Anaesthetic allergy: Overview

Abstract in English, French
Purpose: In this Continuing Professional Development module, we provide a framework for the prompt diagnosis and management of perioperative anaphylaxis.

Principal findings: Anaphylaxis in the perioperative period can lead to sudden cardiorespiratory compromise. Hypotension, tachycardia, and bronchospasm are the most common presenting signs of anaphylaxis; however, they are nonspecific, making diagnosis challenging. Associated factors that support a diagnosis of anaphylaxis include the timing of symptom onset, a lack of response to first-line vasopressors, evidence of severe hypovolemia, and the appearance of a rash. Treatment should not be delayed in the absence of cutaneous findings, as hemodynamic compromise is often the main presenting feature. Appropriate treatment involves administering epinephrine, resuscitating with fluids, protecting the airway, and removing any triggering agents.

Conclusions: Anaphylaxis is a challenge to diagnose and clinically manage in the perioperative period. Provider vigilance, a high index of suspicion, and timely treatment are necessary to ensure the successful resuscitation and safety of the patient.

Abstract
Determining the etiology of perioperative anaphylaxis is a challenging task, as multiple medications are often administered simultaneously during anesthesia. This is compounded by the paucity of validated skin testing. While drug challenges are the definitive means of assessing for IgE-mediated drug allergy, they must be weighed with the risk of severe reaction. As such, multidisciplinary collaboration is warranted to ensure drug provocation testing is performed thoughtfully and safely. Here, we present a case of an 18-year-old male with juvenile kyphosis who underwent anesthesia prior to spinal fusion surgery. He was given intravenous fentanyl, propofol, dexamethasone, remifentanil, tranexamic acid, methadone, and cefazolin. Additionally, iodine, chlorhexidine, and tincture of benzoin were applied topically. Shortly after the start of anesthesia and prior to incision, he developed bronchospasm, hypoxia, hypotension, and pulseless electrical activity with a return of spontaneous circulation following cardiopulmonary resuscitation. A tryptase level drawn during the event was elevated at 23.7 μg/L (reference range: 0-11.4 μg/L). Months later, the patient underwent skin prick and intradermal testing in an allergy clinic, which was largely unrevealing for a culprit. Given the absence of validated predictive values for skin testing, drug provocation testing was performed with the patient admitted to the intensive care unit due to the high-risk nature of testing. Medications were selected for a challenge after multidisciplinary discussions with specialists in anesthesia and surgery based on the availability of alternative medications. Following negative drug provocation testing to intravenous dexamethasone, intravenous fentanyl, oral midazolam, intravenous methadone, and intravenous tranexamic acid, as well as topical challenges to chlorhexidine, iodine, and tincture of benzoin, the patient was instructed to continue to avoid cefazolin, propofol, and remifentanil and was able to subsequently undergo spinal fusion surgery safely. This case demonstrates a systematic approach for high-risk drug allergy testing that was facilitated by collaboration with allergy, intensive care, anesthesia, and surgery.

Abstract
Background: Perioperative anaphylaxis (PA) is a rare life-threatening complication of anesthesia, with few descriptions of its diagnosis and outcomes in the pediatric population. Many agents can be potential culprits, and drug provocation testing (DPT) to confirm the diagnosis is limited by the nature of anesthetic drugs. PA diagnosis and culprit identification remain a challenge. For patients with limited drug options, desensitization has not been reported. This study evaluated the results of skin and laboratory testing for pediatric patients with PA and provides the protocol and outcome of the first desensitization to cisatracurium, a neuromuscular blocking agent (NMBA).

Methods: Patients ≤18 years old with PA from 2019 to 2024 were included, and medical records were retrospectively reviewed, which comprised serum tryptase levels, results of skin testing (ST), basophil activation testing (BAT), and outcomes.

Results: Eleven patients were included. Tryptase was elevated in seven of 10 (70%) tested patients. ST yielded positive results for nine of 10 (90%), and two of 11 (18.2%) had positive BAT.

Results: A culprit agent was identified in 10 of 11 (91%). The most common drugs were NMBAs (70%) and beta-lactam antibiotics (20%). One patient with a positive DPT to NMBAs and limited alternatives was successfully desensitized to cisatracurium with a 3-bag, 12-step protocol.

Conclusion: The most common drug culprits of PA in children were NMBAs and were identified by ST. Tryptase correlated with PA. BAT served as adjunctive diagnostic tests. Desensitization to cisatracurium was possible.