2.3 CPR & AED Use

Cardiopulmonary resuscitation and early defibrillation are the most critical interventions for a patient in cardiac arrest. The quality of CPR directly impacts patient survival.

High-Quality CPR Components

The American Heart Association emphasizes these key components of high-quality CPR:

1. Push hard - Adequate compression depth
2. Push fast - Adequate compression rate (100-120/min)
3. Allow complete chest recoil - Do not lean on the chest between compressions
4. Minimize interruptions - Keep pauses to less than 10 seconds
5. Avoid excessive ventilation - Do not over-ventilate the patient

CPR Specifications by Age Group

Hand Placement and Technique

Adults and Children:

• Place the heel of one hand on the center of the chest on the lower half of the sternum
• Place the other hand on top, interlocking fingers
• Keep arms straight, shoulders directly over hands
• Compress straight down

Infants (2025 AHA Update):

• Use the heel of one hand or the two thumb-encircling hands technique on the lower half of the sternum (just below the nipple line); use the heel of one hand if you cannot encircle the chest
• For two thumbs, place them side by side on the sternum and encircle the infant's chest with both hands
• The two-finger technique was eliminated in the 2025 AHA Guidelines because it rarely achieved adequate depth
• Support the infant on a firm surface
• Compress to a depth of about 1.5 inches (1/3 AP diameter)

Compression-to-Ventilation Ratios

• 30:2 = Universal ratio for single rescuer (all ages) AND 2-rescuer adult CPR
• 15:2 = 2-rescuer CPR for children and infants (because pediatric arrest is more often respiratory in origin)
• With an advanced airway in place = Continuous compressions at 100-120/min with 1 breath every 6 seconds (10 breaths/min), no pausing

Full Chest Recoil

• Allow the chest to fully return to its normal position after each compression
• Do not lean on the chest between compressions
• Leaning reduces venous return and decreases coronary perfusion
• Rotate compressors every 2 minutes (or every 5 cycles of 30:2) to prevent fatigue and maintain quality

Minimizing Interruptions

• Interruptions in compressions reduce coronary perfusion pressure
• Limit interruptions to less than 10 seconds (for pulse checks, defibrillation, airway management)
• Pre-charge the AED during compressions to minimize pause time
• Have the next compressor ready to switch immediately

AED (Automated External Defibrillator) Use

The AED is used to analyze the heart rhythm and deliver a shock if a shockable rhythm is detected.

Shockable rhythms:

• Ventricular fibrillation (V-fib) - Chaotic, disorganized electrical activity
• Pulseless ventricular tachycardia (V-tach) - Rapid organized rhythm without a pulse

Non-shockable rhythms:

• Asystole - No electrical activity ("flatline")
• Pulseless electrical activity (PEA) - Organized rhythm on monitor but no pulse

AED Pad Placement

Standard anterior-lateral placement:

• Right pad: Upper right chest, below the clavicle, to the right of the sternum
• Left pad: Left side of the chest, below the armpit (left mid-axillary line)

Pediatric considerations:

• Children under 8 years / under 55 lbs: Use pediatric pads or dose attenuator if available
• If pediatric pads are not available, use adult pads
• For infants/small children: if pads risk touching, use anterior-posterior placement (one on chest, one on back)

AED Special Considerations

Hands-Only CPR

The AHA recommends hands-only CPR (compressions without rescue breaths) for:

• Untrained bystanders witnessing sudden cardiac arrest in adults
• Trained bystanders who are unwilling or unable to provide ventilations

Push hard and fast in the center of the chest at a rate of 100-120 compressions per minute until EMS arrives or an AED is available.

High-Performance CPR Pitfalls

Even trained rescuers lose CPR quality in predictable ways. The most common are leaning on the chest (preventing full recoil, which blocks the heart from refilling), drifting too slow or too fast off the 100-120/min target, excessive ventilation that raises chest pressure and cuts venous return, and long pauses for pulse checks, intubation, or moving the patient. Use a metronome or the AED feedback prompts to hold rate and depth, swap compressors every 2 minutes before fatigue degrades depth, and pre-charge the AED during compressions so the only pause is the few seconds needed to clear and shock.

The single best predictor of survival is the chest compression fraction — the percentage of arrest time that hands are actually compressing — so every avoidable interruption directly lowers the patient’s chance of survival.