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Nitrous oxide for painful procedures
Nitrous oxide is a colourless, sweet smelling gas, that when mixed in equal proportions with oxygen has excellent and strong analgesic or pain killing effects. Relaxation, sedation and a feeling of dissociation may be experienced. Onset is rapid, usually within a few minutes. Duration is short so it is eliminated quickly. Its use is safe with minimal side effects.
The gas is prescribed by a doctor and administered by a trained nurse. A continuous mask or hand held demand valve are the usual methods to deliver the gas. The advantage of the patient controlled demand system is that overdose or over-sedation is much less likely to occur. Absorption occurs through the lungs. Analgesic tablets may be used to supplement the effects.
The gas is indicated for short painful procedures. Common uses include muscle paralysing injections, filler injections, removal of sutures, removal of drains, minor procedures and dressing changes. It is contra-indicated with impaired levels of consciousness, sedated patients, airway restrictions, pneumothorax, chronic lung diseases, very low temperatures (-6’C), tracheostomy or laryngectomy patients (demands valve but not the continuous flow mask), bowel obstruction and long periods of use.
Advantages are being non-invasive, rapid onset, short duration, patient controlled (on demand use), safety and minimal side effects. Disadvantages are listed as drowsiness, dry mouth and excitability. Blood changes usually only occur with frequent or long term use. Excessive breathing may cause dizziness or tingling. Rarely nausea and vomiting may be experienced.
It is important to carefully explain and demonstrate the use which then includes consent. Single use, disposable mouth pieces are used. Regular, steady breaths for a few minutes, establishes correct blood levels and this is maintained by normal breathing. Most practitioners will monitor the pulse and blood oxygen levels. Careful observation after the procedure ensures full elimination of the gas. Our practice recommends waiting for 30 minutes or feeling completely free of any effects before driving.
No adverse effects have been noted in breast feeding mothers. Eight studies have not shown any evidence of foetal malformations in humans, when used during pregnancy.
Nitrous oxide is a beneficial adjuvant to rooms based procedures. It is highly effective and well tolerated with a high level of safety.