Objective To check the efficiency of nitrous oxide as an analgesic method in our department.

Methods Prospective study based on collected data obtained (September 2007 to April 2008) at Emergency and Intensive Care Paediatrics Services. Reported items include: age, weight, procedure, use of other analgesic drug, vital sign monitoring, adverse effects, staff satisfaction and procedure duration.

Results We have collected data about 52 patients. Median age: 7.91 years (range 10 months to 15 years). 48 children (92.31%) were ⩾3 years old and four (7.69%) were younger. Procedures performed: lumbar punctures (40.38%); fractures or dislocation reduction (19.23%); laceration repairs (9.61%); onco-haematology procedures (19.23%, eight cases): bone marrow aspirations (3), intrathecal therapy (3), bone marrow aspirations with intrathecal therapy (2) and others (5.76%, three cases): foreign body extraction (1), venous cannulation (1), arthrocentesis (1). Nitrous oxide was used as the only systemic analgesic in 96.15%. In 30% of the aforementioned group a local anaesthesic was also employed: EMLA cream was applied in nine cases and six patients received lidocaine local infiltration. In two cases we employed endovenous fentanyl. Median inhalation length: 7.79 minutes; post-anaesthetic state of 4.89 minutes. Adverse reactions: (7.69%): nausea (1), vomiting (1), agitation (1) and headache with hyperventilation (1), which disappeared after some minutes. Staff satisfaction: excellent (63.46%), satisfied (26.92%) and poor (9.61%).

Conclusions Nitrous oxide is effective to perform short and relatively painless procedures, with few, light and transitory side effects. Age is an important factor, with worse results in children <3 years old, due to their lack of collaboration.