Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 15
Chemical Agents of Opportunity for Terrorism:
TICs & TIMs
Cyanide: Diagnostic Testing
• ABG
– Anion gap metabolic acidosis
• VBG
– “Arteriolization ” of venous blood gas
• Lactate
– Elevated
• Blood cyanide levels
– Whole blood or serum
– 2-3 day turn around time
Module Four – Cyanide & Fumigants
15
The clinical laboratory can be useful in making the diagnosis of cyanide poisoning. Anion
gap metabolic acidosis is usually present and is due to the presence of large amounts of
lactate (L-lactate).
Arteriolization of the venous blood gas may be present. That means that the arterial
blood, when passing through the capillaries, does not have its oxygen removed by the
tissues (since their mitochondrial electron transport chain is blocked by cyanide) and the
blood passes into the venous system with lots oxygen.
Blood cyanide levels from either whole blood or serum can also be obtained but these
are usually performed outside the hospital setting and have a 2-3 day turnaround time.
One characteristic of cyanide poisoning is the “arteriolization” of the venous blood gas.
This is due to a very poor oxygen extraction ratio from the capillary blood as it passes
from artery to vein, and a very high content of oxyhemoglobin in the venous blood. It is
generally felt that O2 saturation on a venous blood gas (VBG) over 80% is suggestive of
cyanide (or other mitochondrial enzyme) poisoning. One simple assessment for cyanide
poisoning is to look at the color of the venous blood: arterial blood is bright red while
venous blood should be deep red. Arteriolization is when the venous blood looks bright
red like arterial blood.
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