Nitrous oxide

Indications & Dose:

Maintenance of anaesthesia in conjunction with other anaesthetic agents

• BY INHALATION

Adult: 50–66 %, to be administered using suitable anaesthetic apparatus in oxygen

Analgesia

• BY INHALATION

Adult: Up to 50 %, to be administered using suitable anaesthetic apparatus in oxygen, adjusted according to the patient’s needs

IMPORTANT SAFETY INFORMATION

Nitrous oxide should only be administered by, or under the direct supervision of, personnel experienced in its use, with adequate training in anaesthesia and airway management, and when resuscitation equipment is available.

Contraindications:

Side Effects:

Depression of white cell formation . hypoxia . megaloblastic anaemia . neurological toxic effects

Hypoxia Hypoxia can occur immediately following the administration of nitrous oxide; additional oxygen should always be given for several minutes after stopping the flow of nitrous oxide.

Prolonged exposure Exposure of patients to nitrous oxide for prolonged periods, either by continuous or by intermittent administration, may result in megaloblastic anaemia owing to interference with the action of vitamin B12; neurological toxic effects can occur without preceding overt haematological changes. Depression of white cell formation may also occur.

PREGNANCY

May depress neonatal respiration if used during delivery.

BREAST FEEDING

Breast-feeding can be resumed as soon as mother has recovered sufficiently from anaesthesia.

MONITORING REQUIREMENTS

Assessment of plasma-vitamin B12 concentration should be considered in those at risk of deficiency, including the elderly, those who have a poor, vegetarian, or vegan diet, and those with a history of anaemia.

Nitrous oxide should not be given continuously for longer than 24 hours or more frequently than every 4 days without close supervision and haematological monitoring.

DIRECTIONS FOR ADMINISTRATION

For analgesia (without loss of consciousness), a mixture of nitrous oxide and oxygen containing 50% of each gas  is used.

Cautions:

Entrapped air following recent underwater dive . pneumothorax . presence of intracranial air after head injury . recent intra-ocular gas injection

CAUTIONS, FURTHER INFORMATION

Nitrous oxide may have a deleterious effect if used in patients with an air-containing closed space since nitrous oxide diffuses into such a space with a resulting increase in pressure. This effect may be dangerous in conditions such as pneumothorax, which may enlarge to compromise respiration, or in the presence of intracranial air after head injury, entrapped air following recent underwater dive, or recent intra-ocular gas injection. 

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Lactations:

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Counselling:

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Patient And Carer Advice: