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As soon as possible, place the CO alarm back in its proper location to assure continuous protection from carbon
6.6
monoxide poisoning.
6.7
When household cleaning supplies or similar contaminants are used, the area should be ventilated.
WARNING! The following substances can affect the sensor and may cause false actions: methane, propane,
isobutene, isopropanol, ethylene, benzene, toluene, ethyl acetate, hydrogen sulfide, sulfur dioxides, alcohol-based
products, paints, thinner, solvents, adhesives, hair sprays, after shaves, perfumes, and some cleaning agents.
WARNING! Your CO alarm will not be operational and will not monitor for CO levels without battery.
WARNING! This apparatus is designed to protect individuals from the acute effects of carbon monoxide exposure. It
will not fully safeguard individuals with specific medical conditions. If in doubt consult a medical practitioner.
7.
CARBON MONOXIDE (CO) OVERVIEW
7.1
Toxic effects
Carbon monoxide (CO) is a colorless, odorless, nonirritating gas classified as a chemical asphyxiant and whose toxic
action is a direct result of the hypoxia produced by a given exposure. CO is rapidly absorbed through the lungs,
diffuses across the alveolar capillary membrane, and is reversibly bound with hemoglobin as carboxyhemoglobin
(COHb) however, a minute amount is present in the plasma. The affinity of hemoglobin for CO is over 200 times its
affinity for oxygen. This reduces the oxygen carrying capacity of the blood, and influences the dissociation of
oxyhemoglobin, which further reduces the oxygen supply to the tissues. CO is chemically unchanged in the body and
is eliminated in expired air. The elimination is determined by the same factors that applied during absorption. The
half-life while breathing room air is 2h - 6,5 h depending on the initial COHb level. If the CO level in the inhaled air is
constant, the level of COHb in the blood will approach an equilibrium (saturation) state after several hours. However,
the rate at which the equilibrium is reached depends on many factors, e.g., lung ventilation rate (physical activity)
and alveolar capillary transfer, cardiac parameters, blood hemoglobin concentration, barometric pressure, oxygen,
and carbon dioxide concentration in the inhaled air, but the two most important factors in determining the COHb
level are the CO concentration and the duration of exposure.
The effects of different saturation blood COHb levels on healthy adults:
% COHb
0.3 - 0.7
0.7 - 2.9
2.9 - 4.5
4
- 6
7
- 10
10
- 20
20
- 30
30
- 40
40
- 50
60
- 70
Source: U.S. Environmental Protection Agency 1984
The relationship between the CO concentration and the duration of exposure can be calculated for a given %COHb,
by parameterizing the above factors.
7.2
Chronic effects on high-risk groups
Individuals with coronary artery disease exposed to low levels of CO show reduced ability to exercise and the time of
onset of exercise-induced angina pectoris in such patients exposed to low levels of CO is reduced. Carbon monoxide
readily crosses the placental barrier and may endanger the normal development of the foetus. Several high-risk
groups are particularly sensitive to the effects of CO because of various organ impairments or specific changes,
mainly:
a)
those whose oxygen carrying capacity is decreased due to anemia or other hemoglobin disorders.
b)
those with increased oxygen needs such as those encountered in fever, hyperthyroidism, or pregnancy.
c)
those with systemic hypoxia due to respiratory insufficiency.
d)
those with heart disease and any vascular insufficiency.
Effects
Normal range in non-smokers due to endogenous CO production
No proven physiological changes
Cardio-vascular changes in cardiac patients
Usual values observed in smokers, impairment in psychomotor tests
Cardio-vascular changes in non-cardiac patients (increased cardiac output and coronary blood flow)
Slight headache, weakness, potential burden on foetus
Severe headache, nausea, impairment in limb movements
Severe headache, irritability, confusion, impairment in visual acuity, nausea, muscular weakness,
dizziness
Convulsions and unconsciousness
Coma, collapse, death
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