Decontamination Exam 1

Question 1

Which meds can be used via NG tube?

Answer 1

• activated charcoal

- WBI products

Question 2

What are various methods for decontamination?

Answer 2

• emesis
• gastric lavage
• activated charcoal
• whole bowel irrigation
• hemodialysis

Question 3

indication for emesis

Answer 3

no indication

Question 4

efficacy of emesis

Answer 4

• reliable vomiting

- unreliable in drug recovered (range 6-89%)

Question 5

contraindications of emesis

Answer 5

• Non-toxic ingestions - emesis should not be used as a method of punishment.
• Prior significant vomiting - ipecac induced emesis is no better than “natural” emesis, and would not be expected to recover additional material.
• Any patient who is comatose, seizing, hypotensive, or has lost his/her protective airway reflex.
• The patient who is presently awake, but may be expected to rapidly deteriorate before emesis has been completed.
• Caustic agents may cause additional injury during emesis.
• Aspiration risk: ingestions of poorly absorbed hydrocarbons.
• Sharp objects and other foreign body ingestions.
• Need for rapid administration of oral antidotes, such as NAC, especially approaching 6-8 hours after acetaminophen ingestion.
• Late in pregnancy
• Hypertensive crisis or intracranial hypertension.

Question 6

complications of emesis

Answer 6

• Intractable vomiting (rare)
• Diarrhea
• Aspiration
• Myocardial toxicity - associated with extract of ipecac
• Neuromuscular weakness
• Mallory-Weiss tear of the esophagus
• Lethargy
• Spontaneous abortion

Question 7

indications for gastric lavage

Answer 7

• not indicated but considered in:
• Potentially life-threatening poisoning and presentation within 1 hour.
• Potentially life threatening poisoning with drug with anticholinergic effects and presentation within 4 hours
• Ingestions of sustained release preparation of significantly toxic drug

Question 8

contraindication for gastric lavage

Answer 8

Corrosive ingestions or esophageal disease

Question 9

gastric lavage technique

Answer 9

• Protect airway (endotracheal intubation) if patient is stuporous or comatose.
• Lie patient on their left side.
• Insert a large bore double lumen orogastric tube.
• Aspirate stomach contents.
• Use a small cycle lavage of 50-100 mL (and then aspirate).
• Lavage is rarely indicated beyond 5 minutes, unless tablets are still actively being returned.

Question 10

complications of gastric lavage

Answer 10

• may increase gastric delivery of tablets into the small bowel, especially those that have formed into large clumps. This could lead to increased absorption.
• Aspiration of gastric contents occurs in about 3% of patients.
• Esophageal rupture is a very rare but potentially fatal complication.
• Profound bradycardia, cardiac arrest, and asystole may be precipitated by lavage in poisonings with propranolol, calcium channel blockers and other drugs affecting cardiac conduction.

Question 11

Which toxic substances are minimally decontaminated with charcoal?

Answer 11

PHAILS

• Pesticides
• Hydrocarbons, Heavy metals
• Acid/Alkali, Alcohols
• Iron
• Lithium
• Solvents

Question 12

mechanism of activated charcoal

Answer 12

• drugs are carbon-based and their side chain adhere to carbon compounds
• activated charcoal provides a large surface area of carbon that it can bind to
• cathartics given to shorten GI time so that the bound drug can leave the body
• giving with water or sorbitol results in equal efficacy

Question 13

indications for activated charcoal

Answer 13

• Drug ingested is adsorbed by charcoal and has significant potential for toxicity
• Time since ingestion is less than 1
• The drug has significant enterohepatic recirculation
• The drug delays gastric emptying and time since ingestion is less than 4 hours
• The drug is in a controlled release preparation and time since ingestion is less than 12-18 hours
• Single dose not as effective as multiple-dose

Question 14

administration of activated charcoal

Answer 14

• for kids, can be mixed with something to make it palatable but may decrease efficacy
• in adults, goal is to drink 50g within 20min (if cannot, do via NG tube)

Question 15

complications of activated charcoal

Answer 15

• Charcoal aspiration
• Bowel obstruction may occur when excessive doses are administered.
• Hypotension / tachycardia may occur due to hypovolemia if a cathartic is administered. This develops due to fluid shift into the bowel

Question 16

indications for Multiple-Dose Activated Charcoal (MDAC)

Answer 16

“Charcoal Doesn’t Polish the Queen’s Tea set”

• Carbamazepine
• Dapsone
• Phenobarbital
• Quinine
• Theophylline

Question 17

mechanism of MDAC

Answer 17

• Repeated doses of activated charcoal can increase the clearance of drugs by interrupting enterohepatic recirculation.
• Gastrointestinal dialysis: Lipid soluble drugs of relatively low molecular weight are able to move from the gut capillaries back into the lumen (if there is a diffusion gradient) and be bound to charcoal (which maintains the gradient).
• should be used until clinical condition improves; most of the time, less than 12 hours

Question 18

indications for whole bowel irrigation (WBI)

Answer 18

• Medications not absorbed by charcoal (e.g., iron and lithium)
• Sustained release preparations (e.g., bupropion and verapamil)
• Other toxins that form pharmacobezoars (e.g. salicylates)

Question 19

mechanism of WBI

Answer 19

• Whole bowel irrigation physically flushes tablets from the gastrointestinal tract.
• uses large volumes of an iso-osmolar solution (polyethylene glycol, PEG-ELS, Golytely®) that is not absorbed

Question 20

administration of WBI

Answer 20

• Oral or via NG tube
• If the patient agrees to drink the solution, they should be reassessed after 15 minutes to determine their compliance. Many patients require administration via NG tube.
• Some patients may require an antiemetic if they are vomiting. Metoclopramide or ondansetron are usual initial choices.
• endpoint: clear rectal effluent (after 4-5L of fluid consumption within 2-4H)

Question 21

What kind of characteristics must a drug / poison in order to use hemodialysis effectively in removing them from the body?

Answer 21

• Low molecular weight (< 500 Daltons)
• Highly water soluble
• Low volume of distribution (< 1 L/kg)
• Low protein binding
• The toxic effects of the poisons should be serious, related to the plasma concentration, and not treatable easily by less invasive means.

Question 22

Which drug / poison can be removed by the body using hemodialysis?

Answer 22

• Ethanol
• Methanol
• Ethylene glycol
• Lithium
• Salicylates
• Theophylline

Question 23

adverse effects of hemodialysis

Answer 23

hypotension

Question 24

Skin Decontamination

Answer 24

• The contaminated skin should be washed thoroughly with soap and water.
• If possible, water from a tap, a hose or a shower should be used to wash the body, or water may be poured from a bucket.
• Clothing should be removed carefully while bathing the skin with a stream of water.
• Some poisonings such as hydrofluoric acid require special decontamination.

Question 25

Ocular Decontamination

Answer 25

• If a poison enters eyes, they should be washed thoroughly for 15 minutes with running water.
• The patient should continuously blink during the procedure.
• If blurring of vision, pain or redness persists, an ophthalmologist should be consulted.