Intro to pain management (Granone) Flashcards
Goals and Objectives
- Understand pain pathophysiology and its effects
- Discuss types of pain and pain pathway
- Become familiar with methods for recognizing pain in veterinary patients
- Become familiar with the assessment of pain in veterinary patients
Negative consequences of pain
- behavioral
- physiological
- neurohumoral
- metabolic
- immunological
Definition of pain
(physiology of pain)
- An unpleasant sensory and emotional experience with actual or potential tissue damange
Primary afferent nerve fibers
Information sent to brain
Sensory afferent nerve fibers
- Dedicated to response of noxious stimuli
Protective response
Withdrawal from stimuli
Nociception
- Detection of potential or actual damaging stimuli and transmission of information to the brain
5 processes of nociception
- transduction
- transmission: to dorsal horn of spinal cord
- modulation
- projection: by afferent neurons
- perception
Nociceptors
- nerve ell endings, initiate the sensation of pain, transduce electrical signals at site of tissue disruption
Activation of nociceptors by
- heat
- cold
- chemical
- mechanical stimuli
Dorsal horn receives electrical signals from primary sensory nerve fibers
- alpha-beta fibers
- alpha-gamma fibers
- c fibers
Brain
(physiology of pain)
- signals received => physiologic and behavioral responses initiated
Hyperalgesia
- increase in painfulness of noxious stimuli, reduced pain threshold
- inflammation => hyperexcitability due to reduction in threshold => inc responsiveness = peripheral sensitization
Allodynia
- pain following non-painful stimuli
- peripheral nerve and tissue injury => change in CNS
- central sensitization
Windup pain
- perceived increase in pain intensity over time
- repeated delivery of painful stimulus
- frequency dependent increase in excitability of spinal cord neurons => afferent C fibers
- Difficult to treat
Somatic pain
- related to wall of body cavity
- musculoskeletal pain
Visceral pain
- poorly localized
- mechanical stimuli (stretching of viscera)
- Ischemia
- Chemical and thermal stimuli
- Change in somatic muscle tone, autonomic responses
Recognition of pain
- challenging aspect of pain management
- owner info regarding behavior changes
- no single parameter pathonomonic for pain
- may be masked in unfamiliar situations
- acute vs. chronic
equine pain exhibition
- draught horses more stoic
- foals and young horses more likely to exhibit pain
- owner/handler may be good source of info
Indicators of pain, stress and well-being
- attitude
- behavior
- posture
- activity
- appearance
- appetite
indicators of pain, stress and well-being in horses
normal factors plus
- facial expression
- interaction with people
- response to handling
- willingness to perform work
classic sign of thoracic pain in a cow
head extended
objective pain assessment
- HR, RR, BP, rectal temp
- weak correlation between inc HR and pain
- Plasma cortisol, catecholamine and beta-endorphin concentrations
- variability between concentration and marker of pain
*all of these are non-specific combine with other tools
Categories of pain scales
- simple descriptive pain scale
- numerical rating scales
- composite pain scoring scales
Simple descriptive pain scale
- mild, moderate, severe pain
- very basic tool, not validated
Numerical rating scales
- numerica units assigned to different categories of behaviors
therapeutic pain managment
- preemptive analgesia
- provide analgesia prior to noxious stimuli
- decrease drug requirements during maintenance and recovery of anesthesia
- multimodal analgesia
- use of more than one modalit of analgesia to obtain additive or syndergistic effects
- reduction in the dose of each drug used
Pharmaceutical pain management
- NSAIDS
- Opiods
- local anesthetics
- a2 agonists
- xylzine
- dexmetatomidine
Therapeutic pain managment
- pharmaceutical
- NSAIDS
- opioids
- local anesthetics
- alpha 2 agonists
- Nutritional-nutraceutical (lack of clinical studies)
- glucosamine
- chondroitin sulfate
- Complimentary therpies
- acupuncture
- chiropractic
- physical
- ultrasound
Summary
- pain is a multi-faceted complex experience
- no single parameter pathognomonic for pain
- multiple tools to help with assessment of pain and the therapeutic approach
- protocol should include preemtive and multimodal therapeutics when possible
- responsibility to strive to alleviate pain
