Non-invasive Methods of Measuring Lung Volume

The study design was chosen so that the investigators can directly compare results produced from wearable respiratory devices to spirometry. In order to do this in a protocolised manner, pulmonary function testing (PFT) clinic was chosen as the location of the study. Prior to the protocol being agreed, this was discussed and approved by the medical and nursing team in charge of the pulmonary function clinic. The investigators also approached patients in PFT clinic to discuss the proposed protocol and if they felt it was suitable for someone attending the clinic. The investigators received positive responses form this and any comments were considered in the final protocol.

Potential participants will be identified when they are booking into their clinic appointment. All patients will be attending PFT clinic as part of their clinical care; none will be attending as part of the study only. Patients will be asked if they would like to participate in the study after receiving the patient information leaflet and given time to ask any questions. The investigators aim to recruit 50 patients. This was deemed a suitable number to be able to undertake machine learning analysis with sufficient data. The investigators aim to recruit these 50 patients by attending PFT clinic weekly for approximately 3 months. They will vary the days of the week/clinic times they attend to gain a range of different patient groups as PFT clinics vary across the week.

After participants are fully consented, baseline data will be collected. This will involve a medical questionnaire that they will be asked to complete. The following data will be collected using the questionnaire:

Patient demographics: Age, sex, height, weight Comorbidities including past medical and surgical history Smoking status Alcohol status Current medications used Allergy status Reason for spirometry testing

Once the questionnaire is completed the participants will start the measurement section of the study. They will have two respiratory measurement devices attached. The Go Direct Respiration Sensor and a biosignal respiratory belts will both be fitted over light clothing so that participants will wear both sensors at once. They work in different ways but both use chest movement during breathing to determine respiratory effort and respiratory rate. They fit as bands around the chest. The investigators will aim to place the devices in similar positions in all participants (around the centre of the chest at the breast bone). Before confirming their placement, participants will be asked if the devices are comfortable and allow for normal breathing. These devices will track chest movement for the duration of the spirometry test and during timed activities of sitting, speaking, and walking. Once fitted, participants will continue with their spirometry appointment as planned. Some results from their spirometry testing will be noted in a secure database. This will include their inspiratory reserve volume, expiratory reserve volume, tidal volume and forced expiratory volume. The values alone will be recorded with no other patient data from the clinic appointment. At the end of the appointment, once they are back at baseline breathing, participants will be asked to read a short standardised script (in the form of a simple poem) over the course of 1-2 minutes that will allow us to analyse breathing patterns during speech. This will be coordinated with audio recordings of the speech which will be used in later data analysis of speech breathing. This may occur in the clinic room or another quiet room opposite the clinic depending on clinic timings. The final task before removal of the devices will be a short walk down the corridor outside of the clinical room to assess breathing during light exercise. This will be a set distance of 75 meters and should take around 1 minute to complete. Variability in timing of the walk will be accepted due to different patient walking speeds. The total data collection will take approximately 30 minutes. There should not be any additional clinic time required as the speech assessment and walking assessment can be undertaken outside of the clinic room. When the devices are removed, participants will be asked if they wish to comment on anything they felt during the study including discomfort from wearing the devices. The spirometry data will be collected by the PFT team as part of their routine testing and as such should not be influenced by the study. The researcher will not be involved in the spirometry testing portion of the study and therefore should not bias any results obtained.

Once the bands are removed the data will be downloaded onto a secure laptop with all patient identifying information removed. Following the collection of data for all 50 patients, the investigators aim to spend a further 1-2 months analysing the data and comparing it to the spirometry results. The final report will be available within 24 months of the study start date.

There will not be any planned interim analysis.

Inclusion criteria

• Subject: Human participants
• Gender: Any
• Aged 18 years and over.
• Able to give informed consent in English.
• Physically able to take part including a simple walking exercise
• Either in a asymptomatic participant group or planned for spirometry testing

Exclusion criteria

• Significant chest deformity or having a medical device fitted in (e.g. Implantable cardioverter defibrillator (ICD), Spinal cord stimulator, Pacemaker, etc)
• Pregnant
• Unable/uncomfortable to use a chest belt device for any reason.
• Patients <18 years old
• Unable to read and speak in English to an understandable level
• Unable to walk (aided or unaided) for 1 minute