DEFIBRILLATION and CARDIOVERSION

ACLS

DEFIBRILLATION

Is the therapeutic use of controlled electric current over a brief period of time

This will temporarily stuns an irregulalry beating heart in an attempt to terminate fatal / lethal dysrhythmias.

Purpose of Defibrillation

The purpose of the shock is to produce temporary asystole.

The shock attempts to completely depolarize the myocardium and provide an opportunity for the natural pacemaker to resume normal activity.

Physiology of Cardiac Conduction

Principles of Early Defibrillation

Most frequent initial rhythm in sudden cardiac arrest is ventricular fibrillation.

The most effective treatment for ventricular fibrillation is defibrillation.

The success of defibrillation diminishes rapidly over time.

VF tends to convert to asystole within a few minutes.

Ventricular Fibrillation

Ventricular rhythm rapid and chaotic QRS complex wide and irregular, no visible P

waves

Ventricular Tachycardia

Rate: Usually between 100-250 bpm P wave: obscured QRS: wide and bizarre Conduction: as with PVCs Rhythm: three or more ventricular beats in a row, may

be regular or irregular May stop or start suddenly

Normal Components of the ECG waveform

Types of Defibrillator

Manual Defibrillator Automatic Defibrillator

Automated external defibrillator

Manual Defib Automated external defibrillator

Manual Defibrillator

Accesibility Availability of the staff Skills / Mental / emotional capability Power source Reliability of the equipment Legal considerations Ethical issues

Automated External Defibrillator

Fully automated Availability Training / capability Safety/ time factor Expensive Technical errors

Automated External Defibrillator

Has a micropressor that actually interprets the heart’s electrocardiographic activity of the client.

Shocks are automatically delivered with the use of adhesive pads as needed according to the machine’s own interpretation.

An AED at a railway station in japan

Buttons of AED

On and off power Analyze-interprets Shock- delivers shock Voice synthesizer- gives instruction Tape recorders- tapes events of cardiac

arrest

INDICATIONS Ventricular Fibrillation

Ventricular tachycardia

Reminders

Electrical safety first Avoid using alcohol Avoid placing paddles near the monitoring

electrodes

Paddle Placement

RIGHT – right of the upper sternum just below the right clavicle.

2nd intercostal space

LEFT – left of the nipple in the midaxillary line

5th intercostal space anterior axillary line

External defibrillation Implantable defibrillator

Reminders

Do not position paddles over the pacemaker. Do not place paddles by over nitro patches to

avoid burning the skin. Do not place paddles over the ECG monitoring

leads ECG LEAD PLACEMENT

White –right Red- ribs Black - left

Transthoracic Impedance

Resistance to the current flow If transthoracic is high, a low energy shock

may fail to pass enough current through the heart to achieve defibrillation.

Determining factors in Transthoracic impedance

Paddle size 8.5- 12 cm

Electrode skin coupling material Gel paste Self adhesive gelled pads Defib k-pad

Phase of ventilation Paddles to chest contact pressure

11 kg/ 25 lbs

If gel is to be used, rub the two paddles together.Crush cart should always be ready including the intubation set.Safety measures should be observed.If pulseless VT or VF occurs, turn the Synch switch off and Defibrillate.

Defibrillation Sequence

Action Announcements1. Switch on.

2. Place coupling pads/gel in correct position

3. Apply paddles

4. Check ECG rhythm and confirm no pulse

5. Select non-synchronised (VF) setting

6. Charge to required energy level "Charging"

7. Ensure no-one is in contact with anything touching the patient

"Stand clear"

8. Press paddle buttons simultaneously "Shocking now"9. Check ECG rhythm

SYNCHRONIZE- CARDIOVERTER

UNSYNCHRONIZE- DEFIBRILLATOR

VS

CCLINICAL SCENARIO

Unwitnessed arrest Witnesses arrest

vs

QUICK LOOK PRECORDIAL THUMP

PRECORDIAL THUMP

Class II-B DEFIBRILLATOR- ACCEPTABLE AND PROBABLY HELPFUL

Striking the center of the sternum using the hypothenar aspect of the fist from a height of no more than 12 inches

How much initial dose ?

It depends on the type of defibrillator you are using.

MONOPHASIC DEFIBRILLATOR

360 Joules fixed dose

Biphasic Defibrillator

150-200 joules for Biphasic truncated exponential waveform

120 joules for the rectilinear biphasic waveforms

In between shocks

Must provide 5 cycles of CPR Hook the patient to the cardiac monitor Start an IV Line for possible drug

administration

POST - DEFIBRILLATION

Monitor : Neurological status Cardiovascular status Respiratory status Blood values

CARDIOVERSION

Delivery of timed but direct electrical shocks to the heart as an emergency or elective treatment performed by an MD or certified healthcare provider

INDICATIONS

Dysrhythmias refractory to medications Ventricular tachycardia with pulse Atrial fibrillation Atrial flutter

Pointers

Remove dentures/ jewelries Empty bladder Obtain 12-L ECG and write

“Preconversion” Have emergency and intubation set ready.

Preparation

Explain the procedure Turn the defibrillator and set for the

synchronous mode Sedation as ordered Expose the client’s chest and expose the

pads

QUIZ

.  Defibrillation is the therapeutic use of controlled electric current to permanently stun an irregularly beating heart in an attempt to terminate fetal dysrhythmias  

. 2 The natural pacemaker of the heart is the SA node located in the left atrium.

3.Most frequent initial rhythm in sudden cardiac arrest is ventricular fibrillation.

 

 

4. .  You are in the emergency room attending to a patient with the following vital signs : CR : 0 RR:0 BP : NONE. The next thing to do is defibrillate the patient

5. The ECG monitor of a patient in the ICU reads Ventricular fibrillation, No pulse was noted and patient is unconscious. The timing for defibrillation for this patient should be after administration of IV fluids.  

6. A nurse is at a railway station in a developed country when a 70 yr old man collapse. An automated external defibrillator is available nearby. A manual defibrillator is likewise available at a nearby ER. One advantage of AED is that it can be operated without a cardiac monitor

7. A nurse should place a defibrillator paddle near a monitoring electrode

8. It is best to place the Right paddle below the right breast of a female patient.  

9. A nurse found a nitro patch near the left side of the nipple, this can be ignored while or during placement of defibrillator paddles.  

10.  The ECG monitor of an ICU patient reads Ventricular tachycardia. Patient is pulseless. The nurse should turn the synch switch on.  

II. Arrange the items in an orderly Defibrillation sequence from 1-9

_______Charge to required energy level _______Place coupling pads/ gel in correct

position _______Check ECG _______Ensure that nobody is touching the

patient _______Select the non-synchronize setting _______Apply the Paddles _______Press the buttons simultaneously _______Switch on the Defibrillator _______Confirm pulse

III. Identification : ______1. Initial dose of a monophasic

defibrillator ______2.Initial dose of a biphasic

defibrillator the heart performed by an MD.

______3. Indicated for patient with pulse and V-Tach

______4. Indicated for patient with V-fib and No pulse

5. Elective procedure involving the delivery of timed electric shock direct to the heart and performed by an MD

In between defibrillation, how many cycles of CPR must be delivered before analyzing the ECG Rhythm