https://www.gosh.nhs.uk/conditions-and-treatments/procedures-and-treatments/multiple-breath-washout-test/
Multiple Breath Washout test
A multiple breath washout (MBW) test is a non-invasive lung function test used to measure how efficient gas mixing is in the lungs. These tests are typically performed in specialist centres.
This page from Great Ormond Street Hospital (GOSH) describes what will happen during an MBW test.
What does the test involve?
The test involves your child breathing on a circuit for approximately 3 minutes, this may be performed by your child wearing a facemask (children under 6 years of age) or using a silicone mouthpiece like a snorkel and wearing a nose clip (those over 6 years of age).
The test measures the ‘wash-out’ of the nitrogen which we all have in the air in our lungs. To do this your child will breathe air followed by 100% oxygen through the circuit, while we measure the nitrogen being breathed out. The test outcome measurements are the Lung Clearance Index (LCI) and Functional Residual Capacity (FRC), these are the results reported to your doctor and care team.
Whilst on the breathing circuit we need your child to breathe in and out normally. To ensure they are relaxed and comfortable to do this we offer a distraction. During testing they can choose to watch their favourite programme or film.
We’ll repeat this a few times to obtain technically acceptable results, with plenty of rest allowed between trials.
How long will it take?
The appointment takes approximately 30 minutes, but some tests may be slightly longer in younger patients who need to time to familiarise themselves with the equipment.
Important
Please note, the person bringing your child for the test should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.
Further information
If you need any further advice or information about Multiple breath washout, you can contact the Lung Function Lab on 020 7405 9200 ext 5456 or via the MyGosh portal.