MLSCI 466 - Lec 12-14 Poison Control

how common are accidental and intentional poison exposures

very common

% of calls NPDS for children <6yr

39%

how common are poison-related fatality cases in children

rare

% of calls for pharmaceuticals

51%

where do most poison exposures occur

at home (92% of cases)

where do the second most poison exposures occur

on site/non-healthcare facilities (67% of cases)

most common route of poisoin exposure

ingestion (78%)

are poison exposures usually intentional

no they are usually unintentional (78%) of cases

most common poison children are exposed to

household cleaners

most common poison adults are exposed to

analgesics first, followed by other prescription meds

most common cause of fatal exposures

acetaminophen poisoning

approach to poison-exposed patient

ABCDEF - airway, breathing, circulation, decontamination (avoid absorption), elimination (enhance excretion), and find an antidote

airway (ABCDEF)

goal is to protect airway early and continually reassess

reasons the airway can be in danger

• sedation causing low airway smooth muscle tone

• inhalation of toxin or vomit

• increased secretion

breathing (ABCDEF)

goal is to breathe for the patient

what must we consider if the patient's breathing is poor but airway is open

• sedation

• aspiration

ways to breathe for the patient

• mouth-to-mouth

• bag-valve-mask ventilation (BVM)

• advanced airway

4 airway devices

1. oral airway

2. nasal airway

3. LMA

4. endotracheal tube

oral airway

airway device that is firm and can bypass floppy tongue

nasal airway

airway device that is well tolerated, similar to oral airway

Laryngeal Mask Airway (LMA)

airway device that sits on top of esophagus, it is longer lasting than the nasal device and is used in shorter operative cases

endotracheal tube

more definitive, longer-lasting airway device

circulation (ABCDEF)

• assess for signs of poor perfusion (i.e. can heart pump O2)

• evaluation HR, BP, skin temp, pulses, urine output

• establish vascular access early in poisoned patients

radial pulse

also known as peripheral pulse, check wrist

carotid pulse

also known as central pulse, check trachea

what do we do if we cannot find a pulse

do CPR (compressions, airway, breathing)

signs of poor perfusion

• tachycardia

• tachypnea

• hypotension

• mottled skin

• altered mental status

• weak pulses

• delayed capillary refill

• cool skin

treatment for poor perfusion

• IV fluids (saline, ringer's lactate)

• medications to increase BP (inotropes) -> epinephrine, norepinephrine, dopamine, dobutamine

4 vascular access ways

1. peripheral IV (most common)

2. intraosseous (IO)

3. central line (if pt is stable)

4. umbilical vein (if baby)

decontamination (ABCDEF)

goal is prevent or minimize absorption

options to decontamination

• activated charcoal (most common)

• emetic

• whole bowel irrigation

• gastric lavage

IPECAC

emetic used to induce vomiting that is no longer recommended by medical professionals

ideal timeframe for gastric lavage

within 4 hours

what is a gastric lavage

stomach pumping

Complications of gastric lavage

aspiration pneumonitis + GI tract perforation; evidence of efficacy is unclear

ideal timeframe for activated charcoal

within first hour

how does activated charcoal work

binds some drugs to render them inactive

complications of using activated charcoal

aspiration (pneumonitis of lungs) + small bowel obstruction

what doesn't activated charcoal work on

PHAILS: pesticides, hydrocarbons, acids and alkali, iron, lithium, and solvents

what is whole bowel irrigation

• decrease absorption by decreasing transit time

• uses PEG thru nasogastric tube until effluent becomes clear

• done if previous options weren't working

when do we do whole bowel irrigation

exposure to iron, lead, lithium OD, sustained release tablets

elimination (ABCDEF)

goal is to enhance excretion

when is elimination done

for rlly sick patients or those with potential for severe deterioration

urine alkalization

administration of IV NaHCO3 to produce urine with a pH of 7.5 or more

top reason we do urine alkalization

for salicylate poisoning

what can urine alkalization increase urine elimination of

• salicylate

• chlorpropamide

• 2,4-dichlorophenoxyacetic acid and Mecoprop (herbicides)

• fluoride

• methotrexate

• phenobarbital

medication properties of hemodialysis

• low Vd

• single-compartment kinetics

• low endogenous clearance

• MW less than 500 daltons

• water soluble

• not bound to plasma proteins

substances that can be dialyzed

STUMBLE: salicylates, theophylline, uremia, methanol. barbituates, lithium, ethylene glycol

antidote for acetaminophen

N-acetylcysteine (NAC)

antidote for anticholinergic

Physostigmine

Antidote for benzodiazepines

Flumazenil

antidote for carbon monoxide

oxygen

antidote for cyanide

hydroxocobalamin, sodium nitrite, sodium thiosulfate

antidote for digoxin

digoxin-specific Fab

antidote for ethylene glycol

ethanol, fomepizole

antidote for iron

deferoxamine

antidote for methanol

ethanol, fomepizole

antidote for methemoglobinemia

methylene blue

antidote for opioids

naloxone

antidote for organophosphates

atropine, pralidoxime

questions to ask to when poisoned patient admitted to ER

• what?

• when?

• how much?

• what is the patient’s weight

actions to take to determine poisoned patient history

• obtain all prescription bottles, count pills

• identify all unknown tablets

  • talk to patient’s family/friends

  • call prescribing physician/pharmacy

• search home and belongings

components of tox physical exam

• vital signs (HR, RR, BP, T, O2 sat)

• skin (hot or cold to touch, wet?dry?)

• pupils (big? small?)

• bowel (absent or hyperactive)

• neurologic exam

• other clues such as spastic patient? rigid tone?

what does miotic refer to

constricted pupil

what does mydriatic refer to

dilated pupil

toxin associated with bitter almond smell

cyanide

toxin associated with carrot smell

water hemlock

toxin associated with fishiness

zinc or aluminum phosphide

toxin associated with fruity smell

ethanol, acetone, isopropyl alcohol, chloroform

toxin associated with garlic smell

arsenic, DMSO, organophosphates, yellow phosphorus

toxin associated with glue smell

toluene, solvents

toxin associated with pear smell

paraldehyde, chloral hydrate

toxin associated with rotten egg smell

hydrogen sulfide, DMSA, N-acetylcystine

toxin associated with shoe polish smell

nitrobenzene

toxin associated with winter green smell

methyl salicylate

how can electrocardiograms help us in tox

some toxins may demonstrate characteristic electrocardiograms

what is a toxidrome

a constellation of clinical signs and symptoms caused by a toxin → doctors use this when highly suspicious pt is poisoned along with complete patient history and a detailed physical exam to determine a treatment

examples of common toxidromes

• sedative/hypnotic

• opioid

• cholinergic

• anticholinergic

• sympathomimetic

examples of sedatives/hypnotics

• quaaludes

• benzodiazepines

• barbiturates

• ethanol

another name for quaaludes

methaqualone

examples of benzodiazepines

• lorazepam (ativan)

• diazepam (valium)

• chlordiazepoxide (lithium)

“azz-sounding drugs”

examples of barbiturates

• amobarbital (amytal)

• pentobarbital (nembutal)

• secobarbital (seconal)

“barbitals”

what do sedatives/hypnotics do

general anesthesia → a complete loss of awareness and reflex activity

system effects of sedatives/hypnotics

• pupils: N

• RR: ↓

• BP, HR: sl ↓

• skin: N

• mental status: sedated

• bowel sounds: N

antidote for sedatives/hypnotics

flumazenil

is flumazenil commonly used?

no—it is rarely used because for chronic users of sedatives/hypnotics, they end up seizing

examples of opioids

• heroin

• morphine

• codeine

• oxycodone

• fentanyl

• opium

• hydromorphone

• percocet

• tramadol

respiratory effect of opioids

pronounced respiratory depression—RR is often diminished before decreases in BP or HR occurs

triad of symptoms in opioid OD

• pinpoint symptoms

• unconsciousness

• respiratory depression

true or false: diagnosis can be confirmed by naloxone

true

what do opioid overdoses require

close observation and usually airway intervention

system effects of opioid

• pupils: small, fixed

• RR: ↓

• BP, HR: sl ↓

• skin: N

• mental status: euphoria to coma

• bowel sounds: ↓

what is often prescribe in conjunction with opioids

stool softeners

antidote for opioids

naloxone

examples of cholinergics

• organic phosphorous compounds

• carbamates

• certain mushrooms

examples of organic phosphorous compounds

many pesticides, nerve gases (ex. sarin gas)

mushrooms with cholinergic properties

Boletus sp., Clitocybe sp., Inocybe sp.

Not magic mushrooms!

are cholinergic poisonings common

they are uncommon but important to recognize:

• most frequently caused by pesticides

• unsuspected dermal contamination

• foundation of “nerve" agents”

cholinergic symptoms

massic discharged of parasympathetic nervous system:

• patient is “wet” (e.g. sweat, vomit, diarrhea, tears)

• CNS (e.g. confusion, coma, seizures)

• skeletal muscle weakness

• miotic pupils

• bradycardia

system effects of cholinergics

• pupils: small, fixed, lacrimation (teary)

• RR: N or ↑

• BP, HR: ↑ or ↓

• skin: wet

• mental status: confusion/drowsiness to coma, seizures

• bowel sounds: ↑

• other: SLUDE and the Killer B’s, pulmonary edema, fasciculations, weakness → paralysis