What are the recommended steps to achieve return of spontaneous circulation (ROSC) in an adult patient experiencing cardiac arrest of unknown etiology?

Achieving Return of Spontaneous Circulation (ROSC) in Adult Cardiac Arrest

Immediately begin high-quality chest compressions at a depth of at least 2 inches (5 cm) and rate of 100-120/minute, deliver epinephrine 1 mg IV/IO every 3-5 minutes, defibrillate shockable rhythms as soon as available, and continue this cycle in 2-minute intervals until ROSC is achieved. 1, 2

Initial Response and CPR Initiation

Activate emergency response and begin compressions within 10 seconds:

• Check responsiveness by loudly calling the patient's name and tapping shoulders 2
• Simultaneously assess breathing and pulse within 10 seconds—look for absent or agonal respirations 2
• Immediately shout for help and activate the emergency response system 1, 2
• Send someone to retrieve an automated external defibrillator (AED) without delay 2
• Start chest compressions immediately without removing clothing first 1

High-Quality CPR Technique (Critical for ROSC)

Compression parameters must be precise:

• Push hard: at least 2 inches (5 cm) depth 1, 2
• Push fast: 100-120 compressions per minute 1, 2
• Allow complete chest recoil between compressions—do not lean on the chest 1, 2
• Minimize interruptions to less than 10 seconds; pauses longer than this markedly reduce coronary perfusion 1, 2
• Rotate compressors every 2 minutes or sooner if fatigued to maintain quality 1, 2

Ventilation strategy:

• Deliver 30 compressions followed by 2 breaths (30:2 ratio) 1, 2
• Each breath should be delivered over 1 second with visible chest rise 3
• Avoid excessive ventilation—this raises intrathoracic pressure and reduces cardiac output 1, 2

Defibrillation Protocol

For shockable rhythms (VF/pulseless VT):

• Apply the AED as soon as available; do not pause compressions while preparing the device 2
• Deliver a single shock when prompted 1, 2
• Use biphasic energy of 120-200 J initially (follow manufacturer recommendation; if unknown, use maximum available) 1
• Subsequent shocks should be equal or higher energy 1, 2
• Immediately resume CPR with chest compressions after shock delivery—do not check pulse or rhythm before compressions 1, 2
• Continue CPR for a full 2 minutes before the next rhythm analysis 1, 2

Medication Administration

Epinephrine is the cornerstone medication:

• Give epinephrine 1 mg IV/IO every 3-5 minutes for all cardiac arrest rhythms 1, 2
• Establish IV or IO access as soon as possible 1, 2

For refractory VF/pulseless VT:

• Administer amiodarone: first dose 300 mg bolus, second dose 150 mg 1
• OR lidocaine: first dose 1-1.5 mg/kg, second dose 0.5-0.75 mg/kg 1

Advanced Airway Management

Once an advanced airway is secured:

• Use endotracheal intubation or supraglottic airway device 1
• Confirm placement immediately with waveform capnography or capnometry 1
• Provide 1 breath every 6 seconds (10 breaths/minute) with continuous chest compressions—no pauses for ventilation 1, 2

Important caveat: Recent research suggests ventilation rates of 12-26 breaths/minute may be associated with improved ROSC rates (45% vs 24% for rates >12 vs 6-12 breaths/min), though this contradicts current guidelines and may reflect confounding from high-quality compressions 4. Until further evidence emerges, follow the guideline recommendation of 10 breaths/minute.

Rhythm Checks and ROSC Detection

Perform rhythm analysis every 2 minutes:

• Keep each pause less than 10 seconds 1, 2
• Do not check pulse immediately after shock delivery—this wastes critical time 2, 5
• Check pulse only if an organized rhythm appears during the 2-minute rhythm check 2

Signs of ROSC include:

• Palpable pulse and blood pressure (check carotid artery) 1, 5
• Abrupt sustained increase in PETCO₂ (typically ≥40 mmHg) 1, 5
• Spontaneous arterial pressure waves with intra-arterial monitoring 1, 5

Addressing Reversible Causes (The H's and T's)

Systematically evaluate throughout resuscitation:

• Hypovolemia, Hypoxia, Hydrogen ion (acidosis) 1
• Hypo-/hyperkalemia, Hypothermia 1
• Tension pneumothorax, Tamponade (cardiac) 1
• Toxins, Thrombosis (pulmonary), Thrombosis (coronary) 1

Extracorporeal CPR (ECPR) Consideration

For refractory cardiac arrest:

• ECPR is reasonable for selected patients when performed within a system with appropriate training and equipment 2
• The ARREST trial showed significantly higher survival for patients with shockable rhythms who received ECPR after prolonged resuscitation 2

Common Pitfalls to Avoid

• Never check pulse immediately post-shock—resume compressions instantly 2, 5
• Never hyperventilate—excessive ventilation reduces cardiac output and cerebral blood flow 1, 2
• Never delay defibrillation to establish IV access or give medications in shockable rhythms 3
• Never use atropine routinely in PEA or asystole—it is no longer recommended 2
• Never give routine sodium bicarbonate—it may worsen survival and neurological outcomes 2
• Never interrupt compressions for prolonged periods—each interruption decreases perfusion pressure 2

Post-ROSC Priorities (Once ROSC Achieved)

Immediate hemodynamic targets:

• Maintain mean arterial pressure ≥65 mmHg, preferably >80 mmHg 2, 6
• Target oxygen saturation 92-98% to avoid both hypoxemia and hyperoxemia 1, 2, 6
• Use 100% inspired oxygen until arterial oxygen can be measured reliably 1

Coronary intervention:

• Perform emergent coronary angiography for any patient with ST-segment elevation on ECG 2, 6
• Consider emergent angiography for patients without ST-elevation but with high coronary risk, cardiogenic shock, or presenting arrhythmia of VF/pulseless VT 2, 6