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How Do You Use And Maintain A Defibrillator Machine?

Feb. 29, 2024


Defibrillation is the application of electrical energy to the heart, either through an external shock or internal electrodes, to restore the heart's normal rhythm. 

In cardiac arrest or ventricular fibrillation, the heart cannot pump blood effectively, resulting in insufficient oxygen supply and, in severe cases, sudden death. 

The purpose of defibrillation is to resynchronize the contraction of heart cells and restore normal heart rhythm through the transmission of electrical energy.

The difference between single wave and bidirectional wave

They are two different working modes of the defibrillator.

There are two electrodes on the defibrillator. One-way wave electric defibrillation only emits a current. The time for the current to flow through the body is determined by the resistance of the body. 

Since it is a one-way current, the energy required for defibrillation is relatively large (360J). 

Bidirectional wave electric defibrillation can also send out a reverse current after sending out a current, and can control the time of current flow. 

Since the current flows through the human body twice, the energy required for defibrillation is small (150~200J).


(1) Assessment

Understand the patient's condition, assess the patient's loss of consciousness, disappearance of carotid and femoral pulses, intermittent breathing or cessation, cyanosis of the skin,

disappearance of heart sounds, 

undetectable blood pressure, electrocardiogram status and whether there are ventricular fibrillation waves.

(2) Preparation before operation

1.The defibrillator is in good condition and ready for use. Prepare rescue items, conductive paste, electrode pads, and 5 pieces of gauze in the treatment bowl and place them in an orderly manner.

2.Expose the chest, clean the skin of the monitoring lead area, press the electrode pads, and connect the lead wires.

3.Electrical defibrillation must be equipped with various equipment and drugs required for rescue and cardiopulmonary resuscitation, such as oxygen, suction machines, endotracheal intubation supplies, 

blood pressure and ECG monitoring equipment, and rescue vehicles equipped with conventional rescue drugs, etc. In case of emergency.

4.Turn on the defibrillator correctly and adjust it to the monitoring position; observe the ECG waveform on the display; after checking the defibrillator, report to the examiner that "the equipment is intact, 

the power is sufficient, the connections are normal, and the electrode plates are intact."

5.Report the heart rhythm "The patient has ventricular fibrillation and needs emergency defibrillation"; (the preparation time does not exceed 30 seconds).

(3) Operation

1.Place the patient in the resuscitation position and quickly dry the patient's skin.

2.Select the defibrillation energy, use 360J for monophasic wave defibrillation, and confirm that the electrical cardioversion state is asynchronous.

3.Dry the patient's chest skin quickly. Do not face yourself when holding the electrode pad. Apply special conductive paste to the manual defibrillation electrode pad and distribute it evenly on the two electrode pads.

4.The position of the electrode plate is correct; (the upper edge of the "STERNVM" electrode plate is placed in the second intercostal space on the right side of the sternum. 

The upper edge of the "APEX" electrode plate is placed in the fourth intercostal space in the left midaxillary line). The electrode plate is in close contact with the skin.

5.Charge and say "please leave others alone".

6.The electrode plate pressure is appropriate; observe the ECG oscilloscope again (the report is still ventricular fibrillation).

7.Look around the patient and make sure that no one around him has direct or indirect contact with the patient; (the operator takes a small step back and cannot come into contact with the patient).

8.Press the discharge button with both thumbs at the same time to deliver electric shock defibrillation; (from the activation of the hand-controlled defibrillation electrode pad to the completion of the first defibrillation, 

the entire process does not exceed 20 seconds).

9.After defibrillation is completed, evaluate the defibrillation effect: Continue CPR immediately after defibrillation. After 5 sets of CPR, check the heart rhythm, and perform defibrillation again when indicated. 

Report "defibrillation successful, sinus rhythm restored".

10.Remove the electrode plate.

11.Return the knob to monitoring; clean the defibrillation electrode pads.

12.Assist the patient to get into a comfortable lying position and report: Closely observe changes in vital signs and continue follow-up treatment; 

the patient's condition is stable and ECG monitoring will be stopped as directed by the doctor. Remove the electrode pads and wipe the skin clean.

13.Return the electrode plate to its correct position; turn off the machine.

(4) After operation

1.Dry the chest wall skin, organize the patient's clothes, help the patient lie in a comfortable position, closely observe and record changes in vital signs in a timely manner.

2.Organize supplies.

The clinical application of defibrillation in emergency medicine, cardiac arrest caused by various reasons, ECG manifestations:

Ventricular flutter or ventricular fibrillation: The heart cannot eject blood efficiently.

Heart electromechanical separation: Although there is electrical activity in the heart, it cannot produce effective mechanical contraction of the heart, and there is no heart sound or blood pressure.

Cardiac Arrest: There is neither electrical activity nor contraction of the heart, and the ECG shows a straight line.

The fastest and most effective way to terminate ventricular fibrillation is electrical defibrillation.

How to deal with common problems with defibrillation monitors?

Defibrillation monitors have more functions than ordinary monitors, so the problems encountered during use and maintenance also increase accordingly. Some are caused by the software and hardware 

of the equipment itself, and some are caused by improper operation. The main problems and solutions are as follows:

1. Low voltage power supply (or battery) problem

Most defibrillation monitors are used for both AC and DC. When AC power is used, the internal circuit automatically converts to AC/DC function and charges the battery at the same time. 

When there is no AC power source or when going out for emergency treatment, the battery can be used for power supply. Different battery capacities, 

different monitoring times or times of defibrillation are clearly stated in the general user manual.

Phenomenon: Main functions become unresponsive after powering on (for example: the monitor screen is black, defibrillation is not possible, and recording is not possible).

Judgment and repair: The above phenomena are mostly low-voltage power supply problems. If it still works with batteries, it's usually an AC/DC circuit problem. 

If you can use AC power but not the battery, the battery may be undercharged or invalid. Some defibrillation monitors can only use batteries, and this battery has a capacity indicator, 

so the operator can easily judge the battery capacity. Medical staff cannot eliminate problems with the low-voltage power supply itself and can only be repaired by engineering and technical personnel.

2. Defibrillation unit problems

Phenomenon: The monitoring function and recording function are normal, but defibrillation cannot be performed, or the charging-shock cycle speed is very slow.

Judgment and maintenance: This phenomenon is generally not caused by human operation, but by a fault in the high-voltage charging and discharging circuit or a problem with the energy storage component itself. 

If the electric shock is normal but the charging speed is slow, it is mostly due to a fault in the charging circuit; if it can be charged but cannot deliver an electric shock, 

there is a problem with the discharge circuit. The chance of damage to the energy storage component (high voltage capacitor) is rare.

3. Monitor or recorder issues

Phenomenon: Another common problem with defibrillation monitors is that the monitor only displays a straight line and no ECG display.

Judgment and maintenance: There are many reasons for this situation. First, the electrodes are in poor contact with the human body or fall off; second, 

the ECG threshold is improperly set; third, there are breakpoints in the lead wire; fourth, the circuit failure of the monitor itself, etc. 

If there is no ECG display and the ECG waveform cannot be recorded, the fault is usually caused by the signal operation circuit or human operation, or the recorder itself may be faulty; 

if there is no ECG display but the ECG waveform can be recorded, it is mostly a fault in the display circuit. , and it is a non-human operation failure, which needs to be solved by engineering and technical personnel.

4. Signal processing arithmetic unit (motherboard) problem

Phenomenon: During use, functional disorders are encountered, buttons do not work, parameters cannot be set and changed, etc.

Judgment and repair: This situation is mostly caused by a failure of the central control unit (also known as the motherboard or motherboard), and it is mostly a hard fault. Medical staff are helpless, 

and sometimes even engineering and technical personnel are helpless. Because the motherboard is mainly composed of large-scale integrated circuits and SMD components, 

it is generally impossible to repair and can only be replaced by contacting the company or manufacturer.

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