If you encounter someone experiencing cardiac arrest, do you know how to perform CPR and use an AED? | Science Time
Cardiac arrest refers to the sudden cessation of heartbeat due to various causes, resulting in the instantaneous loss of the heart's contraction and relaxation functions, leading to a complete interruption of blood and oxygen supply to the whole body's tissues and organs, including the brain.
For injured or ill patients experiencing respiratory or cardiac arrest, the optimal window for resuscitation is the "golden four minutes." Prompt on-site cardiopulmonary resuscitation (CPR), combined with the use of an AED, can significantly increase the success rate of resuscitation.
Perform cardiopulmonary resuscitation (CPR).
Artificial circulation can be established immediately.
What should you do if you witness someone experiencing cardiac arrest?
★Step 1: Ensure the safety of the site environment.
Immediately assess the safety of the scene to ensure the safety of rescuers, those being rescued, and others in the vicinity. If the environment is dangerous, quickly remove the hazard or move to a safe area.
★Step 2: Determine if the person being rescued needs CPR.
1. By gently tapping the shoulders and calling out loudly near both ears, determine whether the person being rescued is responsive and whether they have lost consciousness.
2. Take 5-10 seconds to observe the chest for rise and fall to determine if the person is breathing. If the person being rescued is unresponsive and not breathing, cardiac arrest can be confirmed, and cardiopulmonary resuscitation (CPR) needs to be performed.
★Step 3: Immediately dial "120" for emergency medical assistance and ask someone to help retrieve an AED from the nearest facility as soon as possible.
If someone suddenly collapses and is found to be unconscious and not breathing (or only sighing), the rescuer should immediately seek help from those around them, including quickly dialing "120" for emergency medical assistance and obtaining the nearest AED from the location of the incident.
★Step 4: Chest compressions.
The rescuer places their right palm on the center of the victim's chest, at the midpoint of the line connecting the two nipples, and places their left hand on top of the back of their right hand. The fingers of both hands are interlocked, the palms overlap, the fingers are raised, the upper limbs are straight, and the upper body leans forward. Using the weight of their body, the rescuer presses vertically downwards into the patient's chest, ensuring a compression depth of 5-6 centimeters and a compression rate of 100-120 times per minute.
★Step 5: Open the airway. When breathing and heartbeat stop, the muscle tone throughout the body decreases, including the muscle tone of the pharynx and tongue, causing the tongue to fall back and obstruct the airway. The rescuer can place the hypothenar eminence of one hand on the forehead of the person being rescued and press down; the index finger (also known as the "index finger") and middle finger of the other hand are placed together on the chin of the person being rescued and lifted upwards, so that the chin is raised, usually so that the line connecting the angle of the jaw and the earlobe of the person being rescued is perpendicular to the horizontal plane.
Note that if there are signs that the person being rescued may have a spinal injury, the head-tilt/chin-lift maneuver should not be used; instead, the chin-lift maneuver should be used to open the airway.
★Step 6: Mouth-to-mouth resuscitation.
The rescuer pinches the victim's nostrils closed with the thumb and forefinger of one hand, completely covers the victim's mouth with their own lips, and blows air into the victim's mouth twice, each breath lasting about one second. The victim's chest should rise during the breaths, but excessive ventilation should be avoided. After blowing air in, the rescuer releases the victim's nostrils, allowing the victim to exhale passively.
Note that rescuers should first perform 30 consecutive chest compressions, followed by 2 rescue breaths. If possible, a cloth or other object can be used to cover the victim's mouth to avoid direct contact. Signs of successful CPR include: spontaneous breathing; pupils constricting and eye movement; a change from cyanosis to a rosy complexion; the ability to speak; spontaneous movement of the limbs and head; and the ability to feel a pulse in the carotid artery or other major arteries.
Use an AED as early as possible.
Seize the opportunity to save gold
An AED is a portable, easy-to-operate emergency medical device designed for on-site first aid. It uses a built-in computer to analyze and determine whether the injured or ill person needs defibrillation, and if the indications are met, it will automatically deliver defibrillation.
When the heart beats normally, it contracts and relaxes rhythmically to expel and return blood.
When the heart stops beating, the most common fatal arrhythmia is ventricular fibrillation. In this case, the ventricular myocardium contracts rapidly or weakly, and the uncoordinated rapid fibrillation causes the heart to lose its pumping function, resulting in the disappearance of pulse and blood pressure. The blood flow to organs such as the heart and brain and surrounding tissues is completely interrupted, endangering life.
While chest compressions can provide temporary blood supply to vital organs, they are unlikely to restore a spontaneous heartbeat. Early use of an AED (Automated External Defibrillator) for defibrillation, when indicated, can significantly improve the success rate of resuscitation.
Statistics show that more than 80% of cardiac arrests are caused by ventricular fibrillation. In such cases, the only effective rescue method for ventricular fibrillation is electrical defibrillation.
If cardiopulmonary resuscitation (CPR) and AED are performed within one minute of cardiac arrest, the success rate of resuscitation can be as high as 90%. For every minute of delay, the success rate decreases by 10%.
Therefore, grasping the golden opportunity to use an AED is the key to improving the success rate of rescue.
How to use an AED
1. Usage Steps
Step 1: Power on the device.
Once you have the AED, open the cover, press the power button, and then follow the voice and picture prompts.
Step 2: Attach electrode pads.
Apply the electrode pads to the person being rescued according to the diagram on the AED body and electrode plates (make sure the placement is accurate), and insert the plugs of the electrode pads into the sockets of the AED main unit. If there is water or sweat on their chest, wipe it dry quickly before applying the electrode pads.
Step 3: Analyze the heart rhythm.
Ensure no one touches the person being rescued, and wait for the AED's heart rate analysis results to determine if the person needs defibrillation.
Step 4: Defibrillation.
If the AED determines that the person needs defibrillation based on heart rate analysis, it will provide voice prompts. After receiving the "defibrillate" instruction, the rescuer should wait for the AED to recharge and ensure that no one touches the person being rescued. Then, press the "shock" button as instructed. After defibrillation, continue CPR for 5 cycles (approximately 2 minutes), then follow the AED's voice prompts. If the AED indicates that defibrillation is not necessary, the rescuer should continue CPR.
Step 5: Repeat the operation.
Every 2 minutes, the AED will automatically re-analyze the heart rhythm and repeat steps 3-4 until the person being rescued regains spontaneous breathing and heartbeat, or until professional rescuers arrive at the scene.
2. Precautions
Different AEDs may have slightly different usage methods. Rescuers can follow the voice prompts and illustrations.
Authors: Jia Dacheng, Beijing Emergency Medical Center; Zhao Jinchuan, Deputy Chief Physician of the Pre-hospital Emergency Department, Chongqing Emergency Medical Center
Source: "Healthy China" WeChat Official Account
