9.6. CYANIDE POISONING

Related titles

Cyanide, hydrocyanic acid, poisonous substances of general toxic action.

Purpose of assistance

1. Evacuate the patient from the toxic environment.
2. Ensure adequate ventilation, oxygenation and treatment of hypoperfusion.

Description of the patient

Cyanide is a colorless gas with a “bitter almond” smell (only 40% of people have the genetic ability to recognize this smell) or white crystals that combine with iron ions in cells, block the enzyme cytochrome oxidase, respectively, making it impossible for the mitochondria of cells to use oxygen , causing cellular hypoxia.

Inclusion criteria

1. Depending on the state of the substance, cyanide can enter the body by inhalation, ingestion, or seep through the skin. Cyanide poisoning should be suspected in case of contact with smoke or in view of the specifics of the profession (firefighters, for example), in accidents at industrial plants, natural disasters, suicide or murder attempts, chemical and terrorist attacks (provided there are several patients with injuries of unknown etiology) . Non-specific and early signs of poisoning (inhalation, absorption or absorption through the skin) are the following signs and symptoms: fear, dizziness, weakness, headache, tachypnea, nausea, shortness of breath, vomiting, tachycardia.

2. A high concentration of cyanide will cause:

a) pronounced change of consciousness;
b) convulsions;
c) respiratory depression or its stop;
d) arrhythmias (except sinus tachycardia ).

3. The rapid onset of symptoms is related to the severity of poisoning (inhalation or ingestion) and can have fatal consequences, ranging from early hypertension followed by hypotension, acute cardiovascular failure or convulsions/coma, and ending with sudden death.

Exclusion criteria

No recommendations.

Management of the patient

Status assessment

1. Evacuate the patient from the toxic environment.
2. Perform a complete initial examination and, if indicated, remove the patient’s clothing and subsequently cover the patient to prevent hypothermia.
3. Assess vital signs, including body temperature and pulse oximetry (pulse oximetry readings may not correlate with tissue oxygenation in cyanide/smoke poisoning).
4. Connect a cardiac monitor and analyze the arrhythmia results: record a 12-lead ECG.
5. Check your glucose level.
6. Monitor pulse oximetry and ETSO2.
7. Monitor for signs of hypoxia (pulse oximetry below 94%) and respiratory failure regardless of pulse oximetry readings.
8. Identify the specific agent that caused the poisoning – name, time of ingestion/inhalation, amount and duration of ingestion.
9. Collect medical history, including history of cardiovascular disease and prescribed medications.
10. Collect other relevant details of the history.
11. Do a physical examination.

Treatment and intervention

There is currently no widely available test that would give instant results for the presence of cyanide poisoning. Most hospitals will not be able to quickly assess cyanide levels in the body. Therefore, decisions regarding treatment tactics should be based on the clinical history, signs and symptoms of cyanide poisoning. In patients with an appropriate clinical history and one or more signs of severe cyanide poisoning, use the following:

1. 100% oxygen through oxygen mask or AMBU bag.

2. Blood sampling before treatment to the appropriate test tube for the level of lactate and cyanide.

3. Enter one of the following drugs.

1.3. Hydroxycobalamin (recommended as the main drug):

a) adults:

• • • • initial dose of 5 g IV, administered slowly over 15 minutes;
      • each ampoule (5 g) should be diluted in 200 ml of a combined medicinal product with the composition of sodium chloride + potassium chloride + sodium lactate + calcium chloride, sodium chloride 0.9% or 5% glucose solution (25 mg/ml) and administered in a dose of 10-15 ml/min;
      • an additional 5 g can be administered after the consultation;

b) children: enter a dose based on 70 mg/kg (concentration after dilution is 25 mg/ml):

• • • • each ampoule (5 g) should be diluted in 200 ml of a combined medicinal product with the composition of sodium chloride + potassium chloride + sodium lactate + calcium chloride, sodium chloride 0.9% or 5% glucose solution (25 mg/ml) and administered in a dose of 10-15 ml/min;

c) maximum single dose – 5 g.

3.2. Sodium thiosulfate:

a) adults: 12.5 g IV (50 ml of 25% solution);
b) children: 0.5 g/kg IV ( 2 mg/kg of 25% solution).

4. In case of convulsions, provide assistance in accordance with the instruction “Convulsions”.

Patient safety

1. In a multitrauma situation, use appropriate personal protective equipment when evacuating from a toxic environment.
2. If a patient has swallowed cyanide, it will begin to react with the contents of the stomach, generating hydrogen cyanide gas. Provide maximum air circulation in enclosed spaces (ambulance), as the contents of the patient’s stomach may contain hydrogen cyanide gas, which will be released by vomiting or regurgitation.
3. Do not use nitrates in case of possible carbon monoxide poisoning, as they further reduce the ability of hemoglobin to carry oxygen molecules in addition to carbon monoxide.
4. Hydroxycobalamin is the only safe treatment for cyanide poisoning in pregnant women.

Useful information for training

Key points

1. Pulse oximetry reflects the level of oxygen in the blood serum, but it does not accurately reflect the level of tissue oxygen saturation, so the indicators should not be relied on in the case of possible cyanide and/or carbon monoxide poisoning.
2. After administration of hydroxycobalamin, the pulse oximetry indicators cease to be accurate.
3. If a patient swallows cyanide, it will begin to react with stomach acids and cause the production of hydrogen cyanide gas. Provide maximum air circulation in enclosed spaces (ambulance), as the contents of the patient’s stomach may contain hydrogen cyanide gases when released with vomiting and regurgitation.
4. Amyl nitrite and sodium nitrite are no longer used or commercially available.

Corresponding evaluation results

Early and reexamination is critical.

Key elements of documentation

1. Conduct a repeat examination with further indication of signs and symptoms, as the patient’s condition may rapidly deteriorate.
2. Identification of the possible etiology of poisoning.
3. Time of manifestation of symptoms and time of initiation of appropriate treatment of poisoning.
4. Therapy and response to therapy.

Criteria for the effectiveness of aid provision

1. Early control of the respiratory tract in case of rapid deterioration of the patient’s condition.

2. Detailed history of infection:

a) time of entry/exposure;
b) way of contact with the substance;
c) amount of drug or toxin received (carefully collect all residues);< br />d) intake of alcohol or other toxic substances.

3. Choosing the right protocol and treatment.

4. Documentation of details after each reassessment.