The use of Lung Function Screening (Spirometry) for those with respiratory disease
For a peaceful death one must be able to fully exhale and inhale. This allows the rapid exchange of the air in the lungs with the gas in the bag. Some respiratory disease can make this difficult or impossible. The question is, when is lung disease so severe that an alternative method should be used.
Fig: Spirometry to assess lung function before using an Exit Bag
Lung disease is usually broken into two main classifications: ‘Restrictive’ disease where there is difficulty filling the lungs with air, and ‘Obstructive’ disease where there is difficulty emptying the lungs. Emphysema, bronchitis and asthma are all examples of obstructive respiratory disease. Pulmonary fibrosis, sarcoid, or conditions such as scoliosis or obesity or diseases such as motor neurone disease can all cause a restrictive pattern.
For the hypoxic method to work well and bring about a quick, and reliable death, you need to be able to fully exhale (leaving little residual air in the lungs ie not have significant obstructive disease), then fully inhale filling the lungs with Nitrogen (ie. not have significant restrictive disease). Spirometry offers a quick effective screening test to ensure the suitabilty the method.