The epidemiology of anaesthetic anaphylactoid reactions in Australasia

Scandinavian Clinical Practice Guidelines on the diagnosis, management and follow-up of anaphylaxis during anaesthesia

The present approach to the diagnosis, management and follow-up of anaphylaxis during anaesthesia varies in the Scandinavian countries. The main purpose of these Scandinavian Clinical Practice Guidelines is to increase the awareness about anaphylaxis during anaesthesia amongst anaesthesiologists. It is hoped that increased focus on the subject will lead to prompt diagnosis, rapid and correct treatment, and standardised management of patients with anaphylactic reactions during anaesthesia across Scandinavia. The recommendations are based on the best available evidence in the literature, which, owing to the rare and unforeseeable nature of anaphylaxis, mainly includes case series and expert opinion (grade of evidence IV and V). These guidelines include an overview of the epidemiology of anaphylactic reactions during anaesthesia. A treatment algorithm is suggested, with emphasis on the incremental titration of adrenaline (epinephrine) and fluid therapy as first-line treatment. Recommendations for primary and secondary follow-up are given, bearing in mind that there are variations in geography and resources in the different countries. A list of National Centres from which anaesthesiologists can seek advice concerning follow-up procedures is provided. In addition, an algorithm is included with advice on how to manage patients with previous suspected anaphylaxis during anaesthesia. Lastly, Appendix 2 provides an overview of the incidence, mechanisms and possibilities for follow-up for some common drug groups.

Anaphylactic/anaphylactoid reactions to anaesthetic and associated agents. Skin prick tests in aetiological diagnosis

Fifty-one patients were referred in one year (1992) for investigation of immediate type anaphylactic/anaphylactoid reactions during anaesthesia. Skin prick tests were made with 23 anaesthetic and associated agents in the concentrations used clinically. Definite or probable causes were identified by immediate type wealing reactions, supported by the clinical history in 36 of the 46 in whom a diagnosis of anaphylaxis was made. These comprised mainly the neuromuscular relaxants, chiefly suxamethonium (18); atracurium (6); gallamine (2); one each alcuronium; pancuronium; vecuronium and tubocurarine, as well as alfentanil (1); Gelofusine (2); cefuroxime (1) and latex (2). The materials for performing the skin prick test are readily available and it can be very helpful in making important aetiological diagnoses.

Mechanisms of activation of human mast cells and basophils by general anesthetic drugs

A study was performed about the effects of increasing concentrations of muscle relaxants (suxamethonium, d-tubocurarine, vecuronium, and atracurium), hypnotics (propofol, ketamine, and thiopental), opioids (morphine, buprenorphine, and fentanyl), and benzodiazepines (diazepam, flunitrazepam, and midazolam) on the release of preformed (histamine and tryptase) and de novo synthesized (prostaglandin D2: PGD2 and peptide-leukotriene C4: LTC4) chemical mediators from human basophils and mast cells isolated from skin (HSMC), lung parenchyma (HLMC) and heart tissue (HHMC). None of the drugs tested induced the release of histamine or LTC4 from basophils of normal donors. Suxamethonium did not induce mediator release from any type of human mast cell tested. Only the highest concentration of d-tubocurarine used caused histamine release from HSMC and HLMC. Atracurium, more than vecuronium, induced concentration-dependent histamine release from HSMC and HLMC. Propofol induced a concentration-dependent histamine release from HLMC, but not from HHMC. Only the highest concentrations of ketamine and thiopental used caused a significant release of histamine from HLMC. The muscle relaxants and hypnotics examined did not induce any de novo synthesis of PGD2 or LTC4 in mast cells. Morphine only induced histamine and tryptase release from HSMC, but not the de novo synthesis of PGD2. In contrast, buprenorphine caused histamine and tryptase release from HLMC, and not from HSMC, whilst it also induced de novo synthesis of PGD2 and LTC4 in HLMC. Fentanyl did not give any histamine and tryptase release from mast cells. Diazepam and flunitrazepam only induced a small release of histamine from mast cells, whereas midazolam caused the release of histamine from HLMC. The biochemical pathways underlying the release of mediators from human mast cells induced by drugs used during general anaesthesia are different from those underlying the immune release of histamine. From the results obtained with the in vitro model described here, it is clear that new drugs promising for the anesthesiologic arena should be tested in vitro before their potential histamine-releasing activity is experienced in vivo.

Atopy and anaphylactic reactions to suxamethonium

Muscle relaxants are widely used for general anesthesia and may be responsible for IgE-dependent anaphylactic reactions (AR). A controversial issue in the field of drug allergy is whether ARs are more frequent or severe in atopic subjects. Thus, we performed a case-control study comparing the distribution of various clinical and biologic signs of atopy. The case group included 32 patients with a history of AR to suxamethonium, the most commonly used muscle relaxant. The control group included 128 subjects, matched to the case group according to age, gender, and socioeconomic status. The case group consisted mainly of young and middle-aged women. Distribution of symptoms suggestive of atopy and of skin tests and specific IgE to common aeroallergens was similar in both groups. In contrast, total serum IgE level was much higher in the case group, suggesting the presence of specific IgE against suxamethonium or other drugs. Thus, despite previous studies in the literature, atopy is not a risk factor for the occurrence of anaphylactic reactions to muscle relaxants. As AR to suxamethonium is a pure model of an IgE-dependent drug allergy, our data do not support a relationship between atopy and allergic drug reactions.

Anaphylactic reaction during anaesthesia associated with positive intradermal skin test to fentanyl

A 29 year-old female patient suffered vascular collapse which became apparent immediately after general anaesthesia. Resuscitation was prolonged and difficult, and complicated by the need for reoperation. Based on the time history, fentanyl was suspected as the causative agent. Fentanyl allergy was confirmed by skin testing one month later. The case is discussed, and the possible reasons for the delay in appearance of symptoms and signs are considered.

[Severe anaphylactoid accidents occurring during general anesthesia]

Four patients were studied following an anaphylactoid accident occurring during general anaesthesia. Histamine release was assessed on clinical signs, basophil degranulation and, in one case, an early serum histamine peak. Past medical history revealed previous allergies in all cases. An immunological study showed that IgE, CH50, C3 and C4 serum levels were within the normal range. Skin reactivity to histamine was normal in all but one case. In every case, one of the drugs used during the anaesthetic gave a positive skin test and was considered as the causative agent. There were discrepancies between the in vitro and in vivo tests of basophil degranulation, a second drug being positive in one case, and several drugs inducing abnormal degranulation reactions in the other cases. The drugs considered as involved in these accidents are noteworthy: suxamethonium (two cases), fluid gelatin (Plasmion) and droperidol. The results are discussed by the authors.

[Plasma histamine assay in anaphylactoid reactions of the anesthetized subject. Effects of collection methods and plasma preparation on measured histamine]

Plasma histamine assay in man is indicated for the diagnosis of histamine release, as well as the elucidation of the mechanisms of adverse drug reactions, and the identification of clinical situations in anaesthesia and surgery where a pathological plasma histamine level may occur. Normal and pathological plasma histamine levels vary considerably in the literature. Data from various studies, especially one involving 300 patients in Heidelberg (G.F.R.), allow us to define the normal range for human plasma histamine as 0-1.0 ng . ml-1 . Values greater than 1 ng . ml-1 have to be considered as pathological. The problems related to blood collection and plasma preparation are considered here. Any judgement concerning the method described in the test must take into consideration our long experience of 15 years with it, its reliability in clinical conditions, its practicability, its relatively low cost, and finally, the absence of radioisotopes.