Spirometry testing involves inhaling fully, then exhaling fully through the mouthpiece (while the machine measures the volume and rate of gas flow). The spirometer compares one’s results with those expected for a normal person of the same weight, sex and height.
The presence of significant restrictive or obstructive respiratory disease can reduce the chance of a quick loss of consciousness when using the Exit bag method. Note, however, that although the time to loss of consciousness and death may be increased, with a good flow of inert gas, a peaceful death will still occur. The downside is that this prolonged period of time (before one loses consciousness) can cause anxiety and does reduces the appeal of the method.
If underlying respiratory illness is a concern, it may be wise to ask your doctor for a spirometry test to measure your lung function. If your measurements differ significantly from ‘normal’ results, the method may not be the most suitable to use.
Note: Some restrictive lung disease symptoms can be significantly improved with the use of certain drugs. The best example is asthma, where the inhalation of salbutamol (ventolin) prior to a spirometry test can sometimes restore values to near normal. If this is the case, the Exit bag hypoxic method need not be abandoned. The salbutamol should be used immediately before inhaling the nitrogen.