Anaphylaxis Acute Management ABCDE

Anaphylaxis Acute Management ABCDE

Shiken premium Upgrade Banner

Recognition and Immediate Management of Anaphylaxis using the ABCDE Approach

This guide provides an overview of the recognition and immediate management of anaphylaxis using an ABCDE approach. The ABCDE approach can be used to perform a systematic assessment of a critically unwell patient. It involves working through the following steps:

  • Airway
  • Breathing
  • Circulation
  • Disability
  • Exposure

Each stage of the ABCDE approach involves clinical assessment, investigations and interventions. Problems are addressed as they are identified and the patient is re-assessed regularly to monitor their response to treatment. This guide is meant to assist students in preparing for emergency simulation sessions as part of their training, not intended to be relied upon for patient care.

Clinical Features of Anaphylaxis

Anaphylaxis can present in a wide variety of ways, making early diagnosis sometimes difficult. The Resuscitation Council (UK) have devised a set of criteria that if met suggest anaphylaxis is likely:

  • Sudden onset and rapid progression of symptoms
  • Life-threatening airway and/or breathing and/or circulation problems
  • Skin and/or mucosal changes (flushing, urticaria, angioedema)

A history of exposure to a known allergen also helps support the diagnosis of anaphylaxis. Other key points:

  • Skin or mucosal changes alone are not a sign of an anaphylactic reaction.
  • Skin and mucosal changes can be subtle or absent in up to 20% of reactions.
  • There can also be gastrointestinal symptoms (e.g. vomiting, abdominal pain, incontinence).

Tips Before You Begin

General tips for applying an ABCDE approach in an emergency setting include:

  • Treat all problems as you discover them.
  • Re-assess regularly and after every intervention to monitor a patient's response to treatment.
  • Make use of the team around you by delegating tasks where appropriate.
  • All critically unwell patients should have continuous monitoring equipment attached for accurate observations.
  • Clearly communicate how often would you like the patient's observations relayed to you by other staff members.
  • If you require senior input, call for help early using an appropriate SBARR handover structure.
  • Review results as they become available (e.g. laboratory investigations).
  • Make use of your local guidelines and algorithms in managing specific scenarios (e.g. acute asthma).
  • Any medications or fluids will need to be prescribed at the time (in some cases you may be able to delegate this to another member of staff).
  • Your assessment and management should be evidence-based.

Managing Acute Anaphylaxis

When managing potentially acute anaphylaxis scenarios, it is important to begin with a brief handover from a member of the nursing staff. This should include the patient's name, age, background and the reason why the review has been requested. For example, you may be asked to review a patient with anaphylaxis due to rash, facial swelling, shortness of breath and/or wheeze.

Start by introducing yourself to whoever has requested a review of the patient and listening carefully to their handover. When you meet the patient, introduce yourself, including your name and role. Ask how the patient is feeling as this may provide some useful information about their current symptoms.

Make sure the patient's notes, observation chart and prescription chart are easily accessible. Ask for another clinical member of staff to assist you if possible.

Initial Steps

If anaphylaxis is suspected, potential anaphylactoid triggers should be removed immediately (e.g. intravenous antibiotics). You should also ask another member of staff to source adrenaline (1:1000) to allow this to be administered as soon as you have confirmed the diagnosis (there is often an emergency box containing the relevant drugs on the ward).

Clinical Assessment

Can the patient talk?

If the patient can talk, their airway is patent and you can move on to the assessment of breathing.

If the patient cannot talk, look for signs of airway compromise, such as cyanosis, see-saw breathing, use of accessory muscles and stridor. Look for evidence of angioedema which is typically associated with anaphylaxis. Note any evidence of airway swelling such as pharyngeal/laryngeal oedema causing the patient to have difficulty speaking (hoarse voice), breathing, and swallowing (the patient may complain of feeling like their airway is closing up). Open the mouth and inspect for anything obstructing the airway such as secretions or a foreign object.


Head-tilt chin-lift manoeuvre

Open the patient's airway using a head-tilt chin-lift manoeuvre:

  • Place one hand on the patient's forehead and the other under the chin.
  • Tilt the forehead back whilst lifting the chin forwards to extend the neck.
  • Inspect the airway for obvious obstruction. If an obstruction is visible within the airway, use a finger sweep or suction to remove it.

Jaw thrust

If the patient is suspected to have suffered significant trauma with potential spinal involvement, perform a jaw-thrust rather than a head-tilt chin-lift manoeuvre:

  • Identify the angle of the mandible.
  • With your index and other fingers placed behind the angle of the mandible, apply steady upwards and forward pressure to lift the mandible.
  • Using your thumbs, slightly open the mouth by downward displacement of the chin.


Clinical assessment


Review the patient's respiratory rate:

  • A normal respiratory rate is between 12-20 breaths per minute.
  • Tachypnoea is a common feature of anaphylaxis and indicates significant respiratory compromise.
  • Bradypnoea in the context of hypoxia is a sign of impending respiratory failure and the need for urgent critical care review.

Review the patient's oxygen saturation (SpO2):

  • A normal SpO2 range is 94-98% in healthy individuals and 88-92% in patients with COPD who are at high-risk of CO2 retention.
  • Hypoxaemia is a typical clinical feature of anaphylaxis.


Auscultate both lungs:

  • Wheeze is a common finding in anaphylaxis (it can become less apparent with increasing airway obstruction).
  • Reduced air entry is a concerning finding indicating significant airway compromise and a need for senior clinical input.

Investigations and procedures

Arterial blood gas

Take an ABG if indicated (e.g. low SpO2) to quantify the degree of hypoxia.

Oropharyngeal Airway (Guedel)

Airway adjuncts are often helpful and in some cases essential to maintain a patient's airway. They should be used in conjunction with the manoeuvres mentioned above as the position of the head and neck need to be maintained to keep the airway aligned.

An oropharyngeal airway is a curved plastic tube with a flange on one end that sits between the tongue and hard palate to relieve soft palate obstruction. It should only be inserted in unconscious patients as it is otherwise poorly tolerated and may induce gagging and aspiration.

To insert an oropharyngeal airway:

  • Open the patient's mouth to ensure there is no foreign material that may be pushed into the larynx. If foreign material is present, attempt removal using suction.
  • Insert the oropharyngeal airway in the upside-down position until you reach the junction of the hard and soft palate, at which point you should rotate it 180°. The reason for inserting the airway upside down initially is to reduce the risk of pushing the tongue backwards and worsening airway obstruction.
  • Advance the airway until it lies within the pharynx.
  • Maintain head-tilt chin-lift or jaw thrust and assess the patency of the patient's airway by looking, listening and feeling for signs of breathing.

Nasopharyngeal Airway (NPA)

A nasopharyngeal airway is a soft plastic tube with a bevel at one end and a flange at the other. NPAs are typically better tolerated in patients who are partly or fully conscious compared to oropharyngeal airways. NPAs should not be used in patients who may have sustained a skull base fracture, due to the small but life-threatening risk of entering the cranial vault with the NPA.

To insert a nasopharyngeal airway:

  • Check the patency of the patient's right nostril and if required (depending on the model of NPA) insert a safety pin through the flange of the NPA.
  • Lubricate the NPA.
  • Insert the airway bevel-end first, vertically along the floor of the nose with a slight twisting action.
  • If any obstruction is encountered, remove the tube and try the left nostril.


If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.


Make sure to re-assess the patient after any intervention.


Clinical assessment

Tachycardia is a common finding in anaphylaxis and bradycardia is a late sign often suggestive that the patient is peri-arrest.

Haemodynamic shock occurs secondary to fluid compartment shifts resulting in significant hypotension. The patient may complain of feeling faint or lose consciousness if hypotension is severe.

Patients with anaphylaxis are typically peripherally cool, with a thready pulse and prolonged capillary refill time.

Fluid balance assessment

Calculate the patient's fluid balance including oral fluids, intravenous fluids, urine output, drain output, stool output, vomiting. Reduced urine output (oliguria) is typically defined as less than 0.5ml/kg/hour in an adult.

Investigations and procedures

Intravenous cannulation

Insert two wide-bore intravenous cannulas (14G or 16G).

Blood tests

Collect blood tests after cannulating the patient including FBC, U&Es, LFTs, coagulation, CRP, and mast cell tryptase.


Perform an ECG to look for evidence of acute myocardial ischaemia, which may occur secondary to anaphylaxis. An ECG should not delay the emergency management of anaphylaxis.


Intramuscular (IM) adrenaline

Administer IM adrenaline (1:1000) immediately. Adult dose: 0.5ml of 1:1000 l adrenaline should be given IM usually in the lateral thigh.

Chest X-ray

A chest X-ray may be useful in ruling out other respiratory diagnoses if shortness of breath is the primary issue (e.g. pneumothorax, pneumonia, pulmonary oedema). Chest X-ray should not delay the emergency management of anaphylaxis and should only be performed if the diagnosis is in doubt.


Administer oxygen to all critically unwell patients during your initial assessment. This typically involves the use of a non-rebreathe mask with an oxygen flow rate of 15L. In most situations, the advice is to lie the patient flat with their legs elevated (or on their left side if pregnant).

Nebulised bronchodilators

Administer nebulised bronchodilators if there is suspicion of bronchospasm (e.g. wheezing on auscultation):

  • Salbutamol: doses can vary and in severe cases, continuous nebulisation is advised.
  • Ipratropium bromide: 500mcg nebulised


If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.


Make sure to re-assess the patient after any intervention.


Administer 50 mL of 1:1000 epinephrine and repeat every 5 minutes if the patient remains haemodynamically unstable (max 5mL). Injection should be made on the anterolateral aspect of the middle third of the thigh. If two doses do not stabilize the patient, consideration should be given to an adrenaline infusion (decision to be made by consultant/critical care).

Intravenous (IV) Fluids

Patients with anaphylaxis require urgent fluid resuscitation:

  • Administer an initial STAT bolus of 500-1000ml Hartmann's solution or 0.9% sodium chloride.
  • Re-assess the patient after each fluid bolus and administer further boluses as required (large volumes of fluid may be required in the context of anaphylaxis).
  • Patients who are unresponsive to fluid resuscitation will require critical care input for inotropic support.


If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.


Make sure to re-assess the patient after any intervention. If the patient has a cardiac arrest, follow basic life support guidelines.


Clinical Assessment


In the context of anaphylaxis, a patient's consciousness level may be reduced due to hypoxia or hypovolaemia. Assess the patient's level of consciousness using the AVPU scale:

  • Alert: the patient is fully alert, although not necessarily orientated.
  • Verbal: the patient makes some kind of response when you talk to them (e.g. words, grunt).
  • Pain: the patient responds to a painful stimulus (e.g. supraorbital pressure).
  • Unresponsive: the patient does not show evidence of any eye, voice or motor responses to pain.

If a more detailed assessment of the patient's level of consciousness is required, use the Glasgow Coma Scale (GCS).


Assess the patient's pupils:

  • Inspect the size and symmetry of the patient's pupils. Asymmetrical pupillary size may indicate intracerebral pathology.
  • Assess direct and consensual pupillary responses which may reveal evidence of intracranial pathology or lung cancer (e.g. Horner's syndrome).

Drug Chart Review

Review the patient's drug chart for medications which may cause neurological abnormalities (e.g. opioids, sedatives, anxiolytics).


Blood Glucose and Ketones

Measure the patient's capillary blood glucose level to screen for causes of a reduced level of consciousness (e.g. hypoglycaemia or hyperglycaemia). A blood glucose level may already be available from earlier investigations (e.g. ABG, venepuncture).

The normal reference range for fasting plasma glucose is 4.0 – 5.8 mmol/l. Hypoglycaemia is defined as a plasma glucose of less than 3.0 mmol/l. In hospitalised patients, a blood glucose ≤4.0 mmol/L should be treated if the patient is symptomatic.

If the blood glucose is elevated, check ketone levels which if also elevated may suggest a diagnosis of diabetic ketoacidosis (DKA).

Diabetic Ketoacidosis (DKA) Emergency Management ABCDE

Clinical assessment


Take a history and identify potential triggers for anaphylaxis. Looking into relevant medical history may also be necessary if the patient is confused. Collateral history can be obtained from staff or family members if appropriate.


Inspect for evidence of anaphylaxis such as an urticarial rash and angioedema.

Look for potential allergens (e.g. an intravenous antibiotic infusion) and review the output of the patient's catheter and any surgical drains.


Request a CT head if intracranial pathology is suspected after discussion with a senior.


Allergen removal

If a potential allergen is identified and you suspect an allergic aetiology, remove the allergen (e.g. stop the antibiotic infusion).

Airway management

Alert a senior immediately if consciousness level is concerning (GCS of 8 or below). Meanwhile, assess and maintain the patient's airway.


If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.


Non-sedating oral antihistamines (e.g. cetirizine) can be used to treat skin symptoms once the patient has been stabilised.


Re-assess the patient using the ABCDE approach to identify changes in their clinical condition and assess effectiveness of interventions. If signs of deterioration are observed, act upon it immediately. Seek a senior's help if there is no improvement or if you have any doubts.


You should have another member of the clinical team aiding you in the ABCDE assessment, such as a nurse, who can perform observations, take samples to the lab and catheterise if appropriate. Using an effective SBARR handover can effectively communicate the key information to other medical staff.

Next steps

Once the patient is stabilised, revisit history taking to identify triggers for anaphylaxis and explore relevant medical history. Review the patient's notes, charts and recent investigation results.

Emergency Management of Anaphylaxis

Review the patient's current medications and check that any regular medications are prescribed appropriately.


Clearly document your ABCDE assessment, including history, examination, observations, investigations, interventions, and the patient's response.


Discuss the patient's current clinical condition with a senior clinician using an SBARR style handover.

Questions which may need to be considered include:

  • Are any further assessments or interventions required?
  • Does the patient need a referral to HDU/ICU?
  • Does the patient need reviewing by a specialist?
  • Should any changes be made to the current management of their underlying condition(s)?


The next team of doctors on shift should be made aware of any patient in their department who has recently deteriorated.


  1. Australian Prescriber. Emergency management of Anaphylaxis. Available from: LINK.
  2. Resuscitation Council (UK). Emergency treatment of anaphylactic reactions. Available from: LINK.

Join Shiken For FREE

Gumbo Study Buddy

Explore More Subject Explanations

Try Shiken Premium
for Free

14-day free trial. Cancel anytime.
Get Started
Join 10,000+ learners worldwide.
The first 14 days are on us
96% of learners report x2 faster learning
Free hands-on onboarding & support
Cancel Anytime