DEFIBRILLATOR MACHINE BAsic TECHNICAL TRAINING By: Armando Darino Ngojo Senior Biomedical Engr.

Contents Aims & Objectives Introduction Principle Anatomy and Physiology Application Types Operation Safety Maintenance Troubleshooting PPM NGOJO

Aims To provide basic understanding about the Defibrillator Machine To perform and understand the basic technical troubleshooting steps and PPM tasks NGOJO

Objectives - as a result of completing this module, the biomedical technician / engineer should be able to: understand the concept of the Defibrillator including its applications perform and identify basic problems, errors and basic troubleshooting solutions. Perform PPM tasks NGOJO

History 1899 Prevost and Batelli first introduced the concept of electrical fibrillation after  noticing that large voltages applied across the animal's heart could convert  ventricular fibrillation into a sinus rhythm. 1933 1950s 1956 Hooker, Kouwenhoven and Langworthy published an account of successful  alternating current (AC) internal animal defibrillation Kouwenhoven was able to defibrillate dogs by applying the electrodes to  the chest wall, that was the external electric defibrillator. Zoll defibrillated a human subject in the same manner . NGOJO

History 1960s 1970s Edmark and Lown et al found that direct current (DC) or pulse defibrillators  were more effective and produced fewer side effects than AC defibrillator.  The DC pulse waveform was further improved. Experimental internal and external devices were designed to automatically  detect ventricular fibrillation. 1980s Present times The first automatic internal defibrillator was implanted in human A lot of improvements were introduced to the defibrillator with the aim of improving the survival rate of the cardiac arrested patient NGOJO

What is Defibrillator - A device that reverses the Fibrillation of the heart. Fibrillation causes the heart to stop pumping blood, leading to brain damage. NGOJO

Defibrillation 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. It is a common treatment for life threatening cardiac dysrhythmia, ventricular fibrillation, and pulse less ventricular tachycardia. NGOJO

Principle A high voltage electric current is applied to the Heart muscle either directly (Internal Defibrillator) through the open chest or indirectly (External Defibrillator) through the chest wall to terminate Ventricular Fibrillation. NGOJO

Physiology of Defibrillation If enough current is delivered to the heart then a majority of Ventricular cells will be depolarized A critical mass of cells should be simultaneously depolarized to achieve defibrillation NGOJO

Bio Electric Signal Polarization Potassium ions pumped in Sodium ions pumped out Depolarization Potassium ions pumped out Sodium ions pumped in Repolarization Bio Electric Signal NGOJO

Anatomy - Heart Located between the lungs in the middle of chest, behind and slightly to the left of breastbone (sternum) Size of ones fist and shaped like a cone. An average heart pumps 2.4 ounces (70 milliliters) per heartbeat. An average heartbeat is 72 beats per minute. Therefore an average heart pumps 1.3 gallons (5 Liters) per minute. NGOJO

Cont… Heart is divided into four chambers Right Atrium Left Atrium Right Ventricle Left Ventricle A wall of muscle called as a 'Septum', separates all chambers of heart. NGOJO

Normal Cardiac Conduction Electrical pattern ECG tracing Explain the cardiac conduction pathways with the electrical impulse originating in the SA node (right atrium) which travels to the AV node (division of the right and left ventricles), down along the right and left bundle branches to the Purkinje fibers. Intrinsic heart rates at the SA node are 80 bpm, the AV node is 60 bpm, and the ventricular rate (Purkinje fibers) is 40 bpm. NGOJO

Normal ECG tracing NGOJO

when ABNORMALITIES happen…. NGOJO

1. Ventricular Fibrillation Ventricular Fibrillation is a very fast, irregular heart rhythm in the lower heart chambers (ventricles). During VF the heart quivers and pumps little or no blood to the body. Consciousness is lost in seconds. If not treated immediately, VF will cause sudden cardiac arrest NGOJO

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

SAMPLE SHOCKABLE RHYTHMS Ventricular Fibrillation Ventricular Tachycardia NGOJO

2. Atrial Fibrillation Atrial Fibrillation is a very fast, irregular heart rhythm in the upper heart chambers. During AF, the waveform is almost similar to normal waveform but for the loss of 'P' waveform. NGOJO

AF treatment: For Atrial fibrillation, the shock should be avoided to be delivered in the T period otherwise it will lead to Ventricular Fibrillation This is achieved by Synchronous mode NGOJO

Application Emergency department Anesthesiology Cardiology Operation theatre Intensive care areas Ambulance services NGOJO

Types: NGOJO

1. Manual Clinical expertise is needed to interpret the heart rhythm and decide whether to charge the defibrillator and deliver the shock to patient. Energy selection and delivery is given to the patient manually. NGOJO

2. Automatic These defibrillators are small, safe, simple and lightweight with two pads that can be applied to the patient. The defibrillator guides the operator step-by-step through a programmed protocol. It records and analyses the rhythm and instructs the user to deliver the shock using clear voice prompts, reinforced by displayed messages. NGOJO

3. External External Defibrillator is the device which delivers the high energy shock to patients Heart externally on patient's chest by using a Defibrillator Paddle. The maximum energy deliver to the patient is about 360 Joules in Monophasic & 200 Joules in Biphasic Defibrillator. NGOJO

4. Internal Internal defibrillator consist of sterilized internal Handle/Paddle through which shock is delivered directly to the heart. NGOJO

5. AED Automatic External Defibrillator AED can be classified as either fully automatic or semiautomatic. In fully automatic models disposable paddles are kept connected to the patient whilst the AED analyzes the ECG rhythm , decides and determines whether a defibrillation counter-shock is needed. Then the device automatically charges and discharges. Semi Automatic AED analyze the patient's ECG and notify the operator when defibrillation is indicated. The operator then activates defibrillator and discharge. NGOJO

AED Semi Automatic Fully Automatic NGOJO

6. ICD Implantable Cardioverter Defibrillator If it detects an abnormally fast heart rhythm, it either electrically paces the heart very fast or delivers a small electrical shock to the heart to convert the heart rhythm back to normal. The rapid pacing is not felt by the patient but the electrical shock, if used, is felt as a strong jolt in the chest. The ICD is used to treat life-threatening heart rhythms that lead to sudden death. NGOJO

ICD NGOJO

7. Pacemaker A pacemaker is an electronic stimulator that produces periodic electric stimulation to the heart It is classified into two types: Internal Pacemaker External Pacemaker NGOJO

Internal Pacemaker Battery operated device that is implanted inside the patient’s body to pace the Heart NGOJO

External Pacemaker This is used to pace the heart temporally. It may use leads or electrodes for the stimulation NGOJO

What is Joule? It is the unit of energy delivered by the Defibrillator It means - “The energy released in one second by a current of one ampere through a resistance of one ohm” Also called as watt-second NGOJO

- The delivered energy is in the range of 50-360 joules and depends on: intrinsic characteristics of patient patient’s disease duration of arrhythmia patient’s age type of arrhythmia (more energy required for VF) type of the machine used NGOJO

Operating Principle Monophasic Defibrillator Bi- Phasic Defibrillator NGOJO

Monophasic Defibrillator Delivers its current in one forward direction (positive) Requires higher escalating energy levels (200-300J) to convert VF/ pulse-less VT NGOJO

Bi Phasic Defibrillator The Biphasic waveform type defibrillator delivers the current in one direction during the first phase and in opposite direction during the second phase. Biphasic waveform shocks of 200 J are safe, equivalent or higher efficiency than damped sinusoidal waveform shocks of 360 J. NGOJO

Generation of bi-phasic waveform NGOJO

Waveform Comparison NGOJO

Operation Defibrillator: Normal and Synchronous Mode Monitor Recorder Pacemaker NIBP SPO2 CO2 NGOJO

1. Manual Defibrillation Switch 'ON' the Machine Wait for initialisation and self test Make sure it is not in SYNC Mode Apply gel to the paddles Place them properly on the chest NGOJO

Cont… Select 'ENERGY' to be delivered( energy in Joules) Press 'CHARGE' button Wait for Charging to complete. This is usually denoted by a continuous /long beep sound. Apply pressure to the paddles ( 12 Kg of pressure) NGOJO

Cont… Make sure all the personnel are away from the patient Press both 'DISCHARGE' button simultaneously Observe patient and monitor ECG If required, defibrillate again When finished, turn off and clean the paddles NGOJO

2. Synchronization Mode Wait for initialization and self test . Connect ECG leads to get a tall R wave Select 'SYNC / CARDIOVERSION' mode. . Check for sync marker on the QRS waveform . If possible sedate the patient and maintain airway NGOJO

Cont… Apply gel on the paddles and place it properly on chest Select 'ENERGY' to be delivered( energy in Joules) Press 'CHARGE' button Wait for the Charge to be completed. This is usually denoted by a continuous /long beep sound. Press both 'DISCHARGE' button simultaneously and hold till energy is delivered. NGOJO

Cont… Check patient condition and Heart rhythm . If required, defibrillate again Monitor the patient for few hours Switch off and clean the paddles NGOJO

3. Internal Defibrillation Connect the Internal Paddles to the machine Place one paddle over the apex of the left ventricles and the other over the base of the right ventricles Switch on the machine Select Energy Charge and Discharge NGOJO

What are the types of Paddles? NGOJO

Paddle Placement There are two notable methods of paddle placement recommended by AHA Anterior- Anterior Anterior-Posterior NGOJO

Paddle Placement Anterior- Anterior Place one paddle near the second or the third right sternal border and the other on the cardiac apex. NGOJO

Paddle Placement Anterior-Posterior - One paddle on sternum and the other on the left infra-scapular region NGOJO

Important Factors: 1.Time Early defibrillation allows more success or the longer period of VF, the less success of defibrillation. Early initiation of CPR improves the success rate > 8 mins neurological damage sets in > 10 mins survival probability becomes very low NGOJO

2. Energy Level AHA Recommendation for Adults First shock 200 j Second shock 200 j to 300 j Third and above shocks 360 j AHA Recommendation For Paeds First shock 2 joules per Kg Subsequent shock double the energy NGOJO

3. Paddle Size Adult paddles should be 8 to 13 cm in diameter Child paddles should be 4.5 cm in diameter Infants use Anterior Posterior position NGOJO

4. Skin To Paddle Interface Use the right gel Too little gel increases possibility of burn Too much gel causes electric current to arc from one electrode to another If disposable paddles are used check the expire date NGOJO

Block Diagram of a typical Defibrillator machine NGOJO

Power Supply Step up transformers used to convert 240 VAC to 5000 VAC This is converted to DC by rectifier In battery mode the DC is converted to AC by inverter This AC is amplified and then again rectified to DC. NGOJO

Capacitor Most important part of Defibrillator Stores large energy which can be discharged in a short burst Unit of measurement is Farad NGOJO

Inductor Coils of wire that produce a magnetic field when current flow through them Used to prolong the duration of current flow Unit of measurement is Henry NGOJO

Safety NGOJO

Safety - General The Defibrillator generates High voltage. It must be operated by trained, professional and qualified personnel only. Never use defibrillator with improper grounding or electrical leak socket. Keep away the Defibrillator from any x-ray, Ultrasonic or other electronic instruments. NGOJO

Cont… Check the patient lead wire, cable and paddles for any damage or mishandling, otherwise replace the same immediately. Recommend using proper size and placement of recording paper. Clean the print head regularly for clear printout NGOJO

Safety - Monitoring Use only the specified patient cable as recommended by manufacturer. Place the patient cable in proper winding position or hang on to patient cable arm attached with Defibrillator trolley Use good ECG electrodes to monitor ECG waveform. NGOJO

Cont… Don't use damaged patient cable. Confirm there is no ECG waveform because of electrical interference or defective patient cable. This may misinterpreted as QRS in synchronize mode. NGOJO

Safety - Defibrillation Excessive Gels can cause arcing of the current along the chest wall Malfunction of permanent pacemakers can result from placing defibrillator pads or paddles near the pacemaker Defibrillation in the absence of an ECG rhythm (ie, 'blind defibrillation') to be avoided NGOJO

A shock can be accidentally delivered to other rescuers Cont… A shock can be accidentally delivered to other rescuers The initial three shocks should be delivered in sequence, without interruption for CPR, medication administration, or pulse checks. If transthoracic impedance is high, a low energy shock (< 100 J) may fail to generate enough current to achieve successful defibrillation. NGOJO

Never discharge the Defibrillator in Air to check its performance Cont… Alcohol should never be used as conducting material for paddles because serious burns can result. Never discharge the Defibrillator in Air to check its performance Never discharge with paddles shorted Always clean the paddles after use NGOJO

Maintenance - Cleaning For Exterior surface of defibrillator and battery /battery well or compartment Isopropyl alcohol(70% in water) Mild soap and water Chlorine bleach (3% in water) While cleaning take care that solution should not go inside the defibrillator. Use soft cloth for cleaning display, to prevent scratching. NGOJO

Maintenance - Cleaning For Paddles, pads, Electrodes & cables Disposable pads & monitoring Electrodes do not require cleaning. The paddles, paddle cable and patient cable, may cleaned with Alcohol free hand soap Chlorine bleach solution 10%in water Isopropyl Alcohol NGOJO

Maintenance - Cleaning Internal Paddles / Cables Internal Paddle Handle/ Cable / Electrodes can be cleaned ultrasonically, autoclave or steam sterilized but follow the manufacturer's instruction for sterilization procedure NGOJO

PRECAUTIONS The paddles used in the procedure should not be placed:- on a woman's breasts over an internal pacemaker patients. Before the paddle is used, a gel must be applied to the patient's skin NGOJO

RISKS IN DEFIBRILLATION Skin burns from the defibrillator paddles are the most common complication of defibrillation. Other risks include injury to the heart muscle, abnormal heart rhythms, and blood clots. NGOJO

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. NGOJO

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”. NGOJO

PPM (Planned Preventive Maintenance) Qualitative Task PPM Task Quantitative Task Electrical Safety Test NGOJO

Test tool: Defibrillator Analyzer NGOJO

Defibrillator Analyzer Basic Functions Measures output energy Measures cardioversion delay time Measures output of pacemakers Simulates range of ECG waveforms Provides clinical training NGOJO

Practical Training and Assessment NGOJO

Questions!!! NGOJO

THANK YOU NGOJO