Resuscitation 85 (2014) A9–A10
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Editorial
Prognostication following cardiac arrest: Making sense of the data
Survival rates following out of hospital cardiac arrest (OHCA) are improving internationally,1 but the quality of survival is just as important as absolute numbers. A question often asked by the relatives of an OHCA patient, during the early stages of recovery, is: “Will my relative survive, and if so will they have suffered severe brain damage?” The systematic review by Dr. Sandroni and colleagues in this edition of the journal makes further progress towards addressing this challenging problem, and provides the intensive care community with a comprehensive set of guidelines and a flow diagram that is both simple to read and straightforward to understand.2 There remain, however, a number of controversial areas in prognostication following OHCA, several of which are addressed by the authors. Different parts of the world have different approaches to resuscitation and the withdrawal of life sustaining therapy (WLST).3 One question not addressed is what are the costs, both financial and humanitarian, in continuing to provide intensive care to patients in the face of catastrophic brain injury? There are few studies of survival time for patients with catastrophic brain injury, but several months is not uncommon, costing significant sums of money and causing a huge emotional burden on relatives.4 Recent research also suggests that continued futile treatment has a negative impact on the care of others who need critical care, but who are currently within a ward or emergency department.5 Whilst the ideal would be an approach that flawlessly predicts all those who are destined to have a poor outcome, combined with a 0% false positive rate (FPR), there is an increasing acceptance that this worthy ambition for prognostication is practically unachievable. Even myoclonic status epilepticus, once proposed as having a 0% FPR, has been shown to be fallible through misdiagnosis.6 Cardiac arrest is a highly heterogeneous condition, and it is wise to account for this when seeking prognostic information. A patient who suffers a traumatic cardiac arrest with an associated head injury would not necessarily be best served by the same tests as a patient with ventricular fibrillation secondary to a coronary occlusion. Another major issue that is addressed by this review is that of residual sedatives and neuromuscular blocking drugs. The pharmacokinetics of these drugs in critically ill patients are not fully understood, and the increasing use of anti-convulsants is an added confounder. It is well recognised that thiopental and
http://dx.doi.org/10.1016/j.resuscitation.2014.09.021 0300-9572/© 2014 Published by Elsevier Ireland Ltd.
midazolam infusions can interfere with an accurate diagnosis of brain stem death,7 and it is highly likely that similar infusions interfere with prognostication following cardiac arrest. Future trials of prognostication must report accurately on sedative and neuromuscular blocker use, and the times between their cessation and assessment.8 The issue of a “self-fulfilling prophecy” is both important and concerning. It is clear that the commonest mode of death after cardiac arrest in UK intensive care units, and many other countries, is the withdrawal of therapy. Such decisions can almost never be made with 100% certainty, yet they are an almost daily feature for many intensivists. Very few studies address this issue, or examine the effect of clinician knowledge, empathy and experience on improving prognostication. Perhaps the future of prognostication lies with invention and innovation? The proposed algorithm relies on clinical examination (available since the birth of medicine), neurophysiology (in use since the 1950s) and cross sectional brain imaging using CT and MRI (available for three decades). There is some promise shown by novel imaging techniques such as functional MRI and magnetic resonance spectroscopy, but it is also possible that novel tests initially designed for use in other conditions may find an application in prognostication. Clinicians interested in the hypoxic cerebral injury of cardiac arrest often see similarities with other brain trauma in adults, and in the hypoxic injury that can occur at birth.9,10 Such similarities may translate into a common approach, and more reliable methods of assessment. As Sandroni and colleagues demonstrate, no single test is ever likely to offer the perfect solution, and we can therefore anticipate an approach that combines modalities of assessment, tailored to the patient’s individual circumstance. Adult respiratory distress syndrome, sepsis, acute kidney injury and a large number of other diseases are now diagnosed through the combination of clinical, laboratory and radiological findings; so too the identification of irrevocable brain damage. It remains highly unlikely that we will ever have a combination that is 100% secure in its outlook, but this updated guideline does move us a little closer. As a community of clinicians committed to both effective resuscitation and the best possible care, we will continue to strive to improve our ability to prognosticate, whilst simultaneously remaining able to make difficult decisions in a sympathetic and sensitive way. This updated review, published today, takes us another step nearer this goal, and an ability to answer the pivotal question that relatives continue to ask:
A10
Editorial / Resuscitation 85 (2014) A9–A10
“Will my relative survive, and if so will they have suffered severe brain damage?” Conflict of interest statement None declared. References 1. Chan PS, Nallamothu BK. Improving outcomes following in-hospital cardiac arrest: life after death. JAMA 2012;307:1917–8. 2. Sandroni C. Prognostication in comatose survivors of cardiac arrest. Resuscitation 2014;85:1779–89. 3. Berdowski J, Berg RA, Tijssen JGP, Koster RW. Global incidences of out-ofhospital cardiac arrest and survival rates: systematic review of 67 prospective studies. Resuscitation 2010;81:1479–87. 4. Geocadin RG, Koenig MA, Jia X, Stevens RD, Peberdy MA. Management of brain injury after resuscitation from cardiac arrest. Neurol Clin 2008;26:487–506. 5. Huynh TN, Kleerup EC, Raj PP, Wenger NS. The opportunity cost of futile treatment in the ICU. Crit Care Med 2014;42:1977–82, http://dx.doi.org/10.1097/CCM.0000000000000402.
6. English WA, Giffin NJ, Nolan JP. Myoclonus after cardiac arrest: pitfalls in diagnosis and prognosis. Anaesthesia 2009;64:908–11. 7. Walker MB. Residual sedation and brain stem death testing. Anaesthesia 2007;62:418–9. 8. Cook SC, Hadfield RJ, Thomas MJC. More evidence is required before we alter guidance on prognostication following cardiac arrest. Resuscitation 2011;82:1105. 9. Bramlett HM, Dietrich WD. Pathophysiology of cerebral ischemia and brain trauma: similarities and differences. J Cereb Blood Flow Metab 2004;24:133–50. 10. Kochanek PM, Fink EL, Bell MJ, Bayir H, Clark RS. Therapeutic hypothermia: applications in pediatric cardiac arrest. J Neurotrauma 2009;26:421–7.
Matthew Thomas ∗ Jonathan Benger Bristol, United Kingdom ∗ Corresponding author. E-mail address:
[email protected] (M. Thomas)
15 September 2014