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Cyanide (AC, CK)

Cyanide (AC, CK)

Diagnosis

1.
Consider in:

Closed space smoke inhalation/fire victim OR suicide with coma/acidosis

Laboratory worker who suddenly collapses

Ingestion of nitrile compound; ingestion of artificial nail remover

ICU: pt on nitroprusside with MS changes, acidosis

2.
Bitter almond odor (detectable by 40-50%)

3.
Hypoxic symptoms: HA, SOB, confusion, seizure, coma

4.
Shock (hypotension with tachy or bradycardia)

5.
Incr’d lactic acid/coma

6.
Dec. A-V O2 difference (inc. VO2 saturation)

7.
Assoc. abd. pain/emesis; skin cherry-red or cyanotic seizures, respiratory and cardiac arrest

8.
Elevated blood AC:

Mild effects (flushing, tachycardia) at 0.5-1.0 mcg/ml

Coma, convulsions and death at 2.5 mcg/ml

Obtundation at 1-2.5 mcg/ml

9.
Lab: plasma lactate concentration >8 mmol/L, 94% sensitive & 70% specific for blood cyanide concentration >1 mg/L
History

1.
Used by French in WWI without notable military success

2.
US maintained small number of cyanide munitions during WWII

3.
Japan allegedly used cyanide against China during World War II

4.
Iraq may have used cyanide against Kurds in 1980’s
Pathophysiology

1.
Binds cellular cytochrome oxidase causing chemical asphyxia

2.
Hydrogen cyanide, hydrocyanic acid (AC); cyanogen chloride (CK)

3.
AC is rapidly acting lethal agent limited by high LCt50 and high volatility

4.
AC is least toxic of “lethal” agents

5.
Death occurs within 6-8 mins after inhalation

6.
Exist as liquid in munitions, vaporize on detonation; major threat from vapor

7.
Absorbtion:

Inhalation: 58-77%

Oral: 50%

8.
Half life: 0.7-2.1 hrs

9.
LCt50s by inhalation:

AC: 2500-5000 mg-min/m3

CK: 11,000 mg-min/m3

10.
LD50s:

AC: IV is 1.1 mg/kg

AC: skin is 100 mg/kg

11.
Fatal dose: hydrogen cyanide:

Inhalation: (<1 hr): 110-135 ppm

Oral: 0.6-1.5 mg/kg

Dermal exposure of 10% sodium cyanide to large body surface area causes symptoms in 20 mins
Decontamination

1.
Skin decontamination not necessary

2.
Remove wet contaminated clothing

3.
Clean underlying skin with soap and water
Treatment

1.
Antidote (adult): sodium nitrite 10 ml IV and sodium thiosulfate 50 ml IV (target methemoglobin 10-20%)

2.
100% O2; activated charcoal for oral exposure

3.
Remove to fresh air (if O2 not available)

4.
Mechanical ventilation as needed

5.
Circulatory support with crystalloids and vasopressors

6.
Correct metabolic acidosis with IV sodium bicarbonate (1-2 meq/kg)

7.
Seizure control with benzodiazepines

8.
Administration of 100% O2

9.
Investigational: hydroxcobalamin 4 g (can bind 200 mg of cyanide) administered with 8 g of thiosulfate
Disposition

1.
Admit all symptomatic pts to ICU

2.
Asymptomatic pts observed for 2 hrs, then discharged

3.
Survival after 4 hrs (in acute exposure) associated with full recovery

4.
Notify CDC & local health dept
Military Detection/Treatment Kits
(See Chemical Agent ID/Detection)

1.
M256A1, M272 kit, ICAD, M18A2, and M90 detectors detect AC

* Material is taken from the PEPID database
* Copyrighted material – All Rights Reserved
* For more information visit http://www.pepid.com

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