Severe allergic reactions can lead to anaphylactic shock, which can lead to death if not rescued quickly.
Therefore, rescue must race against time, fast and effective!
The first choice for anaphylactic shock is epinephrine, followed by volume expansion and hormone therapy. Correct and timely application of epinephrine and hormones is related to the patient’s life.
01
Anaphylactic shock, the correct application of epinephrine is the key
Comments from friends: “Evidence-Based Internal Medicine” edited by Hu Dayi mentioned in the content of anaphylactic shock rescue that 0.3-0.5 mL of 0.1% epinephrine should be injected subcutaneously or intramuscularly immediately.
Aside from the dosage requirements, how exactly should epinephrine be used?
1. Anaphylactic shock Early administration of epinephrine< span>
2019 “AHA Guidelines for Cardiopulmonary Resuscitation and Cardiovascular First Aid”: It is recommended to use epinephrine for anaphylaxis, which usually results in anaphylactic shock People at risk are prescribed and advised to carry epinephrine auto-injectors.
The recommended dose of epinephrine is 0.3 mg for adults and children over 30 kg, and intramuscular adrenal for children 15 to 30 kg The recommended dose of ketamine is 0.15 mg.
If the patient does not respond to the first dose, and the advanced life support will not be available for 5-10 minutes, give the second dose Adrenaline.
2. Severe allergic reactions Intramuscular injection preferred p>
In most cases of severe allergic reactions, intramuscular epinephrine is the preferred route of administration. If the disease is severe and intramuscular injection does not relieve symptoms, intravenous administration may be considered.
Why not subcutaneously?
Analysis of station friends: According to the hemodynamic changes of shock, the subcutaneous blood supply is definitely insufficient, so the effect of subcutaneous injection is unreliable and unreliable. Stablize. Therefore, it is best to inject intramuscularly or intravenously, but for intravenous administration, it needs to be diluted and then injected with a small dose and slowly injected, or placed in a liquid drip.
As long as it is not resuscitation, intravenous bolus of epinephrine stock solution is strictly prohibited. In allergic hypotension/shock either diluted 10-fold or placed in a fluid IV.
3. Adrenaline is a double-edged sword. The indication must be grasped correctly
Once a decision has been made to administer epinephrine, either intramuscularly or intravenously, the risks of administration should be fully considered. Both overdose and underdose of epinephrine are common mistakes in the rescue of anaphylactic shock.
When epinephrine is given without an indication for intravenous epinephrine, it may cause nausea, vomiting, chest pain, high blood pressure, tachycardia speed, VT, and even VF.
Intravenous epinephrine when indicated but not used may lead to inadequate treatment, aggravated shock and dyspnea.
Therefore, epinephrine is a double-edged sword in the rescue of severe allergic reactions, especially anaphylactic shock.
4. Mode of administration: Dosage and concentration should be understood
Intramuscular: Concentration 1:1000 (ie 1 mg/mL)< /span>, the one-time intramuscular injection is 0.2 to 0.5 mg, that is, 0.2 to 0.5 mL.
Intravenous: Concentration 1:10000 (ie 0.1 mg/mL) span>, for anaphylactic shock without cardiac arrest, 0.05 to 0.1 mg of epinephrine can be administered intravenously(1:10000).
That is, dilute 0.5-1 mg with normal saline to 10 mL each time, and inject it slowly for more than 5 minutes. The drug circulates in the blood vessels and quickly reaches the heart.
In addition Intravenous infusion can be used as an alternative to bolus application.
Reminder:Do not administer intramuscular drugs directly into the vein. If intravenous medication is used, continuous ECG monitoring is required to prevent hypertensive crisis and ventricular fibrillation, so hemodynamic testing is recommended during application.
In addition, after the timely administration of epinephrine, the anti-inflammatory and anti-shock hormones are also essential.
However, there are many types of hormonal drugs. Should patients with anaphylactic shock choose methylprednisolone or dexamethasone?
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Hydrogen, glutinous rice and methylprednisolone, how to choose different opinions
Comments from friends: GlucocorticoidsBecause of its slow onset of action, it is the second-choice drug in anaphylactic shock. The “Evidence-Based Internal Medicine” edited by Hu Dayi mentioned the use of hydrocortisone 200-400 mg or dexamethasone 10-20 mg intravenously.
Why not recommend Methylprednisolone? What is the difference between the use of hydrocortisone and dexamethasone?
It is a matter of opinion about anaphylactic shock, what to choose and how to use hormone medication, and the choice of different clinical situations is also different. We summarize the following points:
Point one:< span>Glucocorticoids have immunosuppressive, anti-inflammatory and anti-shock effects, and also have strong anti-allergic effects, and can also dilate bronchi. But how to choose?
①Hydrocortisone is an endogenous hormone that does not need to be transformed in the body. It is short-acting and weak-acting, and the dosage is large. The 2012 SCC recommends it for septic shock caused by sepsis.
②Methylprednisolone is an exogenous hormone, which needs to be transformed by the liver in the body. It is recommended to use to reduce pulmonary interstitial edema and prevent pulmonary fibrosis.
③Dexamethasone is also an exogenous hormone. Moderate effect, stronger binding to glucocorticoid receptors than the other two, strong anti-inflammatory, and long duration of action. The key is that dexamethasone has a high distribution concentration in small blood vessels of the skin and strong tissue penetration, which can effectively reduce exudation and relieve skin congestion symptoms, especially for anaphylactic shock.
The second point of view:Dexam Methasone is a standing medicine in the rescue car or rescue box, and the source of the medicine is more convenient than methylprednisolone. In addition, dexamethasone can be injected directly without dilution, which is also to gain time for rescuing the patient.
But methylprednisolone is a powder that needs to be diluted before bolus injection, and it is not used in the rescue car, so Generally not used for anaphylactic shock. Although it is some details, it will directly affect whether the rescue process can be fast and effective.
Point 3:Select dexamethasone or For the choice of methylprednisolone, according to the onset time of the two effects, methylprednisolone should still be the first choice, after all, the onset time is fast.
In clinical practice, most doctors like to use dexamethasone when dealing with allergic reactions and anaphylactic shock, but it is just a traditional medication tradition and medication habit.
So, how to use hormones, mainly depends on the focus: Hydrogen has a quick onset of action and a short duration of action, and glutathione is the opposite. In order to take effect quickly, it is naturally hydrogen can; but some people will have a second attack of allergies. At this time, the long-term effect of rice is also remarkable. And methylprednisolone, in both onset time and maintenance time, is in the middle.
However, anaphylactic shock requires comprehensive treatment, fluid rehydration, antihistamine, etc. The patient’s condition and actual situation to choose.
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Anaphylactic shock rescue process
< p>Step 1:Cut off the allergen
(1) Ingestion through skin contact: Common insect bites, such as bees, wasps, etc.
(2) Ingestion by inhalation: the common ones include inhalation of pollen allergy.
(3) Ingestion through digestive tract: For patients with allergic constitution, eating certain foods can also cause anaphylactic shock . Such as eggs, seafood, pineapple, peaches, peanuts(childhood)and so on. If anaphylactic shock is caused by oral intake of food, a gastric tube is required, and gastric lavage is necessary.
(4) Intravenous intake: drug allergy is the most common cause of anaphylactic shock, especially Injectable route of administration, oral drugs can also cause. Drugs that can cause anaphylactic shock, such as antibiotics (penicillin, cephalosporins, etc.), traditional Chinese medicine injections, biological preparations, etc.
Reminder:Understanding the time window of allergic reactions can help to identify allergens. Symptoms appear within 5 to 15 minutes of most drug injections or insect bites. Severe cases can occur within 5 minutes, and the earlier the onset, the more severe the disease. People with food allergies can develop symptoms within 20 to 60 minutes.
Step 2: Keep the airway open
A high-flow oxygen of 4-5 L/min was given, and respiratory secretions were removed in time. Tracheal intubation or tracheostomy is required if necessary.
Step 3:Adrenaline to Help< /span>
Because adrenaline can excite the myocardium, increase blood pressure, relax the bronchial tubes, etc., it can relieve the weak heartbeat, blood pressure drop, breathing, etc. of anaphylactic shock. Difficulty and other symptoms.
Reminder:Epinephrine must not be used directly intravenously in anaphylactic shock, and must be diluted! If it is not diluted, the patient is likely to be “seckilled”.
Step 4:CreateIntravenous access rehydration
In order to facilitate rescue, it is necessary to establish intravenous infusion access as soon as possible, and intravenously push dexamethasone Metasone 5-10 mg, and then given glucocorticoid maintenance therapy as appropriate. Can choose hydrocortisone 200 ~ 400 mg or methylprednisolone 80 ~ 120 mg slowly intravenously.
When systolic blood pressure drops below 80 mmHg, anti-shock drugs, such as intravenous norepinephrine, should be given at the same time: 1 to 2 mg norepinephrine was added to 100 mL of liquid and instilled at a rate of 4 to 10 μg/min. Or give 10 ~ 40 mg of metahydroxylamine added to 100 mL of liquid for slow instillation.
The drip rate can be adjusted at any time according to the fluctuation of blood pressure; other vasoactive drugs with anti-shock can be given at the same time with heart failure. Such as dopamine (5 to 20 mcg/kg/min).
Due to the release of histamine during allergy, the vascular permeability increases, and a large amount of plasma leaks out of the blood vessels, resulting in effective circulating blood Insufficient capacity. Therefore, liquids such as normal saline should be supplemented at the same time to ensure adequate tissue perfusion.
Step 5:Adjunctive Medication span>
The release of histamine is the main culprit in anaphylactic shock, so antihistamine treatment is imperative. Usually promethazine 25 to 50 mg intramuscularly.
Conscious individuals may receive oral cetirizine 20 mg or desloratadine 10 mg. Intravenous injection of 10% calcium gluconate 10-20 mL can also be used for anti-allergy treatment.
Reminder: 10% Calcium Gluconate Injection needs to be diluted with an equal amount of 5% to 25% Dextrose Injection and then slowly injected intravenously, no more than 5 mL per minute , so as not to cause arrhythmia caused by rapid increase in blood calcium. Cardiac glycosides are contraindicated during the use of calcium gluconate.
Anaphylactic shock rescue must race against time. If manpower is sufficient, several steps can be performed at the same time.
In short, the rescue and treatment of anaphylactic shock is a process that tests not only speed, but also doctors’ resilience and clinical knowledge reserves. Correct use of epinephrine and hormones is related to the life and prognosis of patients.
Today’s Topics
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Clinically, have you ever encountered a patient with anaphylactic shock? How is your medication chosen?
First Release: Lilac Garden Breathing Time
Submission: [email protected]
Title: Zhanku Hailuo