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Archive: Dr. Tom 110
Posted January 15, 2008

Readers: Read Dr. Tom’s Commentary on Spirometry to understand the importance of this diagnostic lung test.



What is Carboxyhemoglobin? 
Q. Dear Dr. Tom, I have been feeling awful for months, sleepy and groggy during the day, no energy, losing weight, tremor, new high heart rate and new high blood pressure and high (16.3) Hemoglobin which has been a high normal for a couple of years actually. 
I did some reading and insisted my doctor repeat blood gases, which I had in October and were normal this time she added carboxyhemoglobin (hemoglobin that has carbon monoxide instead of the normal oxygen bound to it.). The blood gases were normal, but the carboxyhemoglobin was 2.0 and the labs normal range went up to 1.6. So mine was high. My PFT in October showed mild hyperinflation. What could this high carboxyhemoglobin represent?
I do feel a strange gassy sensation in my chest and mouth.  I am very frightened and don't know what to do next? God Bless you for doing this forum.


A. Dear Teresa, High carbon monoxide comes from poor ventilation of heating systems, also from smoking. Assuming you do not smoke, I suggest getting your furnace checked for adequate ventilation.

Dr.  Tom


Will Moving to a Different Altitude be a Problem for Me?
Q. I was diagnosed with emphysema 25 years ago after my lung collapsed. I am 55 years old and a nonsmoker. I have no problem breathing my lungs look good and my oxygen level is always 100% so says my GP. I do not have a specialist, as I don't seem to need one.
My question. We are planning on retiring in two years in Fallon Nevada. I currently live in Alaska. Will this change in altitude bring on problems for me. Thank-you for your time.


A. Dear Susan, I do not know the altitudes of the residencies you mention. I assume that if you are fine with no symptoms, you will remain so, unless exposed to extreme altitudes.

Dr. Tom


 Will Using Long Term Oxygen at Night Harm Me?
Q.  Just to start...I am 35 and have had exercise induced and animal induced Asthma since I was six or seven years of age.

I will try and make this brief....about two years ago I found out I was pregnant with my second child...prior to finding this out I knew I was having some trouble with my breathing & oxygen levels at night while sleeping.

 I called my doctor right away after finding out about my baby as I was scared that if I wasn't getting enough oxygen then she in turn would not be. So they had me do nocturnal oximetry test, and sure enough it showed many VERY low (like 65% and 70%) dips in my oxygen saturation.

I, of course, freaked and said oh my, I need to wear oxygen as I am pregnant etc. etc. so they set me up on two liters of oxygen to have while I would sleep. I did another nocturnal oximetry test, and it showed that my oxygen saturations were I went through my whole pregnancy on two liters.

I noticed the very first night on the oxygen, when I woke at two am to go to the bathroom I felt some wheezing in my I took a deep breath and then it was gone. I continued to notice this almost every night when I awoke, as well as when I awoke in the morning....I had to take a few deep breaths and then it would go away. I knew this feeling....mostly I would get it if I had been smoking a lot the night before and went to sleep I would have this sometimes when I woke up, so it was somewhat familiar, but I NEVER would get this any other time, and hadn't had it in a few years. I had quit smoking prior to all of this so it wasn't from this I was just referencing it.

 I then called my primary and asked (in the beginning when this all started) why I was having this reaction....she said it was because my body was not used to having this oxygen and reacted that way....I took that answer and just let it go.

Long story short, after having my daughter I went to have a sleep study done and sure enough I had mild sleep apnea, and that is why I was not getting enough oxygen. So when I was at the pulmonologist one of the doctors said that I really should not have been on that oxygen, and on it for that long of a time.

Here is my question and fear, did I do myself damage by being on two liters of oxygen for over a year? I fear this as I still have that problem of sometimes when I wake in the middle of the night I have that small wheeze going on. I have not been on the oxygen for almost two years now, but I still have this issue. I just find it very odd that I never had this problem before, but after being on the oxygen developed it and now it remains. Obviously this scares me as I have had to think about my lungs and breathing all of my life, and to have this come up scares me that I have done something irreversible to myself, please tell me this will go away?


A. Dear Shannon, The two liters of oxygen you took did not harm your lungs.

Dr. Tom


Questions about Bronchiectasis
Q. Dear Dr. Tom, I have read about a new medication specifically targeted for bronchiectasis.  It is under Phase III Trials from Pharmaxis; it is called Bronchitol. Would you have a medical opinion in regards to this medication?   I am filled with optimism for my mother who has bronchiectasis/ chronic asthma. 
She is on Advair/Atrovent and 24 hour 2L oxygen therapy.  She has been a non-smoker all of her 75 years.  She is doing everything possible to control her disease (eats well/ exercises daily/ breathing exercises/ receives pummelling twice a week). Any suggestions?  
Also, with bronchiectasis is there a hardening of the lung tissue?  I was of the opinion that the alveoli are stretched-out; however, someone recently said they are actually hard.  Please clarify this for me.
Finally, we are considering visiting the Mayo Clinic in Rochester, MN.  Any thoughts?


A. Dear Rose, Bronchiectasis causes damage and dilatation to the larger lung passage of the lungs. Lots of antibiotics are used for flares of infection.
I do not know anything about the new medication for bronchiectasis. I see no particular advantages for going to the Mayo Clinic for your bronchiectasis.  They have some very good doctors, of course. The top speciality hospital for lung diseases is the National Jewish Medical and Research Center in Denver. They have a particular interest in bronchiectasis.

Dr. Tom


What are Linear Densities on Chest X-Rays?
Q. My doctor told me that my x-ray showed several linear densities of the left lung. I would like to know what this means.


A. Dear Ron, These densities are usually of no significance. They may represent old scars. Your own doctor would have to give you a more appropriate explanation for these shadows and how they relate to your health.

Dr. Tom


Having a Hard Time Catching My Breath
Q. Hi Dr. Tom, I am a 43 year old healthy female, although I've had some odd ailments throughout my life (cerebellar infarct at 33 years old, positive anicardiolipin antibodies (autoimmune issues are prevalent on my mom's side, esp. lupus but I don't have that), and most recently a total urethral reconstruction, which is why I am writing.

Well I was getting wheeled out of surgery and when I came to, it was difficult to catch a breath. The nurse told me my blood pressure had dropped precipitously in the OR and she suggested I see a pulmonologist.

I'm not a hypochondriac and wouldn't have thought much of it if I hadn't been already having what I perceived as some potential breathing/lung capacity issues. The last thing I'll mention which puts me over the top is that I have worked out consistently most of my adult life...used to power walk anybody off the road and hardly was out of breath ever - I started running over a year ago (short distances - less than two miles) and for the life of me I can not gather stamina as I think I should. It is still almost painful to make it through a whole 2 miles of trail. I do better on a totally flat treadmill but wondering if I should be tested for anything. I'm a competitive person and bothered I can't gain further strides when i run four to five times per week! Any help is greatly appreciated.


A. Dear Regina, I cannot put together a diagnosis that fits your situation. Since you are a power walker, I doubt that you have a serious condition. You may want to see a pulmonologist to see if you have exercise-induced asthma.

Dr. Tom


Conflicting Interpretations on Chest X-Ray
Q. I had a chest x-ray yesterday, and the doctor pointed out what she called "bilateral enlarged lymph nodes" they were just round white pencil eraser sized spots on each lung, and what she called a large lymph node next to my sternum that was about an inch big on a side view x-ray.  She said she was really concerned and that this is the reason I am short of breath and have chest pains. 

She sent the x-ray to the radiologist for a wet read, and that report came back as normal.  Nothing remarkable seen. I am confused, did she see something not enlarged nodes?  Can that mistake be made? 


A. Dear Rachel, Different doctors may interpret chest x-rays with different conclusions. There is no such thing as a "wet read" anymore, with modern technology.

 I suggest getting to the bottom of this by seeing a pulmonologist who can look at your films and decide what the next step in diagnosis should be, or if nothing more is needed.

Dr. Tom


Trouble Understanding Spirometry Results
Q. Dr. Tom , I have had a spirometry test and the results are as follows:
          pred     test1    %pred
FVC       5.4      4.47       83%
FEV1      4.5      4.12       92%
FEV1%    84       92        110%
FEF25-75 4.77  5.74    120%

I am having problems interpreting the results. Do I have a breathing problem from the results you see above? I have a seven pack year smoker and quit smoking last week should I see a increase in FVC and FEV1. Will going from sedentry to a more active lifestyle help increase my numbers?


A. Dear Nathan, Your spirometry is normal. You will not increase your numbers through exercise, but you may function and feel better.

Dr.  Tom


Q. What is pulmonary mycobacterium avium complex? What is the prognosis?


A. Dear Mike, It is an organism that is common in the environment, and related to tuberculosis. It is not contagious. It requires treatment by an expert in environmental mycobacterial diseases, if it is infecting tissues such as the lung.

Dr. Tom


Tests are Normal Then Why am I Feeling Short of Breath?
Q. I am a 24 year-old male who developed dyspnea following running about nine months ago now.  I have had a constant feeling of shortness of breath ever since that varies throughout the day.  I am able to run six miles a day with no problems but I still have that feeling of shortness of breath at rest. 
I was initially diagnosed with asthma but all of the treatment was ineffective and I proceeded to go to a pulmonologist.  After a normal chest x-ray, echocardiogram, pulmonary functioning test, and methacholine challenge I was taken off of the asthma medications and have had no worsening of the symptoms.  It seems that my physician is out of ideas and not particularly worried about further treatment.
I have felt that the symptoms have been gradually getting better since this all started with many fewer days of really bad feelings of shortness of breath, however a minor feeling still lingers with me at all times.
I know there is a possibility of psychological causes and I would have to say I am in a high stress environment since I am current in my first year of medical school.  However, I never perceive myself as either being anxious or panicky.
I was just curious as to your take on the situation and what further testing you think was warranted to figure out an ultimate cause.


A. Dear Matt, I do not believe you have a serious lung disorder. You can get your spirometry checked for reassurance.
 I remember the anxieties I had about perceived diseases, when I was a medical student. I am not free of this yet at age 75. Stay healthy and enjoy your studies.

Dr. Tom


Pain in Lungs Since Halloween
Q. I got a cold or the flu before Halloween, had asthma attack, went to bronchitis, then to pleurisy. I have been having constant pain in my lungs in the area under my breasts, and around the sides on both sides for two months. Had chest x-ray & CT Scan, these were the only findings, "otherwise unremarkable". "minimal subsegmental infiltrate and/or ateletatic change is present medially in the right middle lobe." 

I just want to know what this means in layman terms, and is this something that will get better on its own with time?  Is this what's causing the terrible pain, or is it still the pleurisy?  Any information you have for me will be helpful. 


A. Dear Marchia This refers to a small area of lung collapse that probably is a residual from a chest infection. It should be followed with another chest x-ray in about three months. I doubt it is causing the pleurisy, because of its location, but this is possible.

Dr. Tom


Doctor Said Nodules Could be Cancer, Why Wait Six Months for Recheck
Q. I have COPD, emphysema and rheumatoid arthritis. I just had a CT Scan my doctor said I have nodules several, which could be cancer, that I'll have to take another CT Scan in six months to see if there's been a change. Is there another test I can take without waiting six months?


A. Dear Lorraine, It depends on the number, size and shape of the nodules, which I assume are not calcified. A follow-up CT in three months would be appropriate.

Dr. Tom


Non-Smoker and Have Lung Problems
Q. I am a 46 year old non-smoker with symptoms of COPD.  I have a chronic cough, and have shortness of breath. My mother had emphysema, but never smoked; she died due to ARDS after a bout of pneumonia at age 59. 

My chest xray results: hyperinflated lungs, FVC is 67% (60% last year), FEV1 is 72% (62% last year), and FEF 25-75 is 57% (last year 47%). My AAT level is 143.  I obviously have something wrong with my lungs.  I started taking Singulair 10 mg last year, and my lung function improved a little. What are your thoughts?


A. Dear Donna, You probably do have a form of familial emphysema, even though your AAT levels are only moderately low. I would follow the advice of an experienced pulmonologist who should manage your case with appropriate medications; that will probably stop your cough and keep you well for a long time.

Dr.  Tom


Is Lung Scarring due to Chemical Inhalation or Smoking?
Q. Hello Dr. Tom and thank-you for this forum.  My question to you is, which is most likely to cause lung scarring, smoking or chemical inhalation?  Is there a test that can be done to determine the cause of my lung scarring?

I had an inhalation injury from a chemical spray that I had used (hydrocarbons and Zonyl were part of the ingredients) in a tile project in my home.  I had a CT scan done which determined that I had scarring in the lower lungs. There was no sign of bronchitis, emphysema, or cancer. After my breathing tests, which turned out to be pretty good, and the CT scans the pulmonary doctor diagnosed my condition as COPD and placed me on Advair

Since this accident, I have shortness of breath while doing activities and I also have a dry cough.  I did not experience any of these symptoms prior to the accident. 

I am also a smoker (I have tried to quit twice since the accident and am still trying) but like I said, I did not have these problems prior. Any thoughts that you can offer would be appreciated.


A. Dear Kim, The accidental inhalation of potentially toxic agents is in the past, and cannot be changed. What must be changed to protect your lung and general health is quitting smoking. It is not an intellectual but a health decision for you. I recognize it is difficult. Good luck and keep trying.

Dr. Tom


Nasal CPAP Masks are Coming Off at Night
Q. Dr. Tom, I work as a RT in Homecare. The majority of my time is spent setting patients up with CPAP/BIPAP machines. Lately, a couple of patients have called saying that they have been waking up in the middle of the night with their mask off. They were asking if this is a common problem. My response was that it is not very common but it does happen and it is part of getting use to sleeping with a mask and CPAP.

As I thought about this occurrence and questioned the patients, I began to wonder if this problem is more or strictly a mask issue? Both of these patients have nasal masks and both were waking around 2am - 4am. I was wondering if they were mouth breathing? I can fix this with a chin strap of a full face mask, but I was wondering what you would advise.


Q. Dear Kerry, I think your explanation and plan for correction is fine. Give it a try. Problems with masks coming off are not common, but remain a challenge for some patients.

Dr. Tom


Six Millimeter Nodular Density and Thymic Tissue Seen on CT Scan
Q. I recently had a chest CT Scant.  The impression read vague, low density 6mm nodular density in the right middle lobe.  When reading the report above I also read a small soft tissue density is noted in anterior mediastinum which has the appearance of residual thymic tissue. 

I was informed of the nodular density, but not about the thymic tissue.  I only found that because I got a copy of report.  

Also I had a chest x-ray eight months before this CT Scan which was normal. Would that 6 mm nodular density have shown up on a chest x-ray?  This is worrying me.  I am 33 yr old female.  Was a social smoker for maybe six years.


A. Dear Kathleen, It is probable that the 6mm lesion seen on CT could be missed or just not large enough to be seen on the previous chest x-ray. You should have a follow-up of this nodule in about four months, which will also show the thymic  shadow and any change in it.

Dr. Tom


Anxious about the Diagnosis of a Minimal Obstruction:
Q. Dear Dr. Tom, I went to the doctor for my yearly checkup, she ordered a chest x-ray which was completely normal. My oxygen level was 100%

Then she gave me a pulmonary function test. This was the long test, which took about 20 minutes.

Here are the results can you please look at them because she is telling me that I have a minimal obstruction. I also have anxiety/panic disorder.

I do have a problem with hyperventalation and breath holding due to my anxiety.

          Pre        ref       %ref
FVC -     3.11       2.66       117
FEV1      2.31       2.22       104
FEF1/FVC    74         83
FEF 25-75%  1.72       2.52       68
FEF 50%     3.17       3.17      100
FEF 75%     0,51       1.12       46
PEF        7.84       5.40       145
MVV        1.08         76       142

Lung volumes
TLC         5.20       443      117
VC         3.11       3.00     104
IC         2.28       1.80     126
RV          2.09       1.64      127
RV/TLC      40           36

Diffusing capacity
DLCO          17.9       21.2    80

Then I had her do the office PFT test that only takes about four minutes because I was so upset and freaking out when she told me the results of the big test.  You see my husband died of lung cancer and I have a handicap daughter so maybe that would explain my fears.

Her are the results of the small test ,she took it that same day.
          Pred     act         %pred
FVC    2.67    2.68          100
FEV1   2.23    2.28          102
FEV1/FVC    83      85          102

This test was done after the big test so I was also tired.

The next day I went to another pulmonary doctor and he gave me the short test. Here are those results.

I was very nervous
         Best     %pred    pred  lln
Fvc (l)  3.04      114      2.66  2.00
Fevi (l) 2.25      101      2.22  1.73
Fev1%      74       88        84    72

Well thats it.

Can you please email me back and let me know what you think? I have been on the internet for days now and finally I found your site.  Please help me.


A. Dear Joann, Your results are normal. You do not have a minimal obstruction. Only refer to the numbers in the short test. The other numbers in the spirometry portion are misleading. You have no lung impairment. Stay well.

Dr. Tom


Lung Nodule Found Since 2006 Chest X-Ray
Q. Dr. Tom - After a bout with the flu that wouldn't go away, the doctor's ordered an x-ray that revealed a lung nodule.

I have since had two CT scans.  The first scan verified that it did exist and wasn't an anomaly on the x-ray.  The pulmonologist thought that the nodule may have been pneumonia, so I was given Avelox for seven days, and then a week later the CT was repeated.  The nodule was still there.

I had a chest x-ray done in 2006 (for an unrelated health matter) and as far as I can see, the nodule is not on the x-ray.

I have uploaded a picture of the 2006 x-ray, and my recent CT scan.  Would you be able to tell me if you can identify the nodule in the 2006 x-ray?


A. Dear Jim, I did not look at the movie, because it may not have all the information I need for a comparison. I think you simply need one more CT scan in about 4 months to see if there is any growth in the nodule we know that you have. You cannot compare nodules seen on chest x-rays with those seen on CT.

Dr. Tom


What Does “E-Time” on a Mechanical Ventilator Mean?
Q. Recently, a doctor asked a respiratory therapist taking care of my uncle who was on a ventilator to "make the e-time longer", the therapist pushed a few buttons. My question is what did the therapist do to the ventilator and what is "e-time" and what is the purpose of it?


A. Dear Janet, The "e" time is the expiratory time, ie the time the ventilator waits for the lungs to empty. Lungs with low elasticity, such as in emphysema, take longer to empty.

Dr. Tom

2024 American Association for Respiratory Care