DEFIBRILLATION and CARDIOVERSIONACLS
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 rhythm rapid and chaotic QRS complex wide and irregular, no visible P waves
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
Automated external 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 hearts electrocardiographic activity of the client. Shocks are automatically delivered with the use of adhesive pads as needed according to the machines 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
Electrical safety first Avoid using alcohol Avoid placing paddles near the monitoring electrodes
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
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
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
8.5- 12 cm Gel paste Self adhesive gelled pads Defib k-pad
Electrode skin coupling material
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 1. 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 7. Ensure no-one is in contact with anything touching the patient 8. Press paddle buttons simultaneously 9. Check ECG rhythm "Charging" "Stand clear" "Shocking now" Announceme nts
Class II-B DEFIBRILLATORACCEPTABLE 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.
360 Joules fixed dose
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
Neurological status Cardiovascular status Respiratory status Blood values
Delivery of timed but direct electrical shocks to the heart as an emergency or elective treatment performed by an MD or certified healthcare provider
Dysrhythmias refractory to medications
Ventricular tachycardia with pulse Atrial fibrillation Atrial flutter
Remove dentures/ jewelries Empty bladder Obtain 12-L ECG and write Preconversion Have emergency and intubation set ready.
Explain the procedure Turn the defibrillator and set for the synchronous mode Sedation as ordered Expose the clients chest and expose the pads
. 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