If the patient goes into cardiac arrest following an anaphylactic reaction - Start cardiopulmonary resuscitation (CPR) immediately following current basic life support (BLS) guidelines.
This website is recommended to refresh knowledge of basic life support. You can also watch a video on performing CPR/defibrillation in an out-of-hospital setting here.
You can see the full guidelines from the Resuscitation Council (UK) by clicking on the following links:
You can watch a video from the Resuscitation Council UK on carrying out CPR in a COVID-19 environment below: