Approach to the Poisoned patient

Hydrocarbons and Volatile SubstancesPresented by: Tonyan Thompson

“What is it that is not a poison?All things are poison and nothing is without poison.It is the dose only that makes a thing not a poison.”

—Paracelsus (1493-1541)

Poisoning • Poisoning occurs when exposure to a substance adversely affects the

function of any system within an organism.• Given a large enough exposure, all substances have the potential to

be poisons.• The setting of the poison exposure may be occupational,

environmental, recreational, or medicinal.

ETIOLOGY• Poisoning may be intentional or unintentional.• Intentional:• Depression• Suicide• Homicide• Recreational drug abuse

• Unintentional (accidental):• Common cause in children• Therapeutic error (e.g., double dose)• Recreational drug experimentation

Portals of Entry• Poisoning may result from varied portals of entry, including:

• inhalation, insufflation, ingestion, cutaneous and mucous membrane exposure, and injection. • Historically most poisonings have occurred when substances are

tasted or swallowed.

Epidemiology • Poisoning is a significant global public health problem. • According to WHO data, in 2004 an estimated 346,000 people died

worldwide from unintentional poisoning. • Of these deaths, 91% occurred in low- and middle-income countries.• In the same year, unintentional poisoning caused the loss of over 7.4

million years of healthy life (disability adjusted life years, DALYs).

Diagnosis – Signs and Symptoms • Neurologic:

• Lethargy• Agitation• Coma• Hallucinations• Seizures

• Respiratory:• Tachypnea, bradypnea, apnea• Inability to protect airway

• Cardiovascular:• Dysrhythmias• Conduction blocks

• Vital signs:• Varies depending on toxic substance• Hyperthermia, hypothermia• Tachycardia, bradycardia• Hypertension, hypotension

Toxidromes• Toxidromes are collections of physical findings that occur with specific

classes of substances.

• The identification of a specific toxidrome is helpful in establishing potential toxic agents when the history is not well defined.

• Odors and skin findings may also provide useful clues.

Toxidrome Representative Agent Most Common Findings Potential intervention

Cholinergic Organophosphate insecticidesCarbamate Insecticides

Muscarinic effects (Salivation, lacrimation, diaphoresis, nausea,vomiting, urination, defecation,Bronchorrhea)Nicotinic Effects (muscle fasiculations and weakness)

Airway protection and ventilation, atropine, pralidoxime

Anticholinergic Scopolamine, Atropine Altered mental status, mydriasis,dry flushed skin, urinary retention,decreased bowel sounds,hyperthermia, dry mucous membranes

Physostigmine (if appropriate),sedation with benzodiazepines,cooling, supportive management

Opioid Heroin, Morphine, oxycodone Central nervous systemdepression, miosis, respiratory depression

Ventilation or naloxone

Sympathomimetic Cocaine, Amphetamine Psychomotor agitation, mydriasis,diaphoresis, tachycardia, hypertension, hyperthermia

Cooling, sedation with benzodiazepines, hydration

History • Ask about the agent or drug, estimated amount or dose, and route of

exposure, as well as whether other individuals were exposed. If possible, the patient’s intent should be determined.• Corroborating information should be obtained from the patient’s

physician, prior medical records, witnesses, or emergency medical technicians. • Ask about the environment in which the patient was found, the

presence of empty pill bottles or containers nearby, any smells or unusual materials in the home, the occupation or hobbies of the patient, and the presence of a suicide note.

Physical Exam• An organized approach is recommended• Undress the patient completely. Check the patient’s clothing for

objects still retained in the pockets or substances hidden on the patient’s body (waistband, groin, or between skinfolds). • Search clothing and belongings with care to avoid being injured by

uncapped needles or sharp objects. • Note any odors on the patient’s clothes.

Physical Exam• General appearance - note any agitation, confusion, or obtundation. • Skin – Look for cyanosis or flushing, excessive diaphoresis or dryness, signs of injury or

injection, ulcers, or bullae. Bruising may be a clue to trauma, a prolonged duration of unconsciousness,or coagulopathy. • Eyes - for pupil size, reactivity, nystagmus, dysconjugate gaze, or excessive lacrimation.• Oropharynx - for hypersalivation or excessive dryness.• Lungs - Auscultate the lung fields to assess for bronchorrhea or wheezing, • Heart - for its rhythm, rate, and regularity. • Abdomen - note the presence of bowel sounds, enlarged bladder, and abdominal

tenderness or rigidity.• Extremities - for muscle tone and note any tremor or fasciculation.

Work up• Laboratory • Electrolytes, BUN/creatinine, glucose• Calculate anion gap: Na + (Cl + HCO3): Normal anion gap: 8–12• Serum Osmolar gap: Calculated osmolality = 2(Na+) + glucose/18 + BUN/2.8 +

ethanol (in mg/dL)/4.6. • Imaging• ECG for dysrhythmias or QRS/QT changes• CT of head for altered mental status not clearly due to toxin• Chest radiograph if suspected aspiration or pneumonia

Treatment - Initial Stabilization• ABCs:• Protect the airway - Endotracheal intubation as needed • Oxygenation - Administer a high concentration of oxygen by mask• Ventilation• IV access• Connect the patient to monitoring Device - Pulse oximetry, Cardiac

monitor, BP, core temperature

• Hypotension:• Administer 0.9% normal saline IV fluid bolus.• Trendelenburg• Vasopressors for persistent hypotension

• Bradycardia:• Atropine• Cardiac pacing

• If altered mental status, administer “coma cocktail”: Thiamine, D50W (or Accu-Chek), naloxone• Dextrose: D50W 1 ampule of 50 mL or 25 g (peds: D25W 2–4 mL/kg) IV• Naloxone (Narcan): 2 mg (peds: 0.1 mg/kg) IV or IM initial dose• Thiamine (vitamin B1): 100 mg (peds: 50 mg) IV or IM

• considered after the medical history, vital signs, and immediately available laboratory data are taken into account

Treatment - General Decontamination• Gross Decontamination• Eye Decontamination• GI Decontamination

Gross Decontamination• Surface decontamination - completely undress patients and

thoroughly wash them with copious amounts of water. • If assistance required – assisted by properly gowned staff. • The towels used to dry patients, patients’ clothing, shoes, socks,

watches, and jewelry should be handled as contaminated material. • If possible, surface decontamination should occur prior to the

patient’s entry into the ED or other areas in the hospital.

Eye Decontamination• Ocular exposures are treated with copious irrigation using isotonic

crystalloid, (normal saline or lactated Ringer’s solution)• Typically at 1 to 2 L per eye depending on the agent.• Application of an ophthalmic anesthetic, such as 0.5% tetracaine, may

be necessary to relieve blepharospasm and facilitate irrigation. • Use of lid retractors may be required for adequate irrigation.

GI Decontamination• Methods used to decontaminate the GI tract have potential

benefits and risks that should be considered prior to their use.• 3

• The three general methods of decontamination involve:• 1. removing the toxin from the stomach via the mouth• 2. binding it inside the gut lumen, or • 3. enhancing transit through the intestines.

• The specific toxin ingested, the time course, and the patient’s clinical status determine the choice of method(s) used

Gastric emptying - Emesis• Ipecac Syrup - Once the preferred technique for gastric emptying,

syrup of ipecac is no longer recommended in the ED.

• Only in rare circumstances, such as immediately after ingestion of a substance not expected to compromise the airway or lead to altered mental status, hemodynamic derangement, or seizure, or after recent ingestion of a highly toxic pill that is known not to fit into the holes of the appropriately sized orogastric tube• Typical dose - 15 mL for children 1 to 12 years of age and 30 mL for

adults, usually followed by sips of water.

Contraindications • Include ingestions that have the potential to alter mental status,

active or prior vomiting, caustic ingestion, exposure to a toxin with more pulmonary toxicity from inhalation than toxicity from GI absorption (e.g., hydrocarbons), and ingestions of toxins that have the potential for inducing seizures. • Rare complications of syrup of ipecac administration include

aspiration, Boerhaave syndrome, Mallory-Weiss tear, and intractable vomiting.

Gastric emptying - Orogastric lavage • Consider in potentially lethal ingestions without known antidote

within 1 hr of ingestion. • Protected airway essential prior to lavage

Indications• Reserved for intubated patients with a depressed level of

consciousness from unknown substances or specific indications such as highly toxic drugs. • May be useful to remove large quantities of alcohol in patients with

acute poisoning.

Method• Tube Size - should be of adequate size to recover pill fragments:

• Adults - 36F to 40F (30 English gauge or 12- to 13-mm outside diameter) • Children - 22F to 24F (8- to 9-mm outside diameter)

• Depth of Insertion of tube - depth that corresponds to the length from the patient’s chin to the xiphoid process.

• Positioning - on the left side (left lateral decubitus), bed tilted head down 20 degrees to reduce the risk of pulmonary aspiration.

• Carefully insert a lubricated lavage tube, correct tube positioning is assessed by insufflation of air. • Siphon the gastric contents into a bucket, checking for tablet material; gentle pressure over the stomach

may facilitate drainage• Small amounts of fluid used to avoid stimulating the propulsion of gastric contents into the duodenum.

• - 200 to 300 mL in adults and 10 mL/kg in children• Body-temperature or at least room-temperature solutions is recommended. Gastric lavage with cool

solutions can induce hypothermia, The volume returned with lavage should be essentially equal to that administered. Lavage is continued until the effluent becomes clear.

• Before the tube is removed, activated charcoal should be instilled, if indicated

Contraindications• There are not adequate facilities and skills available to protect the airway or

deal with any complications that might arise.• Ingestion of pills that are known not to fit into the holes of the orogastric lavage

hose• The substance taken is relatively safe (e.g. benzodiazepines).• The substance ingested is safer in the stomach than anywhere else. This applies

to the following:• – Oily or petroleum-based substances: relatively harmless in the stomach, but accidental

spillage into the lungs during lavage will cause a life threatening pneumonitis.• – Corrosives and caustics: may cause oesophageal perforation, especially with the help of

a lavage tube.

Complications• Insertion of the tube into the trachea• Aspiration • Esophageal or gastric perforation• Hypoxemia during the procedure

TOXIN ADSORPTION IN THE GUT• Activated charcoal• Mulitidose Activated charcoal

Activated charcoal• Agent most often used to decontaminate the GI tract after toxic

ingestion• Prepared by treating heated wood pulp, which creates a large surface

area to bind toxins• Works by adsorbing substances in the gut lumen via Van der Waals

forces, which makes them less available for absorption into the tissues. • Most organic and some inorganic substances are adsorbed by

activated charcoal.

Not adsorbed• Metals (borates, bromide, iron, lithium)• Alcohols• Potassium• Potassium cyanide (poorly absorbed)• Hydrocarbons• Pesticides• Acids, alkali• Solvents

• The benefits of this technique include:• Its ability to decontaminate the gut without requiring invasive

procedures • The rapidity of its administration • and its overall safety in both adults and children• Clinical benefit is more likely if activated charcoal is administered

within 1 hour of toxin ingestion, but potential benefit of administration after more than 1 hour cannot be excluded

Indications • Clear indications for administration of activated charcoal are:• recent ingestion of any drug known to adsorb to it • or ingestion of an unknown agent by a patient with a protected

airway.

• Activated charcoal should be administered in a dose equal to 10 times that of the poison to be absorbed.• An initial dose of 50–100 g (or 1 g/kg for children) will usually ensure

that this ratio is met.• Activated charcoal is typically given in a slurry of water or juice by

mouth or through a nasogastric tube.• Oral or nasogastric tube administration

• Complications : include aspiration and intraluminal impaction in patients with abnormal gut motility.• Contraindicated if caustic ingestion, unprotected airway, or bowel

obstruction • Adverse side effects of activated charcoal administration include

aspiration pneumonitis in the unprotected airway as well as bowel obstruction and perforation

Multidose Activated Charcoal• Used in toxic ingestions that are well absorbed by charcoal and undergo

enterohepatic circulation• Entails the repeated use of activated charcoal to enhance elimination of

ingested toxins.• Toxins with a long half-life and small volume of distribution are most likely to

have their elimination accelerated by repetitive doses of activated charcoal.• theophyllines• carbamazepine• phenobarbital• quinine• dapsone

Multidose Activated Charcoal• Multidose activated charcoal is usually given with a first dose of

1gram/kg body weight (50 to 100 grams) • followed by subsequent doses of 0.25 to 0.50 gram/kg (12.5 grams)

repeated one to three times at intervals ranging from 1 to 4 hours.

Enhancement of Bowel Transit• Cathartics• Whole bowel irrigation

Cathartics• are generally used with activated charcoal to decrease the transit

time for the passage of the activated charcoal and presumably the adsorbed toxin through the GI tract.• The administration of a cathartic without charcoal has no role in the

management of the poisoned patient. • The most popular cathartics are 70% sorbitol (1 gram/kg) or • a 10% solution of magnesium citrate (250 mL for adults and 4 mL/kg

for children)

• Indications – same as those for the administration of activated charcoal. • When multidose activated charcoal is used, only the first dose is

accompanied by a cathartic to limit complications.• Complications - include nausea and abdominal pain, severe volume

depletion, electrolyte imbalances and fluid shifts, and hypermagnesemia in patients with renal compromise. • Contraindications• Ingestion of a substance that will result in diarrhea, age of <5 years,

renal failure (magnesium-containing cathartics are contraindicated), intestinal obstruction, and ingestion of any caustic material.

Whole Bowel Irrigation• no conclusive evidence that this intervention improves the clinical

outcome of poisoned patients. • May be effective for large ingestions of iron, heavy metals, lithium,

and other drugs poorly adsorbed by activated charcoal. • It may also be useful for sustained release or enteric-coated products

not well adsorbed to charcoal. • Whole bowel irrigation can remove drug-filled packets or other

potentially toxic foreign bodies.

Whole Bowel Irrigation• performed by the instillation of large volumes of polyethylene glycol in an

osmotically balanced electrolyte solution that produces rapid catharsis by mechanically forcing ingested substances through the bowel at an accelerated rate• accomplished by infusing the polyethylene glycol solution through a

nasogastric tube.• end point of treatment is clear rectal effluent• Typical doses

• 1.5 to 2.0 L/h in adults• 1 L/h in children 6 to 12 years of age • 0.5 L/h in children <6 years of age

• Contraindications include:• preceding diarrhea • ingestion of substances that are expected to result in significant

diarrhea (except for heavy metals, because these substances do not adsorb well to activated charcoal)• bowel obstruction as evidenced by lack of bowel sounds.• Complications - bloating, cramping, and rectal irritation from frequent

bowel movements

Enhanced Elimination• Urinary Alkalinization• Forced Diuresis

Urinary Alkalinization• Alkalinization promotes excretion of weakly acidic agents through ion

trapping at the renal tubules. (Salicylates, Phenobarbital)• typically achieved by the administration of sodium bicarbonate as

either a 1 to 2 mEq/kg IV bolus or 3 to 4 mEq/kg IV infusion over 1 hour.• Urinary alkalinization is sustained by either intermittent bolus or

continuous infusion of bicarbonate.

• Urinary pH should be monitored frequently (every 15 to 30 minutes) until the urine pH is 7.5 to 8.5• Serum pH should not be allowed to rise above 7.5 to 7.55• Pronounced hypokalemia may result from this procedure and should

be corrected to maintain treatment benefit. • Hypokalemia induces the kidneys to reabsorb potassium and excrete

hydrogen ions, which inhibits the production of alkaline urine. • This may result in relatively acidic urine when compared with the

serum pH.

Risks and Contraindications• Risks associated with urinary alkalinization include volume overload

(heart failure and pulmonary edema), pH shifts, and hypokalemia.

• Therefore, this procedure is contraindicated in patients who cannot tolerate the volume or sodium load, are hypokalemic, or have renal insufficiency.

Forced Diuresis• Has never been shown to be effective for ingestion of any toxin, with

the possible exception of chlorophenoxy herbicides when diuresis is combined with urinary alkalinization.

• Admission Criteria• Altered mental status• Cardiopulmonary instability• Suicidal• Lab abnormalities• Potential for decompensation from delayed acting substance

• Discharge Criteria• Psychiatrically clear• Detoxified• Hemodynamically stable

• Issues for Referral• Patients with unintentional (accidental) poisoning require poison prevention

counseling.• Patients with intentional (e.g., suicide) poisoning require psychiatric evaluation.• Consider substance abuse referral for patients.

Hydrocarbons and volatile substances• Hydrocarbons are a diverse group of organic compounds consisting

primarily of carbon and hydrogen atoms.• Major classes of hydrocarbons:• Aliphatic

• Include kerosene, mineral oil, seal oil, gasoline, solvents, and paint thinners

• Aromatic• Benzene (gasoline .8%), toluene (acrylic paint), xylene (cleaning agent, degreaser)

• Halogenated• carbon tetrachloride (refrigerant, aerosol propellant) and trichloroethane (Spot

remover, typewriter correction fluid)

• Physical properties determine type and extent of toxicity:• Viscosity (resistance to flow):

• Higher aspiration risk from products with lower viscosity

• Surface tension (ability to adhere to itself at liquid’s surface):• Low surface tension allows easy spread from oropharynx to trachea, promoting

aspiration (e.g., mineral oil, seal oil)

• Volatility (ability of a substance to vaporize):• Aspiration risk increases as the volatility increases.• Hypoxia from aromatic hydrocarbons displacing alveolar air

• Main complication from hydrocarbon exposure is aspiration:• Hydrocarbon aspiration primarily affects respiratory and central nervous

systems.

Clinical Manifestation of Hydrocarbon Exposure

Volatile Substances• Most often occurs in teenagers and younger adults • Common solvents abused:• Typewriter correction fluid• Adhesive• Gasoline• Cigarette-lighter fluid

• Sniffing: Product inhaled directly from container• Huffing: Product inhaled through a soaked rag held to face• Bagging: Product poured into bag and multiple inhalations taken from

bag

History • Route, type, quantity, and time of exposure:• Determine intentionality and coingestions

• Symptoms:• Vomiting, respiratory distress, mental status change or pain• Bystander actions or pre-hospital interventions

Physical Examination• Evaluate for airway compromise in patients with decreased level of

consciousness and vomiting • Respiratory symptoms generally occur within 30 min but are frequently

delayed several hours• Monitor for hypoxia, hypotension, and cardiac dysrhythmias• Cyanosis and hypoxia suggest respiratory failure but may result from

methemoglobinemia• Temperature may be elevated at presentation following aspiration and

indicates pneumonitis:• Fever after 48 hr suggests bacterial superinfection

Work Up• Pulse oximetry:

• If abnormal, follow with arterial blood gases.

• Electrolytes; BUN, creatinine, and glucose levels; and liver function tests:• For halogenated and aromatic hydrocarbon exposure• Metabolic acidosis• Hypokalemia

• Carboxyhemoglobin levels for methylene chloride exposure:• Methylene chloride metabolized to carbon monoxide in vivo

• ECG indicated in symptomatic patients and patients who ingest halogenated hydrocarbons.

Work up - Imaging• CXR:• Abnormalities visible 20 min–24 hr after exposure (usually by 6 hr)• Increased bronchovascular marking and bibasilar and perihilar

infiltrates (typical)• Lobar consolidation (uncommon)• Pneumothorax, pneumomediastinum, and pleural effusion (rare)• Pneumatoceles resolve over weeks• Repeat chest radiograph if worsening respiratory symptoms

Treatment – Initial Stabilization• ABCs• IV access and fluid resuscitation if hypotensive or ongoing fluid losses• Oxygen• Cardiac monitor• Naloxone, thiamine, D50W (or Accu-Chek) if altered mental status• Dextrose: D50W 1 ampule of 50 mL or 25 g (peds: D25W 2–4 mL/kg) IV• Naloxone (Narcan): 2 mg (peds: 0.1 mg/kg) IV or IM initial dose• Thiamine (vitamin B1): 100 mg (peds: 50 mg) IV or IM

Treatment - ED• Supportive care• Treat respiratory symptoms:• Oxygen• β2-agonist for bronchospasm (albuterol) –

• Albuterol 2.5–5 mg NEB (peds: 0.15–0.3 mg/kg) for bronchospasm• Endotracheal intubation and mechanical ventilation for respiratory failure• Steroids not indicated for bronchospasm• Avoid using epinephrine in volatile-substance abusers as it may precipitate

dysrhythmias

ALERT• Gastric evacuation not indicated for vast majority of hydrocarbon

ingestions:• Increases risk of aspiration which can cause significant chemical pneumonitis

• Activated charcoal does not bind to hydrocarbons well, and is not indicated except for significant life-threatening coingestants• Cathartics not indicated:• Diarrhea common with hydrocarbon

• Admission Criteria• Symptomatic patients• Patients with potential delayed organ toxicity (carbon tetrachloride or other

toxic additives)

• Discharge Criteria• Observe for 6 hr then discharge:• Asymptomatic patients with normal chest radiograph and pulse oximetry

findings• Asymptomatic patients with abnormal CXR and normal oxygenation and

respiratory rate may be discharged if reliable follow-up is ensured.• Symptomatic patients on presentation who quickly become asymptomatic• Observe volatile-substance abusers until mental status clears.

• Issues for Referral• Psychiatry consultation as needed

Summary• The first priority in treating poisoned patients is assessment and

stabilization of cardiopulmonary function• Next – Decontamination• Gross Decontamination• Eye Decontamination• GI Decontamination

• Gastric Emptying• Toxin adsorbtion in the gut• Enhancement of Bowel Transit• Enhanced Elimination

Hydrocarbons and volatile substances• Aliphatic - eg kerosene, mineral oil, seal oil, gasoline, • Aromatic - Benzene (gasoline .8%), toluene (acrylic paint)• Halogenated - carbon tetrachloride (refrigerant, aerosol propellant)

• Volatile substances • Most often occurs in teenagers and younger adults • Common solvents abused: Adhesive, Gasoline, Cigarette-lighter fluid• Methods – • Sniffing, Huffing, Bagging

Ingestion or aspiration of hydrocarbons mainly impairs the pulmonary system, but CNS, PNS, GI, CVS, renal, hepatic, dermal, and/or hematologic systems may be affected.

Treatment – assessment and stabilization of cardiopulmonary functionSupportive careTreat respiratory symptoms – Oxygen, Beta agonist

“The surest poison is time.”—Ralph Waldo Emerson (1803-1882)