Lecture 4 Toxicology

Continuation of Intro & Decontamination

What is the 4th component of Emergency Stabilization and Life Support?

Control CNS/Respiratory depression

What are “supportive” measures for CNS/Respiratory depression?

atropine, fluid boluses, vasopressors for CV support,

airway management, mechanical ventilation for respiratory support

What drug do you think about to reduce CNS/Respiratory depression, especially to reverse fentanyl (carfentanil)/opioid exposures?

Nalaxone - reverses opioids and agonists

Spent fentanyl patches can have up to ___% original amount, and when ingested can be absorbed ___ via ____ effect.

84%, greatly, first pass

How can you treat fentanyl patch ingestion in a dog?

give naloxone (IM, SQ, IV, intranasal), repeat naloxone as necessary, then emesis or endoscopic retrieval

What drug do you think about to reduce CNS/Respiratory depression, especially to reverse benzodiazepine exposures?

flumazenil, GABA receptor antagonist

What drug do you think about to reduce CNS/Respiratory depression, especially to reverse alpha-2-agonist exposures?

atipamezole, alpha-2-antagonist

What drug is out of favor to treat CNS/Respiratory depression and why?

doxapram because it increases myocardial depression and decreases cerebral blood flow

What is the 5th component of Emergency Stabilization and Life Support?

Control temperatures

You must think about _____ and _____ before doing additional thermoregulatory procedures

underlying cause, correct first

What are the causes of hypothermia?

hypotension, hypovolemia, bradycardia (e.g. hyperkalemia)

How can you correct hypothermia?

heat lamps, warm blankets, warm fluids, warm water bottles

Need to warm ___ to prevent what?

slowly

peripheral vasodilation (loses heat) and result in profound hypotension

What are the causes of hyperthermia?

tremors (e.g. hypocalcemia), seizures (e.g. hypoglycemia)

How can you correct hyperthermia?

control seizures/muscle tremors, IV fluids, water baths, fan

Need to cool ___ to prevent what?

slowly

peripheral vasoconstriction (retain heat) and result in profound hypertension

At what temperature range do you STOP cooling a hyperthermic patient to avoid hypothermia?

103.5 to 102.5

What is the second goal of managing an acutely toxic patient after emergency stabilization and life support?

Establish a working diagnosis by clinical evaluation and diagnostic procedures — “Plan of Attack”

What are components of establishing a working diagnosis?

• Obtain hx

• PE, TPR

• Do math to estimate exposure dose (mg toxicant/kg BW)

• Prioritize problem list

How do you estimate an exposure dose?

need to know body weight, amount ingested, % active ingredient

How do you estimate how much an animal has to ingest to get to toxic dose?

need to know body weight, toxic-lethal dose, % active ingredient

How do you determine if the exposure potential is toxic?

compare dose to the TD for the species, or safety factor of 10 of LD50 for the species or move decimal to left once.

What if there is no literature on the LD50 of a toxicant for the species?

Do an additional safety factor of 10. Move decimal to left twice.

After emergency stabilization and doing math, what is the third goal of managing an acutely toxic patient?

DECONTAMINATE - reduce further absorption

When considering decontamination, you must weigh ____ and ____.

risks and benefits, understand indications and contraindications

The type of method of decontamination will depend on what factors?

• exposure route(s)

• nature of toxicant

• clinical presentation

• time interval

• pre-existing health risks

True or False? No one decontamination method should be used routinely but you should always decontaminate.

False. No one decontamination method should be used routinely and you many choose not to decontaminate for a variety of reasons

What exposure routes do you consider with toxicants?

topical/dermal, ocular, inhalation, oral

What are indications for decontamination for topical exposures?

corrosive acids pH<3 or corrosive bases pH>11

irritants, anything that can be systemetically absorbed (essential oils-potpourri) anything that can cause paresthesia (pyrethrins)

For topical exposures, describe the general decontamination process

dry by brush/vacuum/shave, follow with bath 2-3x with mild liquid dish detergent and rinse with room T water, make sure to dry

How should you decontaminate water soluble liquid topical toxins versus lipid soluble liquid topical toxins?

water soluble = bath at room T water with mild liquid dish detergent 2-3x, rinse, dry

lipid soluble = mechanic’s hand degreaser, bath at room T water with mild liquid dish detergent 2-3x, rinse, dry

What do you have to think about to decontaminate a dermally exposed P?

Wearing PPE

All dermal exposures can turn into ___ and ___ exposures for themselves and other animals in environment.

oral, ocular

What should be considered in the follow-up for topical exposures?

analgesics, E-collar, vitamin E for paresthesia etc.

What are the indications for decontamination for ocular exposures?

irritants, corrosive from dermal exposures

Describe the general decontamination process for ocular exposures

flush up to 15-20 minutes (commercial eye wash, tap water), sedation is often required or topical anesthetic

What should you monitor for with ocular exposures?

pawing, rubbing at eyes, redness, lacrimation, blinking, squinting

What are the indications for decontamination for inhalation exposures?

irritants, corrosives, gas, smoke inhalation, CO (anhydrous ammonia, phosphine gas, house fires)

Describe the general decontamination process of inhalation exposures

remove from environment

ensure patent airway, adequate ventilation, bronchoconstriction/bronchospasm

ET tube, oxygen therapy, anti-inflammatories

What group of animals are particularly sensitive to inhalation exposures?

birbs 🐦