V Fib arrest!

V Fib arrest!

Learning Objectives:

1. Describe the primary ABCD survey.

2. Identify ventricular fibrillation by ECG criteria.

3. Describe the suggested technique for CPR.

4. Describe the role of electrical defibrillation in the management of ventricular fibrillation.

5. Describe optimal defibrillator electrode position.

6. Describe the sequence of commands during electrical defibrillation.

Primary ABCD Survey:

A. Airway - open airway, assess breathing.

B. Breathing - give two breaths.

C. Circulation - assess circulation, if absent start chest compressions.

D. Defibrillation - attach AED or monitor/defibrillator when available.

ECG Criteria for Ventricular Fibrillation:

1. The heart rate is very rapid and the rhythm is not regular.

2. The QRS complex is absent.

3. P waves are absent.

4. There are no P waves or QRS complexes so there is no relationship between them.

5. In ventricular fibrillation, areas of the ventricles are depolarizing and repolarizing in a completely disorganized fashion. All pumping function of the ventricles is lost.

6. The electrocardiogram may show voltage fluctuations. The amplitude of these waves is described by the terms "coarse" and "fine".

7. If it is unclear if the rhythm is ventricular fibrillation or asystole, treat as if it is V Fib since it is the much more successfully treated arrhythmia.

CPR Technique:

1. Early electrical defibrillation is the definitive treatment for V Fib.

2. CPR should be performed until the defibrillator is available. Effective CPR is most important when the first defibrillation attempt is made more than four minutes after the arrest. See the references below.

3. For adults that are not intubated, compress 30 times then deliver 2 positive pressure breaths. Repeat this cycle at 100 compressions per minute.

4. Compress the chest "fast and hard". Compress over the lower half of the sternum but not ver the xiphoid.

5. Allow the chest to fully recoil between compressions.

6. Resume CPR immediately after electrical defibrillation. Continue for 5 cycles of CPR, then assess and continue the treatment algorithm. Three stacked shocks are no longer recommended.

Electrical Defibrillation:

1. Early electrical defibrillation is the definitive treatment for V Fib.

2. Defibrillate as soon as possible. For an unwitnessed arrest outside the hospital, there is some evidence that electrical defibrillation may be more effective after 5 cycles of CPR.

3. The inital energy setting should be 120-200 Jolues for biphasic defibrillators and 200-360 Joules for monophasic defibrillators. Set to 200 Joules if the defibrillator is not clearly labelled as monophasic or biphasic.

4. Resume CPR immediately after electrical defibrillation. Continue for 5 cycles of CPR, then assess and continue the treatment algorithm. Three stacked shocks are no longer receommended.

5. Subsequent shock energy should be equal to or greater than previous shock energy.

Electrode Positioning:

1. The optimum sternal electrode position is just to the right of the upper sternal border below the clavicle.

2. The optimum apex position is to the left of the left nipple with the center of the the electrode in the midaxillary line.

3. Electrodes should be separated and paste should not be on the chest between the paddles.

4. Approximately 25 pounds of pressure should be applied to the paddles at the time of discharge.

Defibrillation Commands:

1. It is critical that clear communication occur between the members of the resuscitation team to improve effectiveness and avoid errors.

2. Position the paddles on the patient and announce to the team "Charging defibrillator - stand clear!"

3. Press the charge button on the apex paddle and state "I am going to shock on three. One, I'm clear." Look to make sure that you are clear.

4. State "Two, you are clear." Look to make sure the entire team is clear.

5. State "Three, everybody's clear." Check again and press discharge buttons simultaneously.

References:

1. Cobb, Fahrenbruch, Walsh, Copass: Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA 1999; 281; 1182-1188.

2. Wik, Hansen: Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrilation: a randomized trial. JAMA 2003; 289: 1389-1395.