Pulmonary function testing during the COVID-19 pandemic: Consensus recommendations by the Indian Chest Society

Abstract

The COVID-19 pandemic caused by the highly infectious SARS-CoV-2 has affected over 15.9 million people across 200 countries and caused more than 643,000 deaths.[1] As on July 27, 2020, India has ~14.5 lakh cases of COVID-19 and the number is still increasing.[2] The coronavirus is a highly infectious virus and spreads through droplets generated during coughing, sneezing, talking, and even breathing. Indirect contact via contaminated surfaces is another possible cause of infection.[3] The virus may remain viable on plastic (polypropylene) and stainless steel for up to 3 days but does not survive on cardboard for >1 day or on copper for >4 h. The virus is inactivated by soap, which destabilizes its lipid bilayer.[4] Screening of patients with non-COVID respiratory disease poses special problems at the triage and fever clinics of the hospital, as it would be difficult if not impossible to rule out COVID. Transmission risks during pulmonary function testing (PFT) for COVID-19 are unknown at present as data available are sparse, but the prevalence of the virus in the community, old age, severity of lung disease, and presence of immunosuppression are significant risk factors determining the risk of infection. PFT is a valuable tool in the assessment of respiratory disease. Spirometry is the key diagnostic test for airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), and is the most commonly performed test. The other tests include lung volumes and diffusing capacity measurement, impulse oscillometry (IOS), bronchoprovocation, and exercise physiology tests. Spirometry is an effort-dependent test wherein the patient takes a deep inhalation and blows forcefully into the spirometer flow sensor for at least 6 s. Many patients often cough during spirometry. Blowing forcefully and coughing are known to produce aerosol droplets that may contain millions of viruses from the respiratory tract, thereby significantly increasing the risk of transmitting SARS-CoV-2 viruses not only to people present in and around the spirometry room but also to other patients who subsequently perform the test in the same room. It is, therefore, important to avoid and postpone all spirometry tests as well as other PFTs unless it is absolutely necessary. Decisions regarding the conduct of PFTs need to balance the potential risks against the benefits from the test in making decisions. Several professional societies have advised to defer PFT still after the COVID-19 pandemic.[5,6,7,8] We concur with this recommendation and would recommend avoiding spirometry and other PFTs, during the COVID-19 pandemic. Physicians will have to rely more on taking a good history and, wherever possible, using validated diagnostic/screening questionnaires to arrive at a diagnosis and limit testing to the minimum required. In the following section, we have outlined the assessment of the need for testing, the precautions to be taken, and suggested approach to the clinical management of common respiratory conditions, without lung function testing.