Entonox

The introduction of a mixture of 50% oxygen and 50% nitrous oxide was first described in the early 1960’s. The 50:50 mix (using oxygen as a carrying gas) imparts the benefits of oxygen, and the pain relief of the nitrous oxide without producing unconsciousness. In midwifery it replaced the use of gas and air and has become a widely used form of analgesia. Its uses are diverse in nature ranging from childbirth, to wound dressings, to dentistry. More and more research is being carried out looking at new applications for this very useful and safe product.

Uses

Entonox is a very potent analgesic with a very rapid onset of action and is quickly eliminated from the body. It is widely used by midwives and the ambulance service, it is also the ideal analgesic for short surgical procedures. Examples:

Childbirth
Acute trauma
Short term relief in dental work
Fracture manipulation
Joint manipulation
Endoscopy
Venopuncture
Wound and burn dressings, wound debridement and suturing

Mode of action

The nitrous oxide in Entonox suppresses spinal impulses and may supress supraspinal pathways. Nitrous oxide is thought to work on the N-methyl-d-aspartase receptors inhibiting pain. It is also thought to have an effect on the GABA cells increasing inhibition of nerve cells causing drowsiness and sleep.

Contra-indications / side effects

Entonox is 50% Nitrous Oxide, and nitrous oxide should not be used with any condition where air is entrapped within a body and where its expansion might be dangerous such as:

Head injuries with impairment of consciousness
Artificial, traumatic or spontaneous pneumothorax
Air embolism
Decompression sickness
Following a recent dive
Following air encephelography
Severe bullous emphysema
During myringoplasty
·Gross abdominal distension
·Maxillofacial injuries.

When using Entonox for more than 24 hours, monitoring of peripheral blood for signs of megablastic anaemia and leukopenia should be undertaken. The nitrous oxide in entonox is readily eliminated from the body but driving should not be undertaken until twelve hours have elapsed from its use. Rarely, inactivation of vitamin B12 may occur which can then interfere with folate metabolism which can result in bone marrow changes. This is usually related to prolonged usage of the gas or where an existing deficiency is present.

Entonox cylinder factsheets

Entonox is available with our new cylinder technology, for a downloadable Entonox CD cylinder (440 litre) factsheet click here. For a downloadable Entonox HX cylinder (2200 litre) factsheet click here.

More information

For more information on Entonox, contact your local account manager for a meeting or to request product related literature. Reference guides, brochures, Parents guide (for childbirth), videos and safety data sheets are available.

You can also call our call centre on 0800 111 333

or e-mail BOC Medical Customer enquiries team.