The most common scenario in which providers should be concerned about cyanide poisoning in children is in a patient rescued from a structure fire. Cyanide is released from things that burn within a home (wood, fabrics etc,.) and is inhaled. Poisoning essentially results in disruption of the electron transport chain, resulting in depletion of ATP. Therefore you can’t do aerobic metabolism, you get acidotic and you become ill. The onset of symptoms is rapid – just a few minutes. It can also come from exposure to industrial metal polishing, insecticides, almonds, cassava and apple seeds. But you really can’t get enough from apple seeds to hurt you.
It causes many symptoms including headache, confusion, dyspnea, chest tightness, nausea, vomiting, altered mental status, seizures, coma, mydriasis, tachypnea/hyperpnea(early), bradypnea/apnea (late), hypertension (early), hypotension (late) and ultimately cardiovascular collapse.
The diagnosis is often difficult and getting cyanide blood levels is not necessarily practical. Cyanide level 0.5–1 mg/L is mild, 1–2 mg/L moderate, 2–3 mg/L and severe >3 mg/L (often equals death).
What is the mechanism of action?
Hydroxocobalamin chelates cyanide and forms cyanocobalamin (a form of vitamin B12) which is excreted in the urine.
When should we use a Cyanokit?
In order to determine if smoke inhalation victims require a Cyanokit, they should present with:
- Exposure to fire smoke in an enclosed area
- Soot present around mouth, nose or oropharynx
- Altered mental status
Supportive labs include an elevated lactate (>8 is bad)
Patients exposed to smoke only need decontamination of hair (wash it) and remove outer clothing.
Ideally the sooner the better. Severe exposures lead to death – but Cyanokits should be given at the scene if possible. This is done in Europe for instance.
How do we dose it?
- Pediatric patient – 70mg/kg IV (max 5g)
- Adults – 5g IV (kids ≥15 years)
Give over 15 minutes, dose can be repeated if an incomplete clinical response is observed (second dose rate is administered over 15 minutes to 2 hours)
What is the expected result?
The patient should experience improvement in the most severe symptoms to some degree. This corresponds with improvement in lactic acidosis. Some positive effects can be seen in 30-60 minutes.
What are the adverse reactions?
- Transient, self-limiting skin reddening (may last up to two weeks)
- Chromaturia red-orange urine (may last up to one week)
- Transient, relative hypertension (resolves within 4 hours)
- Allergic reactions (pustular rash and facial swelling) – treat this with antihistamines and steroids
- Acneiform rash may develop from 7 – 28 days after treatment; will resolve within a few weeks
Preparation of cyanokit is complex, and is included here for reference
Reconstitute each vial with 100 mL of 0.9% Sodium Chloride (may also use LR or D5W) using transfer spike, fill vial to line and leave vial in upright position, the resulting solution has a concentration of 25 mg/mL., rock or rotate the vial for 30 seconds to mix the solution, do not shake the vial, check for particulate matter, solution should be dark red.
If dose is less than 2.5 grams (one vial), calculate volume necessary (dose divided by concentration, 25 mg/mL), and withdraw volume into syringe.
Administration is through a separate IV line from other meds. It can be run on a syringe pump over 15 minutes.