Central  South  Dakota  Medical News
The Clinical View
by Phillip Hoffsten
16 December 2004

FURNACE PROBLEMS:  CARBON MONOXIDE POISONING

     The lady was 83 years old and lived alone in her home in which she had resided for 32 years.  She had many social contacts and friends and had always been very sharp.  But friends had noticed in the past month that she seemed to be struggling.  Her clothes were not as neat as they had been.  The patient was not as spontaneous with her conversation as she had been before.  She complained of headaches and dizziness.  She had lost about 5 pounds over the previous month stating that she was nauseated and just didn’t feel like eating.  Friends came to pick her up for church on Sunday morning and the patient wasn’t even dressed not even knowing that it was Sunday.  Friends brought her directly to the emergency room.

     In the emergency room, routine blood tests were drawn, cardiogram was done, chest X-ray was done and nothing much seemed to be abnormal.  CAT scan of the brain was done to evaluate the possibility that she had had a stroke and that too was normal.

     Emergency room personnel were still scratching their head trying to figure out what might be wrong when one of the nurses commented on the odor of the patient’s hair and clothes.  It was noted to have a strong scent, almost like the exhaust from a car.  It was at that point that the bells in someone’s head rang and it was suggested that the patient might have carbon monoxide poisoning.  To make the diagnosis of carbon monoxide poisoning, a blood test measuring the amount of carboxyhemoglobin in the blood needs to be thought of and then measured.  Indeed, when the patient’s blood tests were run, her carbon monoxide level was around 18% (normal is less than 3%).

     Normal carboxyhemoglobin levels in a person’s blood depend upon their environment.  In South Dakota where we have lots of fresh air, normal values are less than 3%.  In a congested downtown city where there is lots of car exhaust and a person spends a great deal of time on the street, normal levels may be as high as 5 or 6%.  In individuals who smoke a pack of cigarettes per day or more, carboxyhemoglobin levels may run as high as 10%.  Symptoms identified with carbon monoxide poisoning generally occur when values are 12% or more.

      The patient described above was not a smoker.  It was very easy at that point with the aroma of her clothes and hair to make the diagnosis of carbon monoxide poisoning secondary to a malfunctioning furnace.  This event occurred in November when her furnace had just started to be used.  The furnace had not been used all summer or fall and it had not been serviced for six years since her husband passed away. She was placed with a mask providing 100% oxygen and in the course of several hours, her carboxyhemoglobin levels came down to 3%.  By that time, all her nausea had cleared.  Her headache had gone away.  She was thinking clearly again although was still somewhat disturbed by why she was in the emergency room and who had brought her there.  Explanations were provided.  The patient was allowed to leave the emergency room after five hours now feeling well.

     She was advised of the problem regarding her furnace and stayed with friends the next several days until the furnace was adjusted.  The problem was that it had not been cleaned in an extensive period of time and there was an inadequate amount of air being mixed with the fuel oil.  This led to incomplete combustion of the fuel oil explaining the carbon monoxide poisoning and the aroma of unburned fuel.

     Carbon monoxide poisoning is the most common inhaled poisoning that occurs in our society.  As seen in the case above, it is relatively rare in a general practice and very difficult to diagnosis.  A high index of suspicion is necessary. Fortunately, the outcome in a case such as the above will be favorable but if the intoxication is prolonged over several months, permanent abnormalities may occur.  Damage to the areas that cause Parkinson’s disease and even an Alzheimer’s like problem can develop.

     The importance of this column is to remind people to have their furnaces checked on a periodic basis.    Attending to the furnace was something that her husband always attended to and she simply did not know about the need for furnace servicing.  In the elderly, those living alone, those living in older homes with older furnaces, families and friends should be aware that changes in behavior, worsening confusion, fatigue and lack of interest may all be signs of carbon monoxide poisoning.

     The healthcare providers at your local clinics are aware of these types of problems and can be a special help in making the diagnosis and getting appropriate treatment.