How Does CPR Work Physiologically?


The purpose of cardiopulmonary resuscitation is to restore the flow of oxygen, blood circulation, and breathing in an unresponsive patient who has had a cardiac arrest. The emergency procedure can be performed on the spot even by non-medical personnel; however, it can’t be overstated how important it is to have CPR certification through adequate training.

Knowing how to properly administer CPR puts you in a position to make a difference in the event of an emergency. Although still low, studies have shown that CPR can help increase the chances of survival for around 10% of victims out of the hospital and 30% of victims in the hospital.

Nonetheless, the survival rates of the patient increase when the responder understands the physiological mechanisms of CPR. So how does CPR work physiologically? Keep reading to learn more and see how you can obtain your CPR certification if you’re living or working in or around Wesley Chapel, Florida.

How Does Knowing CPR Save Lives?

All individuals who are in the process of obtaining or already have a CPR certification should know the answer to the question, “How does CPR work physiologically?“. That way, they provide a better response in an emergency and thereby increase the victim’s chance of survival.;

Obtaining CPR certification comes with many benefits, but the number one advantage is that you are prepared with the skills and ability to save someone’s life.;

According to the CDC, the majority of individuals who’ve suffered a cardiac arrest die if the emergency takes place outside a hospital. Providing CPR within the first few minutes is crucial as it can double or triple the person’s chances of survival.;

During cardiac arrest, the heart stops pumping blood and, therefore, oxygen to the brain, lungs, and other vital organs. The crucial life-saving benefit of providing CPR is to restore the flow of blood and oxygen to the brain. Without oxygen, the brain experiences a dramatic loss of cells, and this can cause brain injury or irreversible brain damage.

Within one minute of the occurrence of cardiac arrest, the brain begins to suffer from anoxic injuries. Within the three-minute mark, the neurons experience significant damage that prevents the brain from communicating with other organs in the body.;

Understanding the Physiological Mechanisms of CPR

There can be various causes leading to cardiac arrest, but the effect on the heart is always the same: it stops pumping blood to the body, leading to oxygen deprivation in the vital organs.

At the onset of a sudden cardiac arrest, the victim collapses, stops breathing, or their breathing becomes extremely labored and shows no signs of consciousness. In the event, the emergency response consists of assessing whether the person has indeed suffered cardiac arrest.

This is followed by providing cardiopulmonary resuscitation (CPR), whose mechanism is to artificially pump oxygen from the heart to the brain by administering chest compressions. The purpose of compressing and decompressing the chest or thorax is to induce air circulation in the lungs, heart, and brain.;

Why Compressions?

Compressions influence two primary mechanisms that are otherwise performed during normal breathing:;

      • Reducing the volume of oxygen (thoracic volume);

      • Increasing the amount of blood pressure inside the chest (thoracic pressure).

    Applying 100–120 in-deep chest compressions per minute causes forward blood flow while preventing retrograde flow. The release of pressure on the chest allows the heart and vents to fill with blood, resulting in air and blood returning to the lungs at 15–25% of the normal cardiac output. This is the amount of blood flow and oxygen circulation that can increase the chance of survivability in the victim.

    Furthermore, CPR induces coronary perfusion pressure (CPP), leading to increased blood pressure in the heart and the successful return of pulse and spontaneous circulation. CPP takes place during the decompression phase. Clinical research demonstrates the importance of sustained, effective decompressions in maximizing the effectiveness of the resuscitation effort.;

    Releasing pressure from the chest causes the ribcage to recoil, which leads to a drop in blood pressure inside the lungs. A vacuum is created that fills the heart’s right and left ventricles with blood until the next compression. Again, effective decompression of the chest improves the volume of blood that gets pumped with every subsequent compression.


    One of the physiological effects of chest compression is ventilation. Research warns against applying excessive pressure because this inadvertently leads to hyperventilation.;

    In such cases, hyperventilation causes the cerebral blood vessels to contract, decreasing blood flow in the arteries. The ultimate effect is counteracting the heart’s output which is the objective of cardiopulmonary resuscitation.

    Recommended Depth and Rate of Compressions During CPR

    Understanding how CPR works physiologically will help CPR trainees properly apply the recommended depth and rate of compressions. For adult cardiac arrest victims, the ratio is 100 to 120 compressions per minute. The depth of each compression has to be at least 2 inches and no deeper than 2.4 inches.

    The recommended rate of compressions for children victims of cardiac arrest is 100–120 per minute. Infants require an increased rate of around 120 compressions per minute.

    The depth, however, is notably different for children, being recommended at 1.5 inches for infants and around 2 inches for children. As for adults, AHA recommendations warn against applying pressure greater than 2.4 inches for children and adolescents alike.

    Needless to say, the standard procedure needs to follow the Compression-Airway-Breathing sequence when providing CPR to children. The American Heart Association recommends that bystander-administered CPR includes two breaths for every 30 compressions. Bystanders who are unwilling to provide rescue breaths should proceed with chest compression as per the certified CPR course.

    Do Cardiac Arrest Victims Feel Pain?

    Some people may feel deterred from obtaining certification due to the fear of inflicting harm while providing CPR. When the treatment is administered in accordance with certified training, the risk of causing injury is decreased. Nevertheless, it is impossible to completely rule out CPR-sustained complications.;

    At the sudden onset of cardiac arrest, the victim may gasp for air and feel pressure in the chest. The body or head may sustain injuries from the person collapsing. Internal bleeding, fractures, and concussions are all a possibility as a complication of a sudden collapse. However, so far, it has been determined that victims of cardiac arrest are desensitized to pain.

    Because CPR is hugely important in saving lives, Good Samaritan laws at the federal and state levels enable bystanders to provide emergency CPR to victims in good faith without fearing legal repercussions. Simply put, both medical responders and bystanders are provided legal protection when providing CPR with the goal of saving a life.;

    CPR Certification in Wesley Chapel, Florida

    Obtaining CPR certification in Florida may be recommended for your current job or can put you ahead on an employer’s list when applying for one. The typical CPR training takes between three and five hours, and the certificate is valid for two years.;

    Once expired, the cardholder can renew their certification by visiting abbreviated CPR classes at a training center or online. Recertifying your credential enables you to learn about new advances in the field and potential updates to the methods of providing CPR.

    Who Must Have CPR Certification?

    All other employees except physicians, nurses, and EMTs in Florida are not required by law to provide emergency CPR. Nevertheless, having CPR training and certification provides you with the confidence and ability to react in an emergency and save someone’s life.;

    The following are some of the professions in Florida that require or recommend having infant, child, and adult CPR certification:

        • Teachers

        • Podiatrists

        • EMT responders

        • Nurses

        • Child care providers

        • Psychiatrists

        • Sports coaches

        • Athletic program coordinators

        • Lifeguards

        • Fitness instructors

        • Law enforcement officers

        • Firefighters

        • Flight attendants

        • Electricians

        • Social workers

      Current and prospective employees in these and other professions may all benefit from knowing the answer to the question, “How does CPR work physiologically?” And the safest way to be sure of your answer is by obtaining a valid CPR certification in Wesley Chapel, Florida.


      High schools around the country requiring students to complete a CPR course to graduate further demonstrates how crucial this skill can be in emergency situations. With the annual incidence of cardiac arrest occurring in around 356,000 people outside a hospital, you, as an individual, employee, or employer, should be prepared to respond.;

      With the physiological mechanisms of CPR explained it is now easier to understand what the procedure does internally to give the body a fighting chance for survival.