Saturday, October 25, 2014
Can general anesthesia damage the lungs?
I had a shoulder operation under general anesthesia (taking about 2 hours). About 6 days later I had sinus/pituitary surgery (taking about 2-3 hours?) again under general anesthesia. I had a history of asthma but had never required routine medications for that as it rarely reared it`s ugly head. Immediately following the second surgery I developed a respiratory infection that a month to resolve and within <2 months another bout with bronchitis (again taking a month to resolve) and yet again in < 2 months, a third bout with bronchitis. I had another sinus surgery to remove bone (osteomylitis) in the sphenoid/pituitary region (under general anesthesia). My breathing never recovered to normal. Ten months after the 2nd surgery, I had PFTs that showed asthma and I was referred me to a pulmonologist who has me on a boatload of big guns but my breathing (after 4 months on those) has still not recovered to normal. Could this back to back general anesthesia have caused lung damage? A chest x-ray now shows (new ) question of COPD (I am a non-smoker) and a new possible pulmonary nodule. A subsequent CT scan to check the nodule showed it to be `scarring` from inflammatory process. I was curious if the cuase (since it all surfaced immediately following the second surgery) as to if there is a cause/effect relationship that perhaps there might be something that can reverse what has happened or if that is not even a possibility. Thank you so much.
Pulmonary (lung) complications are at least as common as cardiovascular (heart, blood vessels) complications after major surgery, but tend to get less attention.
General anesthesia does have effects on the lungs. During general anesthesia for the procedures you've had (major shoulder operation, pituitary surgery) you will have been intubated and ventilated (breathing machine). Mechanical ventilation and general anesthesia changes the pattern of blood flow and aeration of the lungs. Collapse of small airways (atelectasis) is common, considered normal in fact, but normally resolves over hours to days. Bronchospasm (asthma-like wheezing) can occur.
Recent research shows that some patterns of ventilation (large volumes) can injure the lungs. This is a known effect of long term (days) ventilation in the ICU and might be relevant even in operations as short as 2 hours. This has lead to a change in practice in the ICU, using moderate volume ventilation in place of the higher volumes that were previously standard.
Unfortunately some patients do get lung infections (bronchitis, pneumonia) after surgery. Patients who are generally unwell (frail, malnourished, systemic disease like cancer) are more susceptible. General anesthetic drugs may themselves have effects on the immune system thus predisposing to pneumonia but this is not clear-cut. Patients who smoke are particularly likely to develop pulmonary complications.
A previous history of asthma is likely to put you in a higher risk category. Your CT scan and PFTs suggest asthma or COPD. Recovery from general anesthesia may have "unmasked" your limited pulmonary reserve from low grade chronic lung disease which was previously compensated. COPD is not limited to patients who smoke.
Prevention of pulmonary complications is limited to general things like improving nutrition, avoiding smoking, and possibly helped by exercises known as incentive spirometry which help re-expand the lungs after surgery. If you have asthma it needs to be under best possible control before major surgery. There is unfortunately nothing I can think of that you can do to reverse the problems you have. But please check with your doctor.
Gareth S Kantor, MD
Assistant Professor of Anesthesiology
School of Medicine
Case Western Reserve University