About the PRECARE Study

Sudden cardiac arrest is the leading cause of death in otherwise healthy adults affecting ~25,000 Australians per year, with death occurring in 87-94% of OHCA cases. Extracorporeal life support is a form of peripheral heart bypass and it can be used in the setting of cardiac arrest (ECPR). While the heart is arrested, the machine provides oxygenated blood to the brain, heart and other vital organs, essentially stopping the clock and buying time for the cause of the arrest to be treated and for the heart to recover.

When the heart is in cardiac arrest and no CPR is being performed, this is called a ‘no-flow’ state. When CPR is commenced, this is termed a ‘low-flow’ state. This low flow decreases over time. Good (oxygenated blood) flow is needed to maintain perfusion to the brain, heart and other vital organs. ECPR provides excellent blood flow during cardiac arrest.

ECPR has been used in the hospital setting for some time and has improved cardiac arrest survival rate in the refractory VF population from <5% to 20-33%. One of the key determinants of outcome in this patient population is the duration of the cardiac arrest, that is, how quickly the patient is established onto extracorporeal support. With appropriate patient selection, the quicker the patient is placed onto extracorporeal support, the better the outcome.

PRECARE is a study examining the feasibility of performing ECPR in the pre-hospital setting, with the aim to reduce the low flow time and improve survival rates whilst also improving equity of access to this therapy. Phase 1 of the PRECARE study has been running for 6 months and is complete. Phase 2 of the trial is now commencing. Westmead, Royal Prince Alfred and St Vincent’s are the sites accepting patients for this study. The study is currently run over 3 days: Monday, Thursday and Friday.

ECPR will not work without effective and immediate bystander CPR and the provision of excellent advanced life support, it is a team sport.

Advanced principles and invasive techniques as adjuncts to advanced life support (ALS)

In addition to providing ECPR to eligible patients, the PRECARE medical team also offer advanced, traditionally hospital based interventions, in the pre-hospital setting. The team consist of two consultant doctors and one critical care paramedic. This team are essentially bringing hospital based interventions to the patient. These interventions do not detract or replace paramedic resuscitation, rather they enhance the advanced life support being provided by paramedics.

Insertion of a femoral arterial line to monitor central perfusion pressure, effectiveness of CPR and titration of inotropic support to improve coronary perfusion
Transoesophageal echocardiography to determine optimal compression placement, ensure optimal forward flow with CPR delivery, assess for reversible causes and guide treatment
Real time arterial blood gas analysis to assist with decision making and treatment strategies

While we know that perfusion and oxygenation are the main stays of cardiac arrest management, what we are learning is that there are various cardiac arrest phenotypes and not all cardiac arrests are created equal. To improve survival from cardiac arrest, we need consider tailoring management to the individual patient. Consider heart lung interactions, patient anatomy and pathology impacting on arrest physiology because we are learning that personalised haemodynamic directed CPR can improve outcome.