15 June 2021

Anaphylaxis guidelines approve new adrenaline for infants

Allergies Clinical Paediatrics

Doctors may prescribe 0.15mg adrenaline injector devices to infants and children weighing 7.5–10 kg, according to new anaphylaxis guidelines from the Australasian Society of Clinical Immunology and Allergy (ASCIA).

Using a 0.15 mg adrenaline injector device in these children delivers up to 200% of the recommended 0.01 mg/kg adrenaline dose.

But the injector device poses less risk than the use of an adrenaline ampoule or syringe, where dosing errors and delays in administration increase risks, particularly when administered by non-medical personnel, the updated guidelines state.

The new recommendation will come into effect on September 1, and is based on the safety of adrenaline use in children, and it is supported by international professional consensus. 

The recommendation to use 0.15mg adrenaline autoinjector devices for children weighing 10–20kg and 0.3 mg devices for those over 20 kg remains unchanged.

There have been no reported bone injuries or adrenaline delivery failure cases from a needle tip striking the femur in children weighing less than 10kg, although a theoretical risk exists. Bunching the skin and muscle of the mid-thigh may reduce this risk further.

Infants with anaphylaxis who have received two or three doses of adrenaline may look pale and floppy for some time, but this may not be an indication that more adrenaline is needed. 

ASCIA recommends first undertaking a thorough assessment. Clinicians should also measure blood pressure to check whether additional doses of adrenaline may be required. Administering more than two or three doses of adrenaline in infants may cause hypertension and tachycardia, often misinterpreted as ongoing anaphylaxis. 

Correct positioning of the infant during an anaphylactic episode remains vital because leaving the child upright or walking could lead to death within minutes.

The safest position for an infant or a small child is to lie flat or be held horizontally in the carer’s arms. This positioning improves venous blood return to the heart and should be maintained even when the child appears to have recovered.

If the child presents with respiratory symptoms, they may prefer to sit to help with breathing and to improve ventilation. But they must sit upright with their legs outstretched in front of them and be monitored closely.

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