OBJECTIVE. 1. Define defibrillation. 2. Describe Need and history of defibrillation. 3. Describe the principle and mechanism of defibrillation.

Transcription

1 Defibrillators

2 OBJECTIVE 1. Define defibrillation. 2. Describe Need and history of defibrillation. 3. Describe the principle and mechanism of defibrillation. 4. Types and classes of defibrillator 5. Describe the Automated external defibrillator 6. Identify the precautions and risk 7. Troubleshooting of defibrillator

3 Defibrillator

4 Introduction Definition: Defibrillation is a process in which an electronic device sends an electric shock to the heart to stop an extremely rapid, irregular heartbeat, and restore the normal heart rhythm or make it flat Defibrillation is a common treatment for life threatening cardiac dysrhythmias, ventricular fibrillation, and pulseless ventricular tachycardia.

5 NEED FOR A DEFIBRILLATOR Ventricular fibrillation is a serious cardiac emergency resulting from asynchronous contraction of the heart muscles. Due to ventricular fibrillation, there is an irregular rapid heart rhythm. Fig. Ventricular fibrillation Fig. Normal heart beat

6 NEED FOR A DEFIBRILLATOR Ventricular fibrillation can be converted into a more efficient rhythm by applying a high energy shock to the heart. This sudden surge (shock) across the heart causes all muscle fibres to contract simultaneously. Possibly, the fibers may then respond to normal physiological pace making pulses. The instrument for administering the shock is called a DEFIBRILLATOR.

7 Purpose of defibrillation Defibrillation is performed to correct life-threatening fibrillations of the heart, which could result in cardiac arrest. It should be performed immediately after identifying that the patient is experiencing a cardiac emergency, has no pulse, and is unresponsive.

8 Fibrillations cause the heart to stop pumping blood, leading to brain damage. Defibrillators deliver a brief electric shock to the heart, which enables the heart's natural pacemaker to regain control and establish a normal heart rhythm.

9 Cardiac Arrest Occlusion of the coronary artery leads to ischemia Ischemia leads to infarct which causes interruption of normal cardiac conduction Infarct = VF/VT

10 Shockable Rhythms Ventricular Fibrillation Ventricular Tachycardia

11 DEFIBRILLATOR ELECTRODES Spoon shaped electrode Applied directly to the heart Paddle type electrode Applied against the chest wall Pad type electrode Applied directly on chest wall

12 ELECTRODE PLACEMENT OF AED Anterior electrode pad Apex electrode pad Fig: anterior apex scheme of electrode placement

13 Paddles types There are two types of paddles: 1. Adult size: one should be attached under the right clavicle and the other one under the left nipple. 2. Child size: the same like adult Special considerations: 1. Adult paddles can be used for child one in the front and the other in the back 2. Child paddles can NOT be used for adult due to insufficient voltage delivery.

14 DEFIBRILLATOR types There are two types: 1. Monophasic I. Shock delivers from one paddle II. It goes for one direction III. The maximum joules is Bi-phasic I. Shock delivers from two paddles II. III. It goes for two directions The maximum joules is 200 from each paddle

15 Monophasic pulse or waveform Bi-phasic pulse or waveform

16 Classes of discharge waveform Monophasic pulse or waveform Bi-phasic pulse or waveform

17 Classes of discharge waveform There are two general classes of waveforms: A. MONO-PHASIC WAVEFORM: Energy delivered in one direction through the patient s heart. B. BIPHASIC WAVEFORM : Energy delivered in both direction through the patient s heart.

18 Fig:- Generation of bi-phasic waveform

19 Classes of discharge waveform Fig: Generation of bi-phasic waveform

20 Classes of discharge waveform The biphasic waveform is preferred over mono-phasic waveform to defibrillate. Why????? A mono-phasic type, give a high-energy shock, up to 360 joules due to which increased cardiac injury and in burns the chest around the shock pad sites. A biphasic type, give two sequential lower-energy shocks of joules, with each shock moving in an opposite polarity between the pads.

21 TYPES OF DEFIBRILLATORS Internal External

22 a) Internal defibrillator a) Electrodes placed directly to the heart : e.g..- Pacemaker b) External defibrillator a) Electrodes placed directly on the heart e.g..-aed

23 TYPES OF DEFIBRILLATORS Internal defibrillator Electrodes placed directly to the heart : e.g..-pacemaker External defibrillator Electrodes placed directly on the heart : e.g..-aed

24 External Defibrillators For each minute elapsing between onset of ventricular fibrillation and first defibrillation, survival decreases by 10%. defibrillators should be portable, battery operated, small size. energy in defibrillators usually stored in large capacitors.

25 AUTOMATIC EXTERNAL DEFIBRILLATOR

26 AUTOMATIC EXTERNAL DEFIBRILLATOR AED is a portable electronic device that automatically diagnoses the ventricular fibrillation in a patient. Automatic refers to the ability to autonomously analyse the patient's condition. AED is a type of external defibrillation process. AEDs require self-adhesive electrodes instead of hand held paddles. The AED uses voice prompts, lights and text messages to tell the rescuer what steps have to take next.

27 WORKING OF AED Turned on or opened AED. AED will instruct the user to: 1. Connect the electrodes (pads) to the patient. 2. Avoid touching the patient to avoid false readings by the unit. 3. The AED examine the electrical output from the heart and determine the patient is in a shock able rhythm or not.

28 WORKING OF AED 4. When device determined that shock is warranted, it will charge its internal capacitor in preparation to deliver the shock. 5. When charged, the device instructs the user to ensure no one is touching the victim and then to press a red button to deliver the shock. 6. Many AED units have an 'event memory' which store the ECG of the patient along with details of the time the unit was activated and the number and strength of any shocks delivered.

29 PRECAUTIONS The paddles used in the procedure should not be placed: on a woman's breasts over an internal pacemaker patients on a wet patient, hairy chest, medical patches It should not be used for an infant less than one year Before the paddle is used, a gel must be applied to the patient's skin or paddles with gel

30 Troubleshooting Attach the external and internal paddles if the monitor reads, No paddles. Check to ensure that the leads are securely attached if the monitor reads, No leads. Connect the unit to AC power if the message reads, Low battery. Verify that the Energy Select control settings are correct if the defibrillator does not charge.

31 Troubleshooting Change the electrodes and make sure that the electrodes adapter cable is properly connected if you receive a message of PACER FAILURE. Restart the pacer. Close the recorder door and the paper roll if the monitor message reads, "Check recorder.

32 THANKS