Information for clinicians - Acute Anaphylaxis Clinical Care Standard

What the standard says

A patient with acute-onset clinical deterioration with signs or symptoms of an allergic response is rapidly assessed for anaphylaxis, especially in the presence of an allergic trigger or a history of allergy.

What this means for you

Assess patients immediately for possible anaphylaxis if they present with rapid development of airway, breathing and/or circulation problems, with or without skin or mucosal changes. The presence of an allergic trigger or a history of allergy should heighten suspicion even if the patient is not in severe distress. Symptoms typically occur in two or more body systems, but this can be variable. 

The most common triggers of anaphylaxis are food, insect venom and medicines (Table 1).

After exposure to a trigger, the time until onset of signs and symptoms of anaphylaxis (Table 2) may range from minutes to several hours.

Obtain a history from the patient, noting:

• Recent exposure to substances known to cause an allergic reaction
• Any known allergies for the patient, including previous reactions and treatment
• Any history of anaphylaxis.

Document the time of symptom onset in the patient’s healthcare record.

Consider patient risk factors that potentially contribute to fatal anaphylaxis (for example, older age and cardiovascular and respiratory diseases) and cofactors that are likely to amplify the severity of an allergic reaction (such as exercise or acute infection).

Common differential diagnoses include acute asthma, syncope, panic attacks and septic shock. Rule out other sudden-onset multisystem illnesses. However, a patient who experiences sudden difficulty in breathing, has asthma, and is known to be at risk of anaphylaxis, should be treated as having anaphylaxis.

Monitor patients with allergy symptoms who do not meet the criteria for anaphylaxis, to allow prompt recognition of progression of a mild-to-moderate allergic reaction to anaphylaxis. Reactions can progress to severe involvement of more than one body organ system and rapidly become life-threatening.

Rehearse the anaphylaxis management protocol regularly to ensure prompt recognition of anaphylaxis for patients presenting with allergic reactions.

Consider serial measurements of mast cell tryptase concentrations. Taken during anaphylaxis, results can be useful for identifying the trigger when reviewed after the event, usually by a clinical immunology or allergy specialist.

What the standard says

A patient with anaphylaxis, or suspected anaphylaxis, is administered adrenaline intramuscularly without delay, before any other treatment including asthma medicines. Corticosteroids and antihistamines are not first-line treatments for anaphylaxis.

What this means for you

Immediately on diagnosis of anaphylaxis, administer adrenaline via intramuscular (IM) injection into the mid-anterolateral thigh using a needle of appropriate length. Subcutaneous or inhaled routes for adrenaline are not recommended as they are less effective. Pregnant women experiencing anaphylaxis require the same dose of IM adrenaline as other patients. The recommended doses for IM adrenaline are indicated in Table 3.

Delayed administration of adrenaline is a risk factor for fatal anaphylaxis. If anaphylaxis is suspected in the presence of an allergy or anaphylaxis history, or following exposure to a potential allergen, it is safer to administer adrenaline early than to wait for progression, which may be hard to reverse. There are no absolute contraindications to adrenaline administration in anaphylaxis.

In most situations, IM adrenaline is preferred and is safer than the intravenous (IV) route. Adverse events have been reported in adult patients who received overdoses of IV adrenaline, but these are rare with IM adrenaline.

An IV adrenaline infusion should only be administered when clinically appropriate, and:

• By clinicians trained in the use of IV adrenaline
• In a critical care setting where there is appropriate haemodynamic monitoring available.

Repeated IM adrenaline injections can be given at five-minute intervals if the patient’s symptoms are not improving. Escalate care as per organisational protocols if the patient’s condition is not improving after two to three doses of adrenaline.

Do not administer corticosteroids or antihistamines first-line, as they are not effective in treating anaphylaxis. Corticosteroids have a delayed effect of four to six hours and are adjuncts in the management of anaphylaxis – they do not replace adrenaline. Antihistamines are only helpful for relieving associated urticaria (hives), angioedema and itch. Do not give promethazine or other sedating antihistamines, as the sedating effect can mask deterioration or a biphasic reaction. Injecting promethazine can worsen hypotension and cause muscle necrosis.

Consider the implications of the treatment provided in the healthcare facility and what this communicates regarding adrenaline use. Avoiding adrenaline use in the case of a severe allergic reaction, or preferentially using corticosteroids, bronchodilators or antihistamines, may inadvertently give a message to patients that they should delay using their adrenaline injector, thus increasing potential risk in a subsequent anaphylaxis.

Include a ‘when required’ (prn) order for IM adrenaline on an admitted patient’s medication chart if they have a known allergy and have been prescribed an adrenaline injector. This can expedite the administration of IM adrenaline if the patient experiences anaphylaxis while in care.

What the standard says

A patient experiencing anaphylaxis is laid flat, or allowed to sit with legs extended if breathing is difficult. An infant is held or laid horizontally. The patient is not allowed to stand or walk during, or immediately after, the event until they are assessed as safe to do so, even if they appear to have recovered.

What this means for you

Ensure the patient is in a supine position; do not allow them to stand or walk. Monitor the patient’s blood pressure and elevate their legs if their blood pressure is low. Fatality can occur within minutes if a patient stands or sits up suddenly while they have inadequate perfusion (see Figure 1).

A semi-reclined position sufficient to relieve respiratory distress is allowed while the patient is monitored carefully for any circulatory collapse. Patients who are pregnant or vomiting should be placed on their side in the left lateral (recovery) position.

Infants should be held horizontally (across the body). They must not be held upright or over a shoulder.

Ensure the patient understands that they are not to stand up suddenly or walk until after they have been treated and assessed, and why this is important. Communicate this to other staff caring for the patient.

Assess for circulatory stability after the patient has been adequately treated and before they are allowed to mobilise. This is usually a minimum of one hour after one dose of adrenaline, and four hours if more than one dose of adrenaline is administered.

What the standard says

A patient who has an adrenaline injector has access to it for self-administration during all healthcare encounters. This includes patients keeping their adrenaline injector safely at their bedside during a hospital admission.

What this means for you

For adrenaline to be given as soon as possible after the onset of symptoms of anaphylaxis, it is important for the patient (or their carer) to be able to immediately administer their own adrenaline injector, regardless of the setting. A readily accessible adrenaline injector may also be used by a clinician if necessary.

If a patient has an adrenaline injector, as soon as possible following presentation or admission, assess their capacity to safely use it during the healthcare encounter. This includes:

• Checking their capacity, physical capability and willingness to use their personal adrenaline injector and their ability to recognise the symptoms of anaphylaxis
• Considering medicines administered during the healthcare visit that may impair the patient’s usual ability to recognise and treat anaphylaxis
• Involving a parent, guardian or carer in the assessment when in the paediatric setting
• Involving a family member or carer in the assessment, if appropriate, when a patient is cognitively impaired or lives with a disability.

As part of the assessment, identify a safe place for the adrenaline injector to be kept that allows ease of access for the patient, is in an unlocked location, and maximises the safety of others. Before making the adrenaline injector available, ensure it is suitable for use: check the expiry date, check the viewing window to make sure the solution is clear and that the device has not been used, and ask the patient how it has been stored. If in doubt, make arrangements for the patient to obtain a new device.

The adrenaline injector should be:

• Kept with the patient’s ASCIA Action Plan for Anaphylaxis
• Labelled with the patient’s name.

Notify all staff that the patient has an allergy and has an adrenaline injector with them. This includes at clinical handover in the ward or when the patient temporarily leaves the ward, such as for scans or other tests. Add an allergy alert to the patient’s records, including the electronic medical record (EMR) and electronic patient journey boards.

What the standard says

A patient treated for anaphylaxis remains under clinical observation for at least four hours after their last dose of adrenaline, or overnight as appropriate according to the current Australasian Society of Clinical Immunology and Allergy Acute Management of Anaphylaxis guidelines. Observation timeframes are determined based on assessment and risk appraisal after initial treatment.

What this means for you

Observe patients for at least four hours after the last injection of adrenaline following anaphylaxis. Reassess the patient after four hours. Consider the severity of the reaction, concomitant conditions and history of anaphylaxis when deciding if more time is needed.

When the initial injection of adrenaline for anaphylaxis is administered in general practice or another primary care location, where observation for four hours is not possible, arrange ambulance transfer to an appropriate facility for clinical observation.

Prolonged and biphasic reactions may occur. Biphasic reactions are estimated to occur following 3–20% of anaphylactic reactions, and cannot be predicted.

As per the ASCIA Acute Management of Anaphylaxis guidelines, a patient should be observed overnight if they:

• Had a severe reaction (hypotension or hypoxia)
• Required repeated doses of adrenaline
• Have a history of severe asthma or protracted anaphylaxis
• Have other concomitant illnesses, such as asthma, chest infection or arrhythmia
• Live alone or are remote from medical care
• Have known systemic mastocytosis
• Presented for health care late in the evening
• Cannot easily replace their adrenaline injector on discharge and have no other adrenaline injector.

What the standard says

Before a patient leaves a healthcare facility after having anaphylaxis, they are advised about the suspected allergen, allergen avoidance strategies and post-discharge care. The discharge care plan is tailored to the allergen and includes details of the suspected allergen, the appropriate ASCIA Action Plan, and the need for prompt follow-up with a general practitioner and clinical immunology/allergy specialist review. Where there is a risk of re-exposure, the patient is prescribed a personal adrenaline injector and is trained in its use. Details of the allergen, the anaphylactic reaction and discharge care arrangements are documented in the patient’s healthcare record.

What this means for you

Discuss the suspected allergen with the patient and their carer and provide advice about allergy avoidance. Tailor the patient’s discharge care to the suspected allergen and risk of re-exposure to ensure adequate follow-up and preventive measures.

In most cases this will include:

• An ASCIA Action Plan
• Advice about the allergen or suspected allergen and how to avoid it
• Advice about follow-up visits with their GP and a clinical immunology/allergy specialist
• The Commission Anaphylaxis Discharge Checklist and Discussion Guide
• Prescribing personal adrenaline injector(s), where there is a risk of re-exposure.

See Figures 2 & 3 for discharge requirements according to the type of allergen.

Document the allergen or suspected allergen in the patient’s health record, including food, medicine, and sting or bite exposure in the hours before anaphylaxis. For medicine allergies, include details of the adverse reaction. Upload the anaphylaxis event and document their allergy status in the patient’s My Health Record when local health service arrangements allow.

Provide the discharge documents, including the suspected allergen, discharge care plan and the patient’s ASCIA Action Plan to their general practitioner or ongoing clinical provider within 48 hours of discharge. For patients with a medicine allergy, ASCIA provide a template for documenting the reaction - the ASCIA Record for Drug (Medication) Allergy. This, or a local or electronic equivalent, should be completed and provided to the patient to assist patient information and clinical communication.

Recognise the degree of anxiety the patient and/or their family may experience after an anaphylaxis event. Provide the patient with information about support available in the community, such as Allergy & Anaphylaxis Australia (allergyfacts.org.au/, 1300 728 000), and the Australasian Society of Clinical Immunology and Allergy (ASCIA, allergy.org.au/patients/information).