Despite advances in operative techniques, intraoperative cardiac arrest (IOCA) is a frequent complication that must be managed appropriately to improve the chances of survival and neurological outcomes. New guidelines presented at Euroanaesthesia 2023 address specific recommendations intended to guide the practising anaesthesiologist in the operating theatre.
Perioperative mortality has continued to decrease since the first case of death during anaesthesia was reported in 1848. A meta-analysis published in 2012, which included 87 studies and more than 21 million procedures, showed that mortality in the perioperative period fell from 357 cases per million before 1970 to 34 cases per million between 1990 and 2000. However, the overall mortality associated with IOCA remains a cause for concern. “When you see a mortality of 60% in a place where [the patient] is highly monitored, where there are professionals all around, the equipment is already there, you start asking questions,” said Sharon Einav, MD, from the Hebrew University Faculty of Medicine in Jerusalem, who presented the new guidelines along with Jochen Hinkelbein, MD, from Ruhr-University Bochum, Germany.
This need for improvement prompted a journey that began in 2018, with the first recommendations on managing cardiac arrest in the operating theatre for anaesthesiologists. The guideline working group collaborated with experts from different medical societies in efforts to compile a specific anaesthesia-related guideline for IOCA using information from guidelines of the American Heart Association and the European Resuscitation Council for the practice of anaesthesiology. The working group, chaired by Hinkelbein, then analysed the growing body of literature describing the incidence, causes, management, and outcomes of perioperative cardiac arrest, with the aim to address issues that are relevant to the practice of anaesthesiology and that do not appear in other guidelines. The IOCA guideline, focusing solely on adults who experience cardiac arrest in the perioperative period, was delayed by the COVID-19 pandemic and finally came to light in May 2023.
Understanding the risk factors and potential causes of cardiac arrest is the first essential step in IOCA management, the authors explained. Risk factors for major adverse cardiac events in the perioperative period include age over 75 years, a history of hypertension, high-risk surgery, intraoperative hypotension or hypoxaemia, a history of myocardial infarction, and female gender. Studies have shown that the risk is significantly higher in older adults and in very young patients than in other age groups. To identify patients at high risk of cardiac arrest during anaesthesia, clinicians must be aware of factors contributing to anaesthesia-related cardiac arrest, which include severe systemic disease (ASA class III or higher), emergency surgery, and cardiomyopathy. IOCA occurs mainly due to cardiac dysfunction and acute bleeding, but there may be other underlying causes, which include anaesthesia, the speakers said.
The updated guidelines focus on 25 main recommendations that address various aspects of the management of IOCA, including the treatment of specific underlying conditions, the modality of resuscitation, and parameters used to monitor cardiac arrest.
Closed chest compressions are recommended in all patients who experience cardiac arrest, including those with known or suspected gas embolism. Open chest compressions may be considered only if there is no return of spontaneous circulation (ROSC) with closed compressions and veno-arterial extracorporeal membrane oxygenation is unavailable.
Cardiac arrest due to bleeding, a major cause of IOCA, must be managed simultaneously with haemorrhage control, transfusion for volume replacement, and closed chest compressions. “In patients with exsanguinating and uncontrollable infra-diaphragmatic torso haemorrhage, we suggest immediate aortic occlusion as a last-resort measure,” the authors said. “It’s important to have a plan.” Resuscitative endovascular balloon occlusion of the aorta (REBOA), with insertion of a catheter in the femoral artery, is a common procedure in some European countries, but it is used infrequently in countries like Germany, Hinkelbein said. A thoracotomy with cross-clamping of the descending aorta, performed by a surgeon, is a viable alternative. “You have to stop the bleeding very soon after cardiac arrest,” Hinkelbein added. “Never pump an empty heart; only if there is circulating blood is there a possibility of effective thoracic compressions or open-chest cardiac massage. If you don’t have any blood circulating, your CPR attempts will surely be futile.”
When cardiac tamponade is suspected as the cause of arrest, point-of-care ultrasound should be used to confirm the diagnosis. If the tamponade is confirmed, there is strong evidence supporting the use of either ultrasound-guided pericardiocentesis or a thoracotomy for immediate decompression of the pericardium.
The evidence supporting the use of different monitors of cardiac arrest is weak, the authors explained. However, based on observational studies and expert opinion, end-tidal CO2 (ETCO2) measurements and invasive blood pressure monitoring may play a role in predicting IOCA. Monitoring ETCO2 in intubated patients should be considered, as it may support the prediction of ROSC and survival. However, no absolute cutoff values have been established for this marker, which should not be used as the sole basis for decision-making, the authors said. Invasive blood pressure monitoring should be considered in patients undergoing closed chest compressions to improve the quality of compressions and time the administration of adrenaline. Transesophageal echocardiography may also be a useful tool for identifying the cause of arrest and guiding management in patients who arrest in a location with appropriate equipment and expertise.
Because there is no strong evidence to guide the withdrawal of therapy, the new guidelines recommend individualising this process based on discussions with surgeons and family members.
Crafting novel recommendations based on collaboration between multiple societies has been an arduous process, and the work must continue, Einav noted. However, the updated recommendations should provide anaesthesiologists with a clearer roadmap for the management of IOCA.
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