[Evaluation of analgesic protocol with nitrous oxide and EMLA cream during botulinum toxin injections in children]

Abstract

Aims: To evaluate the efficiency and tolerance of analgesic treatment with nitrous oxide and topical eutectic mixture of local anesthetics (EMLA) in children undergoing botulinum toxin injections for focal spasticity.

Methods: Prospective study including 40 consecutive patients aged 2 to 17 years, most with cerebral palsy, undergoing botulinum toxin injections. Ten had severe cerebral palsy with cognitive deficiency. For most patients the treatment involved several muscles, with several injections per muscle. The total number of injections varied from 1 to 25. The procedure was performed with topical anesthesia with EMLA and inhalation of nitrous oxide (50% nitrous oxide, 50% oxygen). Reactions were recorded by the staff (a practician, a nurse, an auxiliary staff member and an internist) and whether they related to the injection or were nonspecific.

Results: A total of 45% of patients showed no clinical manifestation of pain; for 30%, reactions were crying and withdrawal directly related to the injections; and for 25%, manifestations seemed nonspecific and mainly related to overall anxiety and discomfort. In 3 patients, moderate side effects were observed (visual hallucinations and euphoria).

Discussion: Nitrous oxide analgesic with topical EMLA was efficient for children undergoing botulinum toxin injections but remained insufficient for half of our patients, and modification of the protocol is needed in some cases. Precise evaluation of acute pain is difficult in children with major cognitive deficits. Clinical manifestations are related to pain but also to overall anxiety and stress.