Definition
A state of prolonged deep unconsciousness in which a person cannot be awakened, does not respond to stimuli, and shows reduced or absent reflexes. In the aviation context of dry ice transport, coma is a possible end-stage symptom of carbon dioxide exposure in a poorly ventilated cabin or cargo area.
Plain English
A deep unconscious state where someone cannot be woken up and does not react to sound, touch, or pain.
Context Anchor
Seen in warnings about carrying dry ice in an aircraft, especially where carbon dioxide gas could collect in the cabin or baggage area.
Derivation
From the Greek 'koma' meaning 'deep sleep.' The aviation usage keeps this original sense — not ordinary sleep, but a sleep so deep the person cannot be roused.
Why Pilots Care
Unchecked CO2 buildup from dry ice can rapidly progress to coma, respiratory failure, and death, demanding immediate cabin ventilation and diversion.
Intuition Check
Do not read coma as “very tired” or “asleep.” Here it means a medical emergency where the person is unconscious and cannot be awakened normally.
Example Sentence 1
The handbook warns that excessive dry ice in a poorly ventilated cabin can cause carbon dioxide buildup, leading to drowsiness, unconsciousness, and ultimately coma.
Example Sentence 2
The crew opened all vents immediately when the passenger showed signs that could lead to coma from the dry ice fumes.