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Toronto Notes 2019
Toxicology
Emergency Medicine ER49
Toxicology
“ABCD3EFG” of Toxicology
• basicaxiomofcareissymptomaticandsupportivetreatment • addressunderlyingproblemonlyoncepatientisstable
A Airway (consider stabilizing C-spine)
B Breathing
C Circulation
D1 Drugs
■ ACLS as necessary to resuscitate the patient
■ universal antidotes
D2 Draw bloods
D3 Decontamination (decrease absorption)
E Expose (look for specific toxidromes)/Examine the patient
F Full vitals, ECG monitor, Foley, X-rays
G Give specific antidotes and treatments
• reassess
• callPoisonInformationCentre
• obtaincorroborativehistoryfromfamily,bystanders
D1 – Universal Antidotes
• treatmentsthatwillnotharmpatientsandmaybeessential
Dextrose (glucose)
• givetoanypatientpresentingwithalteredLOC
• measurebloodglucosepriortoglucoseadministrationifpossible • adults:0.5-1.0g/kg(1-2mL/kg)IVofD50W
• children:0.25g/kg(2-4mL/kg)IVofD25W
Oxygen
• donotdepriveahypoxicpatientofoxygennomatterwhattheantecedentmedicalhistory(i.e.,even COPD with CO2 retention)
• ifdepressionofhypoxicdrive,intubateandventilate
• exception:paraquatordiquat(herbicides)inhalationoringestion(oxygenradicalsincreasemorbidity)
Naloxone (central μ-receptor competitive antagonist, shorter t1/2 than naltrexone)
• antidoteforopioids:administrationisbothdiagnosticandtherapeutic(1minonsetofaction) • usedfortheundifferentiatedcomatosepatient
• loadingdose
■ adults
◆ response to naloxone can be drastic, so stepwise delivery of initial 2 mg bolus is recommended ◆ draw up 2 mg to deliver IV/IM/SL/SC or via ETT (ETT dose = 2-2.5x IV dose)
– 1st dose 0.4 mg (for a chronic opioid user, the initial dose may be much smaller)
– if no response, deliver second dose 0.6 mg ■ child– if still no response, deliver remaining 1 mg
◆ 0.01 mg/kg initial bolus IV/IO/ETT
◆ 0.1 mg/kg if no response and opioid still suspected to max of 10 mg ■ maintenance dose
◆ may be required because half-life of naloxone (30-80 min) is much shorter than many opioids ◆ hourly infusion rate at 2/3 of initial dose that allowed patient to be roused
Thiamine (Vitamin B1)
• 100mgIV/IMwithIV/POglucosetoallpatients
• giventoprevent/treatWernicke’sencephalopathy
• anecessarycofactorforglucosemetabolism(mayworsenWernicke’sencephalopathyifglucosegiven
before thiamine), but do not delay glucose if thiamine unavailable • mustassumeallundifferentiatedcomatosepatientsareatrisk
Principles of Toxicology
4 principles to consider with all ingestions: • Resuscitation (ABCD3EFG)
• Screening (toxidrome? clinical clues?) • Decrease absorption of drug
• Increase elimination of drug
Universal Antidotes
DONT
Dextrose
Oxygen
Naloxone
Thiamine (must give BEFORE dextrose)
Administration of naloxone can cause opioid withdrawal in chronic users:
Minor withdrawal may present as lacrimation, rhinorrhea, diaphoresis, yawning, piloerection, HTN, and tachycardia
Severe withdrawal may present as hot and cold flashes, arthralgias, myalgias, N/V, and abdominal cramps
Thiamine is deficient in the malnourished. Consider in patients with alcohol use disorder, anorexia, or malnutrition states