Transmission and modulation Flashcards
Pain experience components
- Detection of tissue injury by the NS (Nociception)
- Conscious perception of pain (noxious stimulus)
- Behavioural responses or changes that occur to protect the individual from further discomfort
Consequence of sympathetic stimulation
-Tachycardia, tachypnea
-peripheral vasoconstriction
-increased myocardial work
-increased myocardial oxygen consumption
-decreased blood flow/oxygen delivery to abdominal organs
Consequence of neuroendocrine effect
-Adrenocorticotropic hormone release
-increased cortisol, NE, Epi
-decreased insulin
Consequence of stress
-decreased appetite
-insomnia
-immunosuppression & delayed healing
-decreased quality of life
Categories of patients you will encounter
- healthy, non painful in for routine procedure
- healthy, underlying orthopedic issue requiring procedure
- chronic condition resulting in mild discomfort
- Undergone some form of trauma in the recent past, will require surgical correction in future
**all will need anesthesia and surgery at some point
Triad of anesthesia
- analgesia
- Muscle relaxation
- loss of consciousness
How does our patient being anesthetized effect the pain response to injury?
-not necessarily perceiving the stimulus as pain
-pain pathways are still firing but conscious aspect is gone
Steps for detecting pain
1.Transduction- noxious stimuli are transformed into electrical signals
2. Transmission- conduction of impulse from peripheral to spinal cord receptors
3. Modulation- amplification or suppression of pain impulses by neurons in spinal cord
4. Perception- processing and recognition of pain in the brain
If pain goes untreated…
-peripheral sensitization
-central sensitization
-hyperalgesia (primary and secondary)
-allodynia (non painful stimulus is believed to be painful by individual)
-wind up pain
Techniques to treat and reduce pain
- Pre-emptive analgesia
- Multimodal analgesia
Pre-emptive analgesia
-1st key strategy when pain is anticipated
-provide analgesia before the insult can significantly reduce both intra and post-operative analgesia requirements
Multimodal analgesia
-combines analgesics from 2 or more drug classes or analgesic techniques that employ different mechanisms of action, targeting different (peripheral or central) pain pathways, thus achieving a synergistic effect at lower analgesic doses
Level of pain
**need to be able to predict the level of pain that a procedure could cause
Mild: castration, mild otitis, minor dental, minor laceration
Moderate: Castration, Spay, urethral obstruction, local burn
Severe: laparotomy, fracture repair, extensive burn, limp amputation
What inhibits transduction?
-local anesthetics, opioids, NSAIDs, corticosteroids
What inhibits transmission?
-local anesthetics
-alpha 2 agonists
