MANAGEMENT OF ACUTE POISONING Kent R. Olson, MD Medical Director - SF Division California Poison Control System

Lessons from history...  A young princess ate part of an apple given to her by a wicked witch  She was found comatose and unresponsive, as if in a deep sleep  Airway positioning and mouth to mouth ventilation were performed, and she recovered fully

Lesson: Best antidote = good supportive care (Love’s first kiss)

Case:  Young man collapsed on the street outside a dance club  Unresponsive  Shallow breathing

Initial management: ABCDs  Airway  Breathing  Circulation  Dextrose, drugs, decontamination

Airway issues  Major cause of morbidity in OD  Risks: Floppy tongue can obstruct airway Floppy tongue can obstruct airway Loss of protective reflexes may permit pulmonary aspiration of gastric contents Loss of protective reflexes may permit pulmonary aspiration of gastric contents

Assessing the airway  “Gag” reflex Indirect measure Indirect measure May be misleading May be misleading Can stimulate vomiting Can stimulate vomiting  Alternatives

Breathing  Assess visually  ABG: pCO2 reflects ventilation  Pulse oximetry provides convenient, noninvasive evaluation of O2 saturation

Pitfalls  pO2 measures dissolved oxygen  Pulse oximetry can miss abnormal hemoglobin states, eg: Carbon monoxide Carbon monoxide Methemoglobinemia Methemoglobinemia

Interventions  Endotracheal intubation Protects airway Protects airway Allows for mechanical ventilation Allows for mechanical ventilation  Reverse coma? Naloxone: note T½ = 60 min Naloxone: note T½ = 60 min Flumazenil? Flumazenil?

Don’t forget GLUCOSE  “A stroke is never a stroke until it’s had 50 of D50”  Give Thiamine 100 mg IM or in IV

Case, continued…  The patient has no gag reflex, and does not resist intubation. However, he is awake and sitting up 2 hours later.  Admits to using “GHB”

GHB  Gamma Hydroxybutyrate Rapid-acting general anesthetic Rapid-acting general anesthetic Structural analogue of GABA Structural analogue of GABA Very short duration Very short duration May see seizure- like movements or hypertonicity May see seizure- like movements or hypertonicity

Case 2  47 year old stockbroker attempts suicide  BP 70/50, HR 50/min  Junctional rhythm  Hx: uses an antihypertensive

Circulation = plumbing  Pump working?  Enough volume (is it primed)?  Adequate resistance (no leaks)?

Management of Hypotension  Hypovolemia? IV fluid challenge IV fluid challenge  Pump? Dopamine Dopamine  Inadequate vascular resistance? Norepinephrine, phenylephrine Norepinephrine, phenylephrine

Antihypertensives  Diuretics  Beta blockers  Calcium channel blockers  ACE Inhibitors  Centrally acting agents (eg, clonidine)  Vasodilators

Calcium channel blockers  Bad ODs!!  Low Toxic:Therapeutic ratio  High mortality

Negative Inotropic Effects Negative Inotropic Effects Decreased Automaticity & Conduction Decreased Automaticity & Conduction Dilated Vascular Smooth Muscle Dilated Vascular Smooth Muscle SVR SVR COHR AV Block SHOCKSHOCK

Calcium antagonists - treatment  Calcium  High doses may be needed

Case 3:  Another patient arrives from the first dance club  Multiple seizures with only brief pauses  Temp 107 F!

Common causes of seizures  TCAs  Amphetamines/cocaine  Isoniazid (INH)  Diphenhydramine  Theophylline  Strychnine

Hyperthermia  Disastrous complication! Brain damage Brain damage Cardiovascular collapse Cardiovascular collapse Rhabdomyolysis Rhabdomyolysis Multiple organ failure Multiple organ failure

Hyperthermia - Treatment  Stop the seizures Benzodiazepines, phenobarbital Benzodiazepines, phenobarbital Vitamin B-6 for INH Vitamin B-6 for INH  Stop muscle hyperactivity Neuromuscular blockers Neuromuscular blockers  External cooling

Gut decontamination after OD  Limit systemic absorption Induce vomiting? Induce vomiting? Pump the stomach? Pump the stomach? Activated charcoal Activated charcoal

Induce vomiting  Syrup of Ipecac?  Soapy water?  Don’t use: Finger gag Finger gag Salt water Salt water Copper sulfate Copper sulfate

Ipecac-induced emesis  Easy to perform, but  Not very effective  Contraindicated: Comatose/convulsing Comatose/convulsing Ingested corrosive or hydrocarbon Ingested corrosive or hydrocarbon Rapid-acting CNS agent Rapid-acting CNS agent  No longer used

Pumping the stomach  Cooperation not required  MD sense of “control”  Punitive value?

Gastric lavage  May stimulate gagging, vomiting  Risky if airway reflexes dulled  Lack of proven efficacy  Used rarely

Activated charcoal  Finely divided powdered material Huge surface area Huge surface area  Binds most drugs/poisons Exceptions: - Iron - Lithium Exceptions: - Iron - Lithium

Activated charcoal  More effective than SI, GL  First choice for most ODs

Whole bowel irrigation  Mechanical flush  Balanced salt solution with PEG No net fluid gain/loss No net fluid gain/loss  Good for: Iron Iron Lithium Lithium Sustained-release pills, foreign bodies Sustained-release pills, foreign bodies

Antidotes:  The best antidote is supportive care  Examples of antidotes: Digoxin-specific antibodies Digoxin-specific antibodies Atropine & 2-PAM Atropine & 2-PAM N-acetylcysteine N-acetylcysteine