Parental consent is usually used as a substitute where a child is too young to give consent for a procedure. In Australia and the UK once a child is able to understand the procedure and associated risks they are considered "Gillick competent" and their consent outweighs the parent's, but until then the parent is the one who gives consent on the child's behalf. Parental consent is also used as a substitute when the child is incapacitated by injury or illness such that they are incapable of giving informed consent. Health practitioners and first aiders can also assume consent in life-threatening situations where the patient is incapable of giving consent (e.g. giving CPR to someone in cardiac arrest).