• Cardiac Catheterization
• Arrhythmias, Cardiac
• Ventricular Fibrillation
• Endovascular Procedures

Since first compiled in 4-5 BCE as the Hippocratic Corpus, medical practice guidelines have served to summarise scientific knowledge and inform clinical management. In 1992, the International Liaison Committee on Resuscitation (ILCOR—the acronym being a deliberate play on words by adding ‘ill’ to the Latin ‘cor’ for heart) was formed by the major world resuscitation councils to carry forward this challenge in emergency cardiovascular care.1 Comprised of recognised international experts in resuscitation, ILCOR has since been charged with conducting evidence reviews of resuscitation science. The quality of this evidence is rigorously evaluated in terms of its certainty, consistency, indirectness, risk of bias and confounding influences using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology2 when formulating recommendations, and represents the current standard for timely and now continuously updated resuscitation-related treatment guidance. The published guidance from ILCOR is then taken by the individual resuscitation councils (such as the American Heart Association, the European Resuscitation Council and others) and adapted to their localities, creating formal regional guidelines.

‘The Joint British Societies’ guideline on management of cardiac arrest in the cardiac catheter laboratory’ presents an additional adaptation of existing resuscitation guidelines.3 In this instance, the guidelines are applied to a specific place for such events—the cardiac catheterisation laboratory, and are tailored to a specific occasion—a witnessed cardiac arrest in a closely monitored patient. The need to adapt guidelines to this setting is understandable. Both the acuity of patients needing cardiac procedures and the complexity of the interventions themselves can provoke spontaneous or iatrogenic events resulting in haemodynamic destabilisation and cardiac arrest in the laboratory. The circumstances surrounding a cardiac arrest in a catheterisation laboratory also create a unique occasion for intervention. That is, unlike out-of-hospital cardiac arrest or arrest in other hospital locations, a patient in the laboratory is typically already being monitored and procedurally prepped. In addition, the event is usually witnessed by skilled providers from its outset; reasons for the arrest’s occurrence are likely already apparent or suspected, and invasive tools readily available for its management. Taken together, adapting resuscitation to this environment is sensible and the participating British Societies, which spanned a wide spectrum of specialties, are to be commended for this endeavour. In recognising this exemplary effort, it is also important to appreciate both the value and limitation of these guidelines.

What the British Societies’ guidelines do well is provide a paradigm for resuscitation that takes advantage of the immediate availability of diagnostic measures, interventional capabilities and professional skills of personnel in the cardiac catheterisation laboratory for witnessed, monitored cardiac arrest. This said, there is cause for caution when advanced procedures are mixed with resuscitation efforts. Interventions in cardiac arrest are more likely to be effective when given in context of ongoing cardiopulmonary resuscitation (CPR) than when its performance is compromised.4 A potential conflict arises when the intervention itself becomes a distraction and detracts from high-quality CPR, or when what is technically required for procedural success is compromised by ongoing CPR. For example, guidewire and catheter manipulation during a percutaneous coronary artery intervention (PCI) may be thwarted by the motion created from ongoing CPR; conversely, a PCI’s success may be short-lived if it culminates in worse survival because of a protracted interruption in chest compressions. In practice, this tension between CPR and procedural concerns requires constant vigilance to both, such that the intended benefit from one does not in process become the bane of the other.

While mainly consistent, there are also some differences between these guidelines and those from ILCOR and its affiliated resuscitation councils, which were likely empirically modified for the laboratory based on expert opinion. For example, ILCOR resuscitation guidelines include prompt use of pharmacological measures for treating symptomatic bradycardia, asystole and pulseless electrical activity, an approach which is widely endorsed by other council guidelines.5 6 In contrast, a drug option for these indications is delayed in the British guidelines until after multiple cycles of CPR, initiation of mechanical CPR, echocardiography and fluoroscopy (figure 1).3 The British guidelines also advocate for withholding CPR and instead administering three serial (stacked) shocks for in-lab monitored cardiac arrest due to ventricular fibrillation or pulseless ventricular tachycardia (figure 1).3 While current resuscitation guidelines acknowledge the rationale for stacked shocks and its practice in special circumstances,6 7 the reported successive decline in shock success during stacked defibrillation attempts (from 78% for the first shock, to 35% for the second, only 14% for the third and <10% thereafter)8 coupled with better survival outcome when single shocks are separated by periods of CPR could seemingly also support a single shock resuscitation strategy in this instance.9 In addition, regardless of approach, performing CPR (although even if only briefly) while a defibrillator is readied for use or during charging would seem more advisable than its being withheld, since CPR puts any idle time before shock delivery to productive life-saving use.

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Figure 1

Protocol for resuscitation of patients who suffer a cardiac arrest in the catheter laboratory. BCIS, British Cardiovascular Intervention Society; BHRS, British Heart Rhythm Society; CPR, cardiopulmonary resuscitation; PCI, percutaneous coronary intervention; PE, pulmonary embolus; PEA, pulseless electrical activity; ROSC, restoration of spontaneous circulation; TAVI, transcatheter aortic valve implantation; VF, ventricular fibrillation; VT, ventricular tachycardia. Reproduced from Dunning et al. 3

A final feature not to be missed in these guidelines is how providers are encouraged to collect data for future research, particularly as various numerical targets for blood pressure, end-tidal CO₂ and other physiological parameters are proposed. Gathering such information during the course of resuscitative care helps to advance science, promote continuous quality improvement and ultimately save more lives. Regardless of place or occasion, this is ultimately what guidelines should be all about.