WASHINGTON

Hello and welcome to Carbon Monoxide Poisoning Prevention Clinical
Education.

I'm Joe Washington, your moderator for this program which is originating
from the studios of the Centers for Disease Control and Prevention in
Atlanta, Georgia.

The CDC works with national and state data sources to monitor, evaluate,
and present information on carbon-monoxide-related illness and death in
the United States. It also monitors and evaluates surveillance data on
carbon monoxide-related illness and death, and works with state and
local agencies to respond to carbon monoxide -related issues.

The goal of this program is to enhance recognition and clinical
management of carbon monoxide poisoning by clinicians, healthcare
providers and public health officials.

Upon successful completion of the program, participants should be able
to:

-   Describe the epidemiology of Carbon Monoxide poisoning

-   Identify the mechanisms of Carbon Monoxide toxicity

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-   Describe the clinical aspects of Carbon Monoxide poisoning

-   Identify the symptoms of Carbon Monoxide poisoning

and

-   Explain the treatment of Carbon Monoxide poisoning

If you would like to apply for continuing education credit for this
webcast, please visit our online system at

www2a.cdc.gov/TCE Online

and enter course number WD1233. The last day to receive credit for this
program is September 20, 2010.

If you would like to review this program at a later date or share it
with a colleague, please note the web address:

[www2a.cdc.gov/phtn/webcast/COPoisonPrev.]{.underline}

Finally, if you have any questions or comments concerning this webcast,
please e-mail us at [coinq@cdc.gov]{.underline}

Now...today's web cast addresses the issue of Carbon Monoxide poisoning.

Carbon Monoxide is known as the "silent killer" because it is a
colorless, odorless, tasteless and non-irritating gas.

It is produced by burning materials containing carbon, such as gasoline
or propane. So, carbon monoxide is often associated with fire or smoke.
Yet, it is not detected by smoke alarms and it can be present even if
there is no fire or smoke.

Because a small, non-polar carbon monoxide molecule can penetrate
through standard drywall, it can pass through dwellings quickly, yet
quietly. Carbon monoxide can disperse through separate units of a
multi-family complex, and, with a density similar to air, distribute
itself throughout an enclosed area.

You can't see it, smell it or taste it, but it can make you sick or even
kill you.

To help us learn more about Carbon Monoxide poisoning, we are fortunate
today to have a distinguished panel of some of the nation's leading
experts on this potentially deadly toxicant.

First, I'd like to welcome Dr. Neil B. Hampson, Medical Director of the
Center for Hyperbaric Medicine at Virginia Mason Medical Center in
Seattle, Washington.

Dr. Hampson is a member of CDC's National Carbon Monoxide Environmental
Public Health Tracking Surveillance Group.

Our next guest is Dr. Eric J. Lavonas, Director of Medical Toxicology
Hospital Services and Medical Director of Hyperbaric Medicine at
Carolinas Medical Center in Charlotte, North Carolina.

Dr. Lavonas is also co-principal investigator of a multi-center CDC
carbon monoxide poisoning screening trial.

And, finally, we welcome Dr. Allison Stock, a toxicologist with the
National Center for Environmental Health at the Centers for Disease
Control and Prevention. Dr. Stock co-leads the agency's Carbon Monoxide
activity.

Welcome to the program.

All over the country, you can hear and read stories daily about carbon
monoxide poisonings.

From Seattle, Washington, after a windstorm:

"One hundred in Northwest stricken by fumes; Carbon Monoxide blamed for
two deaths."

From southern states after Hurricane Katrina, "Exhaust from portable
generator adds to loss of life."

Or from Blacksburg, "21 Virginia Tech Students get carbon monoxide
poisoning from a gas heater leak."

Dr. Allison Stock, whose expertise is in the epidemiology and toxicology
of carbon monoxide poisoning, will tell us just how widespread this
problem really is..

STOCK

Thank you, Joe.

Carbon monoxide is a toxic gas produced from the incomplete oxidation of
carbon during combustion.

Carbon monoxide poisoning kills more Americans every year than any other
acute toxicant. Annually, there are approximately 3800 deaths from fires
or other sources of carbon monoxide. However, 2400 are *intentional* or
suicides.

There are roughly 500 non-fire, unintentional deaths a year. Carbon
monoxide poisoning stands as the third leading cause of unintentional
poisoning death in the United States. In addition, there at least 50,000
cases of non-fatal acute carbon monoxide poisoning annually.

Victims of carbon monoxide poisoning account for thousands of Emergency
Room visits.

A recent study by Dr. Hampson extrapolates state rates for Emergency
Department visits for carbon monoxide poisoning to the 2005 United
States population census. With this updated information, the national
average for Emergency Department visits per year is approximated at
50,000. Even with this revised estimate; however, the impact may still
be underestimated, as carbon monoxide poisoning is notorious for being
under diagnosed.

Most of the people who attempt suicide by carbon monoxide poisoning are
men who poison themselves with automobile exhaust. Sadly, 69% of these
attempts are successful.

On the bright side, we believe that through public education and
regulation, we can prevent almost all of the thousands of unintentional
carbon-monoxide poisonings and deaths that occur each year.

One of the difficulties in that public education process is reaching
those who actually are at higher risk \-- immigrants and minorities.
Studies have shown that they are disproportionately affected by carbon
monoxide, especially after power outages, when gasoline-powered
electrical generators or gas or charcoal briquettes may be
inappropriately used.

Men are affected more often than women. Although males and females are
equally likely to visit emergency departments for CO exposure, males are
more than twice as likely to die from CO exposure. Males might be
exposed to high CO levels during high risk activities such as working in
enclosed garages with generators or power tools. The most impacted age
range is 25 to 44-years-old.

Because of their rapid respiratory rate, infants and children take up
carbon monoxide from their environment more quickly than do adults.

As with almost any poisoning, the elderly are more vulnerable to the
effects of carbon monoxide poisoning.

So are people who have chronic heart disease, anemia or respiratory
illness.

The death rate from Carbon Monoxide poisoning is highest among those
over 75-years-old, and the elderly are at greater risk for adverse
neurological outcomes. Animals are also affected.

Motor vehicles are still a leading source of Carbon Monoxide poisoning.
Incidents involving cars and trucks can be caused by exposure to exhaust
while riding in the back of pick-up trucks, which most often impacts
children; obstruction of the tailpipe by snow or other objects; as well
as malfunctioning systems.

Unintentional carbon monoxide poisoning death rates declined by 80%
since the introduction of the catalytic converter in 1975 and reduced
carbon monoxide emissions. Today, the leading source of non-fire,
unintentional Carbon Monoxide poisonings are from home heating sources
such as furnaces, water heaters, space heaters, lanterns, stoves and
similar appliances.

Smoke inhalation from fires is another important source. So are large
and small engines, including boats, power washers and other gas-powered
tools.

Carbon monoxide poisonings most often occur in enclosed and
semi-enclosed environments where the carbon monoxide can build up.

However, poisoning can also happen in the open air. Carbon monoxide
related morbidity and mortality has been reported to arise with the
exposure to exhaust from gasoline-powered electrical generators on
houseboats as well as direct exposure to carbon monoxide in the exhaust
of a ski boat, from either the swim platform or even among persons
seated in the stern of the boat. Other boating accidents involving
carbon monoxide can result from improper ventilation; back-drafting when
operating a boat at a high angle; or even mooring next to a boat with
its engine running.

Some poisonings are job-related. Employees may be exposed to carbon
monoxide through work with combustion engines or combustible gases,
propane-fueled forklifts,

in plants producing formaldehyde or coke, at steel foundries or pulp
mills, or at the scene of a fire.

From the headlines Joe mentioned, however, you can see that carbon
monoxide poisoning makes the news most often after a power outage, when
loss of electrical power leads to increased use of gasoline-powered
generators, kerosene space heaters, charcoal and hibachi grills, propane
stoves and charcoal briquettes for both cooking and heating indoors.

The use of these alternative fuels and heating devices may be
exacerbated by the use of plastic film or other devices designed to cut
air circulation between the inside and outside.

The location of the generator is a key factor. Those who suffer carbon
monoxide poisoning are most often exposed to a generator kept in a
garage, under a deck, near a window, in a shed, in a carport or in a
basement.

Except for space heaters, *none* of these devices should *ever* be used
inside the home, even in the basement or garage, in a camper or tent, or
even outside near an open window.

Carbon monoxide poisoning is seasonal and can vary by the region of the
country. Over 80% of the carbon monoxide deaths are from home heating
sources such as gas furnances.

As you would expect, in the northern region of the country, most carbon
monoxide poisoning cases occur during the winter heating season, when
there is a greater use of furnaces, charcoal briquettes, and generators.

People may also "warm up" their vehicles in the garage before heading
out into the weather.

In the south, however, power outages most often occur in early autumn,
especially August and September, during hurricane and thunderstorm
season.

CDC investigations in Alabama and Texas following Hurricane Katrina in
2005 found 27 incidents of carbon monoxide poisoning, resulting in 78
nonfatal cases and 10 deaths.  Nearly all were caused by
gasoline-powered generators.

A similar study that again included Alabama, but added Louisiana and
Mississippi, found 51 cases, all but one due to exhaust from a portable
generator. Most occurred within the first week after the hurricane.

## The use of auxiliary fuels and heating devices when there is a heating fuel shortage is a trend which continues to have an ominous potential for increasing exposure to carbon monoxide and its hazard to health.

## WASHINGTON

## Now that we understand the source of carbon monoxide poisoning, Dr. Stock, could you explain the process by which carbon monoxide poisoning occurs in the body. 

## Sure Joe. 

## Carbon Monoxide produces its toxic effects by several important mechanisms. 

## Carbon monoxide enters the body through the lungs, where it binds reversibly to [**hemoglobin**](http://en.wikipedia.org/wiki/Hemoglobin), the principal oxygen-carrying compound in the blood, and in the process, it reduces the blood's oxygen carrying capacity. 

## It binds tightly to the iron sites in hemoglobin, with an affinity 200 to 250 times that of oxygen. This enhanced affinity and impaired oxygen binding is referred to as "the Haldane effect."

When Carbon Monoxide binds to hemoglobin, it produces
[carboxyhemoglobin](http://en.wikipedia.org/wiki/Carboxyhemoglobin),
which inhibits the transport, delivery, and utilization of oxygen. The
levels of oxygen normally released to the tissues are decreased.

Blood oxygen content is decreased in carbon monoxide poisoning,
resulting in tissue hypoxic injury.

Carbon Monoxide also produces tissue toxicity from its avid binding to
intracellular proteins such as myoglobin, the cytocrome a-a~3~ complex
or cytochrome oxidase of the mitochrondrial respiratory chain and
guanylate cyclase.

When Carbon Monoxide binds to
[myoglobin](http://en.wikipedia.org/wiki/Myoglobin), it impairs the
ability of certain tissues, such as the heart, to take up oxygen.
Myoglobins affinity for Carbon Monoxide is approximately 30 to 60 times
greater than that for oxygen.

Binding of Carbon Monoxide to cytochrome oxidase disrupts cellular
respiration and oxygen utilization in all tissues, including the brain.
This binding interferes with the aerobic metabolism and efficient
[adenosine
triphosphate](http://en.wikipedia.org/wiki/Adenosine_triphosphate) or
ATP synthesis. Cells respond by switching to anaerobic metabolism,
causing a lack of energy supply, lactic acidosis, and eventually, cell
death.

Carbon Monoxide causes endothelial cells and platelets to release
[nitric oxide](http://en.wikipedia.org/wiki/Nitric_oxide), and the
formation of nitric oxide derived oxidants, such as peroxynitrate. This
results in endothelial injury and leukocyte sequestration.

The end result is lipid peroxidation by neutrophils, degradation of
unsaturated fatty acids, which can cause delayed demyelinization of
[white matter](http://en.wikipedia.org/wiki/White_matter) in the central
nervous system, cellular swelling and cell and tissue death in certain
areas within the brain.

The brain damage that occurs after recovery from the acute poisoning may
result in cognitive defects, affecting memory, learning and movement.
These delayed neurological effects may develop over days to weeks
following the initial acute poisoning.

WASHINGTON

Thank you, Dr. Stock for covering the epidemiology, demographics and
etiology of Carbon Monoxide poisoning. We now turn to Dr. Lavonas, an
Emergency Room physician, to give us a detailed look at how to diagnose
Carbon Monoxide poisoning in various populations.

#### 

LAVONAS

Thanks, Joe.

The signs and symptoms of carbon monoxide poisoning are variable and
non-specific, so that, unfortunately, many cases go undiagnosed. One
study estimates the rate of missed diagnosis to be as high as 30%.

The most common symptoms in victims of carbon monoxide poisoning are
headache, dizziness, fatigue, nausea or vomiting, trouble thinking,
diarrhea, weakness and shortness of breath.

Unfortunately, these symptoms can also point to viral illness, a benign
headache, or gastroenteritis. In fact, food poisoning was found to be
the most common misdiagnosis in one study.

Some older reports, primarily from autopsy findings, reported that
carbon monoxide poisoning causes cherry-red discoloration of the skin.
In fact, this almost never occurs. Cherry-red skin is rarely noted, even
in the most severe cases of carbon monoxide poisoning.

"Red flags" should raise the provider's attention to do further testing
for Carbon Monoxide poisoning.

First, if a patient complains of headache, nausea, vomiting, or other
common symptoms that could be due to viral syndrome or carbon monoxide
poisoning, but does not have a fever, carbon monoxide poisoning should
be considered.

With a focused history, exposure to a Carbon Monoxide sources may become
apparent. In addition, if a group of patients present with similar
complaints, particularly if no fever is present, Carbon Monoxide
poisoning should be suspected.

Severe Carbon Monoxide poisoning is less difficult to diagnose. In
addition to symptoms, patients develop hard signs of neurological,
cardiovascular and pulmonary dysfunction.

For example, in addition to headache and subjective trouble thinking,
patients may show confusion, slowed thought processing,

irritability, ataxia, seizures, or loss of consciousness.

Cardiovascular involvement may result in hypotension, arrhythmias and
even myocardial ischemia or infarction.

Respiratory distress might include pulmonary edema, tachypnea or
respiratory arrest.

In general, any organ can be affected by Carbon Monoxide poisoning.

Unfortunately, people who are sleeping or intoxicated from drugs or
alcohol can die from carbon monoxide poisoning before ever exhibiting
symptoms.

WASHINGTON

So, Dr. Lavonas, with Carbon Monoxide poisoning being difficult to
diagnose, can you give us some insight on diagnostic testing available
to rule out or confirm the diagnosis?

LAVONAS

The diagnosis of Carbon Monoxide poisoning is based on a suggestive
history and physical finding coupled with confirmatory testing.

Patients should be examined for other conditions, including smoke
inhalation, trauma, medical illness, or intoxication. All women of
childbearing age, who are suspected of having Carbon Monoxide poisoning
should have a pregnancy test.

A neurological examination should include an assessment of cognitive
function. For routine clinical use, a mini-mental status exam, which
takes only five to seven minutes, is adequate. However, there are some
special neuropsychological batteries that have been developed to detect
the subtle impairment in Carbon Monoxide poisoning victims that might be
missed by routine neurological testing.

These tests, however, can be somewhat cumbersome, requiring 30-45
minutes. They must be administered in a quiet area. The patient must be
literate and fluent in English and over age 15. Most clinicians simply
use a good, detailed neurological examination along with an assessment
of cognitive function.

Appropriate, prompt diagnostic testing is very important. The key to
confirming the diagnosis is measuring the patient's carboxyhemoglobin
level.

It is important to know how much time has elapsed since the patient has
left the toxic environment, because that will impact the
Carboxyhemoglobin level. If the patient has been breathing normal room
air for several hours, Carboxyhemoglobin testing may be less useful.

An elevated Carboxyhemoglobin, which is defined as 2% for non-smokers or
greater than 9% for smokers, strongly supports exposure to Carbon
Monoxide and the diagnosis of Carbon Monoxide poisoning. An elevated
blood carboxyhemoglobin level can advance a case from "probable" based
on clinical groups to "confirmed."

Carbon Monoxide levels can be tested either in whole blood or exhaled
air. Blood should be collected is a closed heparinized container and
sent to a lab.

If there are several patients from the same environment, sometimes only
the most seriously affected need be tested. Getting lab results can take
a significant amount of time, even more so if the lab is outside the
hospital. That delay can be detrimental.

The most common technology available in hospital laboratories for
analyzing the blood is the multiple wavelength spectrophotometer, also
known as a CO-oximeter. It measures carboxyhemoglobin as a percentage of
the total hemoglobin. Because a lab co-oximeter can cost \$20,000, not
all hospital laboratories have them.

Most lab co-oximeters can be used to measure arterial blood gases. This
leads to the common misconception that carboxyhemoglobin should be
measured in arterial blood. This is not necessary and subjects patients
to unnecessary risks and pain associated with arterial puncture. Venous
samples are just as good. Venous blood can be placed into a blood gas
syringe or any heparin containing blood sample tube and analyzed on the
co-oximeter. The levels in venous and arterial samples are equivalent.

If carboxyhemoglobin measurement is unavailable in the treating
facility, the patient suspected of having carbon monoxide poisoning may
be acutely transferred to a facility where it is available.

It is suggested that a blood sample be drawn first and sent with the
patient to the receiving hospital. Recent data reported by Dr. Hampson
indicates that human blood stored in vials containing the anticoagulant
heparin remains stable. In fact, carboxyhemoglobin levels in whole blood
samples with heparin are stable with or without refrigeration for up to
four weeks, whether the vial is shipped or transported with the patient.

While we do not recommend shipping the blood sample because of the time
delay, we do recognize that it does happen.

The conventional two-wavelength pulse oximeter is not accurate when
carboxyhemoglobin is present.

Recently, the Food and Drug Administration approved a four-wavelength
pulse oximeter that solves this problem. In addition to measuring heart
rate and oxygen saturation, this new device measures carboxyhemoglobin
levels, all in just a few seconds.

We're hoping that this new technology will bring the capability to
measure caboxyhemoglobin levels to more hospitals. This would speed
diagnosis, reduce the number of misdiagnosed cases, and reduce the need
to send our lab samples for analysis.

While carboxyhemoglobin levels do confirm the diagnosis of Carbon
Monoxide poisoning, it is important to note that severity of illness,
rather than Carboxyhemoglobin levels, should be used to determine the
type and intensity of treatment.

Carboxyhemoglobin levels do not correlate well with severity of illness,
outcomes or response to therapy.

It is also important to note that carbon monoxide can be produced
endogenously as a byproduct of heme metabolism.

It is possible, therefore, for a patient to have an elevated
carboxyhemoglobin level as a result of hemolytic anemia or homolysis due
to sickle cell disease.

Another approach that is occasionally used to document exposure is
measurement of exhaled carbon monoxide with a breath analyzer.
Sometimes, breath analysis can be difficult, since patient cooperation
is needed. This may be complicated in the case of young children or
patients whose mental status is altered.

Normal exhaled air is 0 -- 6 parts per million for non-smokers and up to
70 parts per million for smokers.

Measuring environmental air is yet another consideration. Many fire
departments have the equipment to do these measurements. More than 50
parts per million of carbon monoxide merit further investigation. More
than 100 will likely cause acute symptoms with sufficient exposure time.

In a 2005 study in the Journal of the American College of Cardiology, it
was found that cardiovascular sequelae of Carbon Monoxide poisoning were
relatively frequent, with 37% of patients who were assessed experiencing
a myocardial injury.

So, in patients with severe Carbon Monoxide poisoning, it may be
important to perform an EKG and measurement of blood cardiac markers.

That study showed that patients with Carbon Monoxide poisoning who
develop cardiac enzyme elevations and/or EKG changes have an increased
risk for mortality over the next few years, even with aggressive
treatment. The exact reason for this is unknown.

Unfortunately, right now we do not know which of these patients, if any,
need stress testing, echocardiography, or cardiac catheterization.

An increase in angina can be seen with mild elevation of
Carboxyhemoglobin levels in patients with pre-existing angina. An
increase in arrhythmias in patients with coronary artery disease has
been noted at Carboxyhemoglobin levels of 6%. Severe Carbon Monoxide
poisoning can cause myocardial infarction, even in patients with normal
coronary arteries.

Chest radiography is recommended for seriously poisoned patients,
especially those with loss of consciousness or cardiopulmonary signs and
symptoms.

Brain computed tomography or MRI is also recommended in these cases;
these tests may show signs of cerebral infarction secondary to hypoxia
or ischemia.

To summarize, the diagnosis of Carbon Monoxide poisoning is best made
when an elevated Carboxyhemoglobin level is documented concurrently with
a history, signs and symptoms suggestive of poisoning.

Other testing, such as a fingerstick blood sugar, head CT scan or lumbar
puncture may be needed to exclude other causes of altered mental status
when the diagnosis of Carbon Monoxide poisoning is inconclusive.

WASHINGTON

Thanks, Dr. Lavonas, for walking us through the diagnostic process. We
now turn to Dr. Hampson, who will tell us about the options available to
treat Carbon Monoxide poisoning.

Thanks, Joe. As soon as the first responder or medical practitioner
evaluating the patient suspects the diagnosis of Carbon Monoxide
poisoning, two very important actions should be taken immediately.

One, it is essential to evacuate the area, ventilate the environment and
attempt to determine the source.

The patient and anyone else in the vicinity where the patient was
exposed to carbon monoxide should be removed from that environment and
taken to a safe location. Carbon Monoxide uptake ceases as soon as the
person is removed from the contaminated environment.

The Fire Department may be called to handle that job. No form of
decontamination is required.

Two, 100% oxygen by a tight-fitting face mask should be administered.
This is fundamental to speeding the elimination of carbon monoxide and
improving the delivery of oxygen to affected tissues.

Oxygen therapy is safe, inexpensive, and convenient and greatly enhances
the rate of Carbon Monoxide elimination.

Oxygen therapy should continue until the patient is symptom-free, which
is achieved in about four (4) to five (5) hours for most patients. The
carboxyhemoglobin level should go down to the normal range.

Repeat carboxyhemoglobin measurements are almost never necessary.

For victims of moderate to severe Carbon Monoxide poisoning, the
majority of American experts recommend Hyperbaric Oxygen therapy. It is
estimated that approximately 6 percent of patients suffering from Carbon
Monoxide poisoning who present to hospital Emergency Departments are
treated with Hyperbaric Oxygen, or about 1500 patients per year.

The Undersea and Hyperbaric Medical Society recommends hyperbaric oxygen
therapy for carbon monoxide poised individuals with the greatest
mortality and morbidity risks.

Hyperbaric oxygen should be considered when a patient has one or more of
the following:

-   A carboxyhemoglobin level of more than twenty five to thirty percent

-   Evidence of cardiac involvement

-   Severe acidosis

-   Transient or prolonged unconsciousness

-   Neurological impairment

-   Abnormal neuropsychiatric testing

> A recently published study suggested that people 36-years-old and
> older are at higher risk for long-term cognitive sequelae and,
> therefore, Hyperbaric Oxygen therapy should be considered. In cases of
> milder poisoning, Hyperbaric Oxygen should be considered if surface
> pressure oxygen does not resolve symptoms.
>
> Clinical studies have proven the efficacy of Hyperbaric Oxygen therapy
> in treating Carbon Monoxide poisoning, as assessed by neurocognitive
> testing. In animal models, studies have demonstrated that hyperbaric
> oxygen impacts a number of the other mechanisms of Carbon Monoxide
> toxicity, in addition to enhancing carboxyhemoglobin elimination.

These include:

-   Decreased platelet aggregation and degranulation

-   Decreased neuotrophil chemotaxis

-   Decreased rise in Nitric Oxide levels

-   Clearly demonstrated antioxidant properties

-   Increased dissolved oxygen content in blood

-   Prevention of lipid peroxidaton in the brain; and

-   Preservation of ATP levels in tissue exposed to Carbon Monoxide

> Normally, a single Hyperbaric Oxygen therapy treatment is sufficient
> to render the patient asymptomatic. The optimal number of treatments
> is not known.
>
> A 2002 study in the *New England Journal of Medicine* demonstrated
> that three (3) Hyperbaric Oxygen therapy sessions within twenty-four
> (24) hours reduces the rate of cognitive sequelae when tested both at
> six (6) weeks and even twelve (12) months later, as compared to
> normobaric oxygen. In practice, most hyperbaric practitioners in the
> United States administer one treatment and then provide additional
> treatments if the patient remains symptomatic.

Compared to normobaric mask oxygen therapy, Hyperbaric Oxygen therapy:

-   eliminates Carbon Monoxide from the body more rapidly;

-   improves tissue oxygenation; and

-   reduces the rate of subsequent cognitive dysfunction.

The number of patients treated with hyperbaric oxygen therapy for carbon
monoxide poisoning has not changed significantly in the United States
over the last decade.  Because the number of hyperbaric facilities
treating the condition has increased, the average number of patients
treated per facility has decreased.

However, some issues remain.

While the majority of experts in this country recommend hyperbaric
oxygen therapy for treatment of severe carbon monoxide
poisoning, outside the United States, this treatment remains
controversial.

The criteria for defining which patients are most likely to benefit is
still evolving, sometimes making it difficult for practitioners to make
the treatment decision. Further complicating the matter is that most
hospitals don't have Hyperbaric Oxygen treatment facilities. So, there
can be logistical issues related to transfer as well as added expense.

Therefore, we would advise practitioners considering Hyperbaric Oxygen
therapy to consult with their local experts in making that decision.

Hyperbaric Oxygen *is* the treatment of choice for pregnant women, even
if they are less severely poisoned. Hyperbaric Oxygen is safe to
administer and international consensus favors it as part of a more
aggressive role in treating pregnant women.

Carbon Monoxide moves slowly across the placenta, thus its elimination
from both the mother and the fetus takes roughly twice as long. If mask
oxygen is used, the duration should be doubled.

It is suspected that the fetus may be more susceptible to Carbon
Monoxide poisoning and that miscarriage might result from Carbon
Monoxide poisoning.

Generally, patients with Carbon Monoxide poisoning can be released from
the hospital after four to six hours of oxygen therapy if they are
neurologically normal, have no more than mild symptoms and have no other
unmet medical or psychiatric needs. However, the long-term outcomes are
still uncertain.

In one prospective study, thirty-three percent (33%) of patients not
treated with hyperbaric oxygen had cognitive sequelae and eighteen
percent (18%) had sequellae despite treatment with hyperbaric oxygen.

In addition, forty-three percent (43%) of poisoned patients exhibited
affective problems one year following poisoning.

It also appears that cardiac injury at the time of poisoning increases
the risk of mortality over the following ten (10) years.

All discharged patients should be warned of possible delayed
neurological complications and given instructions on what to do if these
occur. Follow-up should include a repeat medical and neurological
examination in one or two weeks.

Most patients, but not all, will resolve to normal. For some, it will
take weeks, for others, months. But thousands of Carbon Monoxide
poisoned patients will develop lasting signs of brain injury, most
commonly cognitive and personality changes. and some may even develop
Parkinsonism.

Researchers are working to develop antidotes other than hyperbaric
oxygen that can prevent brain injury from carbon monoxide poisoning.
 They are focusing on drugs and chemicals that block the production of
nitric oxide, or that interfere with the biological process of
apoptosis. Apoptosis is a controlled dying-back of undesired cells. It
is a natural process; for example, it is through apoptosis that the
webbed hands and gill slits we all had during fetal development go away
before we are born.

Carbon monoxide poisoning triggers apoptosis, and apoptosis inhibitors
protect against carbon monoxide poisoning in laboratory animals. 
Although most of these chemicals are too toxic to use in man, several do
show promise.  Research is ongoing and we are hopeful of adding new
treatment methods to our arsenal.

WASHINGTON

Thank you, Dr. Hampson, for summarizing the treatment options for Carbon
Monoxide poisoning and the issues surrounding them.

As public health officials and practitioners who see the potentially
devastating effects of Carbon Monoxide poisoning, I am sure you would
like to know what can be done to prevent this problem.

We've asked Dr. Lavonas to give us some insights into steps that can be
taken to prevent Carbon Monoxide poisoning.

LAVONAS

Thanks, Joe.

The vast majority of carbon monoxide poisoning cases are nonfatal. Even
when appropriately treated, however, carbon monoxide poisoning may
result in significant sequelae. Therefore, prevention is extremely
important.

Dr. Hampson emphasized that when a Carbon Monoxide poisoning case is
confirmed, one of the first courses of action is to find the source and
remove everyone from the environment. That action, along with an active
search for secondary cases, is critical to prevention. It is a red flag
that signals an emergency that requires immediate action.

Since we recognize many of the sources of Carbon Monoxide poisoning and
the time of year when they most often occur in various regions, it makes
sense to target public education programs. Storm-related carbon monoxide
poisonings are common, predictable and likely very preventable.

Public service messages in local media can be tied to the appropriate
season, such as before and during cold weather, when indoor heating is
used more often, or to the peak season for storms.

TV Weather Channels and reporters should be educated in advance to
include warnings about Carbon Monoxide exposure risks as storms
approach. This is a valuable public service. Radio broadcasts are most
effective, especially when the electricity goes out and people are
either stranded in cars, or using battery-powered radios at home. Sample
public service announcements are available on the CDC's website.

It is essential that these messages be multilingual to reach immigrants
and minorities, as they are the people who most often fall victim to
Carbon Monoxide poisoning during power outages.

In addition to news media, electrical utility companies and governmental
agencies can help promulgate warnings with regard to carbon monoxide
both when power outages are expected and soon after they occur.

When there is a power outage after a storm, most carbon
monoxide poisonings occur on the second and third days two or three
after the storm. This suggests that there is a window of time for
effective communications regarding the dangers of carbon monoxide
poisonings even after a storm strikes.

There are many simple steps people can take in their homes to prevent CO
poisoning.

For example, with home appliances, people should have their heating
system, water heater and any other gas, oil, or coal burning appliances
serviced by a qualified technician every year.

   

Service experts should also be called in if an odor from a gas
refrigerator\'s cooling unit is detected. That could mean there is a
defect in the cooling unit which could be giving off carbon monoxide.

When purchasing gas equipment, people should only buy equipment carrying
the seal of a national testing agency, such as the American Gas
Association or Underwriters\' Laboratories.

Appropriate venting of gas appliances in a home, cabin or camper can
help avoid carbon monoxide build-up.

Indoor vent pipes should not be perfectly horizontal; they should go up
slightly as they go toward outdoors. This helps prevent carbon monoxide
or other gases from leaking if the joints or pipes aren\'t fitted
tightly. Patching of vent pipes with tape, gum or other products may
allow the carbon monoxide to vent out of the system.

Chimneys should also be checked or cleaned every year to be sure they
are not blocked by debris.  

People can also avoid carbon monoxide build-up in their cars, by having
a mechanic check the exhaust system every year. Just a small leak in a
car\'s exhaust system can lead to an increase in carbon monoxide inside
the car.

Changing government regulation is another approach that could have a
major impact in carbon monoxide poisoning prevention.

Unintentional carbon monoxide poisoning death rates declined by 80%
since automobiles were required to have catalytic converter and carbon
monoxide emissions were reduced.

Introducing emissions control devices to propulsion engines on
recreational boats could also help to reduce carbon monoxide
concentration in the exhaust, thus reducing the risk of carbon monoxide
poisoning.

Until that happens, recreational boaters should turn off the motor
before swimming or body surfing. Exposure to the exhaust system while
the engine or generator is running can expose the swimmer to carbon
monoxide.

Inexpensive Carbon Monoxide alarms have been available since 1989.
However, they are not currently required in boats, automobiles or most
businesses. Many local governments have started to require them in
homes.

For example, in my home community of Mecklenburg County, North Carolina,
cases of severe carbon monoxide poisoning were nearly eliminated after
the passage of a health ordinance that requires all homes to have a
carbon monoxide alarm. Analysis of cases of carbon monoxide poisoning
that occurred after a major ice storm showed that a functioning carbon
monoxide alarm warns occupants before carbon monoxide poisoning becomes
severe.

The plug-in alarm is the best; however, a battery back-up is a must so
that the alarm will continue to function when the power is out.

Some alarms have a digital readout to show the carbon monoxide level in
the room. More advanced alarms actually have detection shutoff switches,
so that the source of the Carbon Monoxide is shut down. Carbon monoxide
alarm batteries should be checked twice a year; an easy reminder is when
changing the clocks during the fall and spring. Batteries should be
replaced yearly.

If a carbon monoxide alarm goes off, residents should leave the area
immediately and telephone nine-one-one (911). There is no home therapy
for carbon monoxide poisoning. People who have symptoms of carbon
monoxide poisoning that do not resolve after a few minutes in fresh air
should seek medical attention in an Emergency Department.

With or without regulation, it is important to recommend that people
place Carbon Monoxide alarms in locations where Carbon Monoxide is
produced. Through public education, ninety-three percent (93%) of homes
today have smoke alarms. Yet, most do not have Carbon Monoxide alarms.

The most important place to keep a carbon monoxide alarm in your home is
near the bedrooms, where it can awaken people from sleep if carbon
monoxide is in the vicinity. In larger homes, additional alarms should
be placed on each level.

Because carbon monoxide levels are about the same from floor to ceiling,
it is perfectly okay to use a combination smoke and carbon monoxide
alarm, or to use a stand-alone carbon monoxide alarm that plugs into the
wall at ankle level. They both do the job well.

However, placing the alarm very close to a furnace or garage may lead to
false alarms. An ideal location is nearby, between the carbon monoxide
source and occupied areas of the home.

A few states and municipalities have enacted laws and ordinances to
prevent Carbon Monoxide exposure at hotels, motels and resorts. New
Jersey, for example, requires carbon monoxide alarms to be either placed
in each guest unit, with an individual or central monitoring
system, or in areas adjacent to rooms containing fuel-burning
appliances.

While smoke alarms were mandated in every U.S. guest room in 1990,
carbon monoxide alarms were not. Portable alarms are available for
travelers to carry with them to their hotel.

Information and education is always more effective when the person you
are trying to reach has a "need to know."

That is why product information at the point-of-sale is so important.
Studies show that the most common reason for hazardous use is ignorance
of Carbon Monoxide exposure.

Yet, if you see the products on the store shelves, it is rare to see an
accompanying warning sign about the potential for carbon monoxide
poisoning.

Labeling on the individual product is desirable.

For generators, the label of the Underwriters Laboratories indicates
that the product meets their safety standards. In addition, pictogram
warning labels are helpful to reach non-English speakers. Samples of
this format are available on the CDC's website.

Although people should always read the owner's manual of any appliance,
and follow its instructions, we know that this sometimes does not occur.
The issue of language is once again a factor as well.

An even better solution to the issue of carbon monoxide poisoning would
be if generators were engineered so that they could be used in the wet
outdoors, placed far enough from building air intakes, and produce as
little carbon monoxide as possible.

Having carbon monoxide sensors tied to a cut-off switch would be ideal,
but that type of technology poses challenges. Hopefully, these changes
will occur in the near future, because they do have the potential to
help prevent many carbon monoxide poisoning cases.

A decline in deaths in this country due to charcoal-related Carbon
Monoxide poisoning was reported by the U.S. Consumer Product Safety
Commission when they revised the warning label on charcoal briquettes in
1998.

[]{.mark}

[]{.mark}

WASHINGTON

Thank you, Dr. Lavonas, for bringing to our attention some of the ways
that people interested in public health can work towards the prevention
of carbon monoxide poisoning.

And, thank you to our viewing audience for your attention during this
webcast. We have attempted to provide you with a solid background on
Carbon Monoxide poisoning. We started with an explanation of it sources
and how it works, and gave you an overview of who most often falls
victim to Carbon Monoxide poisoning.

We have also tried to emphasize the importance of being alert to Carbon
Monoxide poisoning symptoms when making a diagnosis and explained some
of the latest treatment options.

We concluded with some insight into how Carbon Monoxide poisoning can be
prevented.

Resources for professionals interested in addressing the issue of carbon
monoxide poisoning in their community are available online from the
Centers for Disease Control.

Educational materials, including flyers, prevention guidelines, FAQs and
checklists may be downloaded from the website. There are also links to
professional organizations, documents, journal articles on research as
well as clinical trials information. Resources in your local community
are available through a link on to the CDC website.

WASHINGTON

If you would like to review this program at a later date or share it
with a colleague, please note the web address:

[www2a.cdc.gov/phtn/webcast/CO Poison Prev.]{.underline}

Also, if you would like to apply for continuing education credit, please
visit our online system at www2a.cdc.gov/TCE Online and enter course
number WD1233.

Finally, I'd like to thank our guests Doctors Neil Hampson, Eric Lavonas
and Allison Stock for sharing their informative presentations on today's
program.

That brings us to the close of Carbon Monoxide Poisoning Prevention
Clinical Education.

I'm Joe Washington, and it has been my pleasure to be your moderator
today. Good-bye.