What Is Double Sequential External Defibrillation (DSED)?

• DSED = 2 defibrillators, 2 shock vectors, 1 goal: stop refractory VF/pVT.​
• DSED is a safe and effective evidence-based treatment supported by the 2025 AHA Guidelines as grade 2b Level of Evidence

When Do We Use DSED?​

• DSED is an auxiliary component of the Medical Cardiac Arrest Medical Directive—it can only be used as a treatment when a paramedic is appropriately trained and authorized to use it their Ambulance Service Operator.​
• DSED is not a first-line treatment. DSED is used when:​
  • VF or pVT is deemed refractory, which means it has persisted after ✅ 3 consecutive shocks by paramedics or fire​
  • Non-traumatic arrest deemed to be cardiac in origin​
  • Patient is 18 years or older​
  • 2 defibrillators are available​
  • If the second defibrillator belongs to another organization (paramedic service or fire department), that organization has approved their defibrillator for use in DSED and the paramedic is knowledgeable in its use

When Do We Use DSED?​

• SWORBHP supports the use of clinical judgement in determining the orientation of the initial set of defibrillation pads and is not prescriptive of starting in A/L or A/P during an arrest. ​
• TIPS:​
  • ✅ Pads should not touch or overlap.​
  • ✅ Apply one set from each defibrillator.​
• Proper placement ensures distinct electrical vectors that target more of the myocardium.​

How to Deliver the Shocks​

• 🟢 STEP 1: Charge both defibrillators ​
• 🟢 STEP 2: Count down out loud: “3… 2… 1… shock!”​
• 🟢 STEP 3: "Shock 1", "Shock 2" allowing for rapid sequential delivery but not simultaneously.​
• ⚠️ Do NOT deliver shocks more than a second apart — timing is critical.​
• ⚡ Aim for sequential delivery to avoid ineffective or unsafe energy dispersion.​
• Always follow local training and practice this skill in simulation before use in the field!​

Summary​

• DSED is a new auxiliary treatment within the ALS PCS 5.4 for refractory VF or pulseless VT​
  • Think of it as a defibrillation with wider coverage and more power to reset that myocardium​
  • ONLY to be used when trained and authorized in this AUXILIARY treatment​
  • ONLY after 3 consecutive shocks by paramedics or fire​
  • Ensure that other components of standard excellent resuscitation are concurrently ongoing​
  • 2 sets of defibrillators + sets of pads are required​
  • Aim for sequential shocks to allow for the safest and most effective treatment​

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