Aims: To describe the experience of using high concentration nitrous oxide (N 2 O) relative analgesia administered by nursing staff in children undergoing minor procedures in the emergency department (ED) and to demonstrate its safety. Method: Data were collected over a 12 month period for all procedures in the ED performed under nurse administered N 2 O sedation. All children greater than 12 months of age requiring a minor procedure who had no contraindication to the use of N 2 O were considered for sedation by this method. The primary outcome measure was the incidence of a major complication namely respiratory distress or hypoxia during the procedure. Secondary outcome measures were minor complications and the maximum concentration of N 2 O used. Results: Data were collected for a total of 224 episodes of nurse administered N 2 O sedation over a 12 month period. In 73.2% of children no complications were recorded. One major complication was recorded (respiratory distress) and the most common minor complication was mask intolerance in 17%. The mean maximum concentration of N 2 O used was 60.2%. Conclusions: N 2 O is a safe analgesic in children over the age of 1 year undergoing painful or stressful procedures in the ED. It may safely be administered in concentrations of up to 70% by nursing staff after appropriate training.M any ill and injured children attending emergency departments (EDs) require sedation and analgesia for brief procedures that are painful or anxiety provoking but that do not justify a general anaesthetic.1 In our ED these procedures include cannulation, wound repair, minor fracture manipulation, lumbar puncture, bone marrow aspiration, and removal of foreign bodies from ears and noses. Choosing a safe and efficacious sedative agent for these procedures that is suitable for use in the ED is a daily consideration for emergency physicians.Procedural sedation has been defined by the American College of Emergency Physicians as "a technique of administering sedatives or dissociative agents with or without analgesics to induce a state that allows the patient to tolerate unpleasant procedures while maintaining cardiorespiratory function . . ." 2 Relative analgesia refers to this state of analgesia and sedation.Nitrous oxide (N 2 O) has a number of advantages that make its use preferable to other agents for relative analgesia in the ED. It provides analgesia within three minutes of inhalation and this analgesic effect disappears less than four minutes after cessation.3 The physical properties of N 2 O account for its efficacy as a short acting agent. Because it is not metabolised, N 2 O is almost completely eliminated by the lungs in an unchanged state. It does not bind to any carrier proteins during transport and therefore avoids the difficulties of drug interactions. 4 Previous studies have demonstrated that N 2 O may safely be used, when administered by doctors, at concentrations of up to 50% in children for a wide variety of procedures.3 5-10 Our hospital has developed a programme to train nurses...
