1. Types of medical gases
There are 7 kinds of gases commonly used: oxygen, nitrogen, nitrous oxide, argon, helium, carbon dioxide and compressed air.
Medical gases are gases used in a variety of medical procedures such as anaesthesia. The medical gas system also includes vacuum suction system and anesthesia gas scavenging systems.
2. Medical gas properties and uses
(1) Oxygen – is the most basic gas for life, and used medically to supplement oxygen for oxygen-deficient patients. Directly inhaling high purity oxygen is harmful to the human body. Long-term use therefore of oxygen concentration generally does not exceed 30-40%. Patients breathe oxygen through the oxygen flowmeter and critically ill patients breathe oxygen through the ventilator. It is also used in high-pressure tanks to treat diving, gas poisoning, and for drug nebulization.
(2) Nitrous oxide – has an anesthetic and analgesic effect when small amounts are inhaled. It is used as an anesthetic agent when mixed, and fed through a closed ventilator.
(3) Carbon dioxide – is used to inflate the abdominal cavity and colon for laparoscopy and colonoscopies. It is also used for laboratory cultures of bacteria (anaerobic bacteria). It can be made into dry ice by applying pressure (5.2 atmospheres) and cooling (-56.6°C below). Medical dry ice is used for cryotherapy to treat cataracts and vascular diseases.
(4) Argon, Helium – are a colorless, odorless, non-toxic inert gas. It is medically used for argon gas knife, gas knife, and other surgical instruments.
(5) Compressed air – is used to deliver power to oral surgical instruments, orthopedic instruments, and ventilators.
(6) Nitrogen – is a colorless, odorless, non-toxic, non-flammable gas. At room temperature, it is inactive at room temperature and does not react chemically with ordinary metals. Medically used to drive medical equipment and tools. Liquid nitrogen is commonly used in cryosurgery in surgery, stomatology, gynecology, and ophthalmology.