Home lung monitoring has potential to enhance respiratory care

Toronto – Home lung monitoring has the potential to enhance respiratory care. But even with a multitude of affordable devices on the market, there are still technical challenges, a need for more data demonstrating effectiveness, and issues around digital privacy to resolve. There is buzz on the topic because of changes in respiratory care made in response to the pandemic. Many pulmonary function testing (PFT) laboratories were closed or significantly reduced their testing capacity to help mitigate the spread of COVID19, according to a paper in Chest by a group of Toronto respirologists. Because of the pandemic, “both traditional and innovative alternatives to conventional testing must now be explored. These may include peak expiratory flow devices, electronic portable spirometers, portable exhaled nitric oxide measurement, airwave oscillometry devices, and novel digital health tools such as smartphone microphone spirometers and mobile health technologies along with integration of machine learning approaches,” the researchers wrote. They pointed out that the pandemic provided an opportunity to implement existing alternatives to PFT and conduct clinical evaluations of them. New approaches outside the lab may enhance the management of respiratory diseases, empowering patients and giving additional clinical data. Whether new models for testing and monitoring will be adopted post-COVID is uncertain. Many metrics, such as vital signs and symptoms, are already measured remotely, said Dr. Ron Dandurand, an assistant professor of medicine at McGill University. He spoke at the recent virtual annual conference of the Canadian Thoracic Society where he gave an overview of home lung function monitoring (he was not one of the Chest article authors). In Canada, remote monitoring makes sense, especially in areas where patients are geographically distant from testing centers. Widespread use isn’t ready for prime time—but it may be getting close. The past 20 years has seen an explosion in the miniaturization of portable monitoring devices which have increased accuracy and reliability. This makes home monitoring compelling, though there are caveats, he told The Medical Post in an interview. There are three key types of home-use devices that could help manage patients at home; Peak expiratory flow (PEF), spirometry and oscillometry. Handheld PEF devices are already used for patient self-management, usually of asthma. “But it’s not a very reliable metric, because it’s very effort-dependent,” Dr. Dandurand said. Studies investigating the potential for using PEF instead of PFT for the diagnosis and management of patients with asthma and COPD have mixed results. Plus, some studies show that agreement between PEF and spirometry can be highly variable, meaning it’s not a reliable tool for clinical decision-making. Still, “it’s cheap and available, and there’s a long history of using it,” Dr. Dandurand said. PEF is a guideline-recommended option to facilitate patient self-management in asthma but has a less well-defined use in COPD. The next step up is home-spirometry. Spirometry is a forced breathing manoeuvre which measures both forced vital capacity (the total air that comes out after taking a deep breath then breathing out as hard and fast as possible) and forced expiratory volume (FEV1) in one second. “This is a very difficult manoeuvre for patients to do. It needs to be done at least three times for reliability, and it can be exhausting to do.… Nonetheless, it’s a robust but indirect measure of what’s going on with lung mechanics,” he said. Some home-spirometry devices can be coupled with dashboards or communication systems which can get the information directly to the care provider. The biggest challenge with home spirometry is that it is highly dependent on the technique used. “Unless there is a trained technician executing the test in your clinic, it’s very difficult to get good results—which makes even more problems for you when you’re doing it in a home setting,” Dr. Dandurand said. According to the Chest paper, studies of electronic portable spirometers found them “to be comparable with conventional laboratory spirometry in several chronic respiratory conditions, such as asthma and COPD, cystic fibrosis, idiopathic pulmonary fibrosis, and post-lung and hematopoietic stem cell transplant monitoring.” However, there are issues around cost, variable reporting of accuracy levels, and a need to validate results against reference standards when starting them for new patients. Also, lung volume or diffusion capacity measurements still must be done in a lab. Yet, the authors state home-spirometry is useful for a number of patients with chronic lung conditions and may be a valuable in-home alternative to PFTs. The next level up, according to Dr. Dandurand is home-oscillometry which is proving to have several advantages over conventional PFT. “Oscillometry is a way of directly measuring what we’re interested in; the resistive, the elastic and the inertive properties of the respiratory system which together form the impedance related to breathing. And it’s faster and easier, more robust, and more sensitive than spirometry,” he said. The technology can measure small airways function much better than spirometry and this is important because “the small airways probably account for not more than 20% of the resistance of the entire respiratory system. And you have to lose half, if not more, for the traditional spirometry to show an abnormal signal,” he said. Oscillometry provides significantly earlier diagnosis of conditions such as COPD than spirometry. But the technology is not well-known among clinicians, has complex metrics and has a steep learning curve for good interpretation. While there are multiple home-monitoring devices in each of these three categories already on the market, it’s not yet known how much added value they give to clinical care. Studies are still being conducted, and to date many results are mixed. “If these devices become more mature, in my opinion home-monitoring will be the way to go. But they’re not yet ready for widespread use,” Dr. Dandurand said. The researchers writing in Chest stated “Although no current individual alternative is sufficient to replace conventional testing in all patients, many of the options reviewed may provide acceptable and actionable physiological information to improve clinical management.”

Home lung monitoring has potential to enhance respiratory care

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