Transcript Acute Poisoning Managementx

ACUTE POISONING MANAGEMENT
Ayman M. Kamaly, MD
Professor of Anesthesiology
Ain Shams University
[email protected]
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.
II.
III.
IV.
V.
Resuscitation and initial stabilization
Diagnosis of type of poison
Nonspecific therapy
Specific therapy
Supportive care
I. Resuscitation and Initial Stabilization
Initial management: ABCDs
• Airway
• Breathing
• Circulation
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 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
A) History
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•
•
•
•
What?
When?
How much? (mg/kg)
What else?
Why?
• Collateral history
– Paramedics
– Family / friends
– Notes
– Look in pockets – carefully!!!
Look for Clues
B) Examination
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)
III. Non-Specific Therapy
• Aim:
– Reduce absorption of poison from the gut,
– Increase excretion of absorbed poison.
A. Reducing absorption
1) Emesis
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•
•
•
Syrup of Ipecac
Amount of recovered toxin is highly variable
Effective within ONE hour
Contraindicated:
– Comatose/Convulsing
– Ingested corrosive or hydrocarbon*
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”
B. Increasing Excretion
1) Forced Alkaline Diuresis
• Principle: Renal tubular epith is impermeable to
ionized (+) molecules. If the urinary pH is changed
so as to produce more of ionized form, it is trapped
in the tubular fluid & is excreted in the urine.
• Useful in:
– Salicylates,
– Phenobarbital,
– Lithium
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 7.58.5.
– 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
IV. Specific Therapy
V. Supportive Therapy
• Try to maintain functions of CNS, CVS, Renal, …
• Care for coma, seizures, hypotension,
arrhythmias, hypoxia, …
• Exposure to toxins could be through routes
other than ingestion (Cutaneous, Ocular)
• Antidotes are NOT available for every toxin
• However; when Antidote is Present the effect
is Dramatic
Legal Aspects
• 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.
• 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 !!
Clinical Scenarios
Paracetamol
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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
Prescott Nomogram
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
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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.
No need to treat
• Patient is not high risk
• Level at 4 hours is below even the high risk line
Patient 2
• 70 year old man
• Takes 20 paracetamol 6
hours before presenting
• Alcoholic
• No drug history
• Blood level 100mg/L
Treat
• High risk patient
• Level above the high risk line
Patient 3
• 17 year old
epileptic
• 25 tab Panadol 2
hours before
attendance
• Taking
carbamazepine
• Blood level at 4
hours is 120mg/L
Treat
• High risk patient
• Level above the high risk line
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
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