Entonox

Gas and air redirects here, for the 1923 film, see Gas and Air (film)

Entonox, referred to colloquially as gas and air, is an analgesic used to ease pain during labour, trauma and minor surgical procedures. Gas and Air is a 1923 film featuring Stan Laurel. Cast Stan Laurel - Phillup McCann Katherine Childbirth (also called labour, birth, partus or parturition) is the culmination of a Human Pregnancy or Treatment of physical trauma is described here and in First aid. Entonox is the trade name for a mixture of fifty percent nitrous oxide (N₂O or laughing gas) and fifty percent oxygen (O₂). Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Entonox is administered by inhalation from a cylinder at a pressure of 137 bar (in the UK) or from a pipeline supply. A gas cylinder or tank is a Pressure vessel used to store Gases at high Pressure. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure.

Its analgesic effect is strong (equivalent to 5 to 10 mg of morphine) and characterised by rapid onset and offset (i. Medical uses Morphine can be used as an analgesic in hospital settings to relieve pain in Myocardial infarction pain in e. it is very fast-acting and wears off very quickly).

Nitrous oxide is itself active (does not require any changes in the body to become active), and so has an onset in roughly the lung-brain circulation time. lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain This gives it a peak action 30s after the start of administration; Entonox should thus be used accordingly, e. g. use should begin 30s before a contraction becomes painful in labour. It is removed from the body unchanged via the lungs, and does not accumulate under normal conditions, explaining the rapid offset.

Entonox is self administered i. e. there is no requirement for an anaesthetist to be present to (amongst other things) control the mix of nitrous oxide and oxygen.

Nitrous oxide can act as an anaesthetic in high doses. Anesthesia, or anaesthesia (see spelling differences; from Greek grc αν- an-, "without" and grc αἲσθησις Self-administration of Entonox remains safe because if enough is inhaled to start to induce anaesthesia, the patient becomes unable to hold the valve, and so will drop it and soon exhale the residual gas. The 50% oxygen in Entonox ensures the patient will have sufficient oxygen in their system for a short period of apnoea to be safe.

Nitrous oxide and oxygen will separate at low temperatures (<4 °C), which will permit administration of hypoxic mixtures. The Celsius Temperature scale was previously known as the centigrade scale. Thus it should never be given from a cold cylinder, and the cylinder should be inverted a few times to mix the gases before use.

Nitrous oxide is more soluble than oxygen and nitrogen, so will tend to diffuse into any air spaces within the body. This makes it dangerous to use in patients with pneumothorax or who have recently been scuba diving, and there are cautions over its use with any bowel obstruction. Scuba diving is swimming underwater, or taking part in another activity while using a Scuba set.

Entonox is produced by the BOC Group, which also owns the trademark. The BOC Group plc was the official name of the multinational Industrial gas company more commonly known as BOC, and now a part of The Linde Group.

The ability to combine nitrous oxide and oxygen at high pressure while remaining in the gaseous form is due to the Poynting effect (after John Henry Poynting, an English physicist). Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. The ability to combine Nitrous oxide and Oxygen at high Pressure while remaining in the gaseous form is due to the Poynting effect (after John Henry

The Poynting effect involves the dissolution of gaseous O₂ when bubbled through liquid N₂O, with vaporisation of the liquid to form a gaseous O₂/N₂O mixture.

External links

Dictionary

-proper noun

(pharmacology) A mixture of nitrous oxide and oxygen used as an analgesic, especially during labour.