Important safety information
Anaesthetics 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.
Drug safety update
December 2014: Nitrous oxide: neurological and haematological toxic effects
Clinical Guideline 50% Nitrous Oxide / 50% Oxygen (Entonox / Equanox) For Acute Pain Management in Adults, Sept 2020 (Review due 2024)
Desflurane is a rapid acting volatile liquid anaesthetic; it is reported to have about one-fifth the potency of isoflurane. Emergence and recovery from anaesthesia are particularly rapid because of its low solubility. Desflurane is not recommended for induction of anaesthesia as it is irritant to the upper respiratory tract; cough, breath-holding, apnoea, laryngospasm and increased secretions can occur.
Sevoflurane is a rapid acting volatile liquid anaesthetic and is more potent than deslurane. Emergency and recovery are partcularly rapid, but slower than desflurane. Sevoflurane is non-irritant and is therefore often used for inhalational induction of anaesthesia; it has little effect on heart rhythm compared with other volative liquid anaesthetics.
Isoflurane is a volatile liquid anaesthetic. Heart rhythm is generally stable during isolfurane anaesthesia, but heart-rate can rise, particularly in younger patients. Systemic arterial pressure and cardiac output can fall, owing to a decrease in systemic vascular resistance. Muscle relaxation occurs and the effects of muscle relaxant drugs are potentiated. Isoflurane can irritate mucous membranes, causing cough, breath-holding and laryngospasm. Isoflurane is the preferred inhalational anaesthetic for use in obstetrics.
Nitrous oxide is used in sub-anaesthetic concentrations for analgesia. A mixture of nitrous oxide 50% and oxygen 50% (Entonox/Equanox®) is used to produce analgesia without loss of consciousness. Patient self-administration, using a demand valve, is useful in obstetric practice, for painful change of dressings, as an aid to postoperative physiotherapy and in emergency ambulances.