Cyanide

what is the MOT of cyanide?

chemical asphyxiant

how can cyanide be toxic?

1. acute cyanide ingestion or inhalation of glass (rapidly lethal)

2. chemical degradation product found in fires with smoke inhalation

when you experience smoke inhalation, what are some levels you should check?

1. CO

2. cyanide

what is the clinical presentation of acute inhalation/ingestion of cyanide?

rapid LOC and seizure

what is the clinical presentation of mild exposure to cyanide (usually due to fire)?

1. N/V, Headache, Shortness of breath

2. ↑RR

3. ↑BP, ↑HR, altered mental status

what is rare Sx of cyanide toxicity?

odor of "bitter almonds" or "cherry red" skin

what are rapid evaluation tools for cyanide toxicity?

1. lactate (>8 mmol/L) and ABG

2. blood cyanide concentration (diff to obtain in acute setting bc of short half life)

3. Carboxyhemoglobin (>10%; sometimes cant tell if its CO or cyanide)

what are the overall goals of pharmacotherapy with cyanide exposure?

1. prevent death

2. stop seizure (severe)

3. ↑ O2-carrying capacity

4. ↓ need for mechanical ventilation

5. Avoid CNS sequelae secondary to hypoxic injury

6. Reverse metabolic acidosis

7. Prevent arrhythmia and maintain adequate BP

what are the Rx options for cyanide toxicity?

1. sodium nitrate and sodium thiosulfate (Nithiodote; 2 vials)

2. Hydroxocobalamin (Vit B12; Cyanokit)

what is the benefit of Na nitrate and Na thiosulfate in Nithiodote?

-Na nitrate induces deoxygenated Hg form (binds cyanide)

-Na thiosulfate converts cyanide to thiocyanate which is excreted renally

what is the dose for Nithiodote?

1. 10 mL vial (30 mg/mL) of 300 mg Na nitrate, IV i

2. 50 mL vial (250 mg/mL) of 12.5 g Na thiosulfate, IV

what is important to know regarding guidelines for Nithiodote administration in cyanide toxicity?

-dont administer if CO toxicity is present

-same needle/vein may be used

can you administer another dose of Nithiodote?

If Sx of toxicity reappear after 1 hour, may administer another dose of each at 50% of original dose

ADE of Nithiodote?

-allergic RXN

-↓ BP

-N, blue skin, ↓O2 (Na nitrate)

what is the benefit of hydroxocobalamin in Cyanokit?

vit B12 precursor that chelates cyanide from cytochrome system and acts as NO, forming cyanocobalamin thats excreted in urine

what is the dosing for Cyanokit in cyanide toxicity? max dose?

-5 g IV infusion (dilute in 200 mL 0.9% NaCl, LR, or D5W) over 15 min (diluent isn't included)

-max dose 10 mg

can you administer another dose of Cyanokit?

depending on severity of exposure/response to first dose, second dose of 5 g may be infused over 15 min - 2 hrs

what are ADE of Cyanokit?

-red colored urine (5 wk) and skin (2 wk)

-skin rash

-↑BP

-↓lymphocyte

-N, HA, infusion site RXNs

-allergic RXN

-acute tubular necrosis

who should avoid Cyanokit? why?

kidney impairment due to acute tubular necrosis ADE

what are the advantages of Cyanokit over Nithiodote?

-easier pt administration (1 dose)

-↑ shelf life

-no methemoglobin production

-↓ potential to cause hemodynamic instability

what are the disadvantages of Nithiodote in comparison to Cyanokit?

-↑ cost

-interference with lab tests that use colorimetric analysis

-potential inability to perform hemodialysis

what cyanide antidote do most places carry?

Cyanokit

how do you decide when to administer antidotal therapy for cyanide toxicity?

moderate/severe Sx need antidote, supportive care and supplemental O2

what short term sequelae of cyanide toxicity?

-Seizure

-Unresponsiveness

-CV instability

-Death

what long term sequelae of cyanide toxicity?

-cognitive issues

-CV problems

-neurological diseases (can take weeks to develop)

what are the clinical parameters you want to measure with cyanide antidotes?

1. level of consciousness

2. seizures

3. tissue oxygenation

4. vital signs

what are the lab parameters you want to measure with cyanide antidotes?

1. lactate levels

2. ABG

what are the additional labs you want to measure when Cyanokit is administered?

1. ↓ cyanide

2. ↑ SCr, glucose, Hg

3. monitor BUN, SCr and urinalysis for renal impairment for 7 days

if you have severe Sx from cyanide exposure where should you go?

ICU