Breath ammonia in patients with liver disease
Research type
Research Study
Full title
Transforming the management of hepatic encephalopathy using non-invasive breath ammonia, in patients with chronic liver disease.
IRAS ID
310850
Contact name
Julian Hamilton-Shield
Contact email
Sponsor organisation
University Hospitals Bristol NHS Foundation Trust
Duration of Study in the UK
2 years, 0 months, 30 days
Research summary
Research Summary:
The urea cycle (UC) is a series of liver-based biochemical processes that are essential for the removal of ammonia – a toxic by-product of protein breakdown. In healthy individuals, the UC allows ammonia to be converted into urea, which can be removed in the urine. In people with liver disease (LD) or urea cycle defects (UCDs), this process becomes severely impaired, causing ammonia to build up in the body. Elevated levels of ammonia can damage the brain, a condition known as hyperammonaemic encephalopathy (HE). This debilitating condition is difficult to manage, as symptoms vary in context, and over time. For this reason, regular ammonia level testing is essential. Currently the only method for doing so is by measuring ammonia in the blood, which can be problematic on many levels.
We will investigate whether a device (called the AmBeR device) for measuring ammonia in breath correlates with the concentration of ammonia in blood. This device has been trialled in children with UCDs. However, owing to excellent disease management, patient ammonia levels were very low. We will now trial the device in patients with liver disease, as such patients have significantly higher ammonia levels than healthy individuals.
If successful, this device would allow self-management of ammonia levels in a simple and non-invasive way. In addition to significantly improving quality of life, there would also be a significant reduction in time and cost to the healthcare system. The purpose of this proposal is to gather sufficient preliminary feasibility data to warrant such a study through the NIHR.Summary of Results:
The study aimed to answer one question.
Does a device measuring breath ammonia in an individual with liver disease, reflect their blood ammonia levels in a reliable and accurate manner. Blood ammonia levels when raised, are an important measure of liver failure.
The device did not measure breath ammonia in a reliable way to predict what a blood ammonia level is. Thus the device is not yet ready for managing patient care.
REC name
London - Harrow Research Ethics Committee
REC reference
22/LO/0280
Date of REC Opinion
25 May 2022
REC opinion
Further Information Favourable Opinion