Allergy, plasma IgE level and anaphylactoid response: a hypothesis

Adverse reaction to neuromuscular blockers: frequency, investigation, and epidemiology

A survey is presented of neuromuscular drug involvement in 390 clinically severe anaphylactoid reactions (grades II-IV reported to a Sheffield laboratory from 1988 to the end of 1992 from hospitals throughout the UK. Despite advances in patient monitoring and newer drugs, the reporting frequency and individual drug involvement were remarkably similar to those of a previous report from the laboratory in 1988. The highly immunogenic drug suxamethonium still predominated (48% of reports), but there was now much reduced use of the similarly immunogenic drug, alcuronium. The incidence of reactions to vecuronium and atracurium remained similar (12% and 18% reports, respectively) and acceptable to the anaesthetist. However, in choosing drugs for individual patients, the anaesthetist may wish to note that vecuronium reactors mainly showed bronchospasm, and atracurium reactors hypotension. By a systematic laboratory investigation, based on measurement of plasma tryptase and urinary methylhistamine, reaction mechanisms were assessed in 53 reactions. Despite their overall clinical similarity, analysis revealed that only one reaction in three was likely to be due to IgE-mediated anaphylaxis (Type 1). Not only was suxamethonium the most frequently reported drug, but in this study 11 reactions were identified as Type 1 response: no allergic reactions were identified for either vecuronium or atracurium, although single cases were identified for alcuronium, gallamine, and tubocurarine, with two unidentified. The remaining reactions were judged to be non-immune, although most involved mast cell degranulation. These reactions were no less hazardous than Type 1 reactions (one death), and two deaths were recorded. The importance of laboratory investigation as a feature of postreaction care is emphasized.

Recurrent anaphylactoid reaction during caesarean section

A 28-year-old woman presented for emergency Caesarean section at 31 weeks' gestation with deranged liver function and a history of recurrent anaphylactoid reactions during previous pregnancy-related anaesthetics. The anaesthetic management and outcome of this case is presented.

Anaphylactoid reaction to vecuronium followed by systemic reaction to skin testing

An unusual case is presented of a systemic anaphylactoid reaction to tubocurarine and subsequently to vecuronium. Intradermal testing with vecuronium following the latter response was negative at recommended test dose levels but at a higher concentration it initiated a hazardous systemic response. The laboratory investigations and possible mechanisms involved in this unusual case are discussed in detail since they may relate to other patients who experience anaphylactoid responses to anaesthetic drugs and who then undergo intradermal testing.

The effects of cremophor EL in the anaesthetized dog

The effects of cremophor EL were studied in 13 anaesthetized, paralyzed and ventilated dogs. Twenty per cent cremophor EL in a dose of 4.3 +/- 0.92 ml was infused at a rate of 30 ml X hr-1. In seven dogs, thoracopulmonary compliance, heart rate, systemic arterial pressure (SAP), pulmonary pressures (PAP, PCWP, RAP), cardiac output (CO) and platelet and white cell counts, were measured before the injection of cremophor EL, at the end of infusion and 5, 10, 30 and 150 minutes after the end of infusion. In six dogs, SAP, CO, and blood volume were measured before the injection of cremophor EL, at the end of infusion and 10, 30, 90 and 150 minutes after the end of infusion. Plasma histamine and catecholamines were assayed before the injection of cremophor EL and 2, 5, 10, 30, 90 and 150 minutes after starting the infusion. Cremophor EL induced a marked, sustained and significant decrease in SAP at the end of infusion and at 5, 10 and 30 minutes after the completion of the infusion (-68, -71, -70 and -43 per cent respectively), in PCWP, RAP and CO (-78 per cent at the end of infusion, -32 per cent 150 minutes after the end of infusion). Heart rate and systemic vascular resistance did not vary significantly. Pulmonary vascular resistance increased at the end of infusion, five and ten minutes after the end of infusion (+734, +548 and +439 per cent respectively). Plasma volume decreased 10 and 30 minutes after the end of infusion (-28 and -30.5 per cent respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchospasm following the use of vecuronium

A case history is presented which records bronchospasm due to vecuronium. Immunological investigations, including basophil degranulation tests, indicated that the bronchospasm was not caused by direct histamine release and was not IgE mediated. It was of interest that intradermal testing gave a positive wheal response against neuromuscular agents other than those involved in the anaesthetic procedure under investigation. A positive reaction to vecuronium was only obtained when given in a high concentration and accords with the general belief that vecuronium has extremely low potential for histamine release.

Skin testing in the investigation of reactions to intravenous anaesthetic drugs. A prospective trial of atracurium and tubocurarine

Intradermal skin testing is widely used to determine the causative drugs of presumed anaphylactic anaesthetic reactions. This paper sets out to evaluate the usefulness of skin tests, both intradermal and prick testing, in the prediction of anaesthetic reactions. The muscle relaxant drugs tubocurarine and atracurium were chosen for study since they are known to produce a high incidence of minor histaminoid reactions. A trial was conducted in 22 female patients about to undergo elective gynaecological surgery for non-malignant conditions. In intradermal tests, positive wheal and flare reactions to one or other relaxant (diluted 1 in 1,000) occurred in 17 patients and reactions to both drugs in 11 patients. Despite this high incidence of positive reactions, none of the patients had received either drug previously, a view confirmed by the negative results of prick testing. Likewise, when anaesthetized for surgery using atracurium or tubocurarine allocated randomly, the minor histaminoid manifestations observed showed no correlation whatsoever with the intradermal tests results. The results of the trial, combined with external reports to this centre, indicate that intradermal testing of anaesthetic drugs, particularly muscle relaxants, produces a high incidence of false positive results. This probably reflects their pharmacological activity rather than antigenicity. It is recommended, therefore, that skin testing should be reserved for situations in which there are strong indications from laboratory tests, backed by case history, of immune sensitization.

Histaminoid responses to atracurium, vecuronium and tubocurarine

Sixty patients scheduled for elective surgery underwent intradermal testing with 0.1 ml of the following solutions diluted in 0.9% saline: vecuronium and tubocurarine (1 in 1,000), atracurium (1 in 1,000 and 1 in 10,000), thiopentone (1 in 100) and also a 0.9% saline control. Thirty minutes later, an area of erythema of greater than 1.5 cm, or a wheal exceeding 1.0 cm in diameter, was recorded as a positive reaction. The patients then randomly received equipotent doses of atracurium, vecuronium or tubocurarine during a standardized anaesthetic induction. Any cutaneous reaction and the percentage fall in systolic pressure three minutes after administration of the relaxant were recorded. In 51 patients plasma IgE levels were measured. The incidence of positive cutaneous reactions to intradermal and intravenous relaxants was significantly different with each agent (p less than 0.01). The percentage fall in systolic pressure after tubocurarine was significantly different relative to the other two agents (p less than 0.01). This was regarded as reflecting potency in releasing histamine and placed the relaxants in the same order: tubocurarine, atracurium and vecuronium. The response to intradermal administration was no guide to the subsequent response after intravenous administration of the three relaxants. IgE levels below 15 IU X ml-1 occurred significantly more often in females and were associated with a significantly higher incidence of cutaneous reactions after intradermal atracurium (1 in 1,000 and 1 in 10,000) (p less than 0.05 and 0.001 respectively) and tubocurarine (1 in 1,000). With these two agents, generalized flushing after intravenous administration was also more common in this group, relative to the normal/high IgE group.