Skin testing in the preoperative diagnosis of anaesthetic allergy

The Preoperative Detection of Risk of Anaphylaxis during Anaesthesia

In 144 patients who were referred to an anaesthetic allergy clinic because of perceived risk of anaphylaxis during anaesthesia, the only ‘at risk’ group that could be identified was patients with a history of unexplained severe adverse reaction during previous anaesthesia. Twenty-two of 45 patients with such a history had positive skin tests to an anaesthetic drug. Twenty-one positive tests were to neuromuscular blocking drugs and one to an opiate. In 18 of these patients the medical records were available and an adverse event had been recorded consistent with anaphylaxis. On the contrary, investigation of patients without a previous adverse reaction did not appear to be of value. These findings suggest that those patients with a history of a severe undiagnosed adverse event during previous anaesthesia should be investigated with preoperative skin-testing before undergoing further elective surgery.

Pediatric mastocytosis: routine anesthetic management for a complex disease

BACKGROUND

Pediatric mastocytosis consists of a spectrum of clinical variants characterized by increased numbers of resident mast cells in various organ systems. Mast cells are instrumental in mediating anaphylaxis and patients with mastocytosis are at risk to develop provoked and unprovoked episodes of anaphylaxis.

METHODS

We examined perianesthetic records of patients with pediatric mastocytosis who were anesthetized for diagnostic and surgical procedures from 1993 to 2006. In addition, we conducted a literature review of the anesthetic experience in pediatric mastocytosis.

RESULTS

Twenty-two patients with pediatric mastocytosis, with a median age of 3.2 yr (range, 6 mo-20 yr) at the time of the procedure, were anesthetized for 29 diagnostic and surgical procedures. All variants of the disease are represented in this series. Most patients had a history of flushing, pruritus, gastro-esophageal reflux diseases, and abdominal pain; one patient had a history of spontaneous anaphylaxis. Routine anesthetic techniques were used and, despite the complexity of the disease, the perioperative courses were uncomplicated and without serious adverse events.

CONCLUSIONS

We reviewed the main features of pediatric mastocytosis, its anesthetic and perioperative implications, and describe a practical approach to the anesthetic management of pediatric patients with the disease. Although many drugs used routinely in anesthesia reportedly caused mast cell degranulation, deviations from routine anesthesia techniques are not necessarily warranted. However, an understanding of the anesthetic implications of the disease and meticulous preparation to treat possible adverse events are advised.

[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.

Detection of thiopentone-reactive IgE antibodies following anaphylactoid reactions during anaesthesia

A radioimmunoassay was developed to detect IgE antibodies to the anaesthetic induction agent thiopentone. Significant levels of thiopentone-reactive IgE antibodies were found in the sera of two patients who had experienced life-threatening anaphylactoid reactions following administration of the drug. Inhibition experiments revealed that cross-reactivity occurs between the drug-reactive IgE antibodies and four barbiturate analogues pentobarbitone, phenobarbitone, barbitone and methohexital. The assay should supplement skin testing for the detection of patients with potentially lethal sensitivity to thiopentone.