In the emergency department, a sick child is usually seen first by a nurse. Their job is to quickly assess how sick the child is and what immediate care is needed. The nurse will usually use electronic devices to check vital signs, such as body temperature, pulse rate and blood oxygen levels. However, the nurse normally has to manually count the respiration rate (this is the number of breaths taken each minute) because there is no suitable device which can do this automatically. Knowing the respiration rate is very important because if it is not normal, the nurse knows that the child may be seriously ill. Counting the respiration rate of sick children can be difficult and takes up a lot of time, especially if the child is upset, crying or moving about. To overcome this problem we are developing a device that automatically measures respiration rate in children. It works by directly sensing the air coming from the nose or the mouth when held at a small distance (about 30 cm) from the face. So far, the device has been shown to work in a research laboratory at Sheffield Hallam University. The aim is to develop it into a handheld, userfriendly device, ensuring that it complies with strict safety regulations. This application is to carry out an evaluation of our new device against its gold standard, on adult volunteers and on children attending Sheffield Children's Hospital for sleep studies as part of their clinical care. In the future, when nurses use the device they will easily be able to measure each child's respiration rate so that the most seriously ill children will be identified earlier and get correct treatment more quickly. This will ensure that the right children get admitted to intensive care units sooner and, in some cases, child deaths will be prevented.

Inclusion Criteria:

• any person requiring and able to perform a respiratory rate measurement

Exclusion Criteria:

• people assessed as too unwell to participate by clinical team
• people for whom English is not first language as no interpreting service included in budget

Adults or children requiring a respiratory rate measurement