What is the correct placement of automated external defibrillator (AED) pads on a patient?

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Last updated: May 24, 2026 • View editorial policy

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Proper AED Pad Placement

Place AED pads in the anterolateral (AL) position: one pad below the right clavicle just to the right of the upper sternal border, and the other pad in the left midaxillary line below the armpit. This is the standard recommended position that optimizes placement speed and minimizes interruptions to chest compressions 1.

Standard Anterolateral (AL) Positioning

The 2025 AHA and ILCOR guidelines clearly establish the AL position as the primary recommendation for AED pad placement 2, 1:

  • Right pad: Position below the patient's right clavicle, just to the right of the upper sternal border
  • Left pad: Place with its center in the left midaxillary line, below the armpit

Critical placement detail: The lateral pad must be placed in the midaxillary line and not too anteriorly, as this is a common error that reduces defibrillation effectiveness 2. The pad placement is designed to ensure the vector of energy delivery is directed toward the myocardium, including the left ventricle where ventricular fibrillation often originates.

Alternative Anterior-Posterior (AP) Position

If the AL position is not feasible, use the AP position 1:

  • Anterior pad: Place on the left side of the chest, between the midline and the nipple (for females, to the left of the lower sternum, avoiding breast tissue)
  • Posterior pad: Place on the left side of the patient's spine, just below the scapula

Special Considerations for Female Patients

Avoid breast tissue when placing pads 1. Place the lateral pad lateral to or underneath the left breast. Recent evidence from 2024 shows that bra removal may not be necessary - a swine model demonstrated 100% first-shock success even when AED pads were applied directly over the metal underwire of a bra, with no adverse events such as arcing or burning 2, 3. You can adjust the bra's position rather than removing it to minimize delays in defibrillation.

Key Practical Points

Follow the manufacturer's instructions on the AED pads themselves, as these provide visual guidance 1. However, be aware that current AED diagrams vary widely and untrained bystanders frequently fail to achieve accurate pad placement when relying solely on these diagrams 4, 5, 6.

Apply pads directly to bare skin - use pregelled pads or electrolyte gel to improve electrical conduction to the myocardium 2. Remove clothing as needed, but prioritize speed over perfect positioning to minimize delay in shock delivery.

Pad size matters less than placement - studies show no significant difference in defibrillation success between large (113 cm²) and small (65 cm²) pads, though larger pads (8-12 cm diameter) lower transthoracic impedance 1.

Common Pitfalls to Avoid

  • Placing the lateral pad too anteriorly instead of in the true midaxillary line 2
  • Placing pads over clothing rather than directly on skin 5
  • Excessive delay for perfect positioning - speed is critical, and minor variations in placement can be overcome with appropriate defibrillation waveforms 7
  • Removing bras unnecessarily - this delays defibrillation without clear benefit 2, 3

Refractory Ventricular Fibrillation

For patients with persistent VF after 3 defibrillations, consider changing to the AP pad position. A 2025 cluster RCT showed that vector-change defibrillation (switching from AL to AP) resulted in higher survival to hospital discharge (21.7% vs 13.3%; adjusted risk ratio 1.71) and higher rates of VF termination (79.9% vs 67.6%) 1.

References

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.