Principles Of Pain & Analgesia Flashcards
0
Q
Pain results when nocieptors detect this
A
A noxious stimulus
1
Q
What is pain?
A
Unpleasant sensory or emotional experience associated with actual or potential tissue damage
2
Q
Nerve cells in the skin or deep tissues that detect pain
A
Nocieptors
3
Q
What are the 2 types of sensory neurons that detect and transmit pain?
A
A Delta Fibers
C Fibers
4
Q
Sensory neurons that are large ad myelinated
A
A Delta Fibers
5
Q
Sensory neurons that are small and non myelinated
A
C Fibers
6
Q
A Delta Fibers transmit this type of signals
A
Transmit sharp, discrete pain signals that allow the patient to localize the source of pain
7
Q
C Fibers transmit this type of signals
A
Transmit dull, aching, throbbing pain that cannot be easily localized
8
Q
A Delta Fibers transmit this type of pain
A
Somatic pain
9
Q
C Fibers transmit this type of pain
A
Somatic & Visceral pain
10
Q
The Pain Pathway
A
Transduction
Transmission
Modulation
Perception
11
Q
Transduction
A
Transformation of pain stimuli into electrical signals (called action potentials)
12
Q
Transmission
A
The sensory impulses (electrical signals) are conducted to the spinal cord
13
Q
Modulation
A
In the spinal cord, the impulses can be altered by neurons, making pain better/worse
14
Q
Perception
A
The impulses are transmitted to the brain, where they are processed and recognized
15
Q
Multimodal
A
Use different category of drugs to achieve better pain relief analgesia
16
Q
Somatic Pain
A
Arises from the skin, soft tissues, muscles, bones, or joints
(Easily localized through stabbing, throbbing, or aching)
17
Q
Visceral Pain
A
Arises from internal organs
Not easily localized and is characterized by cramping or burning
18
Q
Referred pain
A
Term used to describe the pain that is felt in a body part other than where the actual pain stimulus is coming from
19
Q
Hyperalgesia
A
Increased sensitivity to a stimulus (to pain)
20
Q
Neuropathic pain
A
Arises from direct damage to peripheral nerves or the spinal cord
(May be shooting, sharp, or tingling)
21
Q
Phantom Limb or Stump pain
A
Sensation or pain arising from the missing body part
22
Q
Acute pain
A
Pain has abrupt onset and a relatively short duration of action
23
Q
Chronic pain
A
Has slow onset, and duration of several months to years
24
This type of onset/duration of pain is effectively treated with analgesic drugs
Acute
25
This type of onset/duration of pain may be unresponsive to drug therapy
Chronic
26
Myths about pain in animals
* Pain can be beneficial for healing/recovery
* Animals don't feel pain
* Animals tolerate pain better than humans
27
The 5 freedoms of acceptable animal welfare
1. Freedom from hunger
2. Freedom from physical and thermal discomfort
3. Freedom from pain, injury, and disease
4. Freedom to express normal behavior
5. Freedom from fear and distress
28
Simple pain assessment scale
No pain
Mild pain
Moderate pain
Severe pain
30
Respiratory consequences of untreated pain
Increased RR
| Decreased ventilation
31
GI consequences of untreated pain
Paralytic ileus
32
Urinary consequences of untreated pain
Urine retention
| Na/ H2O retention
33
Metabolic consequences of untreated pain
Break down on muscle, fat, glucose (delay in wound healing)
34
Analgesia
The absence of the awareness of pain, achieved through the use of drugs or other modes of therapy. It applies to the relief of pain without the loss of consciousness.
35
What are the goals for pain control?
* Control pain at every stage
* To administer analgesics before the patient has an awareness of pain
* To prevent windup
36
Preemptive analgesia
The administration of analgesics before the patient has an awareness of pain
37
Preemptive analgesia decreases this
Decreases the analgesic requirements and CNS sensitization
38
Windup
Event caused by a buildup of chemical mediators that intensify the pain response
39
Where does windup occur?
Spinal cord (modulation step)
40
What triggers the Stress Response?
* Anxiety, Infection, Pre-existing disease
| * Anesthesia Trauma
41
What does the Stress Response cause?
* Sympathetic activity
| * Release hormones : Cortisol, ACTH, Catecholamines (epi)
42
Methods of pain control without analgesia
* Endorphins
| * Nursing care
43
Natural pain reliever
Endorphins
44
Endorphins
Endogenous compounds produced by the pituitary gland and hypothalamus that bind to opioid receptors during situations of trauma or stress. They resemble opiates.
45
Other therapies to control mess without meds
```
Heat/cold compress
Hydrotherapy
Acupuncture
Music
Essential oil
Pet them
Talk soothing
Favorite toy available
Clean dry bedding
```
46
Methods of pain using meds
* Opioids
* NSAIDS
* Local Anesthetics
* Alpha2 agonists, ketamine, steroids
47
Classic K9 Stress Leukogram
Mature neutrophilia
Lymphopenia
Eosinopenia
Monocytosis
48
Classic Feline Stress Leukogram
Epinephrine release -
| Neutrophilia, Lymphocytosis
49
What 4 receptors in the brain and spinal cord do opioids act on?
Mu
Kappa
Delta
Sigma (cause hallucination, euphoria/dysphoria)
50
What do opioids act as at each receptor?
Agonist or Antagonist
51
Agonist means?
Stimulating agent
52
Antagonist means?
Blocking agent
53
Some opioids are considered both agonist and antagonist because?
They block one type of receptor and stimulate another
54
Some opioids are considered partial antagonist meaning?
They only partially stimulate some opioid receptors
55
When opioid agents bind to the receptors it can result in these effects
Analgesia
Respiratory depression
Sedation
Dysphoria
56
Pure Antagonist
Naloxone
57
It's also possible to reverse the effects of pure agonists with these drugs
Butorphanol
| Buprenorphine
58
Agonist/Antagonist
Butorphanol
59
Partial Agonist
Buprenorphine
60
Are opioids controlled?
Yes
61
Pure Agonist
Morphine
62
Pure is aka
Full
| Pure agonist = Full agonist
63
This drug reverses opioids
Naloxone
64
Morphine is great for...?
Moderate to severe pain
65
This drug causes excitement in cats (use lower doses)
Morphine
66
Morphine often results in this due to its effect on the CRTZ
Vomiting
67
Why should you give morphine slowly IV?
Severe histamine can occur leading to hypotension and pruritis
68
Other full agonists aside from morphine
Oxymorohone
Hydromorphone
Fentanyl
69
CRTZ
Chemoreceptor Trigger Zone
70
Histamine release causes this
Allergic or anaphylactic reactions!
71
Fentanyl is this kind of drug
Full agonist
72
Full/Pure agonists do this
Stimulate all 4 receptors
73
This drug is commonly used as a transdermal skin patch
Fentanyl
74
How long does it take a Fentanyl patch to reach therapeutic levels in cats?
4-12 hours
75
How long does it take a Fentanyl patch to reach therapeutic levels in dogs?
12-24 hours
76
Fentanyl patches allow blood levels to remain at therapeutic levels for how long in cats?
5 days
77
Fentanyl patches allow blood levels to remain at therapeutic levels for how long in dogs?
3 days
78
Methadone targets this receptor
Mu receptor
79
This drug has the lowest likelihood of causing vomiting
Methadone
80
Methadone is an Antagonist of this receptor
NMDA receptor
81
NMDA Receptor
Receptor found in the spinal cord and is responsible for "windup"
82
Methadone is favorable for treating pain when this is present
Central Sensitization
83
Routes Methadone can be given
IV
IM
SQ
84
What is the onset/ duration of the injectable form of Fentanyl?
Onset of action is: 2 min
| Duration of action is: 20-30 min
85
How long can Methadone last?
4 hours
86
Synthetic opioid that has Agonist effects
Methadone
87
Synthetic opioid that has Full Agonist effects
Meperidine (Pethidine)
88
Meperidine is aka
Pethidine
89
Meperidine primarily targets these receptors
Mu and Delta
90
This drug has weak analgesic properties lasting
Meperidine
91
Meperidine lasts this long
1-2 hours
Can last up to 6 hours
(Short acting overall)
92
Meperidine is most useful as this
Part of the pre-anesthetic protocol
93
Buprenorohine targets this receptor
Mu
94
Buprenorphine is aka
Bupi
| Buprenex
95
Buprenorphine onset/duration of action
Delayed onset: 40min IM, 15min IV
| Duration onset: 6-8 hours
96
Buprenorphine is best used for this
Mild to moderate pain
97
How is Buprenorphine administered to cats?
Given orally
| Applied to the gingiva, under the tongue, or in cheek pouch
98
Butorphanol affects these receptors
Agonist on Kappa and Sigma
| Antagonist on Mu
99
Butorphanol is aka
Torb
| Torbugesic
100
Butorphanol is best used for this
Mild to moderate pain
101
This drug is commonly used as a cough suppressant
Butorphanol
102
Butorohano is commonly combined with a sedative such as these
Desmedetomidine or
| Acepromazine
103
The potent opioids most commonly used for acute pain
```
Morphine
Oxymorohone
Hydromorphone
Methadone
Fentanyl
```
104
Non opioid drug that has Antagonist activity
Tramadol
105
Tramadol affects this receptor
Mu receptor
106
Useful post operative pain med in dogs and cats
Tramadol
107
Is Tramadol controlled?
Yes
108
What is the mechanism of NSAIDS
Inhibit the synthesis of prostaglandins by blocking the enzyme cyclooxygenase
109
Cox 1
Leads to production of beneficial prostaglandins
110
Cox 2
Leads to production of harmful prostaglandins that are present during tissue damage and inflammation
111
Cyclooxygenase
Enzyme that produces prostaglandins and assists in producing thromboxanes
112
Benefits of NSAIDS
```
Not controlled
Little abuse potential
Effective when given orally
Antipyretic effects
No sedative, cardiovascular, or respiratory effects
```
113
Antipyretic effects
Reduces fever
114
Side effects of NSAIDS
GI upset/ulcers due to inhibition of prostaglandins
Hepatic toxicity
Renal toxicity
Inhibits platelet aggregation
115
Do not use NSAIDS concurrently with this
Steroids
116
Why should NSAIDs be used with steroids?
Steroids also block beneficial prostaglandins
117
The 3 NSAIDs we use
Rimadyl
Metacam
Onsior
118
Rimadyl is aka
Carprofen
119
NSAID approved for use in dogs only
Rimadyl
120
NSAID approved for use in both cats and dogs
Metacam
121
NSAID approved for use in cats only
Onsior
122
Rimadyl, Metacam, and Onsior are Cox 1 or 2 selective?
Cox 2 selective
123
NSAIDs given in tablet form
Rimadyl and Onsior
124
NSAIDs given oral AND injectable
Metacam
125
Metacam is aka
Meloxicam
126
Onsior is aka
Robenacoxib
127
These drugs are Alpha-2 Agonists
Dexdomitor
| Xylazine
128
Alpha-2 agonists duration of action
~90 min
129
What do Alpha-2 agonists cause aside from pain control?
Profound sedation
| Bradycardia
130
Alpha-2 agonists are commonly combine with this drug
Butorohanol
131
Are Alpha-2 agonists reversible?
Yes
132
How does Ketamine work?
Works by antagonizing NMDA receptors in the spinal cord
133
Duration of action of Ketamine
Short duration: 30 min
134
Ketamine is effective for this type of analgesia
Intraoperative
135
What is local anesthesia?
The use of a chemical agent on sensory neurons to produce a disruption of nerve impulse transmission, leading to temporary loss of sensation
136
Local Anesthetics exert their effects on neurons located here
In the peripheral nervous system and spinal cord that control pain, heat, cold, and pressure
137
Local anesthesia is safe for this surgical procedure
C-sections
138
Local Anesthetics have few effects on this
The cardiovascular and respiratory systems
139
Local Anesthetics routes of administrations
Topical (short dur. Less pain relief)
| Injection (site clipped&cleaned)
140
Some local anesthetic drugs are combined with this drug
Epinephrine
141
What does epinephrine cause?
Vasoconstriction
142
Local anesthesia cannot be given here
Cannot be given in inflamed tissues
143
Nerve blocks
Injection of a local anesthesia in the proximity of a specific nerve to desensitize a specific anatomic location
144
Ring block
Block nerve that goes around anatomical part
145
Lidocaine onset/duration duration
Onset: 15 min
Duration: 1 hour
146
Bupivacaine onset/duration action
Onset: 40 min
Duration: 6 hours
147
Why does lidocaine and bupivacaine get mixed together?
Better pain relief
| Add Buprenorphine for 2 extra hours of pain relief
148
This drug is toxic if given IV
Bupivacaine
149
What drug is used for epidurals?
Lidocaine (or any other local anesthetic)
| Morphine (last several hours)
150
2 Nerve blocks
Line blocks
| Ring blocks
151
Intraarticular (local anesthetic route)
Injecting local Anesthetics directly into a joint usually after surgery of the joint, immediately after closure of the joint capsule
152
Epidural
Blockage of sensory and motor nerves in the rear, abdomen, pelvis, tail, hind limbs, and perineum
153
Where is an epidural injected?
In between L7 and S1
154
Side effects of local Anesthetics
```
Allergy
Systemic toxicity
Infection
Cranial infiltration
Death
```
155
Neuromuscular Blocking Agents are aka
Muscle-paralyzing agents
156
How do neuromuscular blocking agents work?
These agents act by interrupting normal transmission of impulses from motor neurons to the muscle synapse
They basically send signals telling the muscle to contract
157
Site of action for neuromuscular blocking agents
Neuromuscular junction
158
Neuromuscular junction
This is where acetylcholine is real eased by the neurons to attach to muscle end plates
159
The 2 ways for neuromuscular blocking agents to disrupt the nervous system
Depolarization agents
| Non-depolarization agents
160
Depolarization agents
Cause a single surge of activity at the neuromuscular junction, followed by a refractory period
161
Refractory period
Unable to contract again
162
Non depolarization agents
Block the receptors and the end plate
| No initial surge of activity at neuromuscular junction, no muscle movements
163
What can the neuromuscular blocking agents be reversed with?
Neostigmine or Edrophonium
164
Special technique not commonly used in Veterinary medicine
Neuromuscular blocking agents
165
Special Techniques
Neuromuscular Blocking Agents
| Mechanical Ventilation
166
Neuromuscular B agents allow relaxation of only these muscles
Voluntary muscles
167
Skeletal muscles are affected in this order
1. Facial, neck paralysis
2. Tail, limb, abdominal muscles
Last: intercostal muscles, diaphragm
168
How are Neuro M B agents administered?
Slowly IV
169
Onset/duration action of Neuro M B agents
Onset: 2 min
Duration: 10-30 min
170
Animals on Neuromuscular Blocking Agents require this
Manual or Mechanical ventilation
171
What is the patient's breathing controlled with when using Mechanical Ventilation
Patient's breathing is controlled by Ventilator rather than reservoir bag
172
CV consequences of untreated pain
Increased HR, BP, CO, Arrythmia
