Once a date for lung surgery is set, a string of test appointments unexpectedly follows. One that is never left out is the pulmonary function test. People hearing about it for the first time often wonder, "Why measure the function of a lung that is going to be removed anyway?" But that is actually the whole point. We want to gauge in advance how much work the lungs are doing now, and whether the remaining lung will be able to hold up well even after part of it is removed. If you only find out on the operating table that "there was less lung reserve than expected," it is far too late.
The test itself is simpler than you might think. The basics are clipping your nose shut, biting down on a mouthpiece, and then, as the examiner instructs, taking a big breath in and breathing out all the way with all your strength. It can feel a little embarrassing when someone beside you keeps shouting "More, more, more, keep breathing out!" almost like cheering, but you have to squeeze it out to the very end to get an accurate value. If it doesn't come out well the first time, you repeat it a few times. You may feel dizzy, so if that happens, just say so honestly and rest for a moment. The numbers that come out here, such as FEV1 (the amount you breathe out in one second) or vital capacity, become important material for deciding whether surgery is possible.
One thing I want to ask of you: if you regularly use an inhaler or a bronchodilator, be sure to ask in advance what you should do about it before the test. Some tests deliberately have you stop the medication briefly in order to compare values before and after using it. Don't decide on your own; it is safer to check with your nurse or the testing room. Also, if you rush up the stairs right before the test, or come in after eating a very heavy meal, breathing may be uncomfortable and the results may not come out well. I recommend arriving with time to spare, catching your breath a bit, and then going in.
If the pulmonary function test numbers don't come out as well as hoped, there is no need to lose heart right away. The medical team does not decide based on this one test alone. They judge by putting it all together — the exercise stress test, heart condition, overall fitness, and even the shape of the lungs seen on CT. For borderline cases, they may adjust the extent of surgery or reduce the burden by removing only part of the lung. If there is some time before surgery, walking slowly during that period even when you get short of breath helps, and above all, quitting cigarettes is a great help to recovery. The saying that quitting even right before surgery is better than not quitting is no empty phrase.
The best attitude before entering the testing room is simply to breathe as usual, and then cooperate to the best of your ability when the signal comes. If you tense up and put strain into your shoulders, your breathing actually becomes shallow. It's fine if the result doesn't satisfy you on the first try, so trust the examiner's guidance and follow along. That way you can show the most accurate picture of your body's condition, and in the end that leads to a safer surgical plan.
This article only organizes general information, and matters concerning your own tests or surgery schedule must be discussed directly with your own medical team.