Prevention and emergency treatment of non-occupational CO poisoning

 

Carbon monoxide (CO) is a colorless, odorless and non-irritating asphyxiant gas with a density slightly lower than that of air. Carbon monoxide in the environment is produced by incomplete combustion of carbon-containing substances, mainly during human activities.

 

CO poisoning happens when it is inhaled into the body through the respiratory tract. The affinity between CO and hemoglobin is 200 times that between oxygen and hemoglobin. When people stay in an environment with high concentration of CO, it will enter the blood through the respiratory tract and combine with hemoglobin to form carboxyhemoglobin, which blocks the release and transmission of oxygen, leading to hypoxemia and hypoxia of body tissues, even threatening life in serious cases.

Non-occupational CO poisoning

Non-occupational CO poisoning generally refers to the CO poisoning arising in the daily life of the public, which is different from those occur at production sites.

 

 

1. Households

According to national monitoring data in the past five years, 90.8 percent of non-occupational CO poisoning occurs in households. The main risk factors include:

(1) Using a coal stove, charcoal fire, kang (stove-heated bed), and fire-heated wall, for heating in a poorly ventilated environment.

(2) Improper use and installation of gas water heaters, especially if they are substandard products.

(3) Gas leak from gas stoves or gas pipelines.

2. Other places

The main risk factors of non-occupational CO poisoning in other places include:

(1) Improper use, installation or maintenance of heating appliances, gas storage and equipment, and ventilation devices in catering and accommodation service units such as canteens, restaurants and hotels.

(2) Improper installation and use of exhaust facilities or poor ventilation in restaurants serving charcoal hotpots.

(3) Using small fuel or gas-powered generators in narrow and enclosed garages or basements.

(4) Vehicle exhaust emission or staying in a closed air-conditioned vehicle for a long time.

 

 

The clinical manifestations of non-occupational CO poisoning are related to the concentration of carboxyhemoglobin in the blood, which can be classified as mild, moderate and severe based on the degree of poisoning.

 

（1） Mild poisoning

The concentration of carboxyhemoglobin in the blood is 10 - 20 percent. The main clinical symptoms are cerebral hypoxia, such as headache, tinnitus, dizziness, nausea, vomiting, and even transient loss of consciousness. People with coronary heart disease may experience angina pectoris. The symptoms can disappear quickly if the affected people leave the poisoning environment and get fresh air immediately, generally without sequelae.

 

（2） Moderate poisoning

The concentration of carboxyhemoglobin in the blood is 30 - 40 percent. In addition to the symptoms of mild poisoning, there are also other symptoms such as cherry-colored mucous membranes, flushed face, excessive sweating, accelerated pulse, confusion, unsteady walking, drowsiness, impaired judgment, hallucination, and corneal reflex dullness. 

（3） Severe poisoning

The concentration of carboxyhemoglobin in the blood has reached more than 50 percent. The affected people will develop symptoms like incontinence, cold limbs, pale lips, high body temperature, decreased blood pressure, and respiratory depression.

Prevention of non-occupational CO poisoning

 

1. Heating appliances (such as coal stoves and charcoal fire)

 

(1) Central heating should be a preferred choice in cold weather.

 

(2) When heating appliances such as coal stoves and charcoal fire are used indoors, the coal should be burned out and not covered. Doors and windows should be opened frequently to keep the indoor air fresh.

 

(3) Coal stoves should be installed with a chimney, and the chimney joint should be firmly connected along the stubble (the thick end of the chimney must face the coal stove) to prevent air leakage. It is better to open the chimney mouth in the downwind direction and extend the chimney out of the house.

 

(4)Correctly install and use coal stoves, charcoal fire and other heating appliances, regularly check the stoves and maintain and clean the chimney and air pipe, keeping them unblocked.

 

(5) Heating appliances such as coal stoves and charcoal fire should be far away from flammable, explosive and volatile toxic substances, and should not be placed in the bedroom. It is better to move the stove outside before going to bed at night.

 

(6) Under the meteorological conditions of low pressure and relatively high humidity, such as rain, snow and hail, it is better not to use heating appliances such as coal stoves and charcoal fire. When eating hotpot at home, it's better not to use coal or charcoal hotpot devices. If you use them, it's better to put them in a ventilated hall or keep the doors and windows open for ventilation.

 

(7) When heating appliances such as coal stoves and charcoal fire are used at home, it is better to install a carbon monoxide detector and regularly check and maintain it to ensure its normal operation.

 2. Gas-powered water heaters

 

(1) When purchasing gas-powered water heaters, products up to quality standards and produced by qualified manufacturers should be selected. They must be installed by professionals and can only be used after passing required tests.

 

(2) When using gas-powered water heaters, keep good ventilation, do not take too long to bathe or shower, and check whether the water heaters are completely turned off after use.

 

(3)Regularly check and repair the pressure-reducing valve and skin pipe of gas-powered water heaters, and replace them in time in case of damage, corrosion, gas leak and other problems.

 

(4) When using gas-powered water heaters at home, it is better to install carbon monoxide detectors and regularly check and maintain them to ensure their normal operation.

3. Gas cooking appliances and pipes

 

(1) When purchasing gas cooking appliances, products up to quality standards and produced by qualified manufacturers should be selected. They must be installed by professionals and can only be used after passing required tests. Do not change gas pipeline facilities without permission.

 

(2) When using gas cooking appliances, remember to keep an eye on them and avoid overflowing pans, which may put out the fire and result in gas leak. Remember to make sure the cooking appliance is completely turned off after using it.

 

(3) Regularly check the gas tank, pressure-reducing valve, leather pipe and gas pipeline of the cooking appliance. In case of worn-out, damaged, and rusty parts, or gas leak, replace and repair the relevant parts immediately.

 

(4) When using gas cooking appliances at home, it is better to install carbon monoxide detectors and regularly check and maintain them to ensure their normal operation.

4. Dining stoves (i.e., charcoal hotpots)

 

(1) An exhaust hood should be equipped above the charcoal stove, and be installed and regularly maintained by professionals.

 

(2) Open doors and windows to keep the indoor air fresh, and avoid dining in an airtight compartment for a long time.

 

5.Small fuel or gas-powered generators

 

Do not use small fuel or gas-powered generators indoors, in garages or basements. Use them only outdoors and keep away from doors and windows as well as ventilation and exhaust outlets.

 

6.Vehicles

 

(1) When a vehicle is parked in a garage or basement, do not let the engine run continuously. When the car is switched off, do not leave the air conditioner on for a long time, and do not sleep in the car with doors and windows closed and the air conditioner on.

 

(2) Regularly check the exhaust system of the vehicle to prevent carbon monoxide leakage.

Principles for non-occupational CO poisoning treatment

 

Cut off sources of carbon monoxide

 

1. First, open a window immediately for ventilation to flush the air, and quickly turn off gas stoves, water heaters, pipeline gas, and put out charcoal fire.

 

2. Avoid using lighters or objects that can easily produce sparks.

 

Get out of the poisoning environment immediately

 

1. Quickly remove the patient from the poisoning site to a place with fresh air and good ventilation.

 

2. Loosen the collar buttons of the patient and keep their respiratory tract unobstructed.

 

3. The patient should take a rest so as not to consume too much oxygen, and should be given medical oxygen as soon as possible.

 

4. For moderately and severely poisoned patients, when on-site first aid is given, emergency medical help (dial the number 120) should be called immediately and the patient should be sent to a hospital equipped with a hyperbaric oxygen chamber as soon as possible.

 

5. For critically ill patients with respiratory and cardiac arrest, artificial respiration and cardiac compression should be given immediately, and at the same time they should be quickly transferred to the hospital for emergency treatment.