When sudden cardiac arrest occurs, immediate action is paramount. Cardiopulmonary Resuscitation (CPR) and Automated External Defibrillators (AEDs) are critical interventions. CPR involves chest compressions and, at times, artificial ventilation to sustain blood flow and oxygen. An AED is a portable device that analyzes heart rhythms and delivers an electrical shock.
How CPR Supports Circulation
Cardiopulmonary Resuscitation manually circulates blood to the brain and vital organs when the heart stops pumping. This is achieved through chest compressions, delivered at 100 to 120 beats per minute, pushing 2 to 2.4 inches into the center of the chest.
Between compressions, allow the chest to fully recoil. This recoil helps draw blood back into the heart, ensuring adequate filling. Rescue breaths, when performed, provide oxygen to the lungs, which then enters the bloodstream. This oxygenated blood flow helps delay brain damage and preserve organ function until medical intervention.
How AED Corrects Heart Rhythm
An Automated External Defibrillator addresses the underlying electrical malfunction often responsible for sudden cardiac arrest. The device analyzes the electrical activity of the heart through electrode pads placed on the chest. If it detects a chaotic and ineffective rhythm, such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), the AED advises and delivers an electrical shock.
Ventricular fibrillation involves disorganized electrical impulses that cause the heart’s lower chambers to quiver rather than pump blood effectively. Pulseless ventricular tachycardia is a rapid, ineffective heartbeat that also prevents blood circulation. The electrical shock from an AED temporarily depolarizes the heart muscle, essentially resetting its electrical system. This allows the heart’s natural pacemaker to potentially re-establish a coordinated and effective rhythm. The AED is programmed to deliver a shock only when a shockable rhythm is detected, ensuring appropriate intervention.
Synergy in Saving Lives
CPR and AEDs are designed to be used together, forming a powerful combination that significantly increases survival rates from sudden cardiac arrest. CPR provides artificial circulation, supplying oxygenated blood to the brain and heart, which extends the window of opportunity for a successful resuscitation. However, CPR alone cannot correct the chaotic electrical problem that often causes the heart to stop. The AED targets and corrects the electrical malfunction, allowing the heart to potentially resume its normal pumping action.
Without CPR, vital organs rapidly suffer from a lack of oxygen, reducing the likelihood of a positive outcome even if defibrillation is successful. Conversely, an AED cannot maintain blood flow on its own once the heart’s rhythm is restored. The combined approach ensures that both the mechanical need for blood flow and the electrical need for a stable rhythm are addressed. Research indicates that when CPR is combined with AED use, survival rates can increase considerably, sometimes rising from less than 10% to between 40% and 70%.
Steps for Effective Combined Use
Effective CPR and AED use involves a coordinated sequence of actions. When someone collapses and is unresponsive, the first step is to call for emergency medical services and, if possible, have someone retrieve an AED. Simultaneously, high-quality chest compressions should be initiated.
Once the AED arrives, it should be turned on and the rescuer should follow its voice and visual prompts. The electrode pads are attached to the person’s bare chest as illustrated on the device. The AED will analyze the heart rhythm, and if a shock is advised, the rescuer must ensure no one is touching the person before delivering the shock.
Immediately after a shock, or if no shock is advised, CPR should be resumed without delay, continuing for approximately two minutes. The AED will then re-analyze the rhythm, and this cycle of CPR and AED rhythm analysis continues until emergency medical personnel arrive and take over care.