical stress response
- diminishes intensity of afferent impulses getting to spinal cord
- reduces catecholamine and other stress hormone responses during perioperative period
61
pain assessment
- history of current and persistent pain
- physical exam
- pain attributes (intensity, onset, duration, location, descriptors, what exacerbates or relieves pain)
- behavioral manifestations
- impact of pain on ADLs
- current and past treatments
- are patient's expectations for pain relief realistic?
62
postoperative pain intensity
- orthopedic/trauma on extremities rated highest
- also rated among top 25 - appendectomy, cholecystectomy, hemorrhoidectomy, tonsillectomy
- some laparoscopic procedures ranked unexpectedly high
63
traditional approach to pain mangement
- opioids = mainstay for postoperative analgesia; may be given IV, PO, IM, SubQ, PCA, or neuraxial
- safe and effective pain control used in treating moderate to severe pain
- should be administered via most effective route and limiting S/E
64
side effects of opioids
- N/V
- constipation
- lethargy
- sedation
- respiratory depression
65
Minimum effective analgesic concentration
analgesic blood level at which the patient experiences analgesia and the severity of pain rapidly diminishes
66
opioid induced hyperalgesia
- patients receiving opioids exhibit diminished pain threshold and enhanced pain sensitivity
- escalating opioids worsens pain perception
- not same thing as tolerance, but the two can happen simultaneously
67
mechanism of opioid induced hyperalgesia
- enhanced release of NT
- sensitization of primary and secondary afferents
- upregulation of spinal and supraspinal pathways
- critical component = activation of excitatory NMDA receptor and central glutamatergic system
- demonstrated in patients receiving high-dose intraoperative opioids like fentanyl and remifentanil
68
preemptive analgesia
- pain perception can be decrease by using analgesics capable of inhibiting CNS sensitization before pain stimulus occurs
- drug options = NSAIDs, opioids, LAs, NMDA antagonists, alpha-2 agonists
- still uncertain/debated
69
multi-modal approach to pain management
- may include more than 1 route of admin
- use of different agents allows decreased doses of each, thus reduced side effects
- synergistic effects between drug classes enhances analgesic effects of each drug
- effective in patients at risk of S/E from large doses of opioids
70
central acting non-opioid analgesics
- clonidine
- dexmedetomidine
- gabapentin
- pregablin
- ketamine
- lidocaine
- magnesium
71
spinal acting non-opioid analgesics
- clonidine
- dexmedetomidine
- gabapentin
- ketamine
- lidocaine
- magnesium
72
peripheral acting non-opioid analgesics
- clonidine
- dexmedetomidine
- dexamethasone
- ketamine
- lidocaine
73
NSAIDs
- effective with mild to moderate pain
- adverse effects = GI bleeding, ARF, hepatotoxicity
- avoid in patients with hypersensitivity, significant renal compromise, and PUD
- use with caution in elderly due to increased risk for renal impairment
74
ketamine
- NMDA receptor antagonist
- 0.5 mg/kg bolus followed by infusion at 4 mcg/kg/min
- shown to reduce morphine consumption and pain intensity up to 6 weeks following spine surgery
75
methadone
- D-isomer NMDA receptor antagonist
- 0.2 mg/kg
- shown to have a 50% reduction in post-op opioid consumption and pain scores 48 hours after complex spine surgery
76
anticonvulsants
- gabapentin, pregabalin
- manage spontaneous firing of sensory neurons associated with neuropathic pain (attenuate neuronal sensitization response)
- reduced incidence of chronic post-op pain syndrome
- decrease opioid consumption and neuropathic pain 3-6 months following total knee replacement
77
dexmedetomidine
- alpha 2-agonist
- reduced morphine consumption 2-14 hours post-op; also decreased PONV (most likely to reduced morphine consumption)
- significantly reduces opioid consumption in obese
- increased risk of hypotension and bradycardia
78
clonidine
- reduced morphine consumption 12-24 hours post-op; also decreased PONV (most likely to reduced morphine consumption)
- increased risk of hypotension and bradycardia
79
acetaminophen
- preemptive 15 mg/kg
| - MOA unknown
80
Magnesium
- N-methyl-D-aspartate (NMDA) receptor antagonist
| - 2 g
81
glucocorticoids
- potent anti-inflammatory agents that play a role in reducing post-op pain
- also works to manage PONV
82
infiltration of LAs
- may be done by surgeon at beginning or end of case
| - ilioinguinal and femoral nerve blocks may be placed by anesthetist
83
regional anesthesia
- preferred to provide postop pain control to a specific part of the body
- have peripheral and central nerve blocks
84
regional anesthesia advantages
- eliminating need for IV pain medications
| - earlier discharge of ambulatory patients
85
regional anesthesia disadvantages
- block failure
- bleeding
- hematoma
- neurological injury
86
peripheral nerve blocks
- lumbar plexus
| - interscalene
87
central neuraxial blocks
- spinal
| - epidural
88
neuraxial opioids side effects
- itching (most common)
- nausea
- urinary retention
- respiratory depression (early + Late
- sedation
- CNS excitation
- neonatal morbidity
89
respiratory depression with hydrophilic neuraxial opioids
- onset of analgesia slow, duration prolonged
- intrathecal placement = late respiratory depression (6-12 hours) due to rostral spread; early resp depression does not occur because uptake by systemic circulation is minimal
- epidural placement = early respiratory depression (within 2 hours) since systemic uptake is greater than with intrathecal placement; late resp depression more likely due to rostral spread in CSF
90
respiratory depression with lipophilic neuraxial opioids
- onset of analgesia is rapid with short duration
- early resp depression occurs due to significant systemic uptake with both intrathecal and epidural placement; resp depression most pronounced after epidural placement
- late resp depression does NOT occur because diffusion of lipophilic opioids out of CSF is substantial, therefore rostral spread is minimal
91
alternative approaches
- distraction
- hyponosis
- transcutaneous electrical nerve stimulation (TENS)
- cold
- heat
- immobilization
- positioning
- exercise
92
distraction
- useful as adjunct
- music or imagery
- max benefit if introduced preoperatively
- requires patient cooperation
93
hypnosis
- state of focused attention combined with decrease in external awareness
- may not work on all patients
- social stigma
- conflicting data on efficacy
94
TENS
- thought to produce analgesia by stimulating large afferent fibers
- gate theory of pain suggests that the afferent input from large fibers competes with that from smaller pain fibers
- electrodes applied to same dermatome as pain
- absence of significant S/E
- requires professional to instruct in use
95
cold
- alters pain threshold, reduces swelling, and decreases tissue metabolism
- easy to use
- contraindicated in patients with decreased circulatory state like Raynaud's
96
heat
- decreases joint stiffness and increases blood flow
| - easy to use
97
immobilization
-assists in healing process; i.e. casting
98
positioning
- done Q2H
| - improves blood flow and prevents pressure related injuries
99
exercises
- CPM, ambulation, physical therapy
| - assists with edema and DVT formation
