Cardiac arrest is the most critical clinical emergency any healthcare professional may face. Without immediate intervention, irreversible brain damage begins within 4–6 minutes. Yet high-quality CPR started within the first seconds can double or triple survival rates. Mastering Basic Life Support (BLS) is not optional — it is a requirement for every healthcare worker.
Chain of Survival (AHA 2020)
The American Heart Association defines the chain of survival as the sequence of actions that, executed rapidly, maximize the chances of surviving a cardiac arrest:
- Immediate recognition and activation of emergency services — call 911 (or code blue in the hospital) without delay.
- Early high-quality CPR — effective compressions from the first moment.
- Rapid defibrillation — every minute without defibrillation in VF reduces survival by 10%.
- Advanced life support — response by specialized team.
- Post-cardiac arrest integrated care — ICU, targeted temperature management, coronary angiography if indicated.
Step by Step: BLS in Adults (Healthcare Provider Protocol)
1. Scene safety
Before approaching, verify the environment is safe for both rescuer and patient. Never compromise your own safety.
2. Initial assessment (≤ 10 seconds)
- Responsiveness: Tap shoulders firmly and shout: "Are you okay?"
- Breathing: Observe the chest simultaneously. Gasping or agonal breathing = treat as cardiac arrest.
- Pulse (healthcare provider): Palpate carotid or femoral for no more than 10 seconds. If not clearly detected → begin CPR.
3. Activate emergency services and call for AED
Shout for help. If others are present: assign tasks explicitly ("You — call 911", "You — get the AED"). If alone, call first then begin CPR.
4. Chest compressions
— Position: heel of dominant hand on the lower half of the sternum. Other hand on top, fingers interlaced.
— Arms straight, perpendicular to the patient's chest.
— Depth: 2–2.4 inches (5–6 cm) in adults.
— Rate: 100–120 compressions/minute.
— Allow full chest recoil between compressions.
— Minimize interruptions: < 10 seconds for any pause.
5. Ventilations (if performed)
- Ratio: 30 compressions : 2 ventilations (with 1 or 2 trained rescuers).
- Technique: Head-tilt/chin-lift. Create a tight seal with mask or mouth. Deliver over 1 second, observe chest rise.
- If rescuer is untrained or unwilling to ventilate: Compression-only CPR (hands-only) is equally effective for cardiac-cause arrest in adults.
- With advanced airway (ETT/supraglottic): 10 ventilations/minute asynchronously, without interrupting compressions.
6. AED Use (Automated External Defibrillator)
- Power on the AED and follow voice prompts.
- Place pads: one below the right clavicle, one at the left mid-axillary line (or as indicated on the device).
- Allow AED to analyze rhythm — ensure no one touches the patient during analysis.
- If shock advised: ensure clear ("clear!") and press the shock button.
- Immediately resume CPR after the shock — 2 minutes of compressions before the next rhythm analysis.
Reversible Causes of Cardiac Arrest: the 4H's and 4T's
During CPR, the advanced team should search for and treat reversible causes:
| 4H's | 4T's |
|---|---|
| Hypoxia | Tension pneumothorax |
| Hypovolemia | Tamponade (cardiac) |
| Hypo/hyperkalemia (and other electrolytes) | Thrombosis (pulmonary — PE) |
| Hypothermia | Thrombosis (coronary — MI) |
CPR in Special Circumstances
| Situation | Key Adaptation |
|---|---|
| Pregnancy | Manual left uterine displacement; or left lateral tilt 15–30° if possible |
| Obese patient | Greater compression depth required, more frequent rescuer rotation |
| Drowning | Prioritize 5 rescue breaths before compressions |
| Child (1–8 yr) | 1 or 2 hands, depth 2 inches (5 cm), ratio 15:2 with 2 healthcare rescuers |
| Infant (< 1 yr) | 2-finger or encircling thumb technique, depth 1.5 inches (4 cm) |
Conclusion
BLS is the first and most important tool against sudden cardiac death. Every minute without high-quality CPR brings the patient closer to death or irreversible brain injury. Regular practice, knowing the steps, and staying current with updated protocols is not just a training obligation — it can be the difference between someone living or dying in your hands.