Transcript A Patient of Poisoning in ICU

A Patient of Poisoning in ICU
Dr. Ankit Jain
Initial Assesment
THE TOXICOLOGY PRIMARY SURVEY
A – The Airway
• AIRWAY
– Assess need for intubation.
– Commonest indication is a depressed level of consciousness i.e.
airway protection.
– When in doubt intubate.
– Exceptions
• Hypoglycemia
• Opoid
– Do NOT give Flumazenil to suspected BZD OD.
A – The Airway
• Rapid Sequence Intubation
– Rocuronium instead of SCh. Especially
• Organophosphorous Poisoning
– Toxin inactivates Choline esterases
– Prolonged duration of NMB
• Digoxin
– Hyperkalemia
• Caustic Ingestion
– Awake Approach
– Consider early surgical airway.
B- Breathing
• Toxins may interfere with oxygenation (Tissue Hypoxia)
– Carbon Monoxide
• False normal SpO2 values
– Methemoglobinemia.
• Cyanotic patient with SpO2 of 85%
– Cyanide, Hydrogen Sulfide, and Sodium Azide
• Cellular hypoxia with Normal SpO2
• Intubation and 100% FiO2 in these patients
B- Breathing
• Aspirin/ Salicylates
– What the ABG could look like?
• Acute Respiratory Alkalosis
– Hyperventilation due to stimulation of respiratory center.
• HAGMA (+ Acute resp alkalosis)
– Organic acids eg. lactic acid and ketoacids.
– Salicylate itself plays a minor role.
• Acute Respiratory Acidosis???
– Late
– Early….another poison (Resp depressant)?
B- Breathing (Salicylates)
• Respiratory Alkalosis as a protective mechanism.
– Salicylic acid (Weak acid) as charged and uncharged molecule.
– Uncharged molecule crosses cellular barriers.
– Charged Uncharged (Met Acidosis)
– CNS (Blood Brain Barrier) and Renal (Systemic reabsorbtion)
B- Breathing (Salicylates)
• Avoid Intubation if possible.
• If intubation unavoidable
– Try to maintain pre intubation MV (12 ml/kg at 20 RR)
– Monitor PAW and ABG.
– Avoid sedation till just before intubation.
– Pre and Post intubation NaHCO3
C- Circulation
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Continous cardiac monitioring.
May require invasive monitoring.
Vascular access.
Fluid resuscitation or Inotropes.
C – Circulation
1. Asystole or V Fib.
– Standard ACLS protocols
2. Hypotension
– IV Crystalloids
– Vasopressors – Noradrenaline
– IABP, ECMO in refractory shock
– May require higher doses than non poisoned patients
– Antidotes.
C- Circulation
(Specific Scenarios)
3. Bradycardia + Hypotension (In poisoning)
– Consider
• Digoxin
• CCB
• Beta Blockers
C- Circulation
(Specific Scenarios)
• Digoxin Toxicity
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GI Symptoms: anorexia, nausea, vomiting, diarrhoea, abdominal pain
Hyperkalaemia (early sign of significant toxicity)
CNS: lethargy, confusion
CVS: Increased automaticity, AV block, repolarisation anomalies.
Resistant to standard t-reat-ment-.
Digoxin-specific Fab fragments (digibind)
C- Circulation
(Specific Scenarios)
• Beta blocker Toxicity
– Hypoglycemia, Bronchospasm
– Resucitation
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fluid
beta-agonists
vasopressors
atropine
pacing
– Antidotes
• Glucagon
• High dose Insulin
• Intralipid
C- Circulation
(Specific Scenarios)
• Two beta-blockers require special consideration:
• Propanolol :causes sodium channel blockade - QRS widening - treat with
NaHCO3
• Sotalol :causes potassium efflux blockade - long QT - monitor for Torsade.
C- Circulation
(Specific Scenarios)
• Calcium Channel Blockers
– Hyperglycemia
– Depressed consciousness is rare.
– T-reat-ment• Supportve
• Calcium
C- Circulation
(Specific Scenarios)
4. Monomorphic Wide Complex T-achy-cardia
– Most likely SVT with aberrancy
– Sodium Channel blocked
– Tricyclic antidepressants, antihistamines, Type IA antiarrhythmics,
and cocaine.
– Treatment is sodium bicarbonate
• QRS < 100 msec in limb leads
• pH 7.55
– Avoid Type 1 Antiarrythmics (Procainamide)
C- Circulation
(Specific Scenarios)
5. Polymorphic VT
– Types IA, IC, and III antiarrhythmics, Pentamidine, antipsychotics,
arsenicals, antifungals and antihistamines.
– Treatment
• MgSO4 2 gms IV over 5 mins (x2 more doses)
• Overdrive pacing (Electrical or Isoproterenol )
C- Circulation
(Specific Scenarios)
6. Narrow Complex Tachycardia + Hypertension
– Hyperadrenergic states
– Cocaine, Amphetamines, sympathomimetic drugs.
– Treatment
• BZD
• Phentolamine
• Refractory HTN : NTG, Nitroprusside
– AVOID B-Blockers and antipsychotics.
D- Disability and Neurostabalization
• Coma cocktail.
• Rule out and treat hypoglycemia.
• Naloxone for reversal of respiratory depression secondary to
suspected opoid OD.
• No Flumazenil even if BZD OD suspected.
– Withdrawal Seizures
• Thiamine – Unlikely to reverse coma
D- Disability and Neurostabalization
• Seizures
– Toxicity or Withdrawal
– Drug of Choice:
• Short Acting BZD
• Second line : Propofol
• Avoid Phenytoin
– Ineffective
– Propelene Glycol toxicity.
– High dose pyridostigmine (5 gms IV) in Isoniazid OD
– IV Sodabicarb if seizures due to Na channel blockade.
E – Environment & Electrolytes
• Environment
– Correct hypothermia
• Severe hypothermia (<30 C)
• Active rewarming
– Correct Hyperthermia
• Severe hyperthermia (>40 C)
• Ice bath, sedation, NMB
• Electrolytes
– Correction of electrolyte abnormalities.
DECONTAMINATION
Rationale for Decontamination
• Proportion of the ingested drug still has not absorbed (Esp
Early)
• Could potentially be cleared from the gut
• Reduced total dose of the drug
• Reduced total toxicity
• Ergo, the removal of undissolved drugs should reduce the
toxicity of the overdose!!
Criticism of Decontamination
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Aspiration esp. in unprotected airway
Effectiveness diminishes with time.
Bowel obstruction with charcoal.
Patient outcome not affected in long term as per studies.
Types of Decontamination
• Surface Decontamination
– Strip naked Soap and water body wash.
– Irrigation of the eye.
– Drugs which absorb readily though the skin include the following:
• Glycerol ethers
• Industrial solvents, eg. carbon tetrachloride, trichloroethylene, methylene
chloride, etc.
• Mercury salts
• Lead salts
Types of Decontamination
• Gut Decontamination
– Induced emesis (abandoned)
– Gastric lavage (largely abandoned; only indicated within the first
hour)
– Whole bowel irrigation (only indicated for iron and slow release
enteric coated tablets)
– Activated charcoal, single or multiple doses
Gastric Lavage
• Technique
• Indications
– Should not be applied routinely if ever!
– Within 1st hour of ingestion.
• Contraindications
– Unprotected airway
– Caustic ingestion (due to risk of exacerbating any esophageal or gastric
injury)
– Hydrocarbon ingestion (due to high aspiration risk)
– Patients at risk of GI hemorrhage or perforation (recent surgery, underlying
anatomic abnormality or pathology, coagulopathy)
Gastric Lavage
• Complications
– Aspiration pneumonia
– Increased incidence of intubation vs control.
– Esophageal or gastric perforation
– Laryngospasm, hypoxia, dysrhythmia
– Fluid or electrolyte imbalance
– Push poison beyond pylorus (Making activated charcoal ineffective)
Whole Bowel Irrigation
• Technique
– Large amounts of iso-osmotic PEG-ES administered (NG) until
effluent runs clear.
• Indications
– Sustained-release or enteric coated drugs.
– Iron tablets (Not absorbed by AC)
– Illicit drug packets
Whole Bowel Irrigation
• Contraindications
– leus, bowel obstruction, or intestinal perforation
– Clinically significant GI hemorrhage
– Hemodynamic instability (sequestration of bowel and worsening of
shock)
– Intractable emesis
Activated Charcoal
• Mechanism of Action
– AC is a highly adsorbent powder made of high surface area porous
organic material. Its extensive surface area surface area(2000 m2/g)
is covered with a carbon based network which adsorbs chemicals
within minutes of contact preventing GI absorption and hence
systemic toxicity.
– Highest affinity is for compounds with a molecular weight of 100–
1000 Da
– Many pharmacologically active substances fall within this range
Activated Charcoal
• Indication
– Presentation within 1 hour of injection of toxin.
– Later benefit “cannot be excluded”
Activated Charcoal
• Contraindications
– Depressed consciousness without airway protection.
• Do NOT intubate just for the purpose of AC.
– Late presentation
– Increased risk and severity of aspiration associated with AC use
(hydrocarbon ingestion)
– Need for endoscopy (significant caustic ingestion)
– Toxins poorly adsorbed by AC
– Intestinal obstruction (absolute contraindication).
Activated Charcoal
• Toxins for which AC ineffective
– Drugs which are absorbed too rapidly
• Ethanol
• Paraquat
– Drugs which do not adsorb on to charcoal
• Corrosive substances(strong acids and alkalis)
• Iron
• Lithium
Activated Charcoal
• Administration
– Powder mixed with water (Juice, milk) to form slurry.
– Commercial preparation – suspension with thickening agent
like sorbitol.
– Dose
• Single Dose
– 50 grams (20 – 100 gms)
– Multi Dose
Activated Charcoal
• Multi Dose Activated Charcoal (MDAC)
– Rationale
• NOT more for more effect
• Interruption of enterohepatic recirculation.
• Facilitation of transluminal diffusion from body into the bowel
lumen (“gut dialysis”), followed by excretion
• Reduced absorption of extended or delayed release formulations.
– Indications
• Carbamazepine, Dapsone, Phenobarbital, Quinine, Theophylline
– Dose (MDAC)
• 50 grams loading then 12.5 gms/hour equivalent.
Activated Charcoal
• Complications
– GI side effects like fullness, abdominal pain, nausea, vomiting,
constipation, and diarrhea.
– Aspiration.
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Inadequately protected airway
In association with lavage
Improperly placed nasogastric tube
Bowel obstruction.
ENHANCED ELIMINATION
Forced (Alkaline) Diuresis
• MOA
– Altering the pH converts a lipid-soluble intact acid (HA) or base
(BOH) in the tubular lumen into the charged salt. (A-/B+)
– The charged particle is lipid-insoluble and cannot easily move back
across the renal epithelium. This leads to a marked increase in drug
excretion.
Alkaline Diuresis
• Indications (Toxin Properties)
– Eliminated unchanged by the kidney
– Distributed primarily in the ECF.
– Protein-bound
– Weak acids.
Alkaline Diuresis
• Contraindications
– Renal failure, pulmonary oedema and cerebral oedema,
pre-existing cardiac disease (CI to Sodabicarb).
• Technique
– Get a baseline electrolytes, BUN, S.Creat, glucose, systemic
pH, urinary pH and serum drug concentrations.
– Foleys to measure UO.
– W/F Respiration
Alkaline Diuresis
• Technique
– Goal
• Urine pH > 7.50
• Serum pH 7.55 to 7.60
– Alkalinisation of Urine
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IV NaHCO3
1-2 mEq/kg of 8.4% as bolus.
Infusion with continuous monitoring of Urine and Blood pH.
Do NOT use acetazolamide. (Acidemia)
Alkaline Diuresis
– Complications
• Hypokalemia
• Ionized hypocalcemia
• Alkalemia
Haemodialysis
• Toxic compounds in blood diffuse through a
semipermeable membrane down a concentration
gradient into a dialysate.
• Also treat associated electrolyte imbalance and
acidosis.
Methanol
• Common Drugs
Ethylene glycol
Salicylates
Theophylline
Lithium
Haemoperfusion
• Large surface area of resin or charcoal filter enhances
adsorption by presenting a larger contact surface for the
filtered blood
• Resin filters may also be impregnanted with drug-specific
antibodies
• Spectrum - Drugs adsorbed by activated charcoal.
Theophylline
Carbamazepine
Valproic acid
Procainamide.
Hemodialysis/Haemoperfusion
• Contraindications
– Patient with active hemorrhage or coagulopathy (Require systemic
anticoagulation with heparin).
– Hypotensive patients.
• Complications
– Those with HD plus
– Charcoal embolization.
Exchange Transfusion/Plasmapherisis.
• Rarely Used
• Indications
– Massive hemolysis (arsine or sodium chlorate poisoning)
– Methemoglobinemia, sulfhemoglobinemia (hydrogen sulfide
exposure)
– Neonatal drug toxicity.
Any Questions?
THANK YOU