Validity of Measuring Preoperative Fitness Using Seismofit

Study Overview
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Brief Summary
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Physical fitness levels of people waiting for a planned operation are often measured using an exercise test. This is because fitness levels help doctors make a plan to improve each person's chances of a successful recovery after their planned operation. The exercise test requires skilled staff, expensive equipment, a 1 hour appointment, and the patient to exercise heavily during the test. Ventriject, a small to medium sized enterprise, have designed a device called Seismofit that estimates fitness levels of people from a measurement taken whilst laying down. It measures the vibrations of the chest wall caused by the beating heart and uses this information with additional information, such as height, weight and sex, to estimate fitness. The measurement takes around 5 minutes to perform, does not require heavy exercise, expensive equipment or skilled staff. The Seismofit device was shown to be accurate in young fairly fit people. It has not been tested in people who undergo an exercise test before an operation, who are less fit on average compared to the people that the device was originally tested on. It is likely that the calculations used to estimate fitness levels with the Seismofit device will need to be adjusted for people waiting for an operation. There are two parts to this study. The first part aims to estimate up to 50 people's fitness with the Seismofit device and use directly measured fitness from their standard exercise test before their operation to adjust the calculations for estimating fitness. The second part of this study aims to have a further 50 people undergo the Seismofit device measurement and compare the estimated fitness level with the results from the standard exercise test before an operation. This is to see if the Seismofit device is valid at estimating fitness in people awaiting surgery.

Official Title
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The Validity of a Seismocardiography Device to Estimate Peak Oxygen Uptake in Patients Awaiting Major Elective Surgery

Conditions
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Preoperative Care, Validity

Intervention / Treatment
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* Device: Seismofit


Participation Criteria
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Eligibility Criteria
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Inclusion: Adults awaiting major or complex elective surgery classified by the NICE NG45 guideline Referred for and capable of performing a maximum effort CPET as part of standard care within their preoperative assessment Able to be fully supine for 5 minutes Exclusion: Pacemaker, implantable defibrillator, or any other implantable electronic device in situ Permanent Atrial fibrillation, or other persistent arrhythmia (such as, atrial flutter, bigeminy, trigeminy, frequent premature atrial/ventricular complexes, 2nd degree heart block) documented in the patient's medical history Body mass index (BMI) >35 kg.m-2 Severe COPD (defined as FEV1 % predicted <50% [GOLD report, 2022]) Pectus excavatum or other chest wall deformity Claudication that limits exercise tolerance Unable to perform maximal CPET Refusal to give informed consent Presence of an absolute contraindication to CPET detailed in the POETTS clinical guideline (Levett et al. 2018).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Seismofit Validity<br>Participants will undergo a seismocardiography assessment, whilst supine, using the seismofit device. This will estimate their peak oxygen consumption. Participants will then undergo a maximal cardiopulmonary exercise test (CPET), where peak oxygen consumption will be measured. The Seismofit estimated peak oxygen consumption will be compared with CPET measured peak oxygen consumption (unless prespecified criteria for a maximal exercise test are not met). | Device: Seismofit<br>* The Seismofit device uses seismocardiography to estimate peak oxygen consumption from a resting measurement. This study will assess its validity against the gold standard measure of peak oxygen consumption, cardiopulmonary exercise test, conducted as part of standard care.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phase 1 outcome - refine algorithm | Up to 50 patients awaiting major surgery will have their estimated V̇O2peak (ml/kg/min) recorded using the Seismofit device and actual V̇O2peak (ml/kg/min) measured in their standard preoperative cardiopulmonary exercise test. The Seismofit algorithm will be adjusted using these data points with machine learning. | Up to 6 months | 
| Phase 2 outcome - validity of refined algorithm | The correlation between the new seismofit algorithm estimate of V̇O2peak (ml/kg/min) and CPET measured and verified V̇O2peak (ml/kg/min) in up to 50 preoperative patients that have valid tests in accordance with maximal exercise test criteria stated in the protocol (RER > 1.10 or maximum heart rate attained within 10 beats of predicted maximum). | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bland-Altman analysis | Agreement between Seismofit estimated V̇O2peak (ml/kg/min) and CPET measured V̇O2peak (ml/kg/min) using Bland-Altman analysis. | 12 months | 
| Existing V̇O2peak predicted equation analysis | To calculate the correlation and agreement between existing equations used to predict V̇O2peak (ml/kg/min) with directly measured V̇O2peak (ml/kg/min) to observe how these data compare with the Seismofit correlation and agreement data. | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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VO2max, Seismocardiography, Preoperative Exercise, Peak oxygen uptake, Cardiopulmonary exercise test