Intraoperative Cardiac Arrest: Of Utmost Importance and a Stepchild at the Same Time

See Article, p 627 Even though intraoperative cardiac arrest (IOCA) is considered very rare during general and regional anesthesia,1,2 it is also a potentially catastrophic event for both the patient and the anesthesiologist. An IOCA is distinct from other settings since it occurs in the operating room (OR) and is frequently predicted by patient monitoring or anticipated by the anesthesia care provider. Moreover, underlying causes are not solely attributed to individual patient factors, but also to other perioperative effects (eg, surgery, bleeding, hypoxia, or anesthetic agent). The incidence of IOCA varies widely among recently published studies.1 In its 2015 guidelines, the European Resuscitation Council (ERC) reported an overall incidence for IOCA of 4.3–34.6 per 10,000 procedures.3 However, more specifically, the incidence of anesthesia-related cardiac arrests in noncardiac surgery patients is approximately 90% lower, and ranges from 0.2 to 1.1 per 10,000 in adults4,5 and from 1.4 to 4.6 per 10,000 in children.4 Of note, 30-day mortality after IOCA (70%) is not much lower when compared with out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrest (IHCA).6 Besides such data on the incidence of IOCA, underlying factors, demographic data, treatment protocols, and outcomes are not well known, and thus far, not standardized. One major limitation of recent research is that most published studies are from single centers and contain small patient samples, which significantly limits their internal and external validity, and thus, conclusions. In this issue of Anesthesia & Analgesia, Fielding-Singh et al7 publish an interesting and important study on the epidemiology of IOCA, which analyzed more than 35 million admissions in 2016 in the United States. These authors identified a total of 5230 IOCA cases in the National Inpatient Sample Database, which comprises a large and valid data set. The overall incidence of IOCA was 5.7 per 10,000 cases, which is quite similar to previously published rates. Remarkably, there was an additional cost of $13,184 (US dollars) per surgical case if an IOCA occurred. In their study, Fielding-Singh et al7 also observed several factors (eg, race, cardiac, thoracic, or vascular surgery, history of congestive heart failure, pulmonary circulation disorders, peripheral vascular disease, end-stage renal disease, and fluid and electrolyte disorders) that were independently associated with an increased odds ratio of an IOCA. Heretofore, few studies were able to identify and to present such associated factors. These identified factors may be a viable basis to mitigate an IOCA in specific patients (eg, by artificial intelligence, algorithms, and electronic patient data files) and can, therefore, improve diagnostics and provide a basis for treatment algorithms, future guidelines, and better survival. Specifically, a registry for IOCA is currently lacking, but it would further facilitate such risk analyses and predictive models. Moreover, a specific evidence-based guideline for the treatment of an IOCA does not exist. However, the American Society of Anesthesiology (ASA) presented an expert consensus on how to treat an IOCA.8,9 Although this algorithm demonstrates that diagnosis and treatment of an IOCA could be, at least partially, comparable to an OHCA, it also shows that there are many other contributing factors that must be identified, validated, and addressed for an IOCA. The number of underlying or contributing factors for an IOCA is likely large, and they may have different etiologies. This article by Fielding-Singh et al7 clearly demonstrates the value and benefits of large, electronic patient databases. The authors undertook an exemplary effort in preparing and analyzing the extracted data, and their findings are of the utmost importance in further developing diagnostic and treatment algorithms for IOCA. It is absolutely clear that an evidence-based guideline for the treatment of IOCA is needed to improve patient care and to optimize patient outcomes. DISCLOSURES Name: Jochen Hinkelbein, MD, DESA, EDIC, FAsMA. Contribution: This author wrote the manuscript. Conflicts of Interest: J. Hinkelbein received professional fees for lectures from the following companies: Medupdate GmbH and “Forum für medizinische Fortbildung (FomF).” He also received honoraria from Schöchl Medical Education and Grünenthal. Name: Bernd W. Böttiger, MD, ML, DEAA, FESC, FERC, FAHA. Contribution: This author provided scientific data and finalized the manuscript. Conflicts of Interest: B. W. Böttiger is European Resuscitation Council (ERC) board director of science and research; chairman of the German Resuscitation Council (GRC); member of the Advanced Life Support (ALS) task force of the International Liaison Committee on Resuscitation (ILCOR); member of the executive committee of the German Interdisciplinary Association for Intensive and Emergency Medicine (DIVI); associate editor of the European Journal of Anaesthesiology; coeditor of Resuscitation; and editor of the journal Notfall + Rettungsmedizin. He received professional fees for lectures from the following companies: Medupdate GmbH, “Forum für medizinische Fortbildung (FomF),” Baxalta Deutschland GmbH, Bayer Vital GmbH, ZOLL Medical Deutschland GmbH, C. R. Bard GmbH, GS Elektromedizinische Geräte G. Stemple GmbH, Novartis Pharma GmbH, and Philips GmbH Market DACH. This manuscript was handled by: Stefan G. De Hert, MD.