acute poisoning - management ayman m. kamaly, md professor of anesthesiology ain shams...
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ACUTE POISONING -MANAGEMENT
Ayman M. Kamaly, MDProfessor of Anesthesiology
Ain Shams University
INTRODUCTION
• Acute poisoning is a common medical emergency in any country.
• The exact incidence of this problem in our country remains uncertain.
For effective management of an acutely poisoned victim, 5 steps are required:
I. Resuscitation and initial stabilizationII. Diagnosis of type of poisonIII. Nonspecific therapyIV. Specific therapyV. Supportive care
I. Resuscitation and Initial Stabilization
Initial management: ABCDs
• Airway• Breathing• Circulation
• She was found comatose and unresponsive, as if in a deep sleep,
• Airway positioning and mouth to mouth ventilation were performed,
• and she was fully
recovered.
Lessons:
• Best Antidote = Good Supportive Care(Love’s first kiss)
• Airway issues is a still the major cause of morbidity in toxicology as in other aspects of emergency.
Circulation = Plumbing
• Pump working? Inotrope
• Enough volume (is it primed)? Hypovolemia?
IV fluid challenge
• Adequate resistance (no leaks)? Inadequate vascular resistance?
Norepinephrine, phenylephrine
Initial management: ABCDs
Treat problems as you find them!!• Airway,• Breathing,• Circulation,• Drugs, • Decontamination, • Detoxication,• Disability – GCS/AVPU and Pupils,• DON’T EVER FORGET GLUCOSE.
Don’t forget GLUCOSE
“A stroke is never a stroke until it’s had 50 of D50”
• Empiric administration of dextrose??!• Check the blood sugar using a reliable bedside
test• Administer dextrose ONLY if the RBS is <80
mg/dl.
II. Diagnosis of Type of Toxin
• What?• When?• How much? (mg/kg)• What else?• Why?
A) History Be a Detective
• Collateral history– Paramedics– Family / friends– Notes– Look in pockets – carefully!!!
Look for Clues
Investigations• All Patients
– Glucose– Paracetamol & Salicylate
• As indicated– LFT– RFT, Lytes– Co-ag / INR– CK– ABG / VBG
• Urine toxicology screen
Investigations• Urine toxicology screen
– Pinkish urine --->>> phenothiazine,
– Chocolate colored --->>> met-hemoglobinaemia,
– Oxalate crystals --->>> ethylene glycol,
– Ketonuria (without metab. changes) --->>> Salicylate
Investigations• Abdominal X-Ray (Radiopaque Toxins)
– Chloral hydrate, iodides,
– Heavy metals, iron,
– Sustained release pills,
– Solvents (Chloroform, CCL4)
• Aim:
– Reduce absorption of poison from the gut,
– Increase excretion of absorbed poison.
III. Non-Specific Therapy
1) Emesis
• Syrup of Ipecac• Amount of recovered toxin is highly variable • Effective within ONE hour• Contraindicated:
– Comatose/Convulsing– Ingested corrosive or hydrocarbon*
A. Reducing absorption
2) Gastric Lavage
• Lt Lat Position + head down • to prevent aspiration & ↓ pushing lavage into
duodenum.• If unconscious ETT• Effective within 1-2 hours• Contraindicated:
– Strong corrosive or – Volatile hydrocarbons
3) Activated Charcoal
• Small particle size & enormous surface area,• Bind most drugs & toxins,• Dose: 1 g/kg• Exceptions:
– Iron, Lithium, Metals,– Methanol, Ethanol, Hydrocarbons,– DDT
Activated Charcoal (cont.)
• More effective than Ipecac, Gastric Lavage• First choice for most Over Doses
4) Whole Bowel Irrigation
• Isotonic soln. of Polyethylene glycol (2 L/hr)• Not absorbed from intestine (mechanical
flush)• Good for:
– Iron, Lithium,– Sustained-release pills,– Foreign bodies,– Drug “packets”
1) Forced Alkaline Diuresis• Principle: Renal tubular epith is impermeable toionized (+) molecules. If the urinary pH is changedso as to produce more of ionized form, it is trapped in the tubular fluid & is excreted in the urine.
• Useful in: – Salicylates, – Phenobarbital,– Lithium
B. Increasing Excretion
Forced Alkaline Diuresis (Cont.)
• Method: – D5% - ½ NS + bicarbonate 20-35 mEq/L to produce
a urine output of 3-6 ml/kg/hr & a urine pH 7.5-8.5.
– Diuretics are often needed to maintain high urine flows.
– KCl is added to prevent ↓K+,
• Contraindications: – Shock,– Hypotension, CHF,– Renal failure
2) Multiple-Doses Activated Charcoal• 1 g/kg/1-4 hrs• To maintain intestinal toxin conc. near-zero
(Gastrointestinal Dialysis).• Indicated in toxins with :
– Long ½ life,– Enterohepatic circulation ( Digoxin, Phenobarbitals,
Theophylline),– Sustained-release preparations,– Massive toxin dose to be effectively adsorbed by
single charcoal dose
3) Dialysis (Peritoneal/Hemo)
• For H2O soluble & Low MW compounds.
• Useful in: – Ethanol, Methanol,– Salicylates, – Theophylline, – Ethylene glycol,– Phenobarbital – Lithium
• Try to maintain functions of CNS, CVS, Renal, …
• Care for coma, seizures, hypotension, arrhythmias, hypoxia, …
V. Supportive Therapy
• Exposure to toxins could be through routes other than ingestion (Cutaneous, Ocular)
• Antidotes are NOT available for every toxin
• The 1st sample of gastric lavage should be collected in “clean” container (Contamination !!).
• Container should be sealed using a glue paper before sending for toxicological screening.
Legal Aspects
• After sealing Blood & Urine collection tubes and bottles, pt’s information should be written on the labels & affixed @ the juncture between the cap & the bottle.
• POLICE should be informed !!
Paracetamol
• Very common: 40% poisons admissions• Often asymptomatic• Can be lethal – 200-300 deaths/year• Check blood level at 4 hours• Two treatment lines normal and high risk
Paracetamol metabolism• Metabolised by:
– Glucuronidation (60%),– Sulphation (35%) – Oxidation (10%) by Cytochrome p450
produces NAPQI (toxic hepatocellular necrosis)
• NAPQI detoxified by conjugation with glutathione.
High Risk pt.
• Increased oxidation pathway (enzyme induction)– Chronic alcohol use– Drugs
• Reduces glutathione stores– Malnutrition– Eating disorders– Chronic liver disease
N-Acetylcysteine
• Most effective within 8 hours• Precursor for glutathione production• Can cause anaphylactoid reactions !!• Consider starting before paracetamol result if:
– Presenting > 8 hrs & > 150mg/kg taken– Other accompanying overdose.
Patient 1
• 20 year old woman who takes a handful of paracetamol tablets
• No drug history• No alcohol use• Fit and well• Blood level is 80mg/L
after 4 hrs.
Patient 2• 70 year old man• Takes 20 paracetamol 6
hours before presenting• Alcoholic• No drug history• Blood level 100mg/L
Patient 3• 17 year old
epileptic• 25 tab Panadol 2
hours before attendance
• Taking carbamazepine
• Blood level at 4 hours is 120mg/L
Patient 4
• 35 year old man who presents after taking 24 paracetamol over a period of 24 hours
• No drug history• Fit and well• Blood level 20mg/L
Treat
• Staggered overdoses are difficult• Level is above the treat-line in context to time• Need to monitor Liver function, clotting and renal
function• May need discussing with Liver Unit if abnormal