What is the immediate management for a patient in ventricular fibrillation (V fib) wearing a LifeVest (wearable cardioverter-defibrillator)?

Immediate Management of Ventricular Fibrillation in a Patient Wearing a LifeVest

For a patient in ventricular fibrillation (VF) wearing a LifeVest, allow the device to deliver its shock automatically as it is designed to detect and treat VF with 99% first-shock efficacy and 90% post-shock survival. 1

Understanding the LifeVest Response to VF

• The LifeVest is a wearable cardioverter-defibrillator that continuously monitors heart rhythm and automatically delivers an electric shock when ventricular fibrillation or ventricular tachycardia is detected 1
• The device is designed to be worn 24 hours per day (except during bathing/showering) and provides protection for patients at risk of sudden cardiac death 1
• First shock efficacy of the LifeVest is remarkably high at 99%, with post-shock survival of approximately 90% 1

Management Algorithm During VF Event

Initial Response

• If the patient is wearing a properly functioning LifeVest, the device will:
  • Detect the VF automatically 1
  • Issue alerts to the patient and bystanders 2
  • Deliver a shock automatically if the patient becomes unresponsive 2, 1

If the LifeVest is Delivering Therapy

• Allow the device to complete its shock delivery cycle 2
• Do not touch the patient during shock delivery 2
• After shock delivery, assess the patient's response and rhythm 2

If the LifeVest Fails to Deliver Therapy or is Not Functioning

• Immediately begin CPR with chest compressions 2
• Apply an external defibrillator as soon as available 2
• Deliver a single shock (200J for biphasic defibrillator or 360J for monophasic) 2
• Resume CPR immediately after shock delivery without checking rhythm or pulse 2
• Continue CPR for approximately 2 minutes (5 cycles) before reassessing rhythm 2

Post-Shock Management

• After successful defibrillation, monitor the patient closely for recurrence of VF 2
• Assess vital signs and level of consciousness 2
• If the patient remains unresponsive after shock, continue CPR and ACLS protocols 2
• For responsive patients, provide supportive care and arrange urgent cardiology consultation 2
• Consider administering antiarrhythmic medication if indicated 2

Special Considerations

• The LifeVest may deliver inappropriate shocks in some situations (2% rate of inappropriate shocks) 1, 3
• Inappropriate shocks can be caused by:
  • Atrial fibrillation (32.2% of cases) 3
  • Supraventricular tachycardia (13% of cases) 3
  • Motion artifacts (32.7% of cases) 3
  • Oversensing of electrical signals (18.4% of cases) 3
• In rare cases, VF may self-terminate without requiring shock therapy 4
• Some patients with sustained VF may remain alert if they have a left ventricular assist device 5

Pitfalls to Avoid

• Do not attempt to remove the LifeVest during an active VF event 2
• Do not delay external defibrillation if the LifeVest fails to deliver therapy 2
• Avoid touching the patient during shock delivery to prevent injury to rescuers 2
• Be aware that conscious patients sometimes fail to use response buttons properly to abort inappropriate shocks (67.1% of cases) 3
• After successful defibrillation, do not assume the risk has passed - monitor closely for recurrence 2

The LifeVest is designed specifically to address VF quickly and effectively in at-risk patients, with excellent first-shock efficacy. When functioning properly, it should be allowed to perform its intended purpose while healthcare providers prepare for post-shock management and potential additional interventions if needed.