An anesthetic is a substance that induces anesthesia, a state of temporary loss of sensation and awareness.

An astronaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft.

Emergency services and rescue services are organizations that ensure public safety, security, and health by addressing and resolving different emergencies.

A firefighter is a highly trained individual whose primary role is to extinguish and prevent fires, as well as provide emergency medical services.

A fire department (North American English) or fire brigade (Commonwealth English), also known as a fire company, fire authority, fire district, fire and rescue, or fire service in some areas, is an organization that provides fire prevention and fire suppression services as well as other rescue services.

Hyperbaric medicine is a medical treatment that involves the use of high-pressure oxygen environments, known as hyperbaric chambers, to heal certain medical conditions.

Hyperbaric oxygen therapy (HBOT) is a medical treatment that involves breathing in pure oxygen in a pressurized chamber.