Anaesthetic hypersensitivity reactions in France between 2011 and 2012: the 10th GERAP epidemiologic survey

Neuromuscular blocking agent drug challenge: a literature review and protocol proposal with biological evaluation

BACKGROUND

Drug challenge is the gold standard for identifying causative agents of drug allergies. Although clinical guidelines have recently been published, they do not recommend neuromuscular blocking agent (NMBA) drug challenges. NMBA challenges are rendered difficult by the lack of homogeneity of routine allergy work-ups and the necessity of a specialised setting. Several scenarios support NMBA challenges, such as an ambiguous allergy work-up, a high suspicion of a false-positive skin test or identification of a well tolerated alternative NMBA strategy. Furthermore, routine allergy work-ups may not recognise non-IgE mechanisms, such as IgG or MRGPRX2, whereas drug challenges may reveal them. Finally, if the culprit NMBA is not identified, subsequent anaesthesia regimens will be challenging to implement, resulting in increased risk.

OBJECTIVES

This literature review discusses the indications, strategies, doses, monitoring methods, limitations, and unresolved issues related to drug challenges for NMBAs.

DESIGN

The literature review included randomised controlled trials, observational studies, reviews, case reports, series, and comments on humans.

DATA SOURCES

Studies were retrieved from databases (PubMed) and electronic libraries (OVID, EMBASE, Scopus, etc.).

ELIGIBILITY CRITERIA

All studies that referred to the NMBA challenge were included without publication date limitations.

RESULTS

NMBA challenge may be considered in NMBA anaphylaxis patients with inconclusive or ambivalent IgE diagnostic work-up under controlled conditions (presence of anaesthetists and allergists with continuous monitoring in a secured environment). To illustrate its utility, a case report of a double NMBA challenge in a patient with NMBA cross-reactivity is presented, along with biological explorations to detect subclinical cellular activation, a novel aspect of this procedure.

CONCLUSION

Drug challenges could be implemented during the NMBA allergy work-up under strict safety conditions at specialised centres with close collaboration between anaesthetists and allergists. This could decrease uncertainty and contribute to defining a safer strategy for subsequent anaesthetic drug regimens.

Rocuronium-specific antibodies drive perioperative anaphylaxis but can also function as reversal agents in preclinical models

Neuromuscular blocking agents (NMBAs) relax skeletal muscles to facilitate surgeries and ease intubation but can lead to adverse reactions, including complications because of postoperative residual neuromuscular blockade (rNMB) and, in rare cases, anaphylaxis. Both adverse reactions vary between types of NMBAs, with rocuronium, a widely used nondepolarizing NMBA, inducing one of the longest rNMB durations and highest anaphylaxis incidences. rNMB induced by rocuronium can be reversed by the synthetic γ-cyclodextrin sugammadex. However, in rare cases, sugammadex can provoke anaphylaxis. Thus, additional therapeutic options are needed. Rocuronium-induced anaphylaxis is proposed to rely on preexisting rocuronium-binding antibodies. To understand the pathogenesis of rocuronium-induced anaphylaxis and to identify potential therapeutics, we investigated the memory B cell antibody repertoire of patients with suspected hypersensitivity to rocuronium. We identified polyclonal antibody repertoires with a high diversity among V(D)J genes without evidence of clonal groups. When recombinantly expressed, these antibodies demonstrated specificity and low affinity for rocuronium without cross-reactivity for other NMBAs. Moreover, when these antibodies were expressed as human immunoglobulin E (IgE), they triggered human mast cell activation and passive systemic anaphylaxis in transgenic mice, although their affinities were insufficient to serve as reversal agents. Rocuronium-specific, high-affinity antibodies were thus isolated from rocuronium-immunized mice. The highest-affinity antibody was able to reverse rocuronium-induced neuromuscular blockade in nonhuman primates with kinetics comparable to that of sugammadex. Together, these data support the hypothesis that antibodies cause anaphylactic reactions to rocuronium and pave the way for improved diagnostics and neuromuscular blockade reversal agents.

[Update: Neuromuscular Blockade during General Anesthesia]

The correct use of muscle relaxants and neuromuscular monitoring during anesthesia has been subject of controversial discussions for decades. Particularly important in clinical practice are identification and management of residual neuromuscular blockages and avoidance of associated complications. Despite the differences in the molecular mechanisms of action between depolarizing and non-depolarizing muscle relaxants the blockade of the postsynaptic nicotinic acetylcholine receptor remains a common ending pathway. Due to its unfavorable side effect profile, succinylcholine should only be used in justified exceptional cases. The use of muscle relaxants generally reduces the complication rate in airway management. However, even the single use of muscle relaxants increases the likelihood of postoperative pulmonary complications. These complications associated with the use of muscle relaxants, such as residual neuromuscular blockade, must be anticipated. The application of guideline-based approaches, including continuous neuromuscular monitoring and the application of muscle relaxant reversal agents, may significantly reduce the rate of adverse events associated with the use of muscle relaxants.

Management and treatment of perioperative hypersensitivity

PURPOSE OF REVIEW

Perioperative hypersensitivity reactions are rare but potentially catastrophic events. This review acts to summarize recent recommendations for both immediate and poststabilization management of suspected reactions, alongside practical advice for anaesthetists who may be faced with these events.

RECENT FINDINGS

Prompt treatment is essential but may be hampered by delay in recognition. This can occur because there are multiple differential diagnoses for the observed clinical signs as well as variations in clinical presentation. Resuscitation is dependent on the use of adrenaline and fluids. Adrenaline should be administered in small, titrated intravenous boluses. Low-dose infusions should be commenced early if the response to boluses is poor. Large volume fluid resuscitation may be required to maintain adequate circulating volume. Chest compressions are recommended when there is evidence of inadequate perfusion, rather than waiting until cardiac arrest is confirmed. Antihistamines and corticosteroids are no longer recommended in the immediate management phase. Once the patient has been stabilized, it is important to obtain serial tryptase concentrations to aid the subsequent clinic investigation. The decision to proceed or abandon surgery will be based on an individual risk-benefit analysis. All cases of suspected perioperative hypersensitivity, including fatal cases, must be referred for formal investigation.

SUMMARY

There have been recent updates to management guidelines in perioperative hypersensitivity. Treatment algorithms, treatment packs and referral packs can all help the anaesthetist manage these complex cases, aid the subsequent investigation and ensure patient safety in the future.

Preoperative survey to evaluate the patients' allergy list and its relevance to perioperative care

INTRODUCTION

Perioperative hypersensitivity and allergic reactions can result in significant morbidity and mortality. For routine anesthetic care, allergies are determined from a review of the electronic medical record supplemented by a detailed patient history. Although the electronic medical record is generally assumed to be accurate, it may be that allergies are erroneously listed or not based on sound medical practice. The purpose of the current study is to evaluate allergies listed in the electronic medical record of children presenting for surgery and determine their origin, authenticity, and impact on perioperative care.

METHODS

Eligible patients included those presenting for a surgical procedure in the main operating room, who were ≤ 21 years of age, with a drug allergy listed on the EMR. Prior to intraoperative care, an electronic survey questionnaire containing questions related to medication allergies was provided to a guardian or parent. Two anesthesiology physicians reviewed the survey responses to determine the validity of any reported allergies. A second electronic survey was given postoperatively to the attending anesthesiologist to determine whether the documented allergy impacted anesthetic care.

RESULTS

The study cohort included 250 patients, ranging in age from 5 to 14 years (median age 9 years). All of the patients had at least one allergy listed on the electronic medical record. Seventy of the 250 patients (28%) had more than one drug allergy listed for a total of 351 medication allergies. The majority of the listed allergies were related to antibiotics including 155 (44%) from the penicillin family, 26 (7%) cephalosporins, 16 (5%) sulfonamides, and 36 (10%) other antimicrobial agents. Other commonly listed allergies were 27 (8%) nonsteroidal anti-inflammatory agents and 15 (4%) opioids. The remaining 76 (22%) included a miscellaneous list of other medications. On further review of the allergies, the survey was completed for 301 medications. After physician review, 135 of 301 (45%) responses were considered consistent with IgE reactions "true allergy," 73 (24%) were deemed less relevant to IgE reactions "unlikely true allergy," and 93 (31%) were not related to IgE reactions "not an allergy." Care alterations during surgery were uncommon regardless of whether the issue was assessed as a true allergy (11%), unlikely to be a true allergy (3%), or not a true allergy (13%).

CONCLUSION

A significant portion of the documented allergies in children are not true allergies, but rather recognized adverse effects (apnea from an opioid, renal failure from an NSAIDs) or other nonallergic concerns (gastrointestinal upset such as nausea). Erroneously listed allergies may lead to unnecessary alterations in patient care during perioperative care. A careful analysis of the allergy list on the EMR should be supplemented by a thorough patient history with specific questions related to the drug allergy. Once this is accomplished, the allergy listed should be updated to avoid its erroneous impact on perioperative care.

Relationship between perioperative anaphylaxis and history of allergies or allergic diseases: A systematic review and meta-analysis with meta-regression

STUDY OBJECTIVE

We conducted this meta-analysis to summarize the available evidence and evaluate the relationship between a history of allergies/allergic diseases and perioperative anaphylaxis to offer preventive decision support.

DESIGN

Systematic review and meta-analysis of observational studies.

SETTING

We searched the MEDLINE (OVID), EMBASE, and the Cochrane Central Register of Controlled Trials databases for observational studies. Two investigators independently performed the search, screened the articles, and collected the study details.

MEASUREMENTS

Several databases were systematically searched to evaluate the relationship between a history of allergies/allergic diseases and perioperative anaphylaxis using subgroup analysis, sensitivity analysis and meta-regression.

MAIN RESULTS

A total of 19 studies involving 672 anaphylaxis episodes, 5608 immune-mediated reactions, and 1126 severe episodes met the eligibility criteria and were included in this meta-analysis. Drug allergies, food allergies, a history of allergies, and atopy increased the incidence of perioperative anaphylaxis (Drug allergies, odds ratio [OR] 3.54, 95% confidence interval [CI] 1.07-11.69; Food allergies, OR 2.29, 95% CI 1.23-4.26; A history of allergies, OR 4.86, 95% CI 3.65-6.49; Atopy, OR 3.58, 95% CI 1.47-8.71), but not the presence of immune-mediated reactions and the severity of perioperative anaphylaxis.

CONCLUSIONS

Patients with previous drug allergies, food allergies, a history of allergies, or atopy are more likely to develop anaphylaxis during the perioperative period. Additional studies should be carried out to determine whether a history of allergies/allergic diseases is a major factor for perioperative anaphylaxis when confounders are controlled.

Perioperative anaphylaxis and the principle of primum non nocere

Perioperative anaphylaxis is a rare and unpredictable event that continues to cause patient harm. More work is needed to decrease the risk to patients through measures to limit sensitisation, optimise management and investigation, and ensure that patients are not inadvertently re-exposed to allergens. Robust epidemiological data such as that provided by the consecutive GERAP surveys over the past 30 yr have been invaluable in defining the problem, identifying emerging allergens, acting as a catalyst for change, and stimulating research.

Epidemiology of perioperative anaphylaxis in France in 2017-2018: the 11th GERAP survey

BACKGROUND

Perioperative anaphylaxis is rare but is associated with significant morbidity. This complication has been well described in France by the GERAP (Groupe d'Etude des Réactions Anaphylactiques Périopératoires), a network focused on its study. The epidemiology of perioperative anaphylaxis is evolving, influenced by environmental factors and clinical practice. The aim of this study was to update the epidemiology of perioperative anaphylaxis in France.

METHODS

This multicentre retrospective study was performed in 26 allergy clinics of the GERAP network in 2017-8.

RESULTS

There were 765 patients with perioperative anaphylaxis included. Most cases were severe, with 428 (56%) reactions graded as 3 or 4 according to the Ring and Messmer classification. Skin test results were available for 676 patients, with a culprit agent identified in 471 cases (70%). Neuromuscular blocking agents were the main cause of perioperative anaphylaxis (n=281; 60%), followed by antibiotics (n=118; 25%) and patent blue dye (n=11; 2%). Cefazolin was the main antibiotic responsible for perioperative anaphylaxis (52% of antibiotic-related reactions). Suxamethonium and rocuronium were the main neuromuscular blocking agents responsible for perioperative anaphylaxis with 7.1 (6.1-8.4) and 5.6 (4.2-7.4) reactions per 100,000 vials sold, respectively, whereas cefazolin-related cases were estimated at 0.7 (0.5-0.9) reactions per 100,000 vials sold.

CONCLUSIONS

Our results confirm that most commonly identified triggering agents remain neuromuscular blocking agents. Reactions to antibiotics, particularly cefazolin, are becoming increasingly frequent. The origin of sensitisation to cefazolin is unknown, as no cross-sensitisation has been described, and it should be the subject of further study. Perioperative anaphylaxis should be followed over the years and understood given the changing triggers.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (NCT04654923).

A US-Based Multicenter Retrospective Report of Perioperative Anaphylaxis, 2010-2021

BACKGROUND

US-based perioperative anaphylaxis (POA) studies are limited to single-center experiences. A recent report found that a serum acute tryptase (sAT) >9.8 ng/mL or mast cell activation (MCA) can predict POA causal agent identification. Urinary mast cell mediator metabolites (uMC) have not been studied in POA.

OBJECTIVE

To analyze the epidemiologic data of POA, to determine if sAT or MCA can predict suspected causal agent identification, and to evaluate uMC utility in POA.

METHODS

This study is a retrospective multicenter review of POA cases that were subcategorized by suspected causal agent identification status. sAT, MCA (defined as sAT >2 + 1.2 × serum baseline tryptase), and uMC (N-methylhistamine [N-MH], 11β-prostaglandin-F2α [11β-PGF2α], leukotriene E4 [LTE4]) were recorded.

RESULTS

Of 100 patients (mean age 52 [standard deviation 17] years, 94% adult, 50% female, 90% White, and 2% Hispanic) with POA, 73% had an sAT available, 41% had MCA, 16% had uMC available, and 50% had an identifiable suspected cause. POA cases with an identifiable suspected cause had a positive MCA status (100% vs 78%; P = .01) compared with POA with an unidentifiable cause. An elevated median sAT did not predict causal agent identification. Positive uMC were not associated with suspected causal agent identification during POA. Patients with positive uMC had a higher median sAT (30 vs 6.45 ng/mL; P = .001) and MCA status (96% vs 12%; P = .001) compared with negative uMC patients. Patients with POA had an elevated acute/baseline uMC ratios: 11β-PGF2α ratio > 1.6, N-MH ratio >1.7, and LTE4 ratio >1.8.

CONCLUSIONS

The presence of MCA in POA is associated with suspected causal agent identification. Positive uMC possibly correlate with a higher sAT level and MCA status but require further study. The authors suggest applying an acute/baseline uMC ratio (11β-PGF2α ratio >1.6, N-MH ratio >1.7, and LTE4 ratio >1.87) in patients with POA for MCA when a tryptase level is inconclusive during POA evaluations.

Paediatric perioperative hypersensitivity: the performance of the current consensus formula and the effect of uneventful anaesthesia on serum tryptase

Background

Paired sampling of acute (aST) and basal (bST) serum tryptase has been recommended when investigating patients with a suspected perioperative hypersensitivity (POH) reaction. In the current consensus formula, an aST value exceeding (1.2×bST+2) confirms mast cell activation. The current consensus formula has been validated in adults but not in children.

Methods

We prospectively included 96 children who underwent uneventful anaesthesia and sampled serum tryptase at baseline and 60-90 min after induction. Tryptase changes were then compared with those in 94 children with suspected POH who were retrospectively included from four reference centres in Belgium, France, and Denmark.

Results

We observed a median decrease in serum tryptase during uneventful anaesthesia of 0.41 μg L-1 (-15.9%; P<0.001). The current consensus formula identified mast cell activation in 31.9% of paediatric POH patients. After generating receiver operating characteristic curves through 100 repeated five-fold cross-validation, aST>bST+0.71 was identified as the optimal cut-off point to identify mast cell activation. This new paediatric formula has higher sensitivity than the current consensus formula (53.2% vs 31.9%, P<0.001) with a specificity of 96.9%. Analysis in the subpopulation where a culprit was identified and in grade 3-4 reactions similarly yielded higher sensitivity for the new paediatric formula when compared with the current consensus formula (85.3% vs 61.8%; P=0.008 and 78.0% vs 48.8%; P<0.001, respectively). Internally cross-validated sensitivity and specificity were 53.3% and 93.3%, respectively.

Conclusions

This is the first study suggesting the need for an adjusted formula in children to identify perioperative mast cell activation as tryptase is significantly lowered during uneventful anaesthesia. We propose a new formula (aST>bST+0.71) which performs significantly better than the current consensus formula in our multicentric paediatric population.

Drug-induced hypersensitivity reactions in a Lebanese outpatient population: A decade-long retrospective analysis (2012-2021)

Background

Drug hypersensitivity reactions (DHRs) are becoming more common as a result of increasing prevalence and case complexity. Allergists and clinical immunologists worldwide are challenged daily to adequately diagnose and manage these reactions. Data in the literature regarding DHR outpatient consultations are scarce worldwide, limited in the Middle East, and currently unavailable in Lebanon.

Objective

This retrospective study aimed to evaluate the characteristics of all reported DHRs over 10 years in a tertiary-care allergy clinic in Lebanon.

Methods

We conducted a decade-long (2012-21) retrospective analysis of the archived medical records of patients with a history of DHRs. Demographics, clinical history, diagnostic tools, and characteristics of the DHRs were collected and analyzed.

Results

A total of 758 patients experienced DHRs to therapeutic molecules provided for ambulatory care. Our results identified 72 medications. The most frequently implicated drug classes included β-lactam antibiotics (53.8%), followed closely by nonsteroidal anti-inflammatory drugs (48.9%). Of the 758 patients, 32.6% reported DHRs to multiple molecules, and 11.8% reported concomitant DHRs to 1 or several molecules provided in the perioperative setting. Of those, opioids and neuromuscular blocking agents were the 2 most common therapeutic classes. Furthermore, we evaluated the cross-reactivity between molecules of the same class. In neuromuscular blocking agents, rocuronium and cisatracurium were the most commonly cross-reactive, and for opioids, the most common association we recorded was with morphine and pethidine.

Conclusion

Our findings constitute the first step toward a more comprehensive evaluation of the clinical characteristics of DHRs in Lebanon.

Anaphylaxis mortality in the perioperative setting: Epidemiology, elicitors, risk factors and knowledge gaps

Perioperative anaphylaxis (PA) is a severe condition that can be fatal, but data on PA mortality are scarce. The aim of this article is to review the epidemiology, elicitors and risk factors for PA mortality and identify knowledge gaps and areas for improvement regarding the management of severe PA. PA affects about 100 cases per million procedures. Mortality is rare, estimated at 3 to 5 cases per million procedures, but the PA mortality rate is higher than for other anaphylaxis aetiologies, at 1.4% to 4.8%. However, the data are incomplete. Published data mention neuromuscular blocking agents and antibiotics, mainly penicillin and cefazolin, as the main causes of fatal PA. Reported risk factors for fatal PA vary in different countries. Most frequently occurring comorbidities are obesity, male gender, cardiovascular diseases and ongoing treatment with beta-blockers. However, there are no clues about how these factors interact and the impact of individual risk factors. The pathophysiology of fatal PA is still not completely known. Genetic factors such as deficiency in PAF-acetyl hydrolase and hereditary alpha-tryptasemia, have been reported as modulators of severe anaphylaxis and possible targets for specific treatments. Our review underlines unmet needs in the field of fatal PA. Although we confirmed the need for timely administration of an adequate dose of adrenaline and the proper infusion of fluids, there is no evidence-based data on the proper dose of intravenous titrated adrenaline and which clinical manifestations would flag the need for fluid therapy. There are no large clinical studies supporting the administration of alternative vasopressors, such as glucagon and methylene blue. Further research on pathophysiological mechanisms of PA and its severity may address these issues and help clinicians to define new therapeutic approaches.

Suspected perioperative anaphylaxis: are we making the correct diagnosis?

We provide a commentary on aspects of a prospective study of the epidemiology of perioperative anaphylaxis in Japan (Japanese Epidemiologic Study for Perioperative Anaphylaxis [JESPA]). Accurate diagnosis of perioperative anaphylaxis is important for research but essential for clinical safety. We evaluate the diagnostic approach used in the JESPA study and caution against over-reliance on diagnostic tests that lack sensitivity and specificity when clinical data suggest an immediate perioperative hypersensitivity reaction is likely.

Pholcodine exposure increases the risk of perioperative anaphylaxis to neuromuscular blocking agents: the ALPHO case-control study

BACKGROUND

Neuromuscular blocking agents (NMBAs) are among the leading cause of perioperative anaphylaxis, and most of these reactions are IgE mediated. Allergic sensitisation induced by environmental exposure to other quaternary ammonium-containing compounds, such as pholcodine, has been suggested. The aim of this study was to assess the relationship between pholcodine exposure and NMBA-related anaphylaxis.

METHODS

ALPHO was a multicentre case-control study, comparing pholcodine exposure within a year before anaesthesia between patients with NMBA-related perioperative anaphylaxis (cases) and control patients with uneventful anaesthesia in France. Each case was matched to two controls by age, sex, type of NMBA, geographic area, and season. Pholcodine exposure was assessed by a self-administered questionnaire and pharmaceutical history retrieved from pharmacy records. The diagnostic values of anti-pholcodine and anti-quaternary ammonium specific IgE (sIgE) were also evaluated.

RESULTS

Overall, 167 cases were matched with 334 controls. NMBA-related anaphylaxis was significantly associated with pholcodine consumption (odds ratio 4.2; 95% confidence interval 2.3-7.0) and occupational exposure to quaternary ammonium compounds (odds ratio 6.1; 95% confidence interval 2.7-13.6), suggesting that apart from pholcodine, other environmental factors can also lead to sensitisation to NMBAs. Pholcodine and quaternary ammonium sIgEs had a high negative predictive value (99.9%) but a very low positive predictive value (<3%) for identifying NMBA-related reactions.

CONCLUSIONS

Patients exposed to pholcodine 12 months before NMBA exposure have a significantly higher risk of an NMBA-related anaphylaxis. The low positive predictive values of pholcodine and quaternary ammonium sIgEs precludes their use to identify a population with a high risk of NMBA-related anaphylaxis.

CLINICAL TRIAL REGISTRATION

NCT02250729.

The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: allergen exposure, epidemiology, and diagnosis of anaphylaxis during general anaesthesia

BACKGROUND

Diagnosis of perioperative anaphylaxis is often challenging. This study describes the utility of a newly developed tool for identifying patients with a high possibility of anaphylaxis, and aimed to investigate the frequency of anaphylaxis with each drug during the perioperative period in Japan.

METHODS

This study included patients with anaphylaxis of Grade 2 or higher severity during general anaesthesia at 42 facilities across Japan in 2019 and 2020. We developed and adopted a unique objective evaluation tool yielding a composite score for diagnosing anaphylaxis, which includes the results of skin tests and basophil activation tests, and clinical scores for perioperative anaphylaxis. The number of cases using each drug and the total number of anaphylaxis cases were investigated to calculate the frequency of anaphylaxis.

RESULTS

General anaesthesia was performed in 218 936 cases, which included 55 patients with suspected perioperative anaphylaxis. The developed composite score diagnosed 43 of them with a high probability of anaphylaxis. The causative agent was identified in 32 cases. Plasma histamine levels showed high diagnostic accuracy for anaphylaxis. The top causative agents were rocuronium (10 cases in 210 852 patients, 0.005%), sugammadex (7 cases in 150 629 patients, 0.005%), and cefazolin (7 cases in 106 005 patients, 0.007%).

CONCLUSIONS

We developed a composite tool to diagnose anaphylaxis, and found that the combination of tryptase levels, skin testing, and basophil activation testing results and clinical score improved the certainty of anaphylaxis diagnosis. The incidence of perioperative anaphylaxis in our study was 1 in about 5000 general anaesthesia cases.

CLINICAL TRIAL REGISTRATION

UMIN000035350.

Ten-year outcomes of Perioperative Anaphylaxis Workup Study in Hong Kong (PAWS-HK): Performance of diagnostic modalities

BACKGROUND

Studies on perioperative anaphylaxis (PA) in Asia are lacking. Furthermore, allergy workup for PA has largely been limited to the "silver standard" of skin tests (ST). Using in vitro tests as an adjunct to ST may improve and overcome these diagnostic challenges.

OBJECTIVE

To evaluate the clinical characteristics and diagnostic tests of patients with suspected PA through the Perioperative Anaphylaxis Workup Study in Hong Kong cohort.

METHODS

Patients with a diagnosis of PA over a 10-year period were recruited into the Perioperative Anaphylaxis Workup Study in Hong Kong. We reviewed the medical records, tryptase elevation, and diagnostic tests including ST, specific immunoglobulin E, and basophil activation tests (BAT).

RESULTS

In 151 patients with PA, diagnosis was reached in three-fourths of the cases (113/151, 74.8%). The most common culprits identified were neuromuscular blocking agents (25.8%), β lactams (17.2%) and chlorhexidine (13.9%). Severe anaphylaxis was associated with female sex, older age, elevated acute tryptase levels, and more cardiovascular manifestations during induction. Skin tests remained the most sensitive diagnostic modality overall (66.2%). BAT showed better performance for chlorhexidine and gelofusine anaphylaxis, with sensitivity of 80.0% and 79.6%, respectively. Specific Immunoglobulin E indicated even higher sensitivity (95.2%) than did ST (85.0%) and BAT (80.0%) for chlorhexidine anaphylaxis but performed poorly for other drugs.

CONCLUSION

Neuromuscular blocking agents remain the most common culprit in PA. There was a higher prevalence of gelofusine anaphylaxis in our cohort than was seen in the literature. Skin tests remain the most sensitive testing modality. In vitro tests for chlorhexidine and gelofusine showed promising results, but more studies to further elucidate its use are warranted.

Relationship between ANI and qNOX and between MAC and qCON during outpatient laparoscopic cholecystectomy using remifentanil and desflurane without muscle relaxants: a prospective observational preliminary study

This study was designed to investigate qCON and qNOX variations during outpatient laparoscopic cholecystectomy using remifentanil and desflurane without muscle relaxants and compare these indices with ANI and MAC. Adult patients undergoing outpatient laparoscopic cholecystectomy were included in this prospective observational study. Maintenance of anesthesia was performed using remifentanil targeted to ANI 50-80 and desflurane targeted to MAC 0.8-1.2 without muscle relaxants. The ANI, qCON and qNOX and desflurane MAC values were collected at different time-points and analyzed using repeated measures ANOVA. The relationship between ANI and qNOX and between qCON and MAC were analyzed by linear regression. The ANI was comprised between 50 and 80 during maintenance of anesthesia. Higher values of qNOX and qCON were observed at induction and extubation than during all other time-points where they were comprised between 40 and 60. A poor but significant negative linear relationship (r² = 0.07, p < 0.001) was observed between ANI and qNOX. There also was a negative linear relationship between qCON and MAC (r² = 0.48, p < 0.001) and between qNOX and remifentanil infusion rate (r² = 0.13, p < 0.001). The linear mixed-effect regression correlation (r²) was 0.65 for ANI-qNOX and 0.96 for qCON-MAC. The qCON and qNOX monitoring seems informative during general anesthesia using desflurane and remifentanil without muscle relaxants in patients undergoing ambulatory laparoscopic cholecystectomy. While qCON correlated with MAC, the correlation of overall qCON and ANI was poor but significant. Additionally, the qNOX weakly correlated with the remifentanil infusion rate. This observational study suggests that the proposed ranges of 40-60 for both indexes may correspond to adequate levels of hypnosis and analgesia during general anesthesia, although this should be confirmed by further research.

Neuromuscular blocking agent induced hypersensitivity reaction exploration: an update

Acute hypersensitivity reactions (AHRs) occurring in present-day anaesthesia can have severe, sometimes fatal, consequences and their incidence is increasing. The most frequent allergens responsible for AHR during anaesthesia are neuromuscular blocking agents (NMBAs) (70% of the cases) followed by antibiotics (18%), patent blue dye and methylene blue dye (5%), and latex (5%). Following an AHR, strategies for subsequent anaesthetic procedures (especially the choice of an NMBA) may be difficult to formulate due to inconclusive diagnostic analysis in up to 30% of AHRs. Current diagnosis of AHR relies on the detection of mast cell degranulation products and drug-specific type E immunoglobulins (IgE) in order to document an IgE-mediated anaphylaxis (IgE endotype). Nonetheless, other IgE-independent pathways can be involved in AHR, but their detection is not currently available in standard situations. The different mechanisms (endotypes) involved in peri-operative AHR may contribute to the inconclusive diagnostic work-up and this generates uncertainty concerning the culpable drug and strategy for subsequent anaesthetic procedures. This review provides details on the IgE endotype; an update on non-IgE related endotypes and the novel diagnostic tools that could characterise them. This detailed update is intended to provide explicit clinical reasoning tools to the anaesthesiologist faced with an incomplete AHR diagnostic work-up and to facilitate the decision-making process regarding anaesthetic procedures following an AHR to NMBAs.

Perioperative Hypersensitivity Evaluation and Management: A Practical Approach

Perioperative hypersensitivity (POH) is an uncommon, potentially life-threatening event. Identification of POH can be difficult given the lack of familiarity, physiological effects of anesthesia, draping of the patient during surgery, and potential nonimmunological factors contributing to signs and symptoms. Given the unique nature and large number of medications administered in the perioperative setting, evaluation of POH can be challenging. In this paper, we present a practical approach to management with an emphasis on understanding what happens in the operating room, the overlap of signs and symptoms between nonimmunological and immunological reactions, acute management, and subsequent evaluation. In addition, we provide a strategy for further review of an initially negative evaluation and emphasize the importance of establishing management plans for the patient as well as providing recommendations to the medical, anesthesia, and surgical teams for future surgeries. A critical factor for successful management at all points in the process is a close collaboration between the anesthesia and the allergy teams.

Allergic and other adverse reactions to drugs used in anesthesia and surgery

The list of drugs patients may be exposed to during the perioperative and postoperative periods is potentially extensive. It includes induction agents, neuromuscular blocking drugs (NMBDs), opioids, antibiotics, sugammadex, colloids, local anesthetics, polypeptides, antifibrinolytic agents, heparin and related anticoagulants, blue dyes, chlorhexidine, and a range of other agents depending on several factors related to individual patients’ clinical condition and progress in the postoperative recovery period. To avoid poor or ultrarapid metabolizers to a particular drug (for example tramadol and codeine) or possible adverse drug reactions (ADRs), some drugs may need to be avoided during or after surgery. This will be the case for patients with a history of anaphylaxis or other adverse events/intolerances to a known drug. Other drugs may be ceased for a period before surgery, e.g., anticoagulants that increase the chance of bleeding; diuretics for patients with acute renal failure; antihypertensives relative to kidney injury after major vascular surgery; and serotonergic drugs that together with some opioids may rarely induce serotonin toxicity. Studies of germline variations shown by genotyping and phenotyping to identify a predisposition of genetic factors to ADRs offer an increasingly important approach to individualize drug therapy. Studies of associations of human leukocyte antigen (HLA) genes with some serious delayed immune-mediated reactions are ongoing and variations of drug-metabolizing cytochrome CYP450 enzymes, P-glycoprotein, and catechol-O -methyltransferase show promise for the assessment of ADRs and non-responses to drugs, particularly opioids and other analgesics. Surveys of ADRs from an increasing number of institutions often cover small numbers of patients, are retrospective in nature, fail to clearly identify culprit drugs, and do not adequately distinguish immune-mediated from non-immune-mediated anaphylactoid reactions. From the many surveys undertaken, the large list of agents identified during and after anesthesia and surgery are examined for their ADR involvement. Drugs are classified into those most often involved, (NMBD and antibiotics); drugs that are becoming more frequently implicated, namely antibiotics (particularly teicoplanin), and blue dyes; those becoming less frequently involved; and drugs more rarely involved in perioperative, and postoperative adverse reactions but still important and necessary to keep in mind for the occasional potential sensitive patient. Clinicians should be aware of the similarities between drug-induced true allergic type I IgE/FcεRI- and pseudoallergic MRGPRX2-mediated ADRs, the clinical features of each, and their distinguishing characteristics. Procedures for identifying MRGPRX2 agonists and diagnosing and distinguishing pseudoallergic from allergic reaction mechanisms are discussed.

Perioperative Anaphylaxis

Anesthesiologists routinely manage patients receiving drugs and agents, all of which have the potential for anaphylaxis, the life-threatening presentation of an allergic reaction. Clinicians must be ready to diagnose and manage the acute cardiopulmonary dysfunction that occurs.

Combined Treatment with KV Channel Inhibitor 4-Aminopyridine and either γ-Cystathionine Lyase Inhibitor β-Cyanoalanine or Epinephrine Restores Blood Pressure, and Improves Survival in the Wistar Rat Model of Anaphylactic Shock

Simple Summary

Allergic diseases are presenting a constant increase all over the world and caused by such different substances as food, drugs, and pollens. Anaphylactic shock is the more severe complication of allergy which can induce death if the treatment is not administered immediately. Some patients do not respond to the recommended treatment, intra venous or intramuscular epinephrine. The pathophysiology of anaphylactic shock is still under investigation. The mediators released after the activation of mast cells and basophiles act on endothelial cells and smooth muscle cells, inducing the vasodilation responsible for hypotension and shock. Nitric oxide and hydrogen sulphide are both intracellular mediators that induce vasodilation. The role of potassium voltage dependent channels is suspected. We aimed to demonstrate the ability of a blocker of potassium voltage dependent channels, 4-aminopyridine, alone or in combination with inhibitors of cystathionine γ-lyase to restore blood pressure and improve survival in an ovalbumin rat anaphylactic shock model. The blockade of potassium voltage dependent channels alone or combined with inhibitors of cystathionine γ-lyase, dl-propargylglycine, or β-cyanoalanine restored blood pressure and improved survival. These findings suggest possible investigative treatment pathways for research concerning epinephrine-refractory anaphylactic shock in patients.

Abstract

The mechanism of anaphylactic shock (AS) remains incompletely understood. The potassium channel blocker 4-aminopyridine (4-AP), the inhibitors of cystathionine γ-lyase (ICSE), dl-propargylglycine (DPG) or β-cyanoalanine (BCA), and the nitric oxide (NO) synthase produce vasoconstriction and could be an alternative for the treatment of AS. The aim of this study was to demonstrate the ability of L-NAME, ICSE alone or in combination with 4-AP to restore blood pressure (BP) and improve survival in ovalbumin (OVA) rats AS. Experimental groups included non-sensitized Wistar rats (n = 6); AS (n = 6); AS (n = 10 per group) treated i.v. with 4-AP (AS+4-AP), epinephrine (AS+EPI), AS+DPG, AS+BCA, or with L-NAME (AS+L-NAME); or AS treated with drug combinations 4-AP+DPG, 4-AP+BCA, 4-AP+L-NAME, or 4-AP+EPI. AS was induced by i.v. OVA (1 mg). Treatments were administered i.v. one minute after AS induction. Mean arterial BP (MAP), heart rate (HR), and survival were monitored for 60 min. Plasma levels of histamine, prostaglandin E2 (PGE2) and F2 (PGF2α), leukotriene B4 and C4, angiotensin II, vasopressin, oxidative stress markers, pH, HCO3, PaO2, PaCO2, and K+ were measured. OVA induced severe hypotension and all AS rats died. Moreover, 4-AP, 4-AP+EPI, or 4-AP+BCA normalized both MAP and HR and increased survival. All sensitized rats treated with 4-AP alone or with 4-AP+BCA survived. The time-integrated MAP “area under the curve” was significantly higher after combined 4-AP treatment with ICSE. Metabolic acidosis was not rescued and NO, ICSE, and Kv inhibitors differentially alter oxidative stress and plasma levels of anaphylactic mediators. The AS-induced reduction of serum angiotensin II levels was prevented by 4-AP treatment alone or in combination with other drugs. Further, 4-AP treatment combined with EPI or with BCA also increased serum PGF2α, whereas only the 4-AP+EPI combination increased serum LTB4. Serum vasopressin and angiotensin II levels were increased by 4-AP treatment alone or in combination with other drugs. Moreover, 4-AP alone and in combination with inhibition of cystathionine γ-lyase or EPI normalizes BP, increases serum vasoconstrictor levels, and improves survival in the Wistar rat model of AS. These findings suggest possible investigative treatment pathways for research into epinephrine-refractory anaphylactic shock in patients.

Penicillin Allergy and Perioperative Anaphylaxis

Penicillin allergy is the most commonly reported drug allergy, while perioperative anaphylaxis is overall rare. This review covers the epidemiology of both penicillin allergy and perioperative anaphylaxis both separately and taken together. Considerations regarding anaphylaxis to penicillin during pregnancy are also discussed, since penicillin is the drug of choice for Group B Streptococcus prophylaxis. The minimal cross reactivity between penicillins and cephalosporins is addressed, since the vast majority of patients with a penicillin allergy label can receive perioperative cephalosporins. The management of the patient who has experienced perioperative anaphylaxis, including the importance of allergy referral is covered. Approaches to pre-operative penicillin allergy evaluations and opportunities for education are highlighted.

Acute Urticaria and Anaphylaxis: Differences and Similarities in Clinical Management

Acute urticaria is a common condition that presents with wheals and/or angioedema. However, these symptoms are also frequent in anaphylaxis, a life-threatening reaction that should be immediately diagnosed and treated. In both, mast cells play a central role in the physiopathology. Causes and triggers of acute urticaria and anaphylaxis are similar in general, but some peculiarities can be observed. The diagnostic approach may differ, accordingly to the condition, suspicious causes, age groups and regions. Adrenaline is the first-line treatment for anaphylaxis, but not for acute urticaria, where H1-antihistamines are the first choice. In this paper, we review the main aspects, similarities and differences regarding definitions, mechanisms, causes, diagnosis and treatment of acute urticaria and anaphylaxis.

Incidence of intraoperative anaphylaxis caused by blood products: a 12-year single-center, retrospective study

PURPOSE

Intraoperative anaphylaxis caused by blood products is uncommon, but it is unclear whether the rarity of this reaction is attributable to the difficulty of diagnosis, underreporting, or both. We investigated the incidence of intraoperative transfusion anaphylaxis and its reporting to the hemovigilance system.

METHODS

We retrospectively reviewed cases wherein general anesthesia was used at a single hospital during a 12-year period. Cases of intraoperative anaphylaxis were extracted using an electronic search strategy and determined using the recently developed grading and clinical scoring system. The causative blood products were determined by the onset duration based on literature regarding intraoperative transfusion anaphylaxis cases.

RESULTS

Among the 62,146 general anesthesia cases, 22 cases of intraoperative anaphylaxis were identified, and 11 of the 22 cases received transfusions before the onset of anaphylaxis. Intraoperative transfusion anaphylaxis was defined as occurring within 30 min of transfusion. Finally, nine cases of intraoperative transfusion anaphylaxis were analyzed. The overall incidence of intraoperative transfusion anaphylaxis was 1/3,994, with the highest incidence noted for fresh frozen plasma (1/2146; 95% confidence interval [CI] 1/6610-1/920), platelet concentrate (1/2348; 95% CI 1/92,742-1/422), and red blood cells (1/22,867; 95% CI 1/903,199-1/4,105). No evidence indicated that these cases were reported to the Japanese hemovigilance system, although all intraoperative transfusion anaphylaxis cases were diagnosed by anesthesiologists.

CONCLUSION

The incidence of intraoperative anaphylaxis caused by blood products was higher than that reported and may be underreported to the Japanese hemovigilance system. Further research, particularly multicenter studies, is needed to confirm our results.

End-tidal Carbon Dioxide for Diagnosing Anaphylaxis in Patients with Severe Postinduction Hypotension

BACKGROUND

Perioperative hypersensitivity reactions may be difficult to diagnose during general anesthesia. Postinduction hypotension is the most common sign but is not specific. It was recently suggested that low end-tidal carbon dioxide (ETco2) might be a marker of anaphylaxis (Ring and Messmer grades III to IV immediate hypersensitivity reactions) in hypotensive patients under mechanical ventilation. To test this hypothesis, the authors compared ETco2 in patients with a diagnosis of anaphylaxis and in patients with severe hypotension from any other cause after the induction of anesthesia.

METHODS

This was a retrospective single-center case-control study in which two groups were formed from an anesthesia data warehouse. The anaphylaxis group was formed on the basis of tryptase/histamine assay data and allergy workup data recorded over the period 2010 to 2018. The control (hypotension) group consisted of all patients having experienced severe hypotension (mean arterial pressure less than 50 mmHg for 5 min or longer) with a cause other than anaphylaxis after anesthesia induction in 2017.

RESULTS

The anaphylaxis and hypotension groups comprised 49 patients (grade III: n = 38; grade IV: n = 11) and 555 patients, respectively. The minimum ETco2 value was significantly lower in the anaphylaxis group (median [interquartile range]: 17 [12 to 23] mmHg) than in the hypotension group (32 [29 to 34] mmHg; P < 0.001). The area under the receiver operating characteristic curve (95% CI) for ETco2 was 0.95 (0.91 to 0.99). The sensitivity and specificity (95% CI) for the optimal cutoff value were 0.92 (0.82 to 0.98) and 0.94 (0.92 to 0.99), respectively. In multivariable analysis, minimum ETco2 was associated with anaphylaxis after adjusting for confounders and competing predictors, including arterial pressure, heart rate, and peak airway pressure (odds ratio [95% CI] for ETco2: 0.51 [0.38 to 0.68]; P < 0.001).

CONCLUSIONS

In case of severe hypotension after anesthesia induction, a low ETco2 contributes to the diagnosis of anaphylaxis, in addition to the classical signs of perioperative immediate hypersensitivity.

EDITOR’S PERSPECTIVE

Perioperative Anaphylaxis

Perioperative anaphylaxis is a potentially life-threatening and under-recognized event most commonly caused by antibiotics, neuromuscular blocking agents, dyes, latex, and disinfectants. This review provides updates in the epidemiology and pathogenesis of perioperative anaphylaxis, discusses culprit agents, and highlights the tenets of management including a comprehensive allergy evaluation.

Diagnostic performance of serial serum total tryptase measurement to differentiate positive from negative allergy testing among patients with suspected perioperative hypersensitivity

BACKGROUND

Serum total tryptase has been shown to increase during acute allergic reactions (acute tryptase, T_A ); however, few studies have investigated the values of T_A or a combination of T_A and baseline tryptase (T_B ) to discriminate positive from negative testing in perioperative hypersensitivity reaction (POH) allergy work up. The aim of this study was to determine the diagnostic performance of T_A in order to differentiate positive from negative allergy testing suspected POH and analyze the diagnostic performance of serial tryptase levels using several formulas.

METHODS

All patients from the University hospital of Montpellier and Strasbourg, France who presented with suspected POH and underwent complete drug allergy work-up between March 2011 and December 2019 with available T_A and T_B were included. Four formulas, including a change in T_A >11 (F1), or >2+1.2xT_B (F2), or >3+T_B (F3), or >120%T_B (F4), were applied.

RESULTS

One hundred and sixty-two patients were included, and 131 of them (80.8%) had grade III or IV reactions. Ninety patients had positive allergy testing. The optimal cut-off value of T_A to distinguish positive from negative allergy testing patients was 9.8 μg/L with an AUC of 0.817 (95%CI: 0.752-0.882, p<0.001). The 93% PPV threshold for T_A was 33 μg/L (95.8% specificity). Paired tryptase levels according to formulas F2 and F3 yielded the highest Youden index (0.54 and 0.53, respectively).

CONCLUSION

The optimal cut-off point for T_A for distinguishing positive from negative allergy testing suspected POH was 9.8 μg/L. T_A value of 33 μg/L was required to achieve >90% PPV.

Clinical reasoning in anaphylactic shock: addressing the challenges faced by anaesthesiologists in real time: A clinical review and management algorithms

Acute hypersensitivity reactions to drugs occur infrequently during anaesthesia and the peri-operative period. When clinical presentation includes the classical triad, erythema, cardiovascular abnormalities and increased airway pressure, the diagnosis is evident and the challenge is to prescribe a therapeutic regimen according to guidelines and to manage refractory signs in a timely manner. In many situations, however, the initial clinical signs are isolated, such as increased airway pressure or arterial hypotension. Rendering a differential diagnosis with causes and mechanisms other than acute hypersensitivity reactions (AHRs) is difficult, delaying treatment with possible worsening of the clinical signs, and even death, in previously healthy individuals. In these difficult diagnostic situations, clinical reasoning is mandatory, and guidelines do not explicitly explain the elements on which clinical reasoning can be built. In this article, based on clinical evidence whenever available, experimental data and pathophysiology, we propose algorithms that have been evaluated by experts. The goal of these algorithms is to provide explicit elements on which the differential diagnosis of AHRs can be made, accelerating the implementation of adequate therapy.

Investigation of perioperative hypersensitivity reactions: an update

PURPOSE OF REVIEW

The purpose of this review is to provide an update on how best to manage the investigation of suspected perioperative hypersensitivity reactions based on recent literature and key publications.

RECENT FINDINGS

In the past two years, several very important initiatives have been taken in the field of perioperative hypersensitivity. The 6th national audit project in the United Kingdom has provided new knowledge through a series of studies, including a nationwide prospective study, and the European Academy of Allergy and Clinical Immunology has commissioned a position paper with updated recommendations for investigations. Lastly, a large international working group comprising experts in anesthesiology, allergology, and immunology, the International Suspected Perioperative Allergic Reactions group, has published a series of articles providing updates and new insights into several different key areas of perioperative hypersensitivity.

SUMMARY

The investigation of perioperative hypersensitivity reactions is highly complex and aims to identify the correct culprit to ensure future avoidance but also to disprove allergy to other suspected culprits, making them available for subsequent anesthesia. To achieve this, close collaboration between anesthesiologists and allergists is called upon to ensure the best possible outcome for the patient.

Toxicities of opioid analgesics: respiratory depression, histamine release, hemodynamic changes, hypersensitivity, serotonin toxicity

Opioid-induced respiratory depression is potentially life-threatening and often regarded as the main hazard of opioid use. Main cause of death is cardiorespiratory arrest with hypoxia and hypercapnia. Respiratory depression is mediated by opioid μ receptors expressed on respiratory neurons in the CNS. Studies on the major sites in the brainstem mediating respiratory rate suppression, the pre-Bӧtzinger complex and parabrachial complex (including the Kӧlliker Fuse nucleus), have yielded conflicting findings and interpretations but recent investigations involving deletion of μ receptors from neurons have led to greater consensus. Some opioid analgesic drugs are histamine releasers. The range of clinical effects of released histamine include increased cardiac output due to an increase in heart rate, increased force of myocardial contraction, and a dilatatory effect on small blood vessels leading to flushing, decreased vascular resistance and hypotension. Resultant hemodynamic changes do not necessarily relate directly to the concentration of histamine in plasma due to a range of variables including functional differences between mast cells and histamine-induced anaphylactoid reactions may occur less often than commonly believed. Opioid-induced histamine release rarely if ever provokes bronchospasm and histamine released by opioids in normal doses does not lead to anaphylactoid reactions or result in IgE-mediated reactions in normal patients. Hypersensitivities to opioids, mainly some skin reactions and occasional type I hypersensitivities, chiefly anaphylaxis and urticaria, are uncommon. Hypersensitivities to morphine, codeine, heroin, methadone, meperidine, fentanyl, remifentanil, buprenorphine, tramadol, and dextromethorphan are summarized. In 2016, the FDA issued a Drug Safety Communication concerning the association of opioids with serotonin syndrome, a toxicity associated with raised intra-synaptic concentrations of serotonin in the CNS, inhibition of serotonin reuptake, and activation of 5-HT receptors. Opioids may provoke serotonin toxicity especially if administered in conjunction with other serotonergic medications. The increasing use of opioid analgesics and widespread prescribing of antidepressants and psychiatric medicines, indicates the likelihood of an increased incidence of serotonin toxicity in opioid-treated patients.

Perioperative Anaphylaxis: Evaluation and Management

Perioperative anaphylaxis (PA) is a rare but life-threatening condition that poses diagnostic and management challenges in the operating room. The incidence of severe perioperative reactions is estimated to be approximately 1:7000-10,000. Management involves both immediate stabilization of the patient and identifying the culprit agent. Identification is essential to prevent recurrence of the event in subsequent surgeries and to avoid unnecessary labeling of drug allergy. Identifying all possible exposures including medications, disinfectants, latex, and dyes and choosing the appropriate tests are essential for proper evaluation. To identify the culprit, primary testing modalities include tryptase at the time of the reaction with subsequent levels and skin testing with nonirritating concentrations to the medications and substances utilized during the procedure and those potentially used as alternates. This strategy provides guidance for future surgeries and procedures. Close collaboration between the allergy, anesthesiology, and surgery teams is essential for appropriate management of these patients at the time of the reaction, during the post event evaluation and in preparation for subsequent surgeries.

Mast Cell Activation During Suspected Perioperative Hypersensitivity: A Need for Paired Samples Analysis

BACKGROUND

Perioperative hypersensitivity (POH) reactions constitute a significant clinical and diagnostic challenge. A transient increase in serum tryptase during POH reflects mast cell activation (MCA) and helps to recognize an underlying hypersensitivity mechanism.

OBJECTIVE

To determine the diagnostic performance of different tryptase decision thresholds based on single and paired measurements to document MCA in suspected POH.

METHODS

Acute serum tryptase (aST) and baseline serum tryptase (bST) samples were obtained from patients referred to our outpatients clinic because of clinical POH. Tryptase samples from controls were obtained before induction (Tt₀) and 1.5 hours after induction (Tt₁) in uneventful anesthesia. Different cutoff points for tryptase increase over bST and the percentage increase in tryptase (%T) were calculated and compared with existing thresholds: aST > [1.2 × (bST) + 2] (consensus formula), aST higher than 11.4 ng/mL, and aST higher than 14 ng/mL.

RESULTS

Patients with POH had higher bST and aST levels compared with controls (respectively 5.15 vs 2.28 ng/mL for bST and 20.30 vs 1.92 ng/mL for aST). The consensus formula and a tryptase increase over bST of greater than or equal to 3.2 ng/mL held the highest accuracies to document MCA in POH (respectively 81% and 82%). A bST of higher than 8 ng/mL was present in 4% of controls, 5% of patients with grade 1 POH, 24% of patients with grade 2 POH, 15% of patients with grade 3 POH, and 17% of patients with grade 4 POH.

CONCLUSIONS

Our data endorse the consensus formula for detection of MCA in POH. Furthermore, it shows that a bST of higher than 8 ng/mL was associated with occurrence of anaphylaxis.

Mechanisms of human drug-induced anaphylaxis

Drug-induced anaphylaxis is a hyperacute reaction affecting multiple organs that can be of fatal consequence. Its incidence is increasing, consistent with a global increased sensitization to various allergens and drugs in the population. Few risk factors and mechanisms have been identified from human studies due to the rarity of anaphylactic events and their unpredictability. This systemic reaction is caused by the rapid release of a large range of functionally diverse mediators, including histamine and platelet-activating factor as the main drivers identified. Mechanisms defined from models of experimental anaphylaxis identify drug-specific antibodies of the IgE and IgG class that link the drug to antibody receptors on multiple cell types, causing their activation and mediator release. In the case of drugs with peculiar chemical structures, antibodies may not be necessary because drug-binding receptors, such as Mas-related G protein-coupled receptor member X2, have been identified. This review describes the complex reaction leading to drug-induced anaphylaxis that can involve various antibody classes, various cell types-including mast cells, neutrophils, platelets, basophils, macrophages, and monocytes-and their mediators and receptors that, importantly, can be activated alone or in association to participate in the severity of the reaction.

Use and Interpretation of Acute and Baseline Tryptase in Perioperative Hypersensitivity and Anaphylaxis

Paired acute and baseline serum or plasma tryptase sampling and determination have recently been included as a mechanistic approach in the diagnostic and management guidelines of perioperative immediate hypersensitivity and anaphylaxis. The timing of this paired sampling is clearly defined in international consensus statements, with the optimal window for acute tryptase sampling between 30 minutes and 2 hours after the initiation of symptoms, whereas baseline tryptase should be measured in a sample collected before the event (preop) or at least 24 hours after all signs and symptoms have resolved. A transient elevation of the acute tryptase level greater than [2 + (1.2 × baseline tryptase level)] supports the involvement and activation of mast cells. Here, we provide the clinical, pathophysiological, and technical rationale for the procedure and interpretation of paired acute and baseline tryptase. Clinical examples, up-to-date knowledge of hereditary α-tryptasemia as a frequent cause of baseline tryptase of 7 μg/L and higher, mastocytosis, other clonal myeloid disorders, cardiovascular or renal failure, and technical improvements resulting in continued lowering of the 95th percentile value are discussed. Clues for improved management of perioperative immediate hypersensitivity and anaphylaxis include (1) sustained dissemination and implementation of updated guidelines; (2) preoperative sample storage for deferred analysis; (3) referral for thorough allergy investigation, screening for mast cell-related disorders, and recommendations for future anesthetic procedures; and (4) sustained collaboration between anesthesiologists, immunologists, and allergists.

Drug-induced anaphylaxis during general anesthesia in 14 tertiary hospitals in Japan: a retrospective, multicenter, observational study

Since perioperative anaphylaxis occurs suddenly, and it can be life-threatening, anesthesiologists need to have sufficient knowledge of the epidemiology of perioperative anaphylaxis and appropriate coping strategies to deal with it. Recent studies conducted in Western countries reported the characteristics of perioperative anaphylaxis in each country. However, there are few studies of perioperative anaphylaxis in Japan. To bridge the gap between Japan and other countries, the data of 46 anaphylaxis patients at Gunma University Hospital and 13 neighboring hospitals between 2012 and 2018 were collected and analyzed. The recently developed clinical scoring system was combined with a skin test to include only cases with a definite diagnosis. The most common causative agents were sugammadex, followed by rocuronium, cefazolin, and antibiotics other than cefazolin. Furthermore, the characteristics of anaphylaxis for each causative drug were identified. Time from drug administration to appearance of the first symptom was the longest in the cefazolin group. The incidence of canceled operation was the highest in the rocuronium group. Although it is unclear whether the results of this study can apply to Japan as a whole, the information about the agents responsible for perioperative anaphylaxis and the characteristics of anaphylaxis due to each agent would be helpful to anesthesiologists.

Approach to Perioperative Anaphylaxis in 2020: Updates in Diagnosis and Management

PURPOSE OF REVIEW

The goal of the paper is to review the epidemiology, pathogenesis, diagnosis, and manifestations of perioperative anaphylaxis (POA). We seek to review the most common culprits of POA and different diagnostic modalities for evaluation.

RECENT FINDINGS

Specific IgE testing has a limited role in POA evaluation due to lack of widespread availability and low sensitivity. Basophil activation testing is complementary to skin tests and can assist NMBA sensitivity diagnosis in complex cases. In the past years, there has been an exponential increase in suspected teicoplanin allergic reactions in the European Union. Chlorhexidine is also being increasingly implicated as a culprit in POA. Multiple classes of perioperative medications cause POA. Diagnostic modalities available include skin testing with nonirritating concentrations, basophil activation tests, specific IgE, and drug provocation testing. An accurate record and critical analysis of perioperative events is more important than isolated test results. Future studies evaluating the pathophysiology of these reactions and other therapeutic strategies, such as targeting the MRGPRX2 receptor, are needed.

Perioperative Allergic Reactions: Allergy Assessment and Subsequent Anesthesia

BACKGROUND

Evidence-based guidelines are needed in the United States to improve evaluation of perioperative allergic reactions including recommendations for subsequent anesthesia.

OBJECTIVE

To identify causative agent(s) and evaluate patients' tolerability of subsequent anesthesia in patients evaluated by Allergy/Immunology (A/I) at Massachusetts General Hospital.

METHODS

We performed a retrospective review of patients referred to the outpatient A/I clinic for perioperative allergic reactions between October 2003 and May 2017. Patient demographics, atopic history, and prior adverse drug reactions were reviewed. Patients underwent a comprehensive evaluation with testing including skin testing (ST), drug challenges (when appropriate), tryptase level measurement, and specific IgE to latex measurement. Tolerance of subsequent procedures requiring anesthesia was assessed.

RESULTS

Of 123 patients referred, 74 (60%) were female and the mean age was 46 (±18) years. At least 1 causative agent was identified in 28 patients (24%, n = 28 of 118). Seventeen of 28 (61%) patients were ST positive to an antibiotic, including 13 (46%) positive to cefazolin; 3 patients (11%) had a positive latex specific IgE. Of 85 patients who had subsequent anesthesia with a known outcome, 78 (91%) did not have another perioperative allergic reaction. Two of 5 patients with an elevated baseline tryptase level did not tolerate subsequent anesthesia.

CONCLUSION

The majority of patients safely received subsequent anesthesia after comprehensive A/I evaluation for their perioperative allergic reactions; however, improved algorithmic care is needed in the United States. Among ST-positive patients (24%), antibiotics (especially cefazolin) were the most common culprits. An elevated baseline tryptase level was associated with an increased risk of recurrent perioperative allergic reactions.