Respiratory
Division
Diagnostic Products
Spirometry
Spirometry made Simple 
Occupational Health
It has long been recognised that exposure at work to respiratory sensitisers, such as isocyanates, fumes and dusts, can cause long-term damage to the lungs.
Occupational asthma has to be diagnosed as soon as possible – as well as the effect on long-term health, there can be problems claiming compensation if the condition is not swiftly documented. Generally, occupational asthma is caused by an allergy to a sensitising agent, which, if removed promptly (after swift diagnosis) aids resolution. However, if the asthma remains undiagnosed for any length of time and exposure to the agent continues, irreversible pulmonary damage can result.
Symptoms of breathlessness vary over time; they may occur immediately or hours after the first exposure; sometimes intermittently, causing problems with diagnosis. A direct link with work may only become clear when the patient’s symptoms resolve during the weekends and holidays. Therefore, it is necessary for a detailed occupational history to be taken and any tasks that involve contact with likely sensitisers noted. A single examination on a bellows spirometer in the surgery could be misleading as in some cases of occupational asthma, pulmonary function improves as soon as the subject is removed from the sensitiser.
When occupational asthma is suspected it is essential to establish a pattern of symptoms for each patient. In the past patients have been given a peak flow meter and a diary card to be filled irregularly during working hours. Portable Spirometers with a memory are now available to give to patients, as all the patient has to do is turn on the machine and blow. There are only asked to make a note of their activity, and if they have been taking any medication, but apart from that, the measurements are quite simple.
A device
such as the VM PLUS records both PEF and FEV1, along with the time and date.
Once
the patient returns the spirometer, the data can be collected from the memory
via a computer, and can then be added to the employee’s records. By electronically
memorising the PEF and the FEV1, the results are highly reliable. Compliance
normally improves as there are no time-wasting charts for the patient to complete
and the question mark of possible fabrication of results is removed.
A pattern may emerge where measurements may be reduced in a patient with occupational asthma, and show increased variability during their working week, dependent on exposure to the suspected sensitiser.
The same spirometer can now be used the screen employees whilst they are at their work – periodic assessment of lung function is often needed, but it is difficult for some employees to visit the surgery. By taking the recording spirometer to them, and being able to store up to 20 different patient’s PEF and FEV1 on one machine, the inconvenience to them and their work schedule can be minimised.
