Allergic reaction is a kind of immune reaction, and the substance that causes allergic reaction is called allergens. There are many kinds of allergens, and some components of plants (pollen, dry grass, etc.), animals (chiggers, bee venom, etc.), drugs (penicillin, sulfonamide, etc.), and food (mushrooms, strawberries, oysters, etc.) are allergens for people who are sensitive. Allergic reactions can be caused by contact between the allergen and the mucous membrane of the respiratory tract or skin or by ingestion into the digestive tract. For an allergic reaction to occur, there must be contact between the allergen and the corresponding antibody (mainly IgE), which is a pro-cellular antibody that attaches to the surface of mast cells and basophils, turning them into sensitive cells. Among them, mast cells are widely and abundantly present in the mucosa of the subcutaneous, respiratory, digestive, and reproductive systems, and the cytoplasm is rich in secretory granules. When sensitive mast cells or basophils encounter allergens, they start to secrete a large amount of histamine and other active substances with vasodilatory properties, causing vasodilation, increased capillary permeability, and increased exudate, resulting in local redness, swelling, burning, runny nose, lacrimation, sneezing, and so on. Prompt administration of antihistamines may bring relief. In another kind of allergic reaction (such as allergic asthma), the mast cells secrete slow reaching substance (SRS) instead of histamine, the effect of which is to make smooth muscle contract continuously. Clinically, an allergy test should be performed for drugs that frequently cause allergy, and those that are positive should be abandoned. Allergic patients with known allergens should avoid re-exposure to the allergen if possible. Desensitization is required for drugs that are known to be allergic and have to be used (e.g., trauma patients allergic to tetanus antitoxin).
Common clinical types of infusion reactions.
1.Febrile reaction
It is often caused by the input of pyrogenic substances (pyrogenic sources, dead bacteria, free bacteriophage proteins, other proteins and non-protein organic or inorganic substances), and the mechanism is that some factors during the infusion process directly or reflexively cause systemic capillary spasm, resulting in a series of symptoms due to microcirculatory disorders.
2.Acute pulmonary edema
The mechanism is caused by the rapid increase of pulmonary venous pressure and the subsequent increase of pulmonary capillary pressure, which causes the intravascular fluid to infiltrate into the interstitium and alveoli of the lungs to form acute pulmonary edema.
3.Thrombophlebitis
It is caused by the chemical reaction of the local venous wall caused by the long-term infusion of highly concentrated and irritating drugs, or the long time of placing the irritating plastic tube in the vein, or the local venous infection caused by the lack of strict implementation of aseptic operation during the infusion process.
4.Air embolism
If the air inside the infusion catheter is not exhausted or is unattended during the pressurized infusion, the gas enters the blood circulation because the catheter gas is not exhausted during the infusion, and if the amount of gas is small, it is pressed into the pulmonary artery by the right ventricle and dispersed into the small pulmonary artery and finally reaches the capillaries, so the damage is small. However, if the amount of air is large, the air in the right ventricle blocks the entrance to the pulmonary artery, so that blood cannot enter the lungs, causing severe hypoxia can cause immediate death.
From these we can see that the two are different from each other in terms of mechanism and most of them can be avoided. Especially infusion reactions, if we can do the above mentioned points can reduce the occurrence, for allergic reactions must master the positive test allergy judgment criteria, for can not be fixed to be regarded as allergic, in addition to ask detailed allergy history and family history, this will also reduce the occurrence of allergies, but also can reduce the occurrence of disputes. It is also important to do a good job of training in this area, to know what is an allergic reaction and what is an infusion reaction, and to know how to explain and handle the occurrence of the reaction.
In general, it is not difficult to diagnose allergic reactions and infusion reactions based on experience. However, some are more ambiguous and it is more difficult to really identify them. The two themselves overlap, and one type of infusion reaction is an allergic reaction. Fortunately, the two treatments have a lot in common. So the topic is quite complex, but there are clinical rules to follow.
5. Allergic reactions
First, it should be clear that there is a clear correlation with the type of drug and the physical differences of the patient, while infusion reactions are more associated with the environment and nursing operation of the infusion.
Secondly, the incidence within the time window should be analyzed: allergic reactions are disseminated, while infusion reactions are concentrated within a certain period of time. If the precipitating factors cannot be removed, they will continue to occur.
Again, analyzed in terms of symptoms: allergic reactions are mostly seen as rash, urticaria, angioneurotic edema, induced asthma, anaphylaxis, etc. In contrast, the vast majority of infusion reactions manifest as chills and a sudden rise in body temperature, usually occurring within 30 minutes to one hour after infusion, and some can occur within 15 minutes. Chills are often the first reason for patients to seek a physician again. Drug fever due to allergic reactions occurs more slowly and is stubborn without stopping the drug. The chance of a sudden rise in body temperature is low.
Finally, without taking into account individual differences, clinicians have the notion that some drugs are more prone to allergy and others rarely occur. For example, the first time the same patient gets an infusion of penicillin for a cold and develops a rash, then the first consideration is an allergic reaction. The second time, the infusion of cimetidine for acute gastritis, chills and high fever occurred during the process, then the first consideration is infusion reaction. So it is also more instructive to go along with the drug this teng to feel the melon.
Treatment: both require anti-allergy and hormone use. But allergic reactions then focus on anti-allergic treatment, using epinephrine if necessary. Whereas infusion reactions focus on regressive heat treatment, each with its own characteristics.
There are 4 issues to be noted in the actual treatment.
(1) The treatment should pay attention to control the emotions of the surrounding population.
In the event of both reactions, the family and the patient are more alarmed and emotional, and their will even be fire fights. At this time you should immediately deal with, while treating the patient and family members to comfort, if the vital signs are stable, then you can boldly comfort. To reduce unnecessary trouble.
(2) Must maintain intravenous access.
Patients and family members have such a problem: when a reaction occurs, they will be very frightened to ask the nurse to terminate the infusion and remove the intravenous needle. If the nurse with insufficient determination meets, he or she will react accordingly. The correct approach is that intravenous access must be maintained for backup. Immediately replace on saline and replace the infusion skin strip. Continue the infusion. The next step of treatment is smoother when done this way.
(3) “Correctly” answer questions from the patient and family.
After the infusion reaction has occurred and the treatment has been completed, you will certainly be asked such questions by family members or patients: What’s going on here, is it the wrong medicine or the opposite? How to answer, more headache, right? Here’s how to answer: It’s not the wrong medication, it’s an isolated reaction, and it’s related to the patient’s quality of rest and the original disease. If the patient’s original fever, you can say that it happens to be in the temperature rise period, if the patient accelerates the infusion speed without permission, then more justified lesson: infusion is too fast, the patient can not stand it at once, it is very dangerous, next time can not be like this. Anyway, the treatment was successful, as you justify it. If a person dies, it can not be. In short: you do not tell the truth, or trouble.
(4) Make early preparations: If anaphylaxis occurs, how do you dispense pediatric epinephrine 1:10,000, what is the dose, and will you prepare it immediately? These are practical questions, just make early preparations.
Please note: When you encounter an emergency problem, first of all, be calm, then immediately check the body and hold on to the four major vital signs. Secondly, treat. Again: comfort the patient.