Allergic reactions to anesthesia
Medical condition
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ToursExplore Lably’s 3D toursSuccessful immediate treatment requires prompt recognition by the attending anesthetist, or in the United States, the attending anesthesiologist or nurse anesthetist. Anesthetists are trained to identify signs if an allergic reaction is occurring. The identification of a reaction is made by the recognition of issues including low blood pressure, hives, wheezing, rash, swelling around the eyes or in the mouth and throat, and other breathing difficulties. Adrenaline (epinephrine) remains the mainstay of treatment, with corticosteroids and antihistamines providing limited benefit in the acute situation.
Risk Factors and Mechanisms
Certain factors can increase a patient's sensitivity and incline them to a reaction. Patients with a history of drug allergies are at a higher risk of resulting in hypersensitivity reactions under anesthesia.
Most anesthetic related allergic reactions are IgE-mediated. These antibodies activate mast cells and basophils, which lead to the release of histamine along with other inflammatory mediators. This immune response results in tissues to swell, a difficulty in breathing, and bronchospasm.
Other risk factors include past exposure to other anesthetic agents, genetics, and underlying medical conditions such as asthma or eczema. Reactions may also occur on the first exposure if the patient has been affected with similarly structured substances.
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Recognition and Management
Early recognition of an allergic reaction during anesthesia is crucial as hypersensitivity reactions can progress rapidly. The attending anesthesiologist or nurse anesthetist monitors for clinical signs the whole time anesthesia is being administered. A sudden drop in blood pressure, widespread rash, and airway or facial swelling are examples to what they are looking for. The most common feature is cardiovascular collapse and is often the first indication of a severe reaction.
Future Avoidance
Subsequent investigation aims to determine the responsible agent to allow its future avoidance. Skin testing is often useful to identify potentially cross-reactive compounds and appropriate therapeutic alternatives. This is done weeks after the initial reaction to allow the immune system to reset itself. However, skin testing can be misleading in giving false positive and false negative results.
Anaphylaxis during anesthesia
Although complications during anesthesia are rare, potentially life-threatening consequences may occur if an anaphylactic reaction develops. The severity of the reaction whilst under anesthesia is because the anesthetist is only made aware of the allergy when it is severe enough to compromise the cardiovascular system and the respiratory system. At this stage, there is little time to manage the situation and recognize the severity of the condition.
The immediate management of the issue consists of three processes:
- The withdrawal of the substances
- Interrupting the effects of the preformed substances released in response to toxin presentation
- Prevention of further substance release
Since the full withdrawal of the offending substance is near impossible, the administration of adrenaline is the main treatment to counteract the effects. Once the patient is stable they will need close observation for 24 hours.