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Toronto Notes 2019 Toxicology Emergency Medicine ER51 D3 – Decontamination and Enhanced Elimination
Ocular Decontamination
• salineirrigationtoneutralizepH;alkaliexposurerequiresophthalmologyconsult
Dermal Decontamination (Wear Protective Gear)
• removeclothing,brushofftoxicagents,irrigateallexternalsurfaces
Gastrointestinal Decontamination
• singledoseactivatedcharcoal
■ use of activated charcoal is a source of much debate amongst toxicologists. Evidence of effectiveness
is not strong, and risk of aspiration is high.
■ adsorption of drug/toxin to activated charcoal decreases toxin bioavailability
■ contraindications: caustics, small bowel obstruction, perforation
■ dose: 10 g/g drug ingested or 1g/kg body weight (may vary depending on ingestion) ■ odourless, tasteless, prepared as slurry with H2O
• wholebowelirrigation(veryrarelyused)
■ 500 mL/h (child) to 2,000 mL/h (adult) of polyethylene glycol solution by mouth until clear effluent
per rectum
◆ start slow (500 mL in an adult) and aim to increase rate hourly as tolerated
■ indications
◆ awake, alert, can be nursed upright OR intubated and airway protected ◆ delayed release product
◆ drug/toxin not bound to charcoal
◆ drug packages (if any evidence of breakage emergency surgery)
◆ recent toxin ingestion
• contraindications
■ evidence of ileus, perforation, or obstruction
• surgicalremovalinextremecases
■ indicated for drugs that are toxic, form concretions, or cannot be removed by conventional means
• useofcathartics(i.e.ipecac)intheEDisnotrecommended
Urine Alkalinization
• maybeusedfor:ASA,methotrexate,phenobarbital,chlorpropamide
• weaklyacidicsubstancescanbetrappedinalkaliurine(pH>7.5)toincreaseelimination
Multidose Activated Charcoal
• maybeusedfor:carbamazepine,phenobarbital,quinine,theophylline
• fortoxinswhichundergoenterohepaticrecirculation
• removesdrugthathasalreadybeenabsorbedbydrawingitbackintoGItract
• variousregimens:12.5g(1/4bottle)POq1hor25g(1/2bottle)POq2huntilnon-toxic
Hemodialysis
• indications/criteriaforhemodialysis
■ toxins that have high water solubility, low protein binding, low molecular weight, adequate
concentration gradient, small volume of distribution, or rapid plasma equilibration
■ removal of toxin will lead to clinical improvement
■ advantage is shown over other modes of therapy
■ predicted that drug or metabolite will have toxic effects
■ impairment of normal routes of elimination (cardiac, renal, or hepatic) ■ clinical deterioration despite maximal medical support
• usefulforthefollowingtoxins
• methanol
• ethyleneglycol • salicylates
• lithium
• phenobarbital
• chloralhydrate(trichloroethanol)
• othersincludetheophylline,carbamazepine,valproate,methotrexate
E – Expose and Examine the Patient
• vitalsigns(includingtemperature),skin(needletracks,colour),mucousmembranes,pupils,odours, and CNS
• head-to-toesurveyincluding ■ C-spine
■ signs of trauma, seizures (incontinence, “tongue biting”, etc.), infection (meningismus), or chronic alcohol/drug misuse (track marks, nasal septum erosion)
■ feel the patient’s axillae; in the average patient, should be somewhat moist (if dry, may indicate anticholinergic toxicity)
• mentalstatus