MANAGEMENT OF POISONED PATIENTS

MANAGEMENT OF POISONED PATIENTS

Dr. Shamil AL-Nuaimi MBchB, MSc, PhD Assistant Professor Toxicology & pharmacology


* Paracelsus (1493-1541)‘Grandfather of Toxicology’ “The dose makes the poison” "All things are poison and nothing is without poison, only the dose permits something not to be poisonous."
therapeutic effect
toxic effect
increasing dose

General Information

All chemicals have potential to be poisons if given a large enough dose Poisoning occurs when exposure to a substance adversely affects function of any organ system


Management lines: 1-Clinical Stabilization. 2-Clinical History. 3-Physical Examination. 4-Investigations: -Laboratory -Radiology -ECG

5-Prevention of further absorption: -Topical. -Inhalation. -Gastrointestinal. 6-Enhancement of Poison Elimination: - Alkalinization of Urine. -Dialysis. 7-Use of Specific Antidote. 8-Supportive Care.



Resuscitation
First priorities are ABC’sVital sign including pulse and hypoglycemia must be correctedOnly in very rare incidences does administration of antidote precede stabilizing ABC’s and vital signs

ASSESSMENT

A health care facility’s systematic approach to the assessment of the poisoned or overdosed patient includes performing triage, A) Obtaining the patient’s history, B) Performing a physical examination, andC) Conducting laboratory studies. *

Initial management of the poisoned patient

If the patient’s life is in immediate danger, the goals of immediate treatment are patient stabilization and evaluation and management of airway, breathing, circulation and dextrose (ABCDs). *

(Proper Positioning of the Patient)

(Ensure Patent Airway)

(Insert Airway Tube if needed)

History
Need to obtain as much information as possible about exposure Number of exposed persons, type of exposure, amount or dose, route Patient's intent must be determined Information from patient, witness helpful Check for empty bottles or containers, smells or unusual containers



Physical Exam
Undress patient completely for thorough examination Check clothing for objects or substances Assess general appearance of patient Agitation, confusion, or obtundation Exam skin for bruising, cyanosis, flushing Exam eyes for pupils size, nystagmus, reactivity, dysconjugate gaze, increased lacrimaiton

Physical Exam

Oropharynx for increase salivation or excessive dryness CV: rhythm, rate, regularity Lungs: bronchorrhea or wheezing Abd: bowel sounds, tenderness or rigidity Ext: fasiculations, tremor Neuro: CN, reflexes, muscle tone coordination, cognition, ability to ambulate

(Blue line of chronic lead poisoning)

Toxidrome
A toxidrome is a group of signs and symptoms associated with overdose or exposure to a particular category of drugs and toxins. Recognizing the presence of a toxidrome may help identify the toxin(s) or drug(s) to which the patent was exposed, and the crucial body systems that may be involved.

Toxic syndromes (toxidromes): -Narcotic Toxic Syndrome. -Cholinergic Toxic Syndrome. -Sympathomimetic Toxic Syndrome. Narcotic toxic syndrome: Categorize the patient Coma + Miosis (Pin Point Pupil) + Hypotension + Bradycardia + Low respiratory rate +Hypothermia

Pinpoint Pupils (Narcotics) Normal Pupils

(Pinpoint Pupils)

Toxic syndromes (Toxidromes)

(Some Poisons have Special odor)

Toxicological Screen

In the acute care setting toxicological screen is very limited and does not contribute significantly Toxicological screens may play a role in evaluation of children

List of Drugs Commonly Measured in Hospital Settings

Decision to treat according to concentration: -Lithium -Digoxin -Iron -Phenobarbital -Theophylline -Aspirin -Paracetamol


Action Plasma level: Ex. A patient with a non toxic Digoxin concentration could have symptoms of toxicity. Or a patient with elevated Digoxin level could have no symptoms of toxicity. The rule is to : Treat the patient and not the laboratory data!

Anion Gap & Osmolal Gap:1-Anion Gap: Help in the Differential diagnosis of poisoning.Difference between Sodium vs. Chloride + Bicarbonate Anion gap = Na Conce. mEq/L – (Cl+HCO3) Normal Level is < 12



2-Osmolal Gap: Difference between: Measured plasma osmolality Vs. Calculated plasma osmolality Cal =2 X Na+ (Glucose/18)mg/dl + BUN/2.8 mg/dl Normal: <10 mOsm at freezing point measurement.

C-Radiographic examination: -Limited role. -Lack of Radiopacity. (Undetectable by x ray). Ferrous or Potassium salt could produce significant opacities. Enteric coated formulations or restrained release could be opaque, Lead pica (in children) -CXR. -Plain X ray Of the Abdomen. -CT Scan.

General- management

I.provision of supportive care II.prevention of poison absorption III.enhancement of elimination of poison IV.administration of antidotes

I. Supportive care

Vital signs, mental status, and pupil size cardiac monitoring, ECG Protect airway Intravenous access cervical immobilization if suspect trauma Rule out hypoglycaemia

II.Preventing absorption

Decontamination; A) dermal, B) ocular, C) inhalation, and D) ingestion exposures follow.

Gross Decontamination

Generally; achieved by; undressing patients and washing them thoroughly with copious amounts of water Should occur outside of emergency department All towels and clothing should be put into hazardous waste bags Patient should initially be in isolated area

Eyes

Ocular exposure’s should be treated immediately by copious irrigationUsually 2 L Normal SalineUse of tetracaine may be neededAlkalies require specific considerationsLengthy continuous irrigation until pH < 8.0Need ophthalmologic consult


GI Decontamination
Three general methods involve removing toxin from stomach via the mouth, binding it inside gut lumen, or mechanically flushing it through GI tract Each method has benefits and risks

Gastric Emptying

Emesis: achieved by using syrup of ipecac Dosing: 15 ml for 1-12 years and 30 ml for adults; may repeat once if no emesis in 12 hr 90% vomit within 20 minutes of first dose and 97% vomit with second dose Usually 3-5 episodes of emesis and resolve in two hours; if protracted emesis occurs consider toxin as etiology


Ipecac con’t Contraindications: ingestions with potential for change in mental status, active or prior vomiting, caustic ingestion, toxin with more pulmonary than GI toxicity (hydrocarbons), ingestion of toxins with potential for seizures Complications: aspiration, Mallory-Weiss tear, intractable vomiting Use of Ipecac very limited

Gastric Emptying

Orogastric lavage: 36-40 French tube used in adults and 22-24 French tube in children. Measure from chin to xiphoid and confirm with air insufflation Lavage with room temperature water until it runs clear Charcoal should be used before withdrawal of tube


Orogastric lavage con’t Contraindications: large pills, nontoxic ingestion, non-life threatening, caustic ingestion, airway integrity not secured, more toxic to lung than GI Complications: insertion into trachea, aspiration, esophageal or gastric perforation, decreased O2, inability to withdrawal tube Drug removal range from 35-56% Indicated if within 1 hr of ingestion

Toxin Adsorption in Gut

Activated Charcoal Multiple-Dose Activated Charcoal Cathartics Whole-Bowel Irrigation

Activated Charcoal

Most appropriate agent to decontaminate GI tract Adsorbs toxin in gut lumen Benefits include capability to decontaminate without requiring invasive procedures Safety proven in adults and children Dose 1g/kg

Activated Charcoal

Should not be given if esophageal or gastric perforation suspected or emergent endoscopy possibly neededComplications rare; aspiration or impaction possibleIndications: any drug known to absorb it or after unknown ingestions by pt’s with protected airways

Multi-Dose Charcoal

One dose usually sufficient Indications for multi-dose activated charcoal: ingestion of large doses, substances that form bezoars, slow release toxins, toxins that slow gut function, toxins with enterohepatic or enteroenteric circulation Repeat dose is 0.25-0.5 g/kg

Drugs/Toxins Well Adsorbedby Activated Charcoal

■ Acetaminophen■ Amphetamines■ Antihistamines■ Aspirin■ Barbiturates■ Benzodiazepines■ Beta blockers■ Calcium channel blockers■ Cocaine■ Opioids■ Phenytoin■ Theophylline■ Valproic acid Drugs/Toxins Not Well Adsorbedby Activated Charcoal■ Acids■ caustic alkalis■ Alcohols■ Iron■ Lithium■ Metals cyanidemineral acids, organic solvents, *

(Activated Charcoal)

Cathartics
Osmotic cathartic usually given with activated charcoal70% sorbitol (1 g/kg) or 10% magnesium citrateShown to decrease transit time of activated charcoalNo definitive clinical human data suggest that a cathartic limits toxins bioavailability or changes pt’s outcome

Whole-Bowel Irrigation

Common indications: Heavy metals Iron Lithium Sustained or delayed release formulations Potential for bezoar formation Dose 2L/h adults, children is 50-250 ml/kg

Bowel Irrigation

End point is clear rectal effluent Contraindications: preceding diarrhea, absent bowel sounds or obstruction Complications: bloating, cramping, rectal irritation Antiemetic frequently required Avoid phenergan (slows gut motility)


ΙΙΙ.Enhanced Elimination Alkalinization Acidification of urine Forced diuresis Hemodialysis/Hemoperfusion

Alkalinization

Beneficial in certain ingestions: phenobarbital, chlorpropamide, salicylates, methanol Alkalinization achieved by IV dose of bicarbonate at 1-2 mEq/kg, followed by intermittent boluses or continuous bicarbonate drip for urine pH 7.5-8.0 Profound hypokalemia may result, must aggressively replace

Acidification of Urine

Can somewhat enhance elimination of amphetamines, phencyclidine, and some other drugs.

Forced Diuresis

Never been shown effective for any ingestion Technique should not be used

Hemodialysis/Hemoperfusion

Dialysis reserved for specific toxins: salicylates, methanol, ethylene glycol, lithium, theophylline, amanita (mushrooms) Benefits: removal of toxins already absorbed by gut, ability to remove parent compound and active metabolite


Dialysis con’t Less effective when toxin has large volume of distribution (>1 L/kg), has large molecular weight, or highly protein bound Dialysis rarely contraindicated No dialysis for small children, exchange transfusion should be considered

Haemodialysis is effective to clear some drugs some drugs

Hemoperfusion
Used for decontamination of patient's systemic circulation Involves placing a filter filled with activated charcoal into dialysis circuit Alleviates constraints of protein binding and molecular size Toxins must be well absorbed by charcoal and have small volume of distribution

IV. Antidotes (Antitoxins) and Antagonists), 

In pharmacology, an antagonist is a substance that counteracts the action of another drug. Although the general public often believes there is an antidote for every drug or toxin, the opposite is closer to the truth. There are, in fact, very few antidotes.

Question’s 1) The first priority in resuscitation of a poisoned pt isa) antidoteb) vital signsc) ABC’sd) correction of hypoglycemia

Question’s 2) In the physical exam all of the following are correct except a) undress pt completely b) assess general appearance c) complete neuro exam d) check clothes for objects e) all the above are correct


Question’s 3) Gross decontamination should occur a) in the fieldb) outside EDc) in triage d) in pt’s room

Question’s 4) Which of the following is a method of removing a toxin from the stomach a) via the mouth (emesis) b) binding in the gut (charcoal) c) mechanically flushing through GI tract d) all of the following are correct



Question’s 5) All of the following can be dialyzed except a) phenobarbital b) salicylates c) methanol d) lithium e) ethylene glycol