Testing for spirometry, in the COVID-19 era should follow the same principles for high-quality testing and proper interpretation as previously. (Reference to general procedures). However, two additional aspects must be considered by the occupational physician:
1) Should the testing be temporarily deferred?
2) What procedures are necessary to minimize the risk of infection to the patient and to staff?
The physician should consider whether the testing is actually required, whether it may be deferred, and if any special regulations are applicable. It is premature to speculate whether the pandemic will lead to permanent changes in these practices.
Spirometry involves forced expiratory maneuvers
, creating significant amounts of droplets
. These may contain viruses. In addition, equipment is used by multiple patients, and, in many cases, patients handle non-disposable portions of the equipment. Therefore, we suggest the following:
a) Urgent Requirement:
If spirometry testing is urgently needed for the diagnosis or treatment of a patient, appropriate arrangements should be made. However, such necessity is rare in occupational medicine practice.
b) Routine Periodic Surveillance Testing:
In general, such testing should be delayed until the prevalence of COVID-19 disease in the community decreases and improved exposure control in the testing facility has been instituted. OSHA has provided specific guidance supporting the deferral of such testing for an indefinite time.1
ACOEM has also issued a statement supporting this view.2
c) New patient testing:
The occupational physician should use expert judgment to determine if there is a bona fide reason to conduct the testing at this time or if it may be delayed.
If testing is absolutely needed, procedures should be adjusted to minimize risk to patient and staff. Many of these suggestions are temporary, whereas others may become standard practice in the future.
a) Screen patients with a questionnaire and exclude those with suspicion of active disease. Follow CDC rather guidelines to determine when either covered or exposed patients may be considered to constitute low risk of transmission.
b) Testing should be performed in a well-ventilated room, preferably with exhaust to the outside for HEPA filter, and air recirculation is used. Some recommend that testing be performed in a negative air pressure room; this may often be achieved by modifying the HVAC balance. If portable spirometers are available, testing may be performed out of doors.
c) The room should be carefully disinfected regularly and clean between patients. This will decrease the number of patients who can be tested on any day.
e) A high-efficiency in-line filter should be used between the patient and the spirometer. Equipment with a single use sensor that may be discarded after use by a single patient is preferable to equipment such as pneumotachs used for multiple patients.
f) The in-line microbial filter must not interfere with the accuracy or precision of the spirometer instrument. Therefore, only filters that have been specifically recommended by the manufacturer for use with its equipment should be employed.
g) Testing should nearly always be limited to expiratory flow without recording the inspiratory limb of the flow-volume curve.
h) Staff performing the testing should use adequate respiratory protection
(fit tested N95
). They should use disposable gloves and wash hands thoroughly before and after each test.
i) Testing should generally be limited to spirometry and determination of diffusing capacity.4
Whole body plethysmography may be performed if the party box and equipment are thoroughly disinfected.
Under multiple standards, we should require that the person performing the testing has successfully passed a NIOSH-certified course and that person periodically recertifies. OSHA has issued a statement extending certificates expiring in the 2019-20 year period.
Respirator fit testing is an important part of the respirator evaluation. With poor respirator fit, qualitative testing with Bitrex™ or irritant smoke will induce cough potentially contaminating testing apparatus. Quantitative testing equipment may also be subject to contamination. Some quantitative fit testing apparatus require use of ported respirators which are shared. Manufacturers’ recommendations for cleaning and disinfection of this fit testing equipment and shared respirators, if any, should be followed.
Deferral of fit testing should be considered if the individual has previously been fit tested with the same respirator, and has experienced no facial changes likely to alter respirator fit. Fit testing of new respirator users should not be deferred.
Updates: Professionals responsible for the testing program should regularly check for updates on guidance and requirements. The following are available at the date of writing:
- OSHA Guidance recommending and permitting delay of testing for periodic surveillance1
- ACOEM statement concerning spirometry2
- American Thoracic Society statement about pulmonary function testing3
- European Respiratory Society (ERS) recommendations. This is particularly useful for its emphasis on procedural modifications.4
- OSHA statement on spirometry certification5
- Spirometry in Occupational Health—2020. Journal of Occupational and Environmental Medicine 62.5 (2020): e208-e230.