March 14, 2008
by Dr. Laurence Degelsmith
This is the time of year when we tend to see a handful of patients each week in the emergency department that were sent to rule out carbon monoxide poisoning. Carbon monoxide kills hundreds of people per year across the United States and is responsible for up to fifteen thousand visits to emergency departments annually.
Many of the deaths attributed to carbon monoxide poisoning are suicides, but every so often we hear in the news that an entire family—usually with small children—is lost due to high levels of the poisonous gas throughout their house. This type of tragedy is so easily preventable that it is a shame when it occurs.
Carbon monoxide is a poisonous gas that is produced whenever an organic fuel is burned. This fuel can be gasoline, coal, wood, natural gas, propane or kerosene among others. Carbon monoxide is a natural byproduct of combustion and the gas is odorless, tasteless and colorless, which is why it is known as the “silent killer.”
There are many causes of carbon monoxide toxicity, but the most common accidental sources are from poorly ventilated household appliances, smoke from fires and car exhaust. Kerosene heaters in small rooms without ventilation are also common culprits. Natural gas water heaters or furnaces in basements where the ventilation system has been obstructed are frequent causes of carbon monoxide toxicity to entire families. People, often children, riding in the back of covered pickup trucks or campers with faulty exhaust systems are occasionally victims of carbon monoxide poisoning. Lastly, smoke inhalation victims from house or car fires are commonly affected by high carbon monoxide levels.
A few of the more interesting but less common causes of carbon monoxide poisoning include small boats moving at slow speeds or idling, charcoal grills, indoor arena events such as tractor pulls and tunnel workers exposed to continuous high levels of carbon monoxide from automobile exhaust. Cigarette smokers also have a baseline elevated carbon monoxide level in their blood.
When to suspect carbon monoxide poisoning
The symptoms of carbon monoxide poisoning usually include headache, dizziness, nausea, vomiting and fatigue. Other symptoms may include chest pain and shortness of breath with exertion especially in people with underlying heart disease. Rounding out the remainder of the common but more subtle symptoms are poor concentration, confusion, agitation, drowsiness and ringing in the ears. Loss of consciousness, seizures, coma and death can occur if not treated.
Children and fetuses are more susceptible to carbon monoxide poisoning due to the type of hemoglobin they have in their blood. This hemoglobin has a higher affinity for the carbon monoxide molecule than adult hemoglobin, which causes children to succumb to symptoms much sooner that adults. People with chronic respiratory or cardiac conditions, people with anemia and the elderly are highly sensitive to carbon monoxide. Pets are also sensitive to carbon monoxide and if a pet appears ill along with other members of the family, carbon monoxide must be suspected since pets don’t get ill from viruses transmitted from people.
The challenge of diagnosing carbon monoxide poisoning in the wintertime is that the symptoms are often subtle at first and frequently mimic any common viral illness including the flu. Some common signs of carbon monoxide poisoning rather than the flu include: several people in a household getting sick at the same time, symptoms that improve when going outside and symptoms that begin after turning on a fuel burning device. On the other hand, fevers, aches and swollen glands are not associated with carbon monoxide poisoning.
Making the diagnosis
Carbon monoxide poisoning is diagnosed through a simple blood test. Unfortunately, the diagnosis can get missed if someone gets treated with oxygen for a while and delays going to the hospital. The carbon monoxide level can drop down to a low level by the time the blood test is eventually done.
A normal blood carbon monoxide level is less than 5%. A level of 5 - 15% in a non-smoker is often accompanied by mild symptoms. A level of 15 - 25% is accompanied by more moderate symptoms (severe headache, decreased vision and vomiting). A level greater than 25% is often associated with decreased alertness, seizures, coma and eventually death. Interestingly, smokers have a baseline carbon monoxide level near 10% and may be more resistant to symptoms when exposed to high levels of carbon monoxide.
For everyone, symptoms may not always correlate to the level of carbon monoxide in one’s blood especially if you were already treated with oxygen, which decreases the carbon monoxide level in the blood but may not initially decrease the symptoms, especially if severe. People who present comatose after being exposed to smoke in a fire may pose a special challenge since they may also be suffering from cyanide poisoning, which can occur when certain substances are burned in a fire. The symptoms of severe carbon monoxide toxicity and cyanide toxicity are fairly similar ,but treated in an entirely different manner.
It is possible to have both toxicities and this must be considered in any patient from a fire, especially if they are extremely ill or unresponsive. Cyanide poisoning is treated with intravenous medications to break the cyanide molecule off of the hemoglobin. All the oxygen in the world won’t help a victim of cyanide poisoning since the cyanide prevents the oxygen from binding to the hemoglobin thereby prohibiting the cells of the body from getting oxygen. It’s like the body is suffocating despite being able to breathe.
Treating carbon monoxide poisoning
Treating mild to moderate carbon monoxide poisoning is fairly easy. Step one is to remove the patient from the source of carbon monoxide. Then use, oxygen, oxygen and more oxygen. The oxygen displaces the carbon monoxide molecule from the hemoglobin in the blood. This hemoglobin can now carry an oxygen molecule instead of a carbon monoxide molecule to parts of the body that need it, especially the heart and brain. Patients are kept on 100% oxygen via facemask until their symptoms are mostly gone and their carbon monoxide level drops down to an acceptable level.
For patients with moderate to severe symptoms, a hyperbaric oxygen chamber that provides a high concentration of oxygen at high pressure into the bloodstream is often recommended. The hyperbaric oxygen chamber was considered for years the mainstay of treatment for patients with significant symptoms, but numerous studies have debated its usefulness and some even conclude that hyperbaric oxygen chambers can sometimes worsen one’s condition. The debate continues so the hyperbaric oxygen chamber is not uniformly accepted as necessary. Even with aggressive treatment, which can go on for weeks, permanent neurological problems may remain.
Hyperbaric oxygen chambers are located locally at Phelps Hospital, Westchester Medical Center and Jacobi Medical Center in the Bronx. Most cases of severe carbon monoxide poisoning in Westchester or its neighboring counties would be treated at Westchester Medical Center, especially if any burns were present from a fire.
Prevention is easy and inexpensive
Obviously, a carbon monoxide detector is the simplest way to prevent poisoning in the household. It is estimated that over 90% of American households have smoke detectors, but only 15% have carbon monoxide detectors. There is absolutely no reason not to invest in this inexpensive yet potentially life saving device.
Also, make sure that there is good ventilation whenever using an appliance at home that burns an organic fuel, especially a space heater in a confined space. Verify that exhaust ports for furnaces and water heaters in the house are not obstructed by bird nests or other matter.
I am happy to report that while I have seen several patients over the past few years that have come to the hospital to rule out carbon monoxide poisoning, I haven’t seen a case of significant poisoning in years. I think that most people in Westchester County are educated and well aware of this signs of carbon monoxide poisoning. However, accidental exposures do occur, even in new homes, and it doesn’t take very long for carbon monoxide levels to build up in a house from something as mundane as an obstructed exhaust vent. Please do yourself a favor and make sure that a functioning carbon monoxide detector exists in your home.
Author’s note: This article encompasses general guidelines taken from several published sources as well as my ten years of personal experience as an emergency physician. There will often be exceptions to the above guidelines because the risk vs. benefit ratio of using any medication or treatment will be different for each patient.
Laurence Degelsmith graduated from Horace Greeley High School in 1985, has an undergraduate degree from Washington University in Saint Louis, attended New York Medical College and did his residency in emergency medicine at the University of Michigan. He is an emergency department physician at Northern Westchester Hospital in Mt. Kisco and a member of the Chappaqua Volunteer Ambulance Corps.
Copyright 2008 NewCastleNOW.org