Carbon monoxide is a tasteless, colourless and ordourless gas formed by the burning of petroleum based fuels in combustion engines; and the burning of plastics, coal, and cigarettes.
How Does Carbon Monoxide Affect a Scuba Diver?
Red blood cells contain haemoglobin that attracts gases. Live-giving oxygen is the main gas the haemoglobin “latches” onto. However, carbon monoxide is also easily absorbed by haemoglobin; and binds to the haemoglobin around 200 times stronger than oxygen.
What this means for a scuba diver breathing from a contaminated tank, is that the blood can quickly become “overloaded” with carbon monoxide. This cuts out the oxygen and means the oxygen does not get to the body’s tissues where it is needed to make the cells function correctly.
The result is carbon monoxide poisoning.
Carbon Monoxide Poisoning Underwater
When a scuba diver is underwater with carbon monoxide poisoning, the haemoglobin may be overloaded with carbon monoxide and can’t absorb much oxygen. However, the increased partial pressure of oxygen at depth may result in enough oxygen in the blood to keep the cells oxygenated.
In this situation the diver can function, but when they ascend to a shallower depth, the partial pressure of oxygen will decrease. This will lead to the tissues being starved of oxygen and unconsciousness can occur.
A scuba diver with carbon monoxide poisoning will probably feel unwell while underwater, so should ascend as soon as symptoms occur.
How Does a Scuba Diver Get Carbon Monoxide Poisoning?
One the most common ways for a scuba diver to get carbon monoxide poisoning is from the scuba tank being filled with air contaminated with carbon monoxide.
This can occur if the fresh air intake pipe to the air compressor is next to a source of carbon monoxide, such as the exhaust of the engine driving the compressor.
In some situations, a well-meaning dive shop operator may have the air input pipe to the compressor outside in the fresh air. However, a car with its exhaust running might pull up close to the intake and its carbon monoxide may find its way into the tanks.
Careless location of a compressor’s air intake on a boat can also result in carbon monoxide from the boat’s engine.
How Does a Scuba Diver Avoid Carbon Monoxide Poisoning?
A scuba diver can reduce the possibility of carbon monoxide poisoning by having a quick check of the location of the air intake of the air compressor when getting a scuba tank filled at an unknown filling station.
This is especially important when on a scuba dive holiday.
As carbon monoxide is contained in cigarette smoke, a scuba diver shouldn't have a cigarette just prior to ducking underwater.
Symptoms of Carbon Monoxide Poisoning
The most common symptoms of carbon monoxide poisoning are:
- Cherry-red lips, cheeks and fingernails;
- Dizziness;
- Headaches;
- Staggering;
- Confusion;
- Paralysis.
Unconsciousness and death can result.
Treatment of Carbon Monoxide Poisoning
The first aid treatment for carbon monoxide poisoning is fresh air. This should be in the open deck on a boat; not inside the cabin or near the engine’s exhaust.
Pure oxygen should be administered, if available.
A check up at a hospital or doctor is always advisable for any diving related medical condition; even if the symptoms are mild.
Fortunately carbon monoxide poisoning is rare. However, its impact can be reduced by a scuba diver’s vigilance in being aware of the scuba tank filling station’s procedures.
Bruce Iliff - Hello from an Australian freelancer! I’ve been scratching articles together in Australia in a range of subjects for a number of ...
Join the Conversation