Lecture 29: Euthanasia - Physical Modalities

mechanisms for euthanasia

• direct depression of neurons necessary for life function

• hypoxia

• physical disruption of brain activity

euthanasia should result in

rapid loss of consciousness, followed by cardiac and respiratory arrest and subsequent loss of brain function

examples of acceptable methods of euthanasia

• inhaled anesthetics - conditionally acceptable in small animals

• carbon monoxide or CO2 - conditionally acceptable

• argon or nitrogen - conditionally acceptable in chickens and turkeys

• barbiturates - acceptable

• KCl, MgSO4, MgCl2 - unacceptable unless animal is unconcscious

what is a major active ingredient in several euthanasia solutions?

pentobarbital

pentobarbital

• causes death by severely depressing medullary and vasomotor centers at the high doses used

• cardiac activity may persist for several minutes following administration

what euthanasia drug is added to some products to increase cardiac effects?

phenytoin

euthanasia drugs are not to be used in

animals intended for food purposes

confirmation of death

• death must be confirmed before disposal of body

• lack of pulse/breathing, corneal reflex, or response to firm toe pinch

• inability to hear breath or heart sounds with stethoscope, graying of mucus membranes, and rigor mortis

body disposal

• must be handled in accordance with state and local laws

• use of pentobarbital - legal responsibility to properly dispose of body

US fish and wildlife service recommendations to prevent secondary poisoning

• incineration

• bury deeply

• prevent scavenger access to local landfills

• educate clients - include warning about disposal on euthanasia consent form

• tag animal and outer bags with prominent poison tags

what are physical modalities?

thermotherapy, exercises, massage, proprioception and balance exercises, aquatic therapy, therapeutic ultrasound, electrical stimulation, etc

goals of physical modalities?

• restore, maintain, and promote optimal function

• improve the outcome of patient following major surgery

• enhance the quality of life

who performs physical modality treatments?

• licensed veterinarian

• registered/certified veterinary technician trained in the technique

• a licensed physical therapist educated in veterinary anatomy and physiology

state practice acts

it is the responsibility of the individual practicing veterinary physical therapy to know the legal issues related to both veterinary and physical therapy practice acts in their respective state

basic knowledge needed for physical modality treatments

• behavior

• anatomy

• orthopedic and neurologic evaluation

• tissue healing

• response of musculoskeletal tissue to disuse and remobilization

• exercise physiology

• principals behind therapeutic modalities

complete myofascial exam

• includes all areas of the body, treatment, and diagnosis include the patient as a whole

• includes all aspects of orthopedic and neurologic exam

• helps to narrow down diagnostic tests, formulate a treatment plan, and give owner a prognosis

• can have owner fill out history questionnaire before appointment to save time

active functional assessments

• posture

• gait/mobility

• transfers

• muscle strength test

passive functional assessments

• passive range of motion

• end-feel

• goniometry

• joint play

• flexibility

• muscle girth

• myofascial exam

myofascial trigger point =

taut band of skeletal muscle → often painful, look for local twitch response

pain management

• multimodal approach to treating pain is ideal

• strategy can be adjusted as the patient’s comfort level improves

what sort of environmental modifications for the patient would you be sure to explain to the owner?

flooring, bedding, stairs, nail/foot care, feeding station

cryotherapy

• used during the acute inflammatory phase

• reduces inflammation, edema, and pain → improves mobility, minimizes hematoma formation and reduces muscle spasm

• use a bag of crushed ice, frozen peas, or frozen gel pack with a cloth layer over the skin for 15-25 mins 2-6 times/day

what do cryotherapy machines do?

circulate cold water in a fabric sleeve while applying compression

thermotherapy

• indicated for patients with chronic pain and muscle spasm

• increased tissue temperature leads to vasodilation and increased blood flow → removes accumulated metabolites

• helps with connective tissue excitability and muscle relaxation → reduces overall stiffness

• treatment time of 30-45 minutes

massage

• provides pain relief, relaxation, and promotes circulation

• useful in multiple situations to improve patient comfort and owner bond

• contraindications: open wounds, unstable fractures, severe pain, coagulation disorders, infection, or neoplasia

therapeutic exercises

• stretching

• range of motion

• aerobic conditioning, muscle strength, and endurance training

• correction of gait abnormalities

• use a variety of surfaces to walk on

tips for therapeutic exercises

• movement is life

• use good footing, keep toenails trimmed

• use a harness to support/control patient that does not restrict ROM

• keep session positive with treats and praise

• 2-3 exercises per session

• always warm up and cool down

photobiomodulation

• LASER = light amplification by stimulation emission of radiation

• single wavelength light that leads to a photochemical reaction in the cells

• therapeutic effects include direct pain control, increases release of endogenous opioids, reduction in inflammation, treats muscle trigger points

• useful for managing chronic and minor pain, especially OA and muscle spasms

low-level laser therapy

• clip the treatment area to avoid hair absorbing light

• wash off any iodine or povidone-iodine to allow greater transmission of light

• protective eye gear must be worn to prevent retina damage

• know where and how deep your laser will go and be very careful of problem area

• each laser brand have specific wavelengths

targeted pulsed electromagnetic field (PEMF) therapy

• works by delivering microcurrents that increase blood and lymph flow → reduce edema and pain

• FDA approved for treatment of non-union fractures

• FDA cleared to treat post op pain and edema, OA, plantar fasciitis, and chronic wounds

extracorporeal shock wave therapy (ESWT)

• application of high-energy, high-amplitude acoustic pressure waves to tissue

• the waves travel through soft tissue and fluid and release their energy into tissue when a change in density is encountered

• this energy release is thought to stimulate healing

therapeutic ultrasound (TUS)

• uses high intensity to affect biological tissue

• creates a mechanical energy wave that moves through tissue and the absorbed energy is converted to kinetic energy

• therapeutic effects due to thermal and nonthermal properties

non-thermal effects of TUS

modify cellular function and membrane permeability, stimulates fibroblast activity, increases blood flow, increased protein synthesis, and promotes tissue repair and healing

parameters of TUS

• frequency - depth of sound penetration

• intensity - degree and rate of sound energy and heat production

• higher intensity = greater amount of heat produced, so start with a lower intensity