1 Foundations of Emergency Cardiac Care

Goals and guiding principles

Emergency cardiac care aims to recognize life-threatening problems quickly, support circulation and breathing, treat reversible causes, and coordinate a team so time-sensitive actions are not delayed. These principles summarize the 2025 American Heart Association (AHA) adult guidelines and are educational. In practice, follow current local protocols, your training, and the clinical team leader's direction.

Recognize deterioration and act

First ensure the scene is safe, assess responsiveness, and activate the emergency response system. Ask for a defibrillator and emergency equipment. In a healthcare setting, use the facility's escalation or code process.

For an unresponsive adult, assess breathing and pulse at the same time. Gasping is not normal breathing. A healthcare professional should spend no more than $10$ seconds checking for a pulse; if no definite pulse is felt, presume cardiac arrest and start CPR. If a pulse is present but breathing is absent or abnormal, support ventilation and reassess as directed by the applicable protocol. Do not delay CPR to obtain an ECG or other tests.

For suspected cardiac arrest, begin high-quality CPR and attach a monitor/defibrillator as soon as available. For adults, compress at $100\text{–}120$ per minute, to a depth of at least $2$ inches ($5$ cm), allow full chest recoil, and minimize pauses. Without an advanced airway, use $30:2$ compressions-to-breaths. Change compressors about every $2$ minutes, or sooner if fatigued. After a shock, resume compressions immediately rather than pausing for an immediate pulse check. Avoid excessive ventilation.

Assess patients who have a pulse

When the patient has a pulse, rapidly assess airway, breathing, circulation, mental status, and overall stability. Look for signs of poor perfusion, including altered mental status, hypotension, shock, chest discomfort, or acute heart failure.

Obtain monitoring and a $12$-lead ECG when indicated while assessing vital signs, relevant history, medications, and possible causes. Treat urgent threats as they are found; assessment and intervention often proceed in parallel.

A first decision is whether the patient is in cardiac arrest or has a pulse. If there is a pulse, determine whether the patient is stable or unstable and whether an abnormal rhythm is likely causing the instability. Follow the appropriate current algorithm, such as cardiac arrest, bradycardia with a pulse, or tachyarrhythmia with a pulse, rather than applying one rhythm treatment to every patient. Interpret ECG findings alongside the patient's symptoms and perfusion.

Use algorithms and defibrillation safely

Resuscitation algorithms are structured decision aids that help teams make critical decisions consistently; they do not replace clinical judgment, training, or local protocols. Confirm that the algorithm matches the patient's age group and situation, and use the current version available in your care setting. Follow its decision points, reassess after interventions, and return to the pathway when the patient's condition changes.

In the adult cardiac-arrest algorithm, the first major rhythm decision is whether the rhythm is a shockable rhythm or a nonshockable rhythm. Shockable rhythms call for defibrillation and immediate CPR. Nonshockable rhythms call for CPR and prompt treatment according to the algorithm. In both pathways, maintain CPR quality, reassess rhythm at the indicated intervals, and search for reversible causes.

Do not confuse synchronized cardioversion for selected unstable rhythms with defibrillation for cardiac arrest. Use the device according to training and its prompts. Before delivering a shock, announce that it is coming, ensure nobody is touching the patient or bed, and visually confirm the area is clear. Manage supplemental oxygen and other hazards according to device and facility procedures.

Coordinate the resuscitation team

Clear role assignment helps reduce duplication and missed actions. Depending on team size and setting, roles may include:

• Team leader: Coordinates care, states the working plan, assigns roles, and reassesses the patient and team.

• Compressor: Delivers high-quality compressions and coordinates timely compressor changes.

• Airway/ventilation clinician: Manages ventilation while avoiding excessive breaths and unnecessary interruptions.

• Monitor/defibrillator operator: Applies the device, identifies rhythm-check and shock opportunities, and maintains defibrillation safety.

• Medication and access clinician: Obtains vascular access and prepares or administers therapies under the applicable protocol.

• Recorder/timekeeper: Tracks events, rhythm checks, shocks, medications, and key times; may also announce the next reassessment.

Use closed-loop communication: give a clear request to a named person, have them repeat or acknowledge it, and confirm completion. Share important changes aloud, speak up about safety concerns, and invite team members to identify problems. The leader keeps the team focused while ensuring essential tasks are covered. A brief debrief after the event can identify what went well and what should change.

Continue care after ROSC

Return of spontaneous circulation (ROSC) begins a new phase of resuscitation, not the end of care. Stabilize airway, oxygenation, ventilation, and blood pressure; obtain early diagnostic testing, including a $12$-lead ECG when indicated; and identify and treat the cause of arrest and any complications.

Continue monitoring and arrange appropriate critical care. Use the current post-arrest guideline and local protocol for decisions about oxygen, ventilation, hemodynamics, temperature control, and neurologic management.

Connect the priorities

Effective emergency cardiac care depends on early recognition, rapid activation of help, high-quality CPR, timely defibrillation when indicated, and repeated reassessment. The initial assessment distinguishes cardiac arrest from emergencies in which a pulse remains. Current algorithms organize care around those decisions, while defined roles, clear communication, and attention to safety help the team carry them out. ROSC requires continued stabilization and treatment of the underlying cause.