Severe unexplained metabolic acidosis (lactic).Smell of bitter almonds (only 60-80% of population can detect this).

RBC or serum cyanide levels (unlikely to return in time to be clinically useful).VBG and ABG (narrowing of the venous-arterial PO2 gradient, causes venous hyperoxemia/increased redness - as does CO poisoning).Serum lactate >8 mmol/L has 94% sensitivity.Lactate (normal lactate highly suggests another diagnosis).Smoke inhalation injury (airway compromise).Household and commercial pesticides (diazinon and parathion).Prussic acid (AKA hydrogen cyanide, hydrocyanic acid, or formonitrile).Cyanide chemical weapon agents (Blood agents).Pulmonary chemical agents (Choking agents).Spastic upper motor neuron paraparesis seen in chronic ingestion of inadequately cooked casava.Rhabdo, bright red venules seen on fundoscopy.Bradypnea and pulmonary edema (non-cardiogenic), apnea.Bradycardia, hypotension, arrhythmias, asystole.

Tachycardia, palpitations and hypotension.

CNS stimulation ( Headache, anxiety, confusion).

Inhalation exposure may cause syncope and death after only a few breaths.

Inhaled toxins more rapid than ingested.

Affected by dose, route, formulation and exposure pattern.

They found 50% ROSC in fire victims in full arrest when hydroxycobalamin was administered.

Full arrest without full body burns incompatible with life.

Paris Fire Brigade protocol recommend hydroxocobalamin administration patients who have had known smoke inhalation in an enclosed space with any of the following:

Causes switch from aerobic to anaerobic metabolism despite adequate O2.

Binds to cytochrome oxidase in mitochondria leads to cessation of electron transport.

Pits of peaches, pears, apricots, crab apples.

Gaseous chemical weapon known as prussic acid, hydrogen cyanide, or hydrocyanic acid.

Burning of nitrogen-containing polymers (plastics, wool, silk).

5.2 Cyanide Antidote Package (Lilly kit).

Cyanide antidote kit contains