Evaluation and initial treatment of the acutely poisoned patient Kennon Heard MD CU Emergency Medicine Rocky Mountain Poison and Drug Center

After completing this presentation you will be able to… Describe the stabilization of the poisoned patient Perform a risk-based assessment of a poisoned patient Determine the appropriateness of GI decontamination for a poisoned patient Describe the testing and observation period of a poisoned patient

Stabilization Airway –Most common cause of poisoning death is loss of airway/aspiration –Early airway management prevents the most common cause of death –So intervene early if there is any question about airway compromise

Stabilization Breathing –The most common acid/base disturbances in toxicology are respiratory and metabolic acidosis –Under-ventilation will make acidosis worse –Start off with over-ventilation and adjust based on blood gases –Give everyone oxygen!

Stabilization Circulation –Treat hypotension the same as other causes –Wide complex dysrhythmias slightly different

Stabilization Hypotension Rhythm problem Treat Rhythm No rhythm problem IV fluids Adrenergic vasopressors 1 Antidote 2 Mechanical Support 1.Dopamine, norepinephrine or epinephrine 2.Calcium/glucagon/Insulin, Cyanide antidote

Stabilization Rhythm problem Too slow Atropine Antidote 1 Pacing Too Fast Narrow Sinus Sedation/IVF PSVT Standard ACLS Wide Sodium bicarbonate Standard ACLS 1. Calcium/glucagon/Insulin for CCB/BB; digoxin Fab

Risk Assessment Once the patient is stable, the next decision is if the patient may benefit from decontamination This requires a risk assessment –If you think the patient may develop significant symptoms- decontaminate –If you don’t think they will get sick, don’t decontaminate

Risk Assessment Consider 3 factors Drug –What does the drug do? Dose –Very low doses are not toxic –Very high doses make for different effects Patient –Is this patient more susceptible to toxicity

Risk Assessment Dose Drug effects are dose-dependent –Most toxic effects are an extension of therapeutic effects –Clear history of low dose=toxicity unlikley Massive OD may change that –Loss of specificity –Change in pharmacokinetics –Interference with metabolic pathways Don’t rely on clinical effects if OD is >50 x therapeutic dose

Risk Assessment Drugs for aggressive decontamination High risk –Beta- blockers –Calcium channel blockers –Tricyclic antidepressants –Some antidysrhythmics –Chloroquine –Theophylline –Aspirin Low risk –Acetaminophen* –Opiates (easy to treat) –Seizure meds –Newer antidepressants –Antipsychotics –Sedatives (benzos) –Plants –Lithium *Late toxicity- treatment may decrease need for NAC

Risk Assessment Patient Very old or very young Underlying disease affecting target organ of poison –Med that causes seizure in a pt with a seizure disorder Pt may be tolerant to medication

Risk Assessment Your treatment is determined by your risk assessment –Low risk= minimal decontamination –High risk= aggressive decontamination

Decontamination The goal of decontamination is to decrease the amount of poison that is absorbed from the GI tract into the circulation The options for decon are –Vomiting- induced or spontaneous –Gastric lavage –Activated charcoal –Whole bowel irrigation

Decontamination Vomiting effectively removes poison from the GIT Induced vomiting (ipecac) don’t use it Spontaneous vomiting may be useful –If you see tablets- let them puke –Unless they are at risk for aspiration! Minimally aggressive

Decontamination Gastric lavage –Moderate risk of AE Aspiration GI tract injury –Unclear efficacy No proven survival benefit Aggressive: use for high risk poisons in patients who are intubated Use when charcoal is not effective enough –Lithium, iron, massive aspirin

Decontamination Activated charcoal –Unproven efficacy No effect on undifferentiated poisoning outcome Cannot rule out substantial effect in high risk poisoning –Risks are related to how it is given Patient drinks it- low risk NGT- higher risk Minimally aggressive –Give to patients if they will drink it but will not benefit most so never force it in minimal risk ingestions

Decontamination Whole bowel irrigation –Bowel prep solution to evacuate the GI tract –Used for drugs not effectively removed by charcoal Metals (Li, Iron) Enteric coated or SR medications Body packers –Risk/Benefit not clear –High labor intensity (2L/hr for 5+ hours) –Aggressive

Screening for occult ingestions Serum acetaminophen concentration Serum aspirin concentration Serum chemistry –Check for anion gap acidosis –Check renal function ECG –R wave amplitude>3mm suggests TCA-like effect

Observation Every medication can cause something bad We would like to identify patients before we discharge them But the time course varies from minutes to days –We can’t watch everyone for days 6 hours for most – 24 hours for modified release preparations

Summary Stabilize first Risk assessment –Drug/dose/patient Decontaminate –If the patient may get sick Screening labs Observe 6 hrs for most meds

Additional reading Decon: Daly FF. A risk assessment based approach to the management of acute poisoning. Emerg Med J May;23(5): Intralipid for sodium channel poisons Shannon: Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose, 4th ed Saunders, An Imprint of Elsevier (AVAILABLE ONLINE AT FIRST CONSULT)

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