BOS Education Day 2022

    Today is the first ever BOS Education Day - an initiative from the Lung Transplant Foundation designed to raise awareness and provide education on this very important post-transplant complication. Here we share some information on BOS and how home spirometry can be helpful in the early detection of this condition. 

    What is BOS? 

    BOS stands for Bronchiolitis Obliterans Syndrome. It is a lung problem that can occur after lung transplantation and is the most common form of chronic lung transplant rejection. More than half of lung transplant recipients develop BOS within five years of transplantation. BOS results in a progressive loss of lung function. BOS can also occur following haematopoietic stem cell transplantation (HSCT). 

    The initial symptoms of BOS can mimic a lung infection, but BOS is not due to infection. The main change seen with BOS is scarring of the small airways of the transplanted lung(s). This scarring leads to the narrowing of the airways, limiting airflow with loss of lung function. Early after the onset of BOS, a person may not have any symptoms but will develop breathlessness and chronic cough as BOS gets worse. BOS is a progressive condition but there is high individual variability in the rate of progression and there is no clear way to predict the course of BOS over time for a given person.

    Home Spirometry in the Detection of BOS

    Spirometry is a key test used in the diagnosis of BOS. In particular it is the forced expiratory volume in 1 second (FEV1), which measures the amount of air a patient can blow out in the first second of a forced exhalation, which is important. Patients post-lung transplantation will typically have their lung function monitored at regular intervals, usually around every 3 months. A decline in FEV1 raises the concern for BOS, and several other tests are required to then formally diagnose BOS.

    Clinical trials have shown daily home spirometry has been shown to lead to earlier detection of BOS when compared with standard pulmonary function testing in patients post lung transplant. More frequent home spirometry can also have advantages in the earlier detection of other forms of rejection and infection in patients who are post transplant compared to clinic based monitoring alone.

    For more information on the role of home spirometry in post lung transplantation care you can catch up with a webinar from the Lung Transplant foundation featuring our specialist Joseph Vincent. We partner with multiple lung transplantation centres across the US, UK and Ireland, providing not only home spirometry but also holistic remote monitoring of multiple parameters which are important in post transplant care, such as body weight, blood pressure and temperature. You can read about the clinical experience from these programmes please see the case studies from Ireland’s National Heart and Lung Transplantation Centre and NYU Langone, New York. Or for further information please don’t hesitate to contact us at