[Predictive value of intradermal tests using muscle-relaxing drugs]

A retrospective postal inquiry was carried out to find out a possible relation between the results of intradermal tests carried out for a previous anaesthetic and the course of a second anaesthetic performed afterwards. This study included 350 patients who have had an intradermal test to vecuronium, alcuronium, suxamethonium, gallamine, pancuronium, thiopentone, fentanyl and droperidol between March 1984 and November 1986. Eighty-nine did not reply (25.4%), 183 (52.3%) did not undergo new general anaesthetic since the skin tests, whilst 78 (22.3%) did. The inquiry was then sent to the 73 anaesthetists corresponding to the last group of patients. The 51 complete answers included 62 anaesthetics. Twenty-four patients had negative intradermal tests before the new anaesthetic, the other 27 having had a test positive to at least one muscle relaxant. Of these latter, 16 were given a muscle relaxant during their general anaesthetic, selected among those resulting in a negative intradermal test. Thirteen had undergone skin testing because of an anaphylactic reaction during induction. No new anaphylactic reaction was observed. Three anaesthetists only were not aware of the results of the intradermal tests at the time of the new anaesthetic. These data tend to demonstrate that a muscle relaxant could be injected in a patient who has had a previous anaphylactic reaction with positive intradermal tests, provided that the drug chosen for the new anaesthetic does not give a positive intradermal reaction.