Carbon monoxide poisoning: what is it, how long does it last in the blood?

Around twenty schoolchildren including twelve in absolute emergency were poisoned with carbon monoxide in a school primary school of Saint-Alban, in the Côtes-d’Armor. Significant intoxication can lead to coma and death, sometimes within minutes. According to West France, four helicopters are on site. Around forty firefighters were mobilized. THE Orsec mapemergency and crisis management system, was triggered. “The only treatment to reduce carbon monoxide levels is to stay on oxygen for at least 12 hours. Normally, if it comes back down, there are no after-effects.” testified a SAMU doctor on site.

What is carbon monoxide?

Carbon monoxide is a very toxic, odorless, colorless, asphyxiating gas. : in a confined space it can kill in less than an hour. Carbon monoxide (CO) released when a gas, wood or coal-fired appliance, for example, malfunctions. Combustion does not take place correctly and releases this highly toxic CO. Most of the time, a boiler is the cause, which explains an increase in poisonings in winter.. But what makes carbon monoxide dangerous for the body is the fact that it binds to hemoglobin and blocks the transport of oxygen in the blood. It also prevents oxygen to attach to the organs that need it. In fact, these different organs are no longer sufficiently supplied with oxygen, which leads to death.

How quickly can you die from carbon monoxide poisoning?

Carbon monoxide is an asphyxiating gas that can kill in less than an hour in a confined space.

Headaches, fatigue, dizziness, nausea or vomiting should alert

What causes carbon monoxide poisoning?

Carbon monoxide is produced by the incomplete combustion of a carbon compound due to insufficient oxygen. This phenomenon is due to:

• an insufficient quantity of oxygen in the air (sealed room, insufficient ventilation, blocked air inlet, etc.)
• the presence of impurities in carbonaceous materials, objects of combustion
• insufficient evacuation of combustion gases (poorly connected pipe, blocked or poorly swept chimney, etc.)
• prolonged or inappropriate use of a device
• a malfunction of the device used for combustion.

In homes, the main sources of carbon monoxide are:

• heating systems (wood, coal, gas, butane, gasoline, fuel oil, ethanol, etc.) or hot water production (boilers),
• cooking appliances (stove, barbecue, brazier),
• chimneys,
• vehicle engines in a garage without ventilation,
• generators placed in a garage or cellar.

► In a collective establishment

These sources are also found in performance halls, restaurants, ice rinks, municipal halls or places of worship, for example. Other sources are specific to this type of place like some combustion heaters (gas radiant heating, resurfacer in ice rinks).

Be careful, the symptoms are not typical.

► In a professional environment, the main sources of carbon monoxide are thermal engine tools, gas vehicles (forklifts), ovens but also heating or hot water production systems, generators, etc.

What are the symptoms of carbon monoxide poisoning?

THE Symptoms of carbon monoxide poisoning appear quickly. Be careful, the symptoms linked to CO poisoning are not not typical. These are most often:

• headache,
• nausea and/or vomiting,
• muscle fatigue,
• chest or abdominal pain,
• of balance problems,
• ofa confusion or even brief blackouts.

At a more advanced stage, of the heart problems (rhythm disorders and coronary ischemia), disorders pulmonary (acute lung edema), muscular and visceral disorders (pancreatitis) can occur. Finally neurological manifestations such as convulsions, apraxia (movement disorders), amnesia, agnosia (object recognition disorder), parkinsonism, cortical blindness, incontinence can also be part of the initial symptoms of poisoning. A coma obviously indicates a life-threatening emergency and requires immediate treatment.

► In pregnant womencarbon monoxide poisoning carries a high risk of mortality or harm to the fetus

► Regular exposure, even at low doses of carbon monoxide may manifest as a decline in intellectual performance, learning difficulties, chronic headaches, impaired visual and hearing acuity.or even parkinsonian symptoms” adds our interlocutor.

Faced with the symptoms and following an interview carried out by the doctor in order to highlight the possible causes of poisoning, “the diagnosis is refined by a carboxyhemoglobin dosage (HbCO)that is to say hemoglobin which has fixed carbon monoxide” explains Dr. Perez. When the HbCO is above the thresholds below, it affirms intoxication, lower, no conclusion is possible.

► In the presence of clinical signs:

• HbCO > 6% in a smoker
• HbCO > 3% in a non-smoker

► In the absence of clinical signs:

• HbCO > 10% in a smoker
• HbCO > 6% in a non-smoker

Measuring carbon monoxide in exhaled air is rapid and provides a good correlation with HbCO. It is useful when it comes to confirming the diagnosis before admission to hospital or to situations involving multiple victims. Other examinations may be carried out to assess the consequences of intoxication:

• Blood gases or arterial blood gases which makes it possible to evaluate the respiratory and acid-base function of a patient and which can highlight respiratory alkalosis.
• Electrocardiography (ECG) may show heart rhythm disturbances
• Cardiac enzyme assay
• Blood tests which may reveal hyperglycemia in the event of severe poisoning.
• Chest x-ray looking for lesional edema.
• Pregnancy test in patients of childbearing age.
• Brain imaging whether another cause of altered state of consciousness must be excluded.

We must act very quickly!

What are the treatments for carbon monoxide poisoning?

Significant intoxication can lead to coma and death, sometimes within minutes. We must therefore act very quickly. Even more so when they occur in several people occupying the same room equipped with a combustion appliance and they disappear outside of it. In this case, it is essential

• immediately ventilate the room by opening doors and windows,
• ofevacuate the place
• if necessary call the emergency services by dialing 15 (SAMU), the 18th (the firefighters) or the 112 (European emergency number).
• otherwise call a Poison Control Center. They are available 24/7.

“In the event of poisoning without serious symptoms and if it is neither a child nor a pregnant woman, treatment is based on normobaric oxygen therapy at a very high concentration for at least 12 hours through an oxygen mask. If there are serious criteria (cardiac symptoms, loss of consciousness, etc.) or if it is a pregnant woman or a child, treatment is based on placement in a hyperbaric chamber“, explains Dr. Perez. Patients are then monitored in the hospital and warned of the risk of after-effects.

What are the after-effects and consequences after carbon monoxide poisoning?

Severe and untreated, carbon monoxide poisoning is fatal. Carbon monoxide poisoning can sometimes cause long-term neurological and cardiac after-effects which leave disabling symptoms. “It also increases thehe risk of developing cardiovascular disease in the following ten years“, adds our expert. There are also remote neurological symptoms, despite well-administered and monitored treatment. These can appear in patients who appear to have completely recovered from acute poisoning. They appear after a latency period. from two days to five weeks. so-called “postintervallar” syndrome manifested in particular by symptoms similar to those of Parkinson’s disease, such as chronic headaches, vision problems, mood changes or personality disorders.

• Systematically have heating and hot water production installations checked and maintainedas well as smoke ducts (mechanical chimney sweeping) by a qualified professional, before entering winter.
• Install a carbon monoxide detector. Unlike autonomous smoke alarm detectors (DAAF), mandatory since March 8, 2015, autonomous CO warning detectors (DAACO) are neither mandatory nor subject to construction product regulations. Make sure that the detector chosen is declared by the manufacturer compliant with European standard NF EN 50291 (this notice must appear on the product packaging). During the annual maintenance of your boiler, the qualified professional who intervenes is required to measure carbon monoxide to ensure that your installation does not emit carbon monoxide.
• Ventilate your home every day for at least 10 minuteseven if it’s cold.
• Check that the ventilation systems are in good working order.
• Never obstruct the air inlets and outlets.
• Strictly follow the instructions for using combustion appliances indicated by the manufacturer.
• Never operate auxiliary heaters continuously.
• It is imperative to place the generators outside buildings. In other words: never use a generator in a closed place (house, cellar, garage, etc.).
• Do not heat yourself with appliances not intended for this purpose (camping stoves, ovens, braziers, barbecues, etc.).

Thanks to Dr Noémie Perez, pediatrician.