10/05/2022
Dealing with anaphylactic shock
Anaphylaxis is a generalized acute reaction, this is a serious condition that requires prompt management and emergency care, otherwise it can be life-threatening. In case of needing respiratory support, infusion of Adrenalin, Glucagon, need to be admitted to the emergency department.
1. First aid for anaphylaxis
The principle of emergency emergency for anaphylaxis is to urgently perform CPR on the spot until the airway (Airway), breathing (Breathing), circulation (Circulation) with adrenaline, infusion translated... and then transferred to another place.
Immediately stop exposure to allergens such as drugs, blood and blood products, fluids, oral, topical, eye drops...
1.1. General treatment
In mild cases, antihistamines may be given subcutaneously or methylprednisolone 40-80mg intravenously.
In severe cases, if there is difficulty breathing or low blood pressure, it is necessary to put the patient in the position, with the head low, the legs high. Administer adrenaline 0.5-1mg ampoule intramuscularly into the anterolateral side of the thigh.
For children, dilute 1 ampoule of adrenaline with 10ml of distilled water for intramuscular injection 0.01mg/kg/time. Inject every 10-15 minutes until the radial pulse becomes clear, blood pressure returns to normal, shortness of breath completely decreases.
If the radial pulse is not captured after 1mg/5 minutes of adrenaline injection, continue injecting 0.3-0.5mg of adrenaline every 5 minutes through the femoral vein or the jugular vein until the pulse is captured, then switch to intravenous infusion. continuous veins.
1.2. Specialized treatment
Respiratory treatment should ensure airway clearance, oxygen breathing through glasses or mask. Can emergency tracheostomy if there is glottis edema, squeeze ambu balloon with oxygen, ventilator with 100% oxygen in the first hour, adjust ventilator according to specific condition.
Circulatory treatment includes
Place an intravenous (peripheral) line, if this cannot be established, place a central line through the jugular vein or the femoral vein.
Rapid infusion of sodium chloride 0.9% 1-2 liters, can be combined with colloid or Haesteril 6%, because anaphylaxis always has vasodilation associated with increased vascular permeability.
Continuous intravenous infusion of adrenaline is started at 0.1 ΞΌg/kg and then titrated so that systolic blood pressure is > 90 mmHg.
Emergency cardiopulmonary arrest due to anaphylaxis
Need to handle according to basic or intensive cardiopulmonary arrest emergency protocol.
2. Monitoring and treatment after emergency anaphylaxis
Other treatments that can be used to treat anaphylaxis include:
- Methylprednisolone intravenously 1mg/kg/4 hours or hydrocortisone hemisuccinate 5mg/kg/4 hours intravenously.
- Salbutamol or ventolin by throat spray or aerosol if there is difficulty breathing, can be combined with aminophyline intravenous bolus.
- Antihistamine: intramuscular prometazin 0.5-1mg.
+ Antihistamine H1: usually use Diphenhydramine 1-2 mg/kg or promethazine (Pypolphen) 0.5-1mg/kg every 6-8 hours.
+ Antihistamine H2: Ranitidine: 1-2 mg/kg.
- Combination of H1&H2 antagonists is more effective than H1 antagonists alone in the treatment of anaphylactic skin manifestations.
- Take activated charcoal and laxatives if the allergen is ingested.
- Compression bandages above the injection site or venom entry if present.
After emergency anaphylaxis, the patient should be monitored for:
- Biphasic anaphylaxis: may develop 1 to 72 hours after initial response.
- 5-20% of cases have biphasic anaphylaxis, about 3% need emergency treatment.
- The risk is biphasic: injection of adrenaline with a larger initial dose.
Post-emergency follow-up should be done within the first 4-6 hours, paying special attention to the first 72 hours. Cases at risk of biphasic need to be hospitalized for monitoring. In case of needing respiratory support, infusion of Adrenalin, Glucagon, need to be admitted to the emergency department.
3. Why is adrenaline often used in anaphylaxis?
The specific emergency and treatment regimen for anaphylaxis can vary depending on the qualifications and skills of the physician and the condition of the equipment. In particular, intramuscular adrenaline is still the basic treatment with life-saving properties.
Therefore, adrenaline needs to be prepared before all situations with the risk of anaphylaxis such as intravenous fluids, drug infusion, anesthetic anesthesia, contact with bees...
Mechanistically, adrenaline acts on sympathetic nerve receptors to help resolve most of the symptoms of anaphylaxis, for example vasoconstrictor effects (helps to increase blood pressure, reduce edema, erythema), increase contractility. myocardial contractility, bronchial smooth muscle relaxation...
Studies have shown that, the earlier adrenaline is administered in anaphylaxis, the more effective it is, and most anaphylaxis emergencies fail because of slow adrenaline administration.
However, like other drugs, adrenaline can also cause many unwanted effects, especially when administered intravenously, most commonly tremors in the limbs, chest pain, tachycardia. ..
Some cases of myocardial infarction have been implicated in the use of intravenous adrenaline in the treatment of anaphylaxis, although anaphylaxis itself can also cause this complication.
Intramuscular adrenaline is by far the safest and most effective route of administration in the treatment of anaphylaxis.
In addition to Adrenaline, Corticosteroids and antihistamines such as diphenhydramine, dimedrol should also be used and have good effect on the symptoms of shock in the skin and mucous membranes.
Technical experts and doctors both need to understand the process and how to handle anaphylaxis. It is important that the patient is treated and treated as soon as possible.
