Spreading the word – post-cardiac arrest syndrome

Article Outline

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Cardiac arrest is a truly global term. We all understand immediately what is meant by it, and with the creation of international committees on resuscitation, we increasingly agree how it should be managed.

Emergency nurses have vast experience in cardiac arrest. With the exception of maybe pre-hospital practitioners, we have greater exposure to cardiac arrest than any other specialty. We spend much time and energy in clinical practice and in education learning how best to resuscitate a patient in cardiac arrest. What we do, and how effectively we do it can make a real difference to the outcome for the patient. But it is not only the arrest period itself that is important. Much of what we do is aimed at managing both the primary insult (the cardiac event, the hypoxia), and also preventing secondary injury, e.g. by controlling arrhythmias, or oxygenation; much in the same way as we do when treating traumatic brain injury. Once cardiac output is regained, the resuscitation does not stop, but continues to try to maximise patient outcomes.

In this issue and the next, we have the privilege of reprinting a consensus statement on post-cardiac arrest syndrome. Permission has kindly been granted by the principle authors, and by the publishers of the journals where it was originally available – Circulation, and Resuscitation. This statement brings together all the current evidence about management of the post-cardiac arrest patient, whilst identifying gaps in knowledge which require further exploration. The paper discusses all aspects of this syndrome, including how consensus was reached, and the terminology agreed. The international writing team have agreed the name to reflect the group of physiological processes specific to the post cardiac arrest situation, and also to remove the more generalist ‘resuscitation’ term currently used in much of the related literature. Resuscitation is described as a much wider term, incorporating pre-, intra- and post-arrest periods, and if started early enough, cardiac arrest may be prevented.

The paper describes the pathophysiology of the body in the post-arrest state, enabling readers to contextualise the therapies that might have greatest impact. By understanding how the body responds in arrest, we can better define treatment as it recovers. In clinical practice there is often a sense of futility even in those patients who regain their circulation, but one of the key messages for me from this paper is the breadth of that ‘window of opportunity’ to make a difference. Much of the neurological deterioration associated with cardiac arrest takes place over hours and days, rather than minutes, and is responsive to interventions, such as controlled ventilation and cooling. Myocardial damage and systemic ischaemia equally respond well to intervention post-arrest, with evidence to support increasing interventions in the future. It is often the management of predisposing pathologies, such as acute coronary syndromes, or respiratory disease, that may make post-cardiac arrest care more complex.

The ‘window of opportunity’ is significant for all patients after cardiac arrest, and for the staff managing their care. How many times as emergency care clinicians have we alluded to the prognosis for a patient post-cardiac arrest, basing our assumptions about their ‘downtime’, or their immediate post-arrest state. Having read the paper, I now understand better just how poor these prognostic indicators are, with the risk that we make extreme treatment decisions much too early, without allowing the patient to stabilise. Although there are many associations, it is only neurological examination that has shown to be of any significant prognostic value, and even then it is of limited value on its own. As with all elements of care, using a multi-faceted approach to prognosis is essential.

The paper also critically evaluates the evidence for specific therapies that may, or may not, have an effect on survival. Therapeutic cooling is so far the only treatment to show improved patients outcomes, though it is lack of consistent evidence, rather than no evidence that affects the reporting on other treatments. What is consistent across the interventional evidence is a lack of effective dissemination and implementation. The authors discuss this issue, and suggest frameworks for improvement, which are useful. They also describe challenges to future service provision, and suggest the creation of ‘supercentres’ where post-cardiac arrest patients would be optimally managed, working on the same model as trauma centres. Although controversial for many current providers it is important that groups of clinical experts, such as these, continually challenge how services are provided, or at least accept that current practice may not be enough in the future.

Despite much research and consensus on resuscitation for cardiac arrest, mortality rates have remained relatively consistent for about 50 years. What is obvious about the consensus paper is the clarity about what evidence is available, and what further work is necessary. Due to its length we have split the publication and printed it in sequential issues, but we feel the whole paper is highly relevant to all who work in emergency care. It is hoped that, by reprinting the paper in our journal, we reach out to many who are intimately involved in the cardiac arrest period and may not have access to the original publications, but who will be responsible for spreading the word further.