RES ResusCue.com by ANONAMED

For doctors and clinicians

OHCA is a time disease before it is a diagnosis.

Initial rhythm, witnessed status, bystander CPR, defibrillation interval, low-flow time, etiology, and post-ROSC physiology dominate prognosis.

Defibrillator monitor in an ambulance setting

Registry context

Use survival endpoints precisely.

Population CARES 2024 covered 174.1 million people, about 52% of the U.S. population, with 137,119 reported non-traumatic OHCA events.
Estimated U.S. burden ~263,711 EMS-treated, non-traumatic OHCA cases in 2024 after extrapolation.
Outcomes Sustained ROSC 25.4%; survival to admission 25.7%; survival to discharge 10.5%.
Rhythm Shockable rhythm survival to discharge 31.3%; PEA 11.1%; asystole 2.6% in CARES 2024.
Witnessed Bystander-witnessed survival 16.1%; unwitnessed survival 4.5% in CARES 2024.
Neurology CPC 1-2 is favorable or independent/moderate disability; CPC 3 severe disability; CPC 4 coma/vegetative state; CPC 5 death.

Basic life support

Compression quality is still the core treatment.

Rate and depth

Manual compressions at 100-120/min, depth at least 5 cm in the average adult, avoid excessive depth over 6 cm, and allow full recoil.

Compression fraction

Minimize interruptions. AHA describes a chest compression fraction of at least 60% as reasonable; many high-performance systems target higher when feasible.

Ventilation

Hands-only is appropriate for untrained, unwilling, or unsafe lay rescuers after sudden adult collapse. 2025 AHA and ERC still allow or encourage breaths for trained rescuers, and respiratory/pediatric etiologies need ventilation earlier.

Defibrillation

CPR plus early shock for VF/pVT is the time-critical pair. CARES 2024 reported 47% discharge survival when bystanders delivered the first field shock.

Guideline comparison

Compression-only is a lay-rescuer access strategy, not a universal abolition of ventilation.

AHA 2025 BLS All lay rescuers provide compressions; compression-only is appropriate if untrained or unwilling. Trained lay rescuers may provide breaths. HCPs: compressions and ventilation reasonable for adult cardiac or noncardiac arrest.
ERC / RCUK 2025 Dispatcher-assisted CPR begins as compression-only unless the caller knows rescue breaths. Trained rescuers: 30:2 with breaths delivered only to visible chest rise.
ANZCOR All rescuers perform compressions and minimize interruptions; trained and willing rescuers give rescue breaths for cardiac arrest.
Canada 2025 Adult chest-compression-only CPR can be lifesaving. Heart & Stroke renewed emphasis on breaths for children/infants and breathing-related arrests.
WHO / opioid Opioid overdose is a respiratory emergency: naloxone and ventilation are central if breathing is absent or inadequate; add compressions when no signs of life.
Infection control PPE/barrier devices reduce exposure. AHA 2025 explicitly includes PPE use during CPR as reasonable, while preserving immediate compression priority.
Ambulance responding with emergency lights

Bystander timeline

The handover should reconstruct collapse-to-care intervals.

Capture last known well, witnessed status, bystander CPR start, first AED attachment, first shock, EMS arrival, first rhythm, airway and ventilation interventions, epinephrine timing, ROSC timing, re-arrest, transport timing, and presumed etiology. This is prognostic information, not clerical detail.

Post-ROSC

After pulses return, avoid secondary injury.

O2

Oxygen

Use 100% oxygen until reliable saturation or PaO2 measurement is available. Then avoid both hypoxemia and hyperoxemia; ILCOR suggests SpO2 94-98% or PaO2 about 75-100 mm Hg when measurable.

CO2

Ventilation

Target normocapnia unless patient-specific physiology requires otherwise. ETCO2 may not reflect PaCO2 reliably post-arrest, especially during transport or poor perfusion.

ECG

Reperfusion

STEMI or high suspicion of acute coronary occlusion should trigger urgent cath lab evaluation. Shockable arrest, recurrent VT/VF, cardiogenic shock, or electrical instability may still justify early invasive assessment.

Brain

Neuroprognosis

Delay definitive prognostication, avoid fever, treat seizures, correct hypoxia/hypotension/hypoglycemia, and use multimodal assessment rather than early examination alone.

Advanced therapies

High-resource pathways are selective, time-dependent, and system-dependent.

Thrombolysis and PE

Consider reversible causes. Thrombolysis is not a generic OHCA treatment, but may be lifesaving when massive PE is strongly suspected and arrest/shock persists. Bleeding risk and diagnostic uncertainty are central.

Cath lab and support

PCI addresses acute coronary occlusion. IABP, Impella, VA-ECMO, or durable LVAD pathways may be relevant for selected cardiogenic shock phenotypes after ROSC or during refractory arrest in specialist systems.

ECPR and street ECMO

Prehospital or ED ECPR, including programs described in Paris and other metropolitan systems, is promising for selected refractory arrests: witnessed, short no-flow, high-quality CPR, often shockable rhythm, and rapid cannulation. It is not a substitute for public CPR/AED coverage.

One-year survival

Do not overstate long-term outcome data.

Many public registries report ROSC, admission, discharge, 30-day survival, and CPC or mRS at discharge/30 days. One-year survival is less consistently captured and is highly selected by discharge neurologic status, rhythm, etiology, age, comorbidity, post-arrest shock, and rehabilitation access.

For public education, discharge survival plus favorable neurologic outcome is usually more interpretable than ROSC alone. ROSC is a process milestone; it is not patient-centered survival.

Sources

Core references.