Basic Life Support: A Study Guide for BLS Class

Basic Life Support course allows healthcare providers to learn life-saving techniques. As you complete the course, you will learn to respond to emergencies appropriately and perform CPR and other basic life support skills. In this study guide, we'll give you an overview of what you'll learn in Cardiopulmonary Resuscitation, Automated External Defibrillation, First-Aid, and other Basic Life Support Skills —you'll find everything you'll need for standard procedures. You can also use this BLS study guide to review and help you pass the certification exam. 

Topics included in this course are as follows:

  • Basic Anatomy and Physiology
  • Understanding CPR
  • Chain of Survival
  • Hands-Only CPR
  • One Rescuer Adult CPR
  • Two Rescuer Adult CPR
  • Infant CPR
  • Automated External Defibrillator
  • Choking
  • Recovery Position
  • Airway Management

Key Takeaway

As healthcare providers, it is essential to remember that as real-life emergencies happen, the first order of action is to provide essential care techniques learned through the BLS course, call 911 and perform Cardiopulmonary Resuscitation until paramedics arrive. The participants in this course learn life-saving techniques as solo or team rescuers. This Basic Life Support Course aims to impart knowledge that helps healthcare providers provide Basic life support to individuals undergoing life-threatening medical conditions while the person is waiting for more advanced treatment in a hospital setting.

Our courses are convenient and credible ways of getting online BLS certification training that adheres to the latest American Heart Association and ECC guidelines and is prepared by AHA-trained physicians. 

Chapter 1: Basic Anatomy and Physiology

In Basic Life Support, it's essential to know and understand how the heart, lungs, brain, and cells perform in our body. Here is a brief function of these systems:

Heart: The heart pumps blood that has been deoxygenated by supplying the body's tissues into the lungs. When that blood has been oxygenated in the lungs, it exits the lungs to the left side of the heart, pumped out into the tissues once again to provide oxygen.

Lungs: The lungs take in oxygen to supply the body's vital organs and tissues. They release carbon dioxide into the atmosphere when we exhale.

Brain: The brain needs a steady supply of oxygen. Without it, the brain cells begin to die in 4 to 6 minutes. The brain normally weighs three pounds and uses 20% of the body's oxygen.

Cells: All cells in the body require oxygen to carry out their normal functions. Oxygen deprivation, or hypoxia, will cause cells to die within a few short minutes. 

Chapter 2: Understanding CPR

According to the Center for Disease Control, Cardiac Arrest is the leading cause of death in the United States. Risk factors include smoking, high blood pressure, high cholesterol, lack of exercise, stress, and obesity. There are also unavoidable factors such as age, sex, hereditary, and diabetes. 

During cardiac emergencies, death is most likely to occur after 10 minutes of losing oxygen to the brain. Brain damage is expected within 6 to 10 minutes. Therefore, the rescuer should perform CPR in the 1st 4 minutes to avoid brain damage. It's important to note that the American Heart Association guidelines recommend untrained bystanders to at least perform chest compressions on the patient since studies show chest compressions can be as effective as the combination of CPR.

Chest Compressions: When a rescuer presses down on a victim's chest, blood is forced out of the heart and into the arteries. When pressure on the chest is released, blood is allowed to return to the heart. A small amount of oxygen will be present in the bloodstream for several minutes after the heart ceases to beat, just enough to keep the brain alive. Compressions can keep vital organs functioning until higher-level care is available.

When to Stop CPR

  • The patient regains a pulse
  • The area becomes unsafe
  • The cardiac arrest last longer than 30 minutes
  • The rescuer is too exhausted or ordered to stop

Chapter 3: What is the Chain of Survival?

When preparing to perform CPR, keep the Emergency Cardiovascular Care's Chain of Survival in mind. These are the five steps that you must perform in an emergency:

  1. Immediate recognition of cardiac arrest, call 911.
  2. CPR with emphasis on chest compressions. Continue CPR until medics arrive.
  3. Provide rapid defibrillation with an AED (this is necessary to restore a normal heartbeat) within minutes of the onset of symptoms.
  4. Trained medics administer advanced life support.
  5. Post-cardiac arrest care is administered in a hospital setting.

Chapter 4: What is Hands-Only CPR?

Untrained bystanders should provide hands-only CPR or compression-only CPR for adult cardiac arrest victims, with or without dispatcher guidance. The rescuer should continue doing the chest compressions until an AED or rescuers arrive with additional training. Hands-Only CPR can be enough to sustain an adult in certain situations until help arrives.

Step 1: Call 911
If you have witnessed an adult collapse before you, you should first call 911. If bystanders are with you or within shouting distance, you should begin Hands-Only CPR and tell the other person to call 911 immediately. 

Step 2: Place the victim on their back on a hard, flat surface.

Step 3: Kneel next to the victim, place the heel of one palm on the center of the chest and in line with the victim's nipples. Next, place the heel of the other hand on top of the first and interlock your fingers. Keep your arms and back straight.

Step 4: Chest Compressions

  • Chest compressions are performed at a depth of 2-2.4 inches for adults and 2 inches for children.
  • Deliver compressions quickly and forcefully to help circulate the remaining oxygenated blood to the brain. The speed of compressions is 100-120 per minute. Keep in mind that 120/minute is pretty fast.

Step 5: Continue chest compressions only until professional help arrives.

According to the American Heart Association guidelines, Hands-Only CPR is appropriate only for adults that you have observed become unconscious or stop breathing. It is not recommended for infants and children, and it is not appropriate for an adult you have found unconscious. Still, Hands-Only CPR can be a helpful option for those not certified in CPR or those who haven't recertified in a long time. 

Chapter 5: One Rescuer Adult CPR

If you are alone and come across an individual who is unconscious, follow the steps below

Step 1: Check for consciousness.

To check for consciousness, tap on the victim's shoulder firmly and ask, "Are you OK?" loudly.

Step 2: Call 911

Call 911 or ask someone else to call before performing CPR. Even if you perform CPR on the spot, getting paramedics to the scene as quickly as possible is crucial. If possible, ask a bystander to look for an AED.

Step 3: Check for breathing and open the airway.

While waiting for the emergency medical team, check the breathing for about 10 seconds. If the breathing is normal, put the victim in the recovery position and wait for the responders to arrive. If you do not hear breathing or only hear a few gasps, begin CPR immediately.

Step 4: Begin CPR

Place the victim on their back on a firm, flat surface. Alternate between 30 chest compressions and two rescue breaths, with 2 inches compression depth at a rate of 100-120 compressions per minute. Blow until the chest rises. 

Step 5: Use AED if available

If an AED is available, a bystander in a public place or a family member can use it to deliver a shock to the heart to restore regular rhythm.

Chapter 6: Two Rescuer Adult CPR

If you come across an unconscious victim and another person is available to help, ask that person to call 911 and find an AED while assessing whether the victim needs CPR. If the victim requires CPR, start CPR, beginning with compressions. Here's how to perform CPR when there are two rescuers present:

Step 1: Check for consciousness.

Tap the victim's shoulder and ask if they are okay. If the victim is not breathing or only gasping, stay with the victim.

Step 2: Call 911.

Rescuer 2 will call 911 and leaves to retrieve an AED.

Step 3: Check for breathing and pulse.

Rescuer 1 checks for a pulse. If there's no pulse, the rescuer will begin CPR, starting with chest compressions.

Step 4: Begin CPR

Rescuer 1 will continue giving chest compressions and rescue breaths until Rescuer 2 returns with an AED.

Step 5: Use an AED

  • When rescuer 2 arrives with an AED, place it on the side opposite Rescuer 1, who is performing chest compressions. 
  • Rescuer 2 will turn on the AED and attaches the pads to the victim's chest. Rescuer 1 will continue CPR while the pads are being placed until it is time to analyze the heart rhythm. 
  • Rescuer 2 clears the victim, ensuring neither rescuer touches the victim and waits for the AED to analyze. 
  • Rescuer 2 will push the SHOCK button if a shock is indicated.
  • If no shock is needed, rescuer 2 will resume chest compressions. 
  • During analysis, Rescuer 2 and Rescuer 1 should switch positions to prevent rescuer fatigue and ensure that rescuers provide high-quality chest compressions at the proper rate and depth. 

When the second rescuer returns without an AED:

  • Continue performing chest compressions and count the compressions aloud.
  • Rescuer 2 should keep the person's airway open using the head tilt chin lift maneuver.
  • The second rescuer will give two rescue breaths after every 30 compressions.
  • Rescuers 1 and 2 should switch positions every two minutes, so neither gets tired.

Chapter 7: How to Administer Infant CPR?

Infant CPR has many similarities with child and adult CPR, but special accommodations must be made in hand position and compression depth due to the infant's small size. When administering infant CPR, use the same cycle of 30 compressions followed by 2 breaths.

  1. Hand Position: Place the index finger on the center of the chest in line with the infant's nipples. Lower the middle finger onto the infant's chest. Compress the chest using only these two fingers.
  2. Compression Depth: Chest compressions are pushed to 1/3 the infant's chest diameter or about 1 ½ inch.

Chapter 8: What is an Automated External Defibrillator (AED)?

An AED is a mechanical device designed to assess the electrical output of a victim's heart and provide an electrical shock if needed. It is utilized when a victim experiences sudden cardiac arrest.

How to use an AED?

  1. Assess the victim for SCA.
  2. Immediately call 911. If more than one rescuer is present, provide CPR while the AED is retrieved and prepared.
  3. Once powered on, the machine will instruct the rescuer to place the electrodes (pads) over the victim's heart.
    • Choose adult pads for victims who are 8 years of age or older.
    • You may use adult pads for children below 8 years old, but you should ensure the pads do not touch or overlap.
  4. The AED will scan the victim's heart, checking if the shock is necessary.
    • Ensure that no other person is in contact with the victim while the AED assesses the situation.
    • Rescuers should follow the prompts given by the machine.
  5. AED will charge and automatically shock the victim if necessary. Ensure that no one else is touching the victim to reduce the risk of bystanders being shocked.
  6. Following the initial shock, the machine will reassess the victim to determine if an additional shock is necessary.
  7. Continue CPR when prompted.

Chapter 9. What is Conscious Choking?

Choking is caused when an object blocks the victim's throat or windpipe. For example, adults often choke on large pieces of food. However, children swallow small toy parts or other objects. The universal sign for choking is mimicking choking yourself. First, ask the patient if they are choking because the person is merely coughing. If the patient is unconscious, call 911 and perform CPR.

Infants 12 months or younger

  • Rest the infant on your forearm
  • Perform 5 thumps with the heel of your hand upon the infant's back.
  • If the patient is still choking, turn the infant over, face-up, and perform 5 chest compressions.
  • Repeat the process until the object is removed.

Children and Adults

  • Stand behind the victim.
  • Lean the victim slightly forward and wrap your arms around their waist.
  • Press hard with a closed fist into the abdomen, then grab your fist with your other hand.
  • Perform 5 quick thrusts.
  • If the object still hasn't cleared the patient's throat, repeat the cycle.

Chapter 10: What is Recovery position?

If the victim is breathing and has a pulse, put him in the recovery position while waiting for EMS to arrive. This position keeps the victim's airway open, prevents aspiration of fluids into the lungs, and allows fluid to drain from the mouth. Here's how to put the victim into a recovery position:

  1. Extend the victim's arm closest to you above the victim's head.
  2. Place the victim's leg farthest away from you over his other leg.
  3. Place the victim's arm farthest from you across his chest.
  4. Supporting the head and neck, roll the victim towards you.
  5. Position the victim's top leg so the knee props up the victim's body
  6. Place the victim's hand or arm under the chin to keep the airway open.

Chapter 11: What is Airway Management?

Airway management refers to maneuvers and medical procedures performed to prevent and relieve airway obstruction. Airway management ensures an open pathway for gas exchange between a patient's lungs and the atmosphere. This is accomplished by either clearing a previously obstructed airway or preventing airway obstruction caused by the tongue, foreign objects, the tissues of the airway itself, and bodily fluids such as blood and gastric contents.

Bag Valve Mask

A bag valve mask (BVM) or self-inflating bag is a hand-held device commonly used to provide positive pressure ventilation to a person who is not breathing adequately. The device is required for resuscitation kits for trained professionals in out-of-hospital settings such as paramedics. It is also frequently used in hospitals as part of standard equipment found on a crash carts, emergency rooms, or other critical care settings.

Nasopharyngeal Airway

NPA or nasopharyngeal airway device is a hollow plastic or soft rubber tube that healthcare providers can utilize to assist the oxygenation of the patient. It provides ventilation in patients who are difficult to oxygenate or ventilate via bag-mask ventilation.

Laryngeal Tube

The laryngeal tube is an alternative to the anesthesia facemask. It is a potential tool for providing ventilation in patients with a difficult airways. Healthcare providers can use Laryngeal Tube during spontaneous or controlled ventilation.

Oropharyngeal Airway

An oropharyngeal airway or oral airway (OPA) is an airway adjunct used to maintain or open the patient's airway by stopping the tongue from covering the epiglottis. In this position, the tongue may prevent an individual from breathing.


Also known as the esophageal tracheal airway or esophageal tracheal double-lumen airway, the combitube is a blind insertion airway device (BIAD) used in the pre-hospital and emergency setting. Combitube is designed to provide an airway to facilitate the mechanical ventilation of a patient in respiratory distress.


Also called cricothyroidotomy, Cricothyrotomy is a procedure where healthcare providers place a tube through an incision in the cricothyroid membrane to establish an airway for ventilation.

Frequently Asked Questions

Is BLS and CPR the same thing?

Both CPR and BLS training typically requires keeping the victim's airway open, promoting blood circulation. However, the main difference between BLS and CPR is that BLS also includes lifesaving skills and techniques that are necessary for a medical or hospital setting, which is why health care providers often take this course. 

What is the difference between adult and pediatric CPR?

With an infant, the rescuer uses his mouth to make a seal over the infant's mouth and nose. In performing chest compressions, the rescuer uses only one hand for a child and breathes more gently. As for an infant, the rescuer only uses two fingers.

How do you provide high-quality compressions on a child during CPR?

To give high-quality compressions, push the chest to compress about 1/3 to 1/2 the depth of the child's chest at a rate of 100-120 compressions per minute. Let the chest rise completely each time. These compressions should be hard and fast with no pausing.

How long should a pulse check last?

The American Heart Association recommends checking the pulse for about 10 seconds. The ratio of time spent performing compressions to the total duration of CPR is 80% or higher, as these correlate with increased ROSC and survival to hospital discharge.