Circulatory collapse and the need for cardiopulmonary resuscitation (CPR) is one of the more stressful crises that can occur in the operating room (OR). In such an emergency, it is the responsibility of the anesthesiologist to swiftly recognize and intervene to ensure recovery of spontaneous circulation (ROSC) without further injury. Success requires the necessary reflexive clinical skills, awareness of surrounding equipment, understanding of reversible etiologies, appropriate task delegation, and a composed demeanor. Fortunately, intraoperative cardiac arrest in noncardiac surgery is rare (1-7 cases per 10,000, ~40% 30-day survival) and an OR serves as an almost ideal location for such an event given its advanced monitoring, immediate medication availability, proximity to invasive line equipment, airway management tools, and pacemaking/defibrillation equipment. In addition, timely access to advanced imaging and treatment modalities such as transthoracic and transesophageal echocardiography, extracorporeal membrane oxygenation (ECMO), and cardiac catheterization (for example, emergent coronary stent, thrombectomy, intraaortic balloon pump) enhances the likelihood of a successful outcome.

In addition to the availability of physical resources, cognitive aids can help ensure successful resuscitation. The recent development of easily consulted emergency manuals within reach of the anesthesiologist has greatly facilitated accurate recall of critical resuscitation management steps during highly stressful situations. MGH includes an emergency manual adopted from the Stanford Cognitive Aid Working Group in all of its anesthetizing locations. In addition, simulation of intraoperative code events has become more integrated into the training curriculums of MGH and other institutions, which provides a structured, supportive environment to rehearse decision-making, enhance communication, and establish reflexive mental models. Together, simulation and easy access to emergency manuals promote a calm, quick adherence to optimal management protocols during otherwise difficult circumstances.

Essential to the swift return of spontaneous circulation after sudden cardiac arrest (SCA) are defibrillation for ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT); prompt delivery of effective, minimally interrupted chest compressions to maintain cerebral and cardiac perfusion; and maintenance of effective oxygenation/ventilation. Effective compressions deliver oxygen and energy substrates to the myocardium and increase the likelihood that a perfusing rhythm will return after defibrillation. Appropriate oxygenation and ventilation are critical as hypoxemia inhibits oxygen delivery and hypo/hypercarbia can create decreased cerebral perfusion and unwanted sympathetic surges, respectively. Excessive tidal volumes can also reduce venous return, which inhibits cardiac output during CPR. CPR is more successful the earlier it is started; thus, prompt and clear communication with all team members about the emergency is essential. In the OR, the patient is often poorly positioned for CPR (prone/lateral/elevated) and may have open surgical sites requiring rapid packing. Quick recognition and communication will facilitate optimal positioning and preparation for effective CPR.

There is a tendency after delivering defibrillating shocks to watch the monitors or check pulses for return in cardiac output, but CPR should be resumed immediately after defibrillation as the myocardium has been depleted of oxygen and metabolic substrates and is stunned. When possible, early consideration for patients with presumably reversible causes of cardiac arrest should include alerting the hospital ECMO and emergency echocardiography teams in accordance with institutional capabilities and policy.

The management and algorithms that follow are derived from evidence-based guidelines established through systematic reviews by the American Heart Association (AHA) in collaboration with the International Liaison Committee on Resuscitation, which has switched to a continuous review process since the last edition of this book. This section is current with respect to the 2015 AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care and its yearly supplements up to 2019 for adult and pediatric management, which incorporates basic life support (BLS), advanced cardiac life support (ACLS), and pediatric advanced life support (PALS), which includes neonatal resuscitation.

Table 39.1 lists the AHA classifications used for the strength of recommendation and the quality of evidence used to support most of the protocol interventions presented in this chapter. Note that the recommendation class and quality of evidence are independently established. When helpful, the AHA recommendation class and quality will be provided next to suggestions in the form of Class/Evidence.