WHO Model Prescribing Information: Drugs Used in Anaesthesia
(1989; 60 pages) [French] Voir le document au format PDF
Table des matières
Afficher le documentPreface
Afficher le documentIntroduction
Ouvrir ce répertoire et afficher son contenuPremedication
Fermer ce répertoireGeneral anaesthetics and oxygen
Afficher le documentKetamine
Afficher le documentThiopental
Afficher le documentEther
Afficher le documentHalothane
Afficher le documentTrichloroethylene
Afficher le documentNitrous oxide
Afficher le documentOxygen
Ouvrir ce répertoire et afficher son contenuLocal anaesthetics
Ouvrir ce répertoire et afficher son contenuNon-opioid analgesics
Ouvrir ce répertoire et afficher son contenuOpioid analgesics and antagonists
Ouvrir ce répertoire et afficher son contenuMuscle relaxants and cholinesterase inhibitors
Ouvrir ce répertoire et afficher son contenuBlood substitutes
Ouvrir ce répertoire et afficher son contenuSolutions for correcting water and electrolyte imbalance
Ouvrir ce répertoire et afficher son contenuAntacid for use in obstetric practice
Afficher le documentAnaesthesia at the District Hospital
Afficher le documentSelected WHO publications of related interest
Afficher le documentBack cover


Group: inhalational gas

General information

Pressurized oxygen cylinders for industrial use that contain gas at about 13 000 kPa are acceptable for use in anaesthesia. Cylinders intended for anaesthetic use are supplied with pin-index valves. They contain more than 99% oxygen by volume with small residues of nitrogen or argon. Cylinders should always be connected to anaesthetic apparatus by a suitable pressure-reducing valve and they should be replaced as soon as the cylinder pressure falls below 800 kPa.

Oxygen concentrators have recently been developed that offer a more economical source of oxygen and avert the need for frequent delivery and storage of cylinders.

Clinical information


To maintain an adequate oxygen tension in inhalational anaesthesia.

Dosage and administration

The concentration of oxygen in inspired anaesthetic gases should never be less than 21%.

It may be administered with the anaesthetic gases, or from a face mask or via a nasal catheter.


Combustion or sparking creates a danger of fire or explosion at high oxygen tensions. Use of cautery is contraindicated whenever oxygen is used in combination with ether. Reducing valves should not be greased, since this creates a danger of explosion.

Oxygen should not be used for longer or at a greater concentration than is necessary to prevent hypoxaemia.

Adverse effects

After prolonged administration, concentrations greater than 80% at atmospheric pressure have a toxic effect on the lungs, which presents initially as a mild substernal irritation progressing to pulmonary congestion, exudation and atelectasis.

Use of unnecessarily high concentrations of oxygen in incubators has led to the development of retrolental fibroplasia and permanent blindness in premature infants.


Oxygen is supplied under pressure in cylinders, which must be kept below 25°C.

Cylinders containing premixed oxygen 50% and nitrous oxide 50% are available for analgesia in some countries. However, the constituents separate out at -6°C, in which case adequate mixing must be assured before use. When the two components are supplied from separate cylinders a safety device must be installed that cuts off the flow of nitrous oxide should the oxygen pressure fall.

Identification of cylinders

An ISO standard1 requires that cylinders containing oxygen intended for medical use should bear the name of the contents in legible and permanent characters and, preferably, also the chemical symbol O2. The neck, from the valve to the shoulder, should be coloured white. Cylinders containing nitrous oxide and oxygen mixtures should be similarly labelled, and the neck coloured white and blue.

1International Standard 32. Gas cylinders for medical use - marking for identification of content. Switzerland, International Organization for Standardization, 1977.

vers la section précédente
vers la section suivante
Le Portail d'information - Médicaments essentiels et produits de santé a été conçu et est maintenu par l'ONG Human Info. Dernière mise à jour: le 29 octobre 2018