CompletedInterventional

Feasibility of providing additional oxygen in patients with resistant high blood pressure and obstructive sleep apnoea

High blood pressure that stays high despite medication can increase the risk of heart attacks and strokes. Many people with stubborn high blood pressure also have obstructive sleep apnoea (OSA), a condition where breathing repeatedly stops and starts during sleep. The usual treatment for sleep apnoea is a continuous positive airway pressure (CPAP) machine, which uses a tight-fitting mask. However, many people find CPAP uncomfortable and stop using it. Researchers at Oxford University Hospitals are testing whether breathing extra oxygen at night through soft nasal tubes or a simple mask is a better alternative. Participants first take a simple two-night sleep test at home. Those found to have sleep apnoea will use a home oxygen machine for two weeks. The goal is to see if this treatment is easy to use and acceptable to patients.

At a glance

Status

Completed

Sponsor

University of Oxford

Enrolment target

Start

30 Apr 2021

Estimated completion

31 Dec 2023

Obstructive sleep apnoea in patients with difficult-to-treat hypertension

What is this study about?

High blood pressure is very common, but for some people, blood pressure readings remain high even while taking regular tablets. Doctors call this difficult-to-treat hypertension. Over time, persistent high blood pressure puts extra strain on your heart and blood vessels, raising the risk of serious health conditions such as heart attacks and strokes.

Many people with hard-to-treat high blood pressure also have obstructive sleep apnoea, often without realising it. With sleep apnoea, the muscles in the throat relax during sleep, briefly closing the airway. This causes loud snoring, broken sleep, and drops in blood oxygen levels. These nightly oxygen drops trigger stress responses in the body that can push blood pressure even higher.

The standard treatment for sleep apnoea is a CPAP machine, which blows air through a tight mask to keep the airway open. While CPAP works well, many people find it awkward, noisy, or uncomfortable to wear every night. In an earlier study, researchers found that simply giving people gentle oxygen overnight helped lower their morning blood pressure without needing a tight mask.

This new study is checking whether providing overnight oxygen at home is practical, safe, and comfortable for people with both high blood pressure and sleep apnoea. Because this is a feasibility study, its main purpose is to test the practical setup and see how patients get on with the equipment, paving the way for larger future trials.

Key takeaways

Tests whether gentle overnight oxygen is a practical treatment for people with high blood pressure and sleep apnoea.
Begins with an easy, two-night sleep monitor test done in your own bed.
Participants with sleep apnoea try a home oxygen machine overnight for 14 nights.
Helps researchers gather essential practical information before setting up larger clinical trials.
You continue your usual medications, and taking part is completely voluntary.

Who may be eligible?

You may be able to join this study if you are 18 or older and have high blood pressure that remains higher than normal despite taking at least one blood pressure medicine for at least four weeks. You do not need to know whether you have sleep apnoea, as the researchers will test you for it during the first stage of the trial. You will also need access to the internet, an email address, and a smartphone, tablet, or computer for video and phone appointments.

This study is not suitable for people who have severe kidney or liver disease. You also cannot take part if you have an operation planned during the study period that requires a general anaesthetic, or if you have another serious medical condition that might make taking part unsafe.

Because oxygen can make fires catch and spread quickly, you must have a strictly smoke-free home. You cannot use the oxygen equipment near lit cigarettes, e-cigarettes, or open flames such as candles and gas heaters.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or over.
I have high blood pressure that is not fully controlled despite taking at least one medicine for 4 weeks or more.
I have an internet connection, a compatible device, and an email address for remote appointments.
I live in a home where nobody smokes and where oxygen equipment can be kept away from open flames.
I do not have severe liver or kidney problems and have no surgeries under general anaesthetic planned soon.

Answer every question to see your result.

What does participation involve?

Taking part lasts around three to four weeks and is split into two stages. In Stage 1, you will have two short phone or video calls (around 20 minutes each). The team will send a sleep kit to your home. You will wear a small chest sensor, a finger clip, and soft nasal tubes for two nights while you sleep, then post the kit back in a pre-paid envelope. If the test shows you do not have sleep apnoea, your time in the study ends here.

If the test shows you have sleep apnoea, you will move to Stage 2. You will visit the clinic for about one to two hours. The team will measure your height, weight, neck size, blood pressure, and heart rate, and take a tiny drop of blood from your earlobe to check carbon dioxide levels. You will be given a home oxygen machine and a wristwatch-style monitor to use every night for 14 nights.

After two weeks, you will return to the clinic for a final check-up and return the equipment. You will continue taking your normal blood pressure tablets as prescribed throughout the entire study.

Potential risks and benefits

Taking part may benefit you by finding out whether you have undiagnosed sleep apnoea, and the study team will discuss treatment options with you once the trial ends. The main safety risk is fire, so nobody may smoke or use open flames anywhere near the oxygen machine. Oxygen therapy can occasionally cause mild side effects such as a dry or stuffy nose, minor nosebleeds, or morning headaches. The earlobe blood test can cause a brief pinch and minor bruising. Taking part is entirely your choice, and you can withdraw at any time without giving a reason and without affecting your normal NHS medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

John Radcliffe Hopsital
City only
Oxford, England

Common questions

Do I need to stop taking my regular blood pressure tablets?

No. You should continue taking all your prescribed medications exactly as your doctor told you.

What happens if the sleep test does not record properly?

If the home sleep kit fails to capture a clear recording, the research team can post it to you again so you can repeat the test up to two times.

Is the home oxygen machine loud or difficult to use?

Home oxygen concentrators produce a gentle hum. The research team will show you exactly how to switch it on before sleep and off in the morning.

Do I have to pay for the equipment or postage?

No. All study equipment, home deliveries, and return postage envelopes are provided free of charge.

What happens if the sleep test shows I do not have sleep apnoea?

The team will explain your test results to you, and your participation in the study will end after Stage 1.

How to find out more

Christopher Turnbull

Christopher.Turnbull@ouh.nhs.uk None provided Official trial record

Always speak to your GP or specialist before deciding to take part in a study.