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

Perioperative anaphylaxis

BACKGROUND AND OBJECTIVE

Anaphylaxis remains one of the potential causes of perioperative death, being generally unanticipated and quickly progress to a life threatening situation. A narrative review of perioperative anaphylaxis is performed.

CONTENT

The diagnostic tests are primarily to avoid further major events. The mainstays of treatment are adrenaline and intravenous fluids.

CONCLUSION

The anesthesiologist should be familiar with the proper diagnosis, management and monitoring of perioperative anaphylaxis.

[Perioperative anaphylaxis]

BACKGROUND AND OBJECTIVE

Anaphylaxis remains one of the potential causes of perioperative death, being generally unanticipated and quickly progressing to a life-threatening situation. A review of perioperative anaphylaxis is performed.

CONTENT

The diagnostic tests are important mainly to avoid further major events. The mainstays of treatment are adrenaline and intravenous fluids.

CONCLUSION

The anesthesiologist should be familiar with the proper diagnosis, management and monitoring of perioperative anaphylaxis.

Severe anaphylaxis: the secret ingredient

In this case report, we describe a healthy urological patient who suffered severe intraoperative anaphylaxis to chlorhexidine, an ingredient contained in frequently used lubricants (Instillagel, Endosgel). Chlorhexidine is a well-known skin disinfectant and antiseptic component in mouthwash or other over the counter antiseptic pharmaceuticals. There is little awareness that commonly used lubricants may contain hidden chlorhexidine. After severe intraoperative anaphylaxis, it is important to investigate all potential (including hidden) agents that might have caused this life-threatening reaction.

Anaphylaxis-induced hyperfibrinolysis in pregnancy

Anaphylaxis during pregnancy is rare but life threatening to both mother and fetus. The anaesthetist may be unexpectedly faced with an obstructing airway, severe bronchospasm and cardiac arrest requiring perimortem caesarean delivery to relieve aortocaval compression. We present a case of anaphylaxis-induced hyperfibrinolysis, an infrequently discussed complication that could exacerbate postpartum haemorrhage and hamper resuscitative efforts.

Multi-centre retrospective analysis of anaphylaxis during general anaesthesia in the United Kingdom: aetiology and diagnostic performance of acute serum tryptase

This is the first multi-centre retrospective survey from the United Kingdom to evaluate the aetiology and diagnostic performance of tryptase in anaphylaxis during general anaesthesia (GA). Data were collected retrospectively (2005-12) from 161 patients [mean ± standard deviation (s.d.), 50 ± 15 years] referred to four regional UK centres. Receiver operating characteristic curves (ROC) were constructed to assess the utility of tryptase measurements in the diagnosis of immunoglobulin (Ig)E-mediated anaphylaxis and the performance of percentage change from baseline [percentage change (PC)] and absolute tryptase (AT) quantitation. An IgE-mediated cause was identified in 103 patients (64%); neuromuscular blocking agents (NMBA) constituted the leading cause (38%) followed by antibiotics (8%), patent blue dye (6%), chlorhexidine (5%) and other agents (7%). In contrast to previous reports, latex-induced anaphylaxis was rare (0·6%). A non-IgE-mediated cause was attributed in 10 patients (6%) and no cause could be established in 48 cases (30%). Three serial tryptase measurements were available in 34% of patients and a ROC analysis of area under the curve (AUC) showed comparable performance for PC and AT. A ≥ 80% PPV for identifying an IgE-mediated anaphylaxis was achieved with a PC of >141% or an AT of >15·7 mg/l. NMBAs were the leading cause of anaphylaxis, followed by antibiotics, with latex allergy being uncommon. Chlorhexidine and patent blue dye are emerging important health-care-associated allergens that may lead to anaphylaxis. An elevated acute serum tryptase (PC >141%, AT >15·7 mg/l) is highly predictive of IgE-mediated anaphylaxis, and both methods of interpretation are comparable.

Three suspected cases of sugammadex-induced anaphylactic shock

Background

Sugammadex has a unique mechanism of action and is widely used because of its safety and efficacy. A few recent reports have described allergic reactions to clinical doses of sugammadex. We hereby describe another series of cases of possible anaphylaxis to sugammadex.

Case presentation

We present three suspected cases of sugammadex-induced anaphylactic shock, including a 13-year-old boy who underwent laparoscopic appendectomy, a 75-year-old woman who underwent left knee arthroplasty, and a 34-year-old man who underwent left pansinectomy for sinobronchitis. All three patients received general anesthesia with rocuronium and their tracheas were intubated. Shortly after injection of sugammadex for reversal of rocuronium, all of them experienced a decrease in blood pressure along with mucocutaneous erythema. In the most severe case, reintubation after extubation was required due to difficulty in manual ventilation. All patients recovered with anti-allergic therapy. On later investigation, all three patients had a positive skin reaction to sugammadex.

Conclusion

Our results suggest that physicians using sugammadex should be aware of the possibility of sugammadex-induced anaphylaxis.

Perioperative allergic reactions: experience in a Flemish referral centre

BACKGROUND

The incidence of perioperative anaphylactic reactions is overall estimated to be 1 per 10,000-20,000 anaesthetic procedures. We performed a retrospective analysis of patients referred to a University Allergy Centre in Belgium with the suspicion of an allergic reaction during or shortly after general anaesthesia.

OBJECTIVES

Our aim was to assess the causes of perioperative allergic reactions, to evaluate cross-reactivity among neuromuscular blocking agents (NMBA) and to analyze the diagnostic relevance of tryptase levels in the discrimination between IgE and non-IgE-mediated reactions.

METHODS

A total of 119 patients, referred from 2007 to 2011 were included. The diagnostic protocol consisted in case history, serum tryptase measurements, immunoassays and skin tests.

RESULTS

A diagnosis of IgE-mediated reaction was established in 76 cases (63.9%). The most common agents were NMBA (61.8%), antibiotics (14.5%), latex (9.2%) and chlorhexidine (5.2%). Rocuronium was the most frequently causative NMBA (48.9%). Vecuronium cross-reactivity was established by skin testing in 47.6% of cases. Cisatracurium was the NMBA most frequently tolerated (cross-reaction in 13.9%). In 23.4% of NMBA allergic patients, the reaction occurred on the first exposure. Most IgE-mediated reactions occurred during the induction phase (72.4%). Latex-induced reactions occurred mainly during maintenance and recovery phases (71.4%; p<0.02). Mean tryptase values were significantly higher in patients with IgE-mediated reactions (p=0.0001), than in those with no identified cause.

CONCLUSIONS

NMBA, antibiotics, latex and chlorhexidine were the main culprits of IgE-mediated perioperative reactions. Uncertainties remain concerning the specificity and sensitivity of skin testing. Tryptase assays can be useful in the discrimination of IgE and non-IgE-mediated reactions.

Fatal anaphylaxis with neuromuscular blocking agents: a risk factor and management analysis

BACKGROUND

Anaphylactic reactions to neuromuscular blocking agents (NMBAs) can be severe and even fatal. Our aim was to evaluate mortality rate in France from anaphylactic reactions to NMBAs, to identify risk factors for a fatal outcome, and to describe management of the cases that proved fatal.

METHODS

The French National Pharmacovigilance Database was queried for reports of NMBA anaphylaxis that occurred between January 2000 and December 2011. A questionnaire was sent to regional pharmacovigilance centers to obtain further information on the management of cases with a fatal outcome.

RESULTS

Two thousand and twenty-two cases of NMBA hypersensitivity were retrieved, of which 84 were fatal (4.1%). Among the 1247 cases of severe NMBA anaphylaxis (grades 3 and 4), independent risk factors associated with a fatal outcome in a multivariate analysis were male gender (female gender: OR = 0.4; 95% CI 0.2-0.7; P = 0.0004), an emergency setting (OR = 2.6; 95% CI 1.5-4.6; P = 0.0007), a history of hypertension (OR = 2.5; 95% CI 1.5-4.4; P = 0.0010) or of other cardiovascular disease (OR = 4.4; 95% CI 2.4-8.1; P < 0.0001), obesity (OR = 2.4; 95% CI 1.1-5.3; P = 0.0376), and ongoing beta-blocker treatment (OR = 4.2; 95% CI 1.8-9.8; P = 0.0011). All 31 patients with a fatal outcome received epinephrine in a titrated manner according to international guidelines.

CONCLUSION

Obese males with a history of cardiovascular disease receiving ongoing beta-blocker treatment and undergoing surgery in an emergency setting were at high risk of a fatal outcome after NMBA-induced anaphylaxis. Some epinephrine-resistant cases may play a role in our high mortality rate. New therapeutic approaches need to be developed to treat these cases.

Combined Spinal Epidural Anaesthesia for Caesarean Section and Hysterectomy in a Parturient with Placenta Accreta

Placenta accreta complicates the anaesthetic and surgical approach in caesarean section. In this report, a parturient with placenta accreta and multiple drug allergies who was managed using combined spinal epidural anaesthesia for caesarean hysterectomy is discussed.

Transfusion-associated anaphylaxis during anaesthesia and surgery--a retrospective study

BACKGROUND AND OBJECTIVES

Transfusion-associated anaphylaxis (TAA) is a severe adverse reaction reported to occur in 1:9000-90,000 transfusions. According to the Danish Registration of Transfusion Risks (DART), the frequency is 1:300,000 transfusions, which suggests insufficient reporting of TAA in Denmark. Our aims were to identify possible cases of TAA, to characterize their symptoms and tryptase levels and to investigate the reporting of TAA to the haemovigilance systems.

MATERIAL AND METHODS

We reviewed 245 patients with suspected allergic reactions during anaesthesia and surgery, investigated at the Danish Anaesthesia Allergy Centre (DAAC). Based on the outcome of this investigation, the patients were classified as DAAC positive (confirmed hypersensitivity to identified agent, n = 112), or DAAC negative (no confirmed hypersensitivity, n = 133). Data on case history, details of blood transfusion and results of laboratory and clinical investigations were collected. TAA cases were identified according to the recommendations of the International Society of Blood Transfusion (ISBT).

RESULTS

Ten possible TAA cases (30% of all transfused patients) were identified, all DAAC negative. The frequency of elevated serum tryptase, hypotension and male sex was significantly higher among these cases compared with the remaining DAAC negative (P < 0·05), but not different from the DAAC-positive patients. One case had been reported to the Blood Bank haemovigilance system and none to DART.

CONCLUSION

We identified unreported cases of possible TAA, which resembled the DAAC-positive patients with respect to elevated tryptase and symptoms. By applying the ISBT criteria of adverse transfusion reactions, we conclude that TAA during anaesthesia and surgery is likely to be underreported in Denmark.

Anaphylaxis in the clinical setting of obstetric anesthesia: a literature review

The prevalence of anaphylaxis occurring during pregnancy is approximately 3 cases per 100,000 deliveries. The management of anaphylaxis occurring during the third trimester of pregnancy may be challenging because of the additive effects of aortocaval compression and cardiovascular disturbances of anaphylaxis. In this review, we identify the clinical signs of anaphylaxis occurring during labor and cesarean delivery, discuss the more common allergens that cause anaphylaxis during this clinical setting, and develop a rational approach to the identification of the offending allergen. We also suggest strategies for the management of anaphylaxis occurring during the third trimester of pregnancy, including the prompt administration of epinephrine and emergency cesarean delivery in cases of severe reactions. Evidence is limited to case reports and extrapolation from nonfatal and fatal cases, interpretation of pathophysiology, and consensus opinion.

Early skin testing is effective for diagnosis of hypersensitivity reactions occurring during anesthesia

Allergic skin tests have to be performed 4-6 weeks after an allergic anesthetic reaction. Patients with allergic reactions during anesthesia were prospectively included (n = 44). Skin tests were performed in two stages: (i) Stage 1 (S1), 0-4 days after the reaction; and (ii) Stage 2 (S2), 4-8 weeks after. Five (11.5%) surgical procedures were suspended due to the reaction. Positive skin tests were obtained in 25/44 patients (57%). Allergic diagnosis was carried out at S1 in 15/25 (60%) and at S2 in 10/25 (40%). Three patients resulted positive only in S1. Overall agreement among S1 and S2 skin tests was 70.45%. The kappa statistic was 0.41 (P-value = 0.002). Odds ratio of obtaining a false negative in S1 (compared with S2) was 3.33. Early allergological study is useful, could minimize false negatives, but should be considered as a complement to late skin tests.

Intravenous fluorescein as a cause of immunoglobulin E-mediated anaphylactic shock

We report a patient with severe anaphylactic shock immediately after injection of i.v. fluorescein. The patient recovered without sequela. Immunoglobulin E (IgE) mechanism was highly suggestive with significant increase in serum tryptase, positive basophil allergen threshold sensitivity (CD-sens) and histamine release tests towards fluorescein. This is, to our knowledge, the first report where CD-sens has been used to aid in diagnosing an IgE-mediated anaphylactic shock caused by fluorescein.

Timing of skin testing after a suspected anaphylactic reaction during anaesthesia

BACKGROUND

A delay of 4 to 6 weeks after a suspected anaphylactic reaction has commonly been recommended before performing skin testing. However, sometimes surgery cannot be delayed, and investigation must be done earlier. Recent recommendations suggest that skin testing can be performed immediately after a reaction.

METHODS

We describe three cases in which skin testing was performed within 3 weeks after the suspected anaphylactic reaction. A literature review was undertaken to evaluate cases where skin testing was performed within 3 weeks of a suspected anaphylactic reaction during anaesthesia.

RESULTS

Review of the literature did not give a definite answer to the optimal timing of skin testing after a suspected anaphylactic reaction during anaesthesia.

CONCLUSIONS

Only positive skin tests can be taken into account, and there is little safety data to provide confidence in early skin testing. A protocol of how to act if urgent surgery is necessary is suggested.

Is a positive history of non-anaesthetic drug allergy a predictive factor for positive allergy tests to anaesthetics?

AIMS

International recommendations stipulate not performing screening skin tests to a drug in the absence of a clinical history consistent with that specific drug allergy. Nevertheless, two publications showed that a positive history of non-anaesthetic drug allergy was the only predictive factor for a positive skin test when screening for allergy to anaesthetic drugs was done. We selected from a surgical population 40 volunteers with a prior history of allergy to non-anaesthetic drugs in order to analyse the prevalence of positive allergy tests to anaesthetics.

METHODS

The selected adult patients were tested for 11 anaesthetic drugs using in vivo tests: skin prick (SPT) and intradermal (IDT) tests and in vitro tests: the basophil activation test (BAT) and detection of drug-specific immunoglobulin E (IgE).

RESULTS

The prevalence for the positive SPT and IDT was 1.6% and 5.8% respectively. The result of flow cytometry agreed with the SPT in five out of seven positive SPT (71%). IgEs confirmed two positive SPT with corresponding positive BAT. Ten per cent of the patients had a positive prick test to neuromuscular blocking agents (NMBA). For midazolam none of the SPT was positive, but 11 patients had positive IDT nonconfirmed by BAT.

CONCLUSION

The prevalence of positive in vivo and in vitro allergy tests to NMBAs is higher in our study population. This could be an argument for pre-operative SPT to NMBAs for the surgical population with reported non-anaesthetic drug allergies. A larger prospective study is needed to validate changes in clinical practice.

Anaphylactic shock during hydatid cyst surgery

Intraoperative anaphylactic shock is an unusual complication. Different causes can be involved. Surgery of hydatid cyst is rarely responsible. About a case report of anaphylactic shock due to hydatid cyst surgery, the authors discuss the mechanisms, principles of treatment, and prevention measures of this complication.

Perioperative allergy: therapy

Perioperative allergic reactions manifest in various ways. The majority of systemic reactions occur during anesthesia within minutes of intravenous induction; however, agents which are administered via other routes may cause reactions after more than 15 minutes. Anaphylaxis during anesthesia may present in many different ways and the signs and symptoms, which do not vary from those of anaphylactic reactions in general, may be masked by hypovolemia, light, deep anesthesia or extensive regional blockade. Recommendations for treatment are based on available evidence in the literature. A treatment algorithm is suggested, with emphasis on the incremental titration of adrenaline and fluid therapy as first-line treatment. Increased focus on this subject will hopefully lead to prompt diagnosis and rapid, correct treatment.

A case of propofol-induced oropharyngeal angioedema and bronchospasm

Propofol (2,6-diisopropylphenol) is an ultrashort-acting sedative agent with sedative and amnestic effects that is used not only for anesthesia but also for sedation during minor outpatient procedures and endoscopic examinations. Rare cases of anaphylaxis following propofol administration have been reported in the medical literature. Documentation of anaphylaxis is often lacking because the cause and effect relationship is often hard to prove. Only a minority of patients get referred for allergy testing to confirm the offending drug. Here we report a 74-year-old woman who had an anaphylactic reaction with severe oropharyngeal edema and bronchospasm for a few minutes after receiving propofol during endoscopic examination. An allergy skin test was positive for both propofol and soybean. Soybean in the intralipid is one component of propofol, and we concluded that this anaphylaxis was caused by soybean.

Anaphylaxis to ethylene oxide - a rare and overlooked phenomenon?

Spina bifida patients have been reported to be at increased risk of anaphylactic reactions during general anaesthesia. Following a reaction, latex is often incriminated as spina bifida patients are known to have an increased incidence of latex allergy. Ethylene oxide (EO) has recently been suggested to be an alternative cause, but in many cases reported in the literature, it seems that EO has not been considered as a cause. EO is a highly reactive gas widely used to sterilise heat-sensitive medical devices, and traces of EO can be found in many of the same products as latex. We present the case of a spina bifida patient with a known latex allergy, where EO was found to be the cause of an anaphylactic reaction during general anaesthesia. In addition, we describe measures taken during preparation of a subsequent general anaesthesia to minimise exposure to EO. Spina bifida patients seem to be at increased risk of sensitisation against EO due to repeated exposure, but only limited literature is available. To ensure that EO is considered as a cause in these cases, we recommend that testing for latex and EO go hand in hand following an anaphylactic reaction in this high-risk population.

Allergy to rocuronium: from clinical suspicion to correct diagnosis

BACKGROUND

Allergy to rocuronium can be life-threatening. Correct diagnosis is a prerequisite because of serious consequences of diagnostic error.

OBJECTIVE

To assess skin testing, quantification of specific IgE (sIgE) and flow-assisted activation of basophils [basophil activation test (BAT)] in the diagnosis of rocuronium allergy.

METHODS

This study comprises 104 curarized patients with a history of profound hypotension and severe bronchospasm immediately after induction of anaesthesia. All patients had skin tests, quantification of sIgE and BAT to rocuronium, together with investigations for all relevant compounds administered during anaesthesia that could have evoked the reaction. Diagnosis of rocuronium allergy was considered definite when the patient demonstrated a positive outcome for at least two of the three aforementioned tests.

RESULTS

The positive predictive value for skin testing, BAT and sIgE was 98% (CI 95%: 92-99%), 97% (CI 95%: 88-100%) and 83% (CI 95%: 74-89%), respectively. The negative predictive value for skin testing, BAT and sIgE was 96% (CI 95%: 86-99%), 75% (CI 95%: 67-75%) and 72% (CI 95%: 58-83%), respectively. Cross-reactivity with vecuronium was documented in 69% of the patients.

CONCLUSION

Skin testing merits the status of primary diagnostic investigation to document rocuronium allergy and cannot be substituted by quantification of sIgE or BAT. SIgE can offer a diagnostic advantage in cases where skin tests yield negative results. However, additional tests (e.g. BAT) are of capital importance in patients with negative skin tests and positive sIgE results to help in interpreting the clinical significance of a positive sIgE result. Optimal assessment of cross-reactivity between rocuronium and vecuronium implies both skin testing and BAT.

Drug-specific cyclodextrins with emphasis on sugammadex, the neuromuscular blocker rocuronium and perioperative anaphylaxis: implications for drug allergy

Cyclodextrins, oligosaccharides linked in a circular arrangement around a central cavity, are used extensively in the pharmaceutical industry to improve drug delivery. Their usefulness depends on their capacity to form a drug inclusion, or host-guest, complex within the cavity. In an attempt to improve the delivery of the widely used neuromuscular blocking drug (NMBD) rocuronium, a rocuronium inclusion complex was formed with a chemically modified γ-cyclodextrin. The high binding affinity and specificity of the modified carrier (named sugammadex) for rocuronium (and other aminosteroid NMBDs) led to its use in anaesthesia as an innovative and useful agent for rapid reversal of rocuronium-induced neuromuscular block by sequestering the drug as an inclusion complex. This, in turn, led to the suggestion that sugammadex might be useful to remove the NMBD from the circulation of patients experiencing rocuronium-induced anaphylaxis, a suggestion subsequently supported in case reports where traditional treatment had failed. Successful resuscitations suggested that sugammadex might be a valuable new treatment for such intractable cases but, given the inappropriateness of clinical trials, confirmation or refutation will have to await the slow accumulation of results of individual case reports. Important questions related to antibody accessibility of drug allergenic structures on the rocuronium-sugammadex inclusion complex, and the competition between sugammadex and IgE antibodies (both free and cell bound) for rocuronium, also remain and can be investigated in vitro. The sugammadex findings indicate that the use of carrier molecules such as the cyclodextrins to improve drug delivery will sometimes give rise to changed immunologic and allergenic behaviour of some drugs and this will have to be taken into account in preclinical drug safety assessments of drug-carrier complexes. The possibility of encapsulating and removing other allergenic drugs, e.g., penicillins and cephalosporins, in cases of difficult-to-reverse anaphylaxis to these drugs is discussed.

IgE-sensitization to the cough suppressant pholcodine and the effects of its withdrawal from the Norwegian market

BACKGROUND

IgE-mediated anaphylaxis to neuromuscular blocking agents (NMBA), frequent in Norway, was proposed to be caused by exposure to pholcodine (PHO) carrying the allergenic quarternary ammonium ion epitope. Consequently, the PHO-containing drug was withdrawn from the market in March 2007.

OBJECTIVE

Describe the effects of withdrawal of PHO on IgE, IgE-antibodies and reported frequencies of anaphylaxis to NMBAs.

METHODS

Three hundred sera from supposedly allergic patients sampled yearly through 2006 to 2010 were analysed for IgE antibodies to PHO, suxamethonium (SUX) and morphine (MOR). Furthermore, IgE and preliminary reports from the Norwegian Network for Anaphylaxis under Anaesthesia (NARA) were monitored.

RESULTS

PHO exposure was associated with IgE sensitization to PHO, MOR and SUX. However, after withdrawal, within 1 year, antibody prevalences to PHO and SUX fell significantly from 11.0% to 5.0% and from 3.7% to 0.7%, respectively. At 3 years, SUX had fallen to 0.3%, PHO to 2.7% and MOR to 1.3%. By 2 years, the prevalence of elevated IgE was significantly reduced. After 3 years, the incidence of reported suspected anaesthetic anaphylaxis fell significantly, both the total number, the reactions related to NMBAs and those with IgE antibodies to SUX.

CONCLUSIONS

Withdrawing of PHO lowered significantly within 1-2 years levels of IgE and IgE antibodies to PHO, MOR and SUX, and, within 3 years, the frequency of NMBA suspected anaphylaxis. The results strengthen the PHO hypothesis considerably and equally the need to question the existence of cough depressants containing PHO.

Perioperative Allergy: Clinical Manifestations

Adverse drug reactions or side effects are usually expected, dose dependent, and occur at therapeutic doses. Anaphylactic and anaphylactoid reactions are unexpected and dose independent and can occur at the first exposure to drugs used during anesthesia. Perioperative anaphylaxis is a severe and rapid clinical condition that can be lethal even in previously healthy patients. The initial diagnosis of anaphylaxis is presumptive. A precise identification of the drug responsible for the adverse reaction is more difficult to establish in the case of anaphylactoid reaction because the adverse reaction could result from additive side effects of different drugs injected simultaneously. The timing of the reaction in relation to events, e.g. induction, start of surgery, administration of other drugs, i.v. fluids, is essential for the diagnosis. Generally, reactions are predominant in the induction and recovery phases, and manifested mainly as cutaneous symptoms. Reactions to drugs coincide with the phases when they are administered. Reactions to antibiotics are more frequent in the induction phase, to neuromuscular agents in the initiation and maintenance phases and to non-steroidal anti-inflammatory agents in the recovery phase. The differential diagnosis of any adverse reaction during or following anesthesia should include the possibility of anaphylaxis.

Anesthesia in the patient with multiple drug allergies: are all allergies the same?

PURPOSE OF REVIEW

During the preoperative evaluation, patients frequently indicate 'multiple drug allergies', most of which have not been validated. Potential allergic cross-reactivity between drugs and foods is frequently considered as a risk factor for perioperative hypersensitivity. The aim of this review is to facilitate the recognition of risk factors for perioperative anaphylaxis and help the management of patients with 'multiple drug allergies' during the perioperative period.

RECENT FINDINGS

Neuromuscular blocking agents (NMBAs) and antibiotics are the most common drugs triggering perioperative anaphylaxis. Quaternary ammonium ions have been suggested to be the allergenic determinant of NMBAs. Even though the 'pholcodine hypothesis' has been suggested to explain the occurrence of NMBA-induced allergy, this concept remains unclear. Although many practitioners believe that certain food allergies present an issue with the use of propofol, there is no role to contraindicate propofol in egg-allergic, soy-allergic or peanut-allergic patients. IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, but there is no cross-reactivity between them. The allergenic determinants have been characterized for fish, shellfish and povidone iodine and remain unknown for contrast agents.

SUMMARY

There are many false assumptions regarding drug allergies. The main goal of this article is to review the potential cross-reactivity among specific families of drugs and foods in order to facilitate the anesthetic management of patients with 'multiple drug allergies'.

Peri-operative anaphylaxis

Peri-operative anaphylaxis is an important cause for mortality and morbidity associated with anaesthesia. The true incidence is unknown and is most likely under reported. Diagnosis can be difficult, particularly as a number of drugs are given simultaneously and any of these agents can potentially cause anaphylaxis. This review covers the clinical features, differential diagnosis and management of anaphylaxis associated with anaesthesia. The investigations to confirm the clinical suspicion of anaphylaxis and further tests to identify the likely drug(s) are examined. Finally the salient features of common and rare causes including non-drug substances are described.

Preoperative evaluation of patients with history of allergy

The prevalence of allergic reactions in general population shows a constant rise. It has been estimated that up to 40% of surgical patients have a positive history of some kind of allergy. These patients represent a challenge during perioperative evaluation, since they can be exposed to a large variety of drugs and substances during surgery and anesthesia. A lot of adverse drug reactions show similar clinical presentation with allergic reactions. The latter are usually poorly explored since preoperative allergology testing is performed in a limited number of patients. Management of patients with history of allergy is impeded by the fact that most of allergens cross-react in a manner that is not always easy to predict. Allergies can manifest themselves with a broad spectrum of clinical symptoms, ranging from mild skin symptoms such as itch and urticaria, to a life-threatening anaphylactic reactions followed by hypotension, bronchospasm and cardiovascular collapse. Prevention of allergic reactions during perioperative period requires detailed history taking in order to identify patients at risk, optimization of anesthesia strategy, pharmacological premedication and further allergology diagnostic work-up in selected cases.

Follow-up after anaesthetic anaphylaxis

background: the anaesthetic allergy clinic has been established at our institution for 30 years. Our practice has been to give patients a letter detailing the results of their investigations to pass on to subsequent anaesthetists. Our aims were to assess the adequacy of this letter in ensuring this vital communication, and to quantify the effectiveness of our recommendations on the safety of future anaesthesia.

METHODS

a project was undertaken to contact 606 previous clinic patients living in New South Wales by using last known addresses on our database, public telephone listing and local doctors. The review also involved collecting information, where available, about subsequent anaesthesia and the adequacy of information transfer about medications given safely or otherwise at this time.

RESULTS

of 606 patients, 246 were contactable. Of these, 183 had been anaesthetised subsequently, all safely. It was found that in only 11 cases had the patient's clinic letter been updated with the information from subsequent anaesthesia. We updated the letters of 82 patients with new information to improve the safety of drug selection for future anaesthesia.

CONCLUSIONS

although clinic testing allowed a high degree of safety in subsequent anaesthesia, it is evident that there is a need for systems to be implemented to improve the flow of patient anaesthetic allergy information after subsequent anaesthesia.

Shaping the future of Scandinavian anaesthesiology: a position paper by the SSAI

Traditionally, Scandinavian anaesthesiologists have had a very broad scope of practice, involving intensive care, pain and emergency medicine. European changes in the different medical fields and the constant reorganising of health care may alter this. Therefore, the Board of the Scandinavian Society of Anaesthesiology and Intensive Care Medicine (SSAI) decided to produce a Position Paper on the future of the speciality in Scandinavia. The training in the various Scandinavian countries is very similar and provides a stable foundation for the speciality. The Scandinavian practice in anaesthesia and intensive care is based on a team model where the anaesthesiologists work together with highly educated nurses and should remain like this. However, SSAI thinks that the role of the anaesthesiologists as perioperative physicians is not fully developed. There is an obvious need and desire for further training of specialists. The SSAI advanced educational programmes for specialists should be expanded and include formal assessment leading to a particular medical competency as defined by the European Union of Medical Specialists (UEMS). In this way, Scandinavian anaesthesiologists will remain leaders in perioperative, intensive care, pain and critical emergency medicine.

Perioperative anaphylaxis

The incidence of immune-mediated anaphylaxis during anesthesia ranges from 1 in 10,000 to 1 in 20,000. Neuromuscular blocking agents are most frequently incriminated, followed by latex and antibiotics, although any drug or substance used may be a culprit. Diagnosis relies on tryptase measurements at the time of the reaction and skin tests, specific immunoglobulin E, or basophil activation assays. Treatment consists of rapid volume expansion and epinephrine administration titrated to symptom severity.