Ventricular Fibrillation (VENTRICULAR FIBRILLATION) is a chaotic ventricular rhythm resulting in non-perfusing ventricular movement i.e. no actual ventricular contractions. VENTRICULAR FIBRILLATION is the most common initial rhythm disturbance in sudden cardiac arrest. There are multiple causes for VENTRICULAR FIBRILLATION. The most common causes include, but are not limited to: acute myocardial infarction, myocardial ischemia (angina), cardiomyopathy, digitalis toxicity, hypoxemia, acidosis, electrolyte disturbances, electrocution and drug overdose or toxicity.
The need for early defibrillation is clear and should have the highest priority for patients in Ventricular Fibrillation and./or Pulseless Ventricular Tachycardia. Since these patients will all be in cardiac arrest, adjunctive equipment should not divert attention or effort from Basic Cardiac Life Support (BCLS) resuscitative measures; early defibrillation and Advanced Cardiac Life Support (ACLS). Remember: rapid defibrillation and early ACLS are the major determinants of survival.
Different brands and models of AED/SAED have a variety of features and controls and may differ in characteristics such as paper strip recorders, rhythm display methods, energy levels, and messages to the operator. Each EMS provider must be properly trained to utilize the AED/SAED in a timely manner.
ASSESSMENT / TREATMENT PRIORITIES
1. Maintain universal blood & body fliud precautions.
2. Determine unresponsiveness, absence of breathing and pulselessness.
3. Consider all potential non-cardiac causes of cardiac arrest. (i.e. trauma, overdose, electric shock, etc.)
4. Initiate CPR and assist ventilations while awaiting defibrillator.
5. Basic and/or Intermediate providers must activate a paramedic level system (ACLS) as soon as possible, if available.
6. Contraindications: consciousness; respiratory arrest with pulses; obvious signs & symptoms of death; children 8 years of age and under or weighing less than 30 kg (66 lbs); and while in a moving ambulance.
TREATMENT: 1st RESPONDERS / BASIC EMTs
1. Maintain universal blood & body fliud precautions.
2. Determine unresponsiveness and cardiopulmonary arrest.
3. Initiate CPR.
4. Administer high concentration of oxygen with assisted ventilations.
5. Initiate early defibrillation if AED/SAED is immediately available.
a. Perform CPR until defibrillator is available, attached and operable.
b. Turn defibrillator on.
c. Attach defibrillator electrodes to patient while verbalizing (when applicable) report to AED/SAED recorder.
d. Analyze rhythm status.
e. Determine if defibrillation (shock) is indicated or not.
6. Activate ALS intercept as soon as possible, if available.
7. (a) If shock is indicated:
SHOCK INDICATED: Follow sequence:
(energy ranges depending on machine)
* Defibrillate, 1st setting (200-240 J) reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 2nd setting (200-300 J) reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 3rd setting (300-360 J)
If no pulse, continue CPR for one (1) minute.
Reanalyze cardiac status (ECG/Pulses). If shock indicated,
Repeat set of three (3) shocks 360 J.
IF SHOCK INDICATED: Follow sequence:
* Defibrillate, 360 J reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 360 J reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 360 J
If no pulse, continue CPR for one (1) minute.
Reanalyze cardiac status (ECG/Pulses). If shock indicated, Repeat set of three (3) shocks 360 J.
IF SHOCK INDICATED: Follow sequence:
* Defibrillate, 360 J reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 360 J reanalyze cardiac status (ECG). If shock indicated,
* Defibrillate, 360 J
If no pulse, continue CPR.
Initiate transport as soon as possible, with or without ALS.
Notify receiving hospital.
During transport reanalyze cardiac status (ECG/Pulses) after every 3-5 minutes of CPR or as directed by Medical Control*. If shock indicated, Repeat set of three shocks at 360 J.
*Note: Never analyze while vehicle is in motion. Vibration may interfere with appropriate reading, and may cause accidental electrical discharge
7. (b) If no shock is indicated:
NO SHOCK INDICATED: Follow sequence:
Check pulse.
If no pulse, continue CPR for one (1) minute.
Reanalyze cardiac status (ECG/Pulses)
a. If shock indicated, follow shock indicated protocol.
b. If no shock indicated, check pulse.
Check pulse.
If no pulse, continue CPR for one (1) minute.
Reanalyze cardiac status (ECG/Pulses)
a. If shock indicated, follow shock indicated protocol.
b. If no shock indicated, check pulse.
Check pulse.
If no pulse, continue CPR for one (1) minute.
Reanalyze cardiac status (ECG/Pulses)
a. If shock indicated, follow shock indicated protocol.
b. If no shock indicated, check pulse.
After three (3) "NO SHOCK" messages are received,
Initiate transport as soon as possible, with or without ALS.
Notify receiving hospital.
During transport, reanalyze cardiac status (ECG/Pulses) after every 3-5 minutes of CPR or as directed by Medical Control. If shock is indicated, follow Shock Indicated Protocol.
NOTE:
COORDINATION OF ACLS PROVIDERS WITH PERSONNEL USING AED/SAED
With the increasing availability of AEDs/SAEDs, ALS-trained emergency personnel will interact frequently with AED/SAED-trained personnel. The following guidelines are suggested for this interface:
1. ALS-trained (and authorized) providers always have authority over the scene.
2. Upon arrival, ALS-trained providers should ask for a quick report from the automated defibrillation providers and direct them to proceed with their protocols. This is particularly applicable when ALS-trained providers are unfamiliar with the operation of the AED.
3. ALS-trained providers should use the AED for additional shocks and rhythm monitoring whenever possible. They can direct the providers to operate the AED. To save time, avoid disorganization, and allow a coordinated transfer of care, ALS providers should not remove the AED and attach a separate conventional defibrillator unless the AED in use lacks a rhythm display screen. Most AEDs have the capacity for manual override by ALS-trained providers, should that be necessary. The method and ease of manual override will vary among models.
4. ALS-trained providers should consider the shocks delivered by the AED operators as part of their ALS protocols. For example, if the patient remains in VENTRICULAR FIBRILLATION after three shocks by the AED, then ALS personnel should enter the ALS VENTRICULAR FIBRILLATION treatment sequence at the point at which the first three shocks have been delivered. Consequently, ALS providers should move immediately to perform endotracheal intubation, establish IV line access, and administer epinephrine.
5. In most circumstances, the AED should be removed and a conventional defibrillator attached only when the patient has regained a spontaneous rhythm or is ready for transport to another location. Some models of AEDs/SAEDs lack a rhythm display monitor; thus, ALS personnel will want to attach a conventional defibrillator when clinically convenient.