What is General Anesthesia?
General anesthesia is the use of medications that cause you to lose consciousness. It is usually the most appropriate means of keeping you in a safe and comfortable position while undergoing a surgical procedure, during which you will not be aware of what is happening to you. General anesthetic (General Anaesthetic) can be administered in two ways. The medications can be given intravenously, usually into the arm or hand. Alternatively, you can breathe gases through a mask.
How Common is an Allergic Reaction to Anesthesia?
Fortunately, severe allergic reactions during anesthesia are rare, occurring once in every 5,000 to 25,000 anesthesia cases. Unfortunately, these reactions can sometimes be fatal, with a mortality rate of up to 3%.
What are the Signs and Symptoms of This Type of Allergy?
It is well known that the most severe form of allergic reactions is referred to by the term “anaphylactic shock – Anaphylaxis.” During an allergic reaction, the patient may experience difficulty breathing resulting from the closure of the airways and respiratory passages. Swelling of the face and mouth can occur, and a reddish skin rash is also sometimes observed. The heart and blood vessels are affected, and this is the hallmark of the condition: an increase in heart rate and blood pressure can drop to dangerously low levels.
What are the Substances Responsible for This Type of Allergy?
Among the cases of hypersensitivity attributed to Neuromuscular Blocker Agents, the following substances have been classified in descending order of importance: Suxamethonium, Vecuronium, Atracurium, Pancuronium, Rocuronium, Mivacurium, and Cisatracurium.
What are the Risk Factors That May Lead to This Condition?
The prevalence of this condition has been reported to be significantly higher in females.
Anaphylactic reactions rarely occur in children, and most cases of sensitization occur due to rubber/latex.
It has been generally agreed that atopy is one of the risk factors for allergic diseases, as there are allergy cases that have been reported with a high prevalence rate.
There is no evidence that multiple anesthetics would trigger an allergy to a particular anesthetic agent. However, if an allergy has developed during previous anesthesia procedures, there is a high probability of anaphylactic shock occurring if an anesthetic from the same product is administered again.
What are the Main Groups of These Substances?
There are two main groups:
(1) Esters
Esters contain anesthetics such as Cocaine, Procaine, Tetracaine, Chloroprocaine, and Benzocaine. Currently, Benzocaine is used routinely only in dentistry, and its use is limited to topical application. The others are most commonly used nowadays in the field of obstetrics and in regional anesthesia or Spinal Anesthesia, which is a type of anesthesia used for surgical procedures by injecting the anesthetic into the cerebrospinal fluid surrounding the spinal cord. In general, a patient known to be sensitive to any ester anesthetic product is likely to also be sensitive to all other anesthetic drugs from the esters group. The use of anesthetic substances that include ester compounds can be avoided entirely, as 5% lidocaine gel works just as well as a topical anesthetic for numbing the gums before giving an injection.
(2) Amines
Amines include Lidocaine, Mepivacaine, Bupivacaine, Articaine, and Prilocaine. Since doctors currently use anesthetic substances in which amines are the main component, and they no longer use anesthetic substances based on esters, we see that there are virtually no allergic reactions to local anesthetic medications administered by injection. If you have experienced allergic reactions at a dental clinic, it is likely that the reaction was due to the topical anesthetic applied before the injection, or to the preservatives used in the anesthetic that contain vasoconstrictors to constrict blood vessels (Vasoconstrictors).
What About the Protective Preservatives in These Substances?
Based on the case, the patient may show a normal allergic reaction to a local dental anesthetic injection. It is likely that in reality they are sensitive only to the preservative bisulfite (Bisulfite), which is used to stabilize the vasoconstrictors.
How Do We Diagnose an Allergy to Anesthetic Agents?
One of the most commonly used skin tests by doctors for testing is the True Utility Reaction Test (E.U.R.T.). This is the patch test (Patch Test), which is performed by applying 23 allergenic substances to the skin on 12 polyester patches. One of the patches contains a mixture of several anesthetic substances, and is used to test for allergies to local anesthetic medications in general. A clinical history consistent with a delayed local skin reaction to substances applied topically, along with a positive test result, is considered sufficient to diagnose the condition.
How Can We Manage Allergy to Anesthetic Agents?
Managing this type of allergy involves identifying other agents that the patient can tolerate. When evaluating patients to determine their tolerance and other factors, we usually recommend choosing a substance from a different chemical group. Information on cross-reactivity between topically applied substances is limited, although there is evidence of cross-reactivity within each group of substances and less evidence of minimal cross-reactivity between the two groups. Therefore, we suggest selecting one or more medications from the group of topically applied substances as an alternative substance for the patch test.
