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Cyanide
Aka: Cyanide, Hydrogen cyanide, Hydrocyanic acid, Cyanogen chloride
- See Also
- Chemical Weapon
- Mechanism
- Site of action
- Inhibits Cytochrome A3
- Absorbed effect (Hydrogen cyanide, Cyanogen chloride)
- Binds ferric ions in mitochondrial cytochromes
- Cell unable to perform aerobic metabolism
- Local respiratory effects (Cyanogen chloride)
- Pulmonary Intoxicant (Chlorine type effect)
- State
- Temperature below 78 F: Liquid and Vapor
- Temperature above 78 F: Gas
- Route of exposure
- Percutaneous
- Inhalation
- Life threatening dose: 110 ppm for 30 min
- Lethal dose: 270 ppm
- Ingestion
- Lethal dose: >200 mg
- Sources
- Weapon or intentional toxin
- Tobacco Smoking (0.4 mcg/ml)
- Foods: Fruits, seeds and pits
- Prunus Seeds (plums, cherries, peaches, nectarines, apricots and almonds)
- Lima beans
- Cassava plant roots (staple in some parts of world)
- Smoke Inhalation (Structure fires)
- Especially plastics (acrylonitrile)
- Industrial use Hydrogen cyanide (300,000 tons)
- Nitroprusside metabolite
- Agents
- Hydrogen cyanide (Hydrocyanic acid, AC)
- Cyanogen chloride (CK)
- Symptoms: Low level Cyanide Vapor exposure
- Intense eye, nose and airway irritation
- Increased Rate and depth of breathing
- Dizziness
- Headache
- Agitation
- Confusion
- Nausea, Vomiting and Abdominal Pain (with ingestion)
- Signs: High Cyanide Vapor exposure
- Immediate
- Diaphoretic
- Pupils normal or large
- Hypertension and reflex Tachycardia
- Effects at time 15 Seconds
- Transient increased Breathing Rate, depth
- Effects at time 30 Seconds:
- Seizure
- Effects at time 2 to 4 Minutes
- Respiratory arrest from central apnea
- Effects at time: 4 to 8 Minutes
- Terminal Hypotension
- Bradyarrhythmia
- Cardiac Arrest
- Effects at time 6 to 8 Minutes
- Death
- Signs: Presentations
- Acidemia or acute confusion AND
- Syncope in lab or industrial worker
- Smoke Inhalation
- Suicide attempt
- Ingestion (e.g. Prunus seed, Acetonitrile)
- Labs
- Whole Blood Serum Cyanide effects
- Results are typically delayed
- Mild effects: 0.5-1.0 mcg/ml
- Lethal effects: >2.5 to 3 mcg/ml
- Arterial Blood Gas
- Metabolic Acidosis with High Anion Gap
- Serum Lactic Acid high
- Lactic Acid
- Typically elevated >8 mmol/L
- Differential Diagnosis
- Nerve Agent
- Miosis
- Increased Rhinorrhea and oral secretions
- Hydrogen Sulfide
- Rotten egg odor
- Carbon Monoxide Poisoning
- Pink, healthy looking skin with Hypoxia
- Detection
- Odor
- Bitter almonds (Only detectable by 50% of people)
- Detection Kits
- Hydrogen cyanide (AC)
- M256A1 (7.0 mg/m3)
- M272 (20.0 mg/m3)
- ICAD (250 mg/m3)
- M18A2 (8.0 mg/m3)
- M90 (30 mg/m3)
- Cyanogen chloride (CK)
- MINICAMS (130 ppbv)
- Draeger (0.25-5 ppm)
- M93A1 Fox (46 mg/m3)
- Management: General
- Decontamination
- Vapor: None (other than removal from exposure)
- Minimal risk of off-gassing
- Liquid: Remove clothes, brush off dry powders and wash skin with soap and water
- Ingestion
- May consider Activated Charcoal if acute ingestion and controlled airway
- Supportive care
- Oxygen at 100% via Non-Rebreather Mask
- Stabilize airway
- Correct acidosis
- Intravenous FluidResuscitation if hypotensive
- Disposition
- Other patients, with normal serum bicarbonate and Lactic Acid: Observe for 4 to 6 hours
- Observe ingestion patients for longer period
- Management: Antidotes
- Antidote: Cyanokit (IV Hydroxycobalamin)
- Indications: Smoke Inhalation (Paris Fire Brigade Protocol)
- Known Smoke Inhalation in an enclosed space AND
- One of the following criteria
- Altered Mental Status
- Soot in nares or mouth
- Full cardiopulmonary arrest (without full body burns incompatible with life)
- Dosing
- Adult: Hydroxycobalamin (Vitamin B12a) 5 grams IV over 15 minutes
- Child: Hydroxycobalamin (Vitamin B12a) 70 mg/kg (up to 5 g) IV over 15 minutes
- Efficacy
- Resulted in 50% ROSC rate in full arrest Smoke Inhalation patients
- Much safer empiric therapy than the Lily Kit (Methemoglobinemia, Hypotension)
- References
- Fortin (2006) Clin Toxicol 44 (suppl 1):37-44 +PMID:16990192 [PubMed]
- Borron (2007) Ann Emerg Med 49(6): 794-801 +PMID:17481777 [PubMed]
- Antidote: Lily Kit (2 Step Process)
- First: Sodium Nitrite to form Methemoglobin
- Dosing: Sodium Nitrite
- Adult: 300 mg (10 ml) IV (1 ampule of Pasadena kit) at 2.5 to 3 ml/min
- Child: 0.33 ml/kg of 3% solution IV over 10 min
- Alternative
- Amyl Nitrate crushed and inhaled
- Contraindications
- Concurrent Carbon Monoxide Poisoning (e.g. Smoke Inhalation)
- Further interferes with Hemoglobin oxygen carrying capacity
- Adverse effects
- Hypotension (Nitrites related)
- Methemoglobinemia with secondary Hypoxemia
- Mechanism
- Convert Hemoglobin iron from ferrous (Fe 2+) to ferric (Fe 3+)
- Cyanide selectively binds methemoglobin instead of mitochondria
- Next: Sodium thiosulfate to act as sulfur donor
- Adult: 12.5 g or 50 ml (1 large bottle in Pasadena kit, 25% solution)
- Child: 250 mg/kg or 1.65 ml/kg (up to 12.5 g) IV of 25% standard solution
- Allows for enzymatic conversion (via rhodanese) of Cyanide to a renally excreted form
- Prevention
- Activated Charcoal in chemical protective mask
- Absorbs Cyanide and provides full protection
- Triage
- Immediate
- Presentation within minutes of exposure
- Seizures or recent apnea with circulation intact
- Minimal
- Mild effects and out of exposure
- Delayed
- Recovering from mild effects or successful therapy
- Expectant
- Apnea and circulatory failure
- Course
- Observe survivors for 24-48 hours after exposure
- References
- Koch (2016) Crit Dec Emerg Med 30(9): 23
- Mell in Herbert (2015) EM:RAP 15(3): 4-5
- Medical Response to Chemical Warfare and Terrorism
- US Army Medical Research Institute Chemical Defense
- Video-Teleconference: 4/20/00 to 4/22/99
- Video-Teleconference: 12/5/00 to 12/7/00
- Text: 3rd Edition, December 1998