BNF for Children 2011-2012

634 15.1.2 Inhalational anaesthetics BNFC 2011–201215 AnaesthesiaBreast-feeding breast-feeding can be resumed assoon as mother has recovered sufficiently fromanesthesiaSide-effects see notes aboveIndication and doseInduction of anaesthesia. By inhalation through specifically calibratedvaporiserChild 1 month–18 years initially 0.5% thenincreased gradually according to response to 2–5%in oxygen or nitrous oxide-oxygenMaintenance of anaesthesia. By inhalation through specifically calibratedvaporiserChild 1 month–18 years 0.5–2% in oxygen, oroxygen-air, or nitrous oxide-oxygenISOFLURANECautions see notes above; interactions: Appendix 1(anaesthetics, general)Contra-indications see notes abovePregnancy may depress neonatal respiration if usedduring deliveryBreast-feeding breast-feeding can be resumed assoon as mother has recovered sufficiently fromanaesthesiaSide-effects see notes aboveIndication and doseInduction of anaesthesia. By inhalation through specifically calibratedvaporiserNeonate increased gradually according toresponse from 0.5–3% in oxygen or nitrous oxideoxygenChild 1 month–18 years increased graduallyaccording to response from 0.5–3% in oxygen ornitrous oxide-oxygenMaintenance of anaesthesia. By inhalation through specifically calibratedvaporiserNeonate 1–2.5% in nitrous oxide-oxygen; additional0.5–1% may be required if given with oxygenaloneChild 1 month–18 years 1–2.5% in nitrous oxideoxygen;additional 0.5–1% may be required if givenwith oxygen alone; caesarean section, 0.5–0.75%in nitrous oxide-oxygenSEVOFLURANECautions see notes above; susceptibility to QT-intervalprolongation; interactions: Appendix 1 (anaesthetics,general)Contra-indications see notes aboveRenal impairment use with cautionPregnancy may depress neonatal respiration if usedduring deliveryBreast-feeding breast-feeding can be resumed assoon as mother has recovered sufficiently fromanaesthesiaSide-effects see notes above; also urinary retention,leucopenia, agitation; cardiac arrest, torsade depointes, dystonia, and seizures also reportedIndication and doseInduction of anaesthesia. By inhalation through specifically calibratedvaporiserNeonate up to 4% in oxygen or nitrous oxideoxygen,according to responseChild 1 month–18 years initially 0.5–1% thenincreased gradually up to 8% in oxygen or nitrousoxide-oxygen, according to responseMaintenance of anaesthesia. By inhalation through specifically calibratedvaporiserNeonate 0.5–2% in oxygen or nitrous oxide-oxygen,according to responseChild 1 month–18 years 0.5–3% in oxygen ornitrous oxide-oxygen, according to responseNitrous oxideNitrous oxide is used for maintenance of anaesthesiaand, in sub-anaesthetic concentrations, for analgesia.For anaesthesia it is commonly used in a concentrationof 50 to 66% in oxygen as part of a balanced techniquein association with other inhalational or intravenousagents. Nitrous oxide is unsatisfactory as a sole anaestheticowing to lack of potency, but is useful as part of acombination of drugs since it allows a significant reductionin dosage.For analgesia (without loss of consciousness) a mixtureof nitrous oxide and oxygen containing 50% of each gas(Entonox c , Equanox c ) is used. Self-administrationusing a demand valve may be used in children whoare able to self-regulate their intake (usually over 5 yearsof age) for painful dressing changes, as an aid topostoperative physiotherapy, for wound debridementand in emergency ambulances.Nitrous oxide may have a deleterious effect if used inchildren with an air-containing closed space sincenitrous oxide diffuses into such a space with a resultingincrease in pressure. This effect may be dangerous inthe presence of a pneumothorax, which may enlarge tocompromise respiration, or in the presence of intracranialair after head injury. Hypoxia can occur immediatelyfollowing the administration of nitrous oxide; additionaloxygen should always be given for severalminutes after stopping the flow of nitrous oxide.Exposure of children to nitrous oxide for prolongedperiods, either by continuous or by intermittent administration,may result in megaloblastic anaemia owing tointerference with the action of vitamin B 12; neurologicaltoxic effects can occur without preceding overt haematologicalchanges. For the same reason, exposure oftheatre staff to nitrous oxide should be minimised.Depression of white cell formation may also occur.Assessment of plasma-vitamin B 12 concentration shouldbe considered before nitrous oxide anaesthesia in childrenat risk of deficiency, including children who have apoor or vegetarian diet and children with a history ofanaemia. Nitrous oxide should not be given continuouslyfor longer than 24 hours or more frequently thanevery 4 days without close supervision and haematologicalmonitoring.