pain Flashcards
Pain Is Defined As:
An unpleasant sensory or emotional experience associated with actual or potential tissue damage
Define NOCICEPTION
neural encoding of impending or actual tissue damage
Allogenic Substances
- Serotonin
- Histamine
- Prostaglandins
- Hydrogen ions
- Cytokines
- Adenosine
Physiological/adaptive pain
Warning pain after noxious stimuli
Pathological/clinical pain?
Response to tissue damage
Sharp or dull burning
Allodynia
Wind up
Neuropathic or Nervous system dysfunction example
phantom limb pain
Somatic vs Visceral pain
Somatic = superficial or deep
Skin, tissues, muscles bone.
Visceral = Dull, achy, spasm like,
disease process or abnormal
function of internal organ
Peripheral Transmission route
nerve endings to spinal cord
Central Transmission
spinal cord to thalamus
Pain modulation function
Either inhibit or facilitate pain at nociceptor in spinal cord
Analgesic drugs
- NSAIDs
- Paracetamol
- Opioids
- Local anaesthetics
- Antidepressants
- Anticonvulsants
Morphine – Sch 2
onset:
Lasting effects cats and dogs:
Slow onset of action (30 minutes)
Lasts 3-4 hours in dogs/ 8 hours in cats
Does morphine induce vomiting
Can induce vomiting if the animal is not in pain
Analgesics that are used in epidural
Morphine
Routes of administration Mophine
Slow IV, bolus, CRI, IM, or SC
Methadone – Sch 2
- Similar effect to Morphine
- Does not cause vomiting
- Lasts 3-4 hours
- IV, IM or SC
Fentanyl – Sch 2
100x more potency than Morphine
* Rapid onset IV (2 minutes)
* Lasts 20 minutes
* Respiratory depressant
* IV, CRI or transdermal
Buprenorphine – Sch 3
45mins to achieve peak effect
Lasts 6 hours
IV, IM or SC
Oral transmucosal in cats
Combined with ACP for a pre-med
Butorphanol
- Lasts 1-1.5 hours
- IV, IM or SC
Triple for cats
Butorphanol, Medetomidine and Ketamine
Butorphanol AKA
Torbugesic
NSAIDs AKA
Carprofen, Meloxicam
NSAIDS contraindications
Patients with pre-existing or subclinical renal disease
Trauma/shock patients until stable
Local Anaesthetics function
Acts on nerve fibres and prevents them from transmitting
impulses to CNS.
Types of Local Anaesthetics
Topical
Field block
Local infiltration of tissues
Ring block
Intrasynovial
Brachial plexus block
analgesia distal to the elbow
Lignocaine (Lidocaine) given IV
can cause cardiac arrest or syncope
Working times for Lignocaine without and with adrenaline
Without adrenaline: 5 minutes
and lasts 50-90 minutes
With adrenaline lasts 80 minutes
Bupivacaine
local anaesthetic
Lignocaine (Lidocaine)
Local anaesthetic
Bupivacaine is less or more potent than lignocaine
4 x more potent than lignocaine
Bupivicaine lasting effect length
lasts up to 8 hours
Epidural location
L7 and S1
How does an epidural work
Drug injected into the epidural space to block the nerves as
they leave the spinal cord
CRI
Constant Rate Infusions
CRI function
Maintains a constant plasma concentration of the drug
What drugs are used in MiLK CRI
Morphine, Ketamine and Lidocaine in a 0.9% Saline
or Hartmann’s bag
MiLK CRI are not recommended in
Cats-due to lidocaine toxicity
