How Many Compressions Are Needed in CPR
Short answer
CPR requires performing 30 chest compressions followed by 2 rescue breaths in a continuous cycle until emergency help arrives or the person recovers. Compressions should be delivered at a rate of 100 to 120 compressions per minute and with enough depth to keep blood circulating to vital organs effectively.
What is CPR and why are chest compressions crucial?
Cardiopulmonary resuscitation (CPR) is an emergency procedure used when a person's heart stops beating, known as cardiac arrest. Its main goal is to manually pump blood through the body by pressing on the chest, keeping oxygen-rich blood flowing to the brain and other vital organs. Chest compressions physically squeeze the heart between the sternum and spine to push blood out. Without compressions, blood does not circulate, leading to brain damage and death within minutes. Rescue breaths deliver oxygen to the lungs, but chest compressions maintain circulation, which is critical for survival. Knowing the correct number and rhythm of compressions ensures you provide life-saving care effectively.
For example, if you see someone collapse and they are unresponsive and not breathing normally, the first step is to call 911. Then immediately start chest compressions by placing your hands in the center of their chest and pushing straight down firmly and quickly to simulate the heart pumping blood.
How many chest compressions should you perform before giving breaths?
CPR guidelines recommend performing 30 chest compressions followed by 2 rescue breaths—this is called the 30:2 compression-to-breath ratio. This sequence balances maintaining blood flow with oxygen delivery. Performing 30 compressions consecutively minimizes interruptions in blood flow, while the 2 breaths provide oxygen to the lungs. Interrupting compressions too frequently reduces the heart’s ability to pump blood effectively.
To do this correctly:
- Place the heel of one hand on the center of the person’s chest (on the lower half of the breastbone).
- Place your other hand on top and interlock your fingers.
- Keep your elbows straight and shoulders directly above your hands.
- Press down hard and fast, about 2 inches deep for adults, allowing the chest to fully rise back up between compressions.
- Perform compressions at a steady pace until you reach 30.
- Then give 2 rescue breaths (explained later) and immediately resume compressions.
Repeat this cycle continuously until emergency responders arrive or the person begins to show signs of life.
How fast should CPR compressions be performed?
Chest compressions should be done at a rate of 100 to 120 compressions per minute. This means about two compressions every second, maintaining a steady rhythm. Compressions that are too slow don’t circulate enough blood, while compressions that are too fast may be too shallow or ineffective.
To maintain the correct pace, count aloud using numbers like “one, two, three, four...” at a steady rhythm, aiming for about two counts per second. Another practical method is to think of the beat of a song with a tempo of about 100 to 120 beats per minute, such as “Stayin’ Alive” by the Bee Gees.
Here is a simple timing guide for compressions:
| Time (seconds) | Number of Compressions (approximate) |
|---|---|
| 15 | 25 |
| 20 | 33 |
| 30 | 50 |
For example, if you perform compressions for 30 seconds, aim to complete about 50 compressions to stay within the recommended speed.
What is the correct ratio of compressions to breaths in CPR?
The standard adult CPR ratio is 30 compressions followed by 2 rescue breaths. After completing 30 compressions, pause just long enough to give the 2 breaths, then immediately return to compressions. This pattern keeps interruptions in chest compressions brief, maintaining circulation while providing oxygen.
When giving rescue breaths:
- Tilt the person’s head back by placing one hand on their forehead and two fingers under the chin to lift it.
- Pinch the person’s nose closed.
- Take a normal breath, cover their mouth with yours forming a tight seal, and blow air into their mouth for about 1 second.
- Watch for the chest to rise; if the chest doesn’t rise, reposition the head and try a second breath.
If you cannot or do not want to give breaths, performing continuous chest compressions alone (hands-only CPR) is still beneficial and recommended for untrained rescuers.
Why do CPR guidelines recommend 30 compressions before breaths?
The 30:2 ratio was chosen to provide a balance between circulating blood and giving oxygen. Chest compressions keep blood flowing to vital organs, while rescue breaths supply oxygen. Performing 30 compressions before pausing for breaths minimizes interruptions, which is important because stopping compressions reduces blood flow to the brain and heart.
In practice:
- You deliver 30 compressions in about 18 seconds without stopping.
- Pause briefly to give 2 breaths, which takes about 4 seconds total.
- Quickly resume compressions.
This method ensures the heart is pumped continuously most of the time, with brief interruptions to provide oxygen.
What steps should you take before starting CPR compressions?
Before starting compressions, follow these important steps in order:
- Check the scene for safety: Ensure you and the victim are not at risk from traffic, fire, or other hazards.
- Check the person’s responsiveness: Tap the person’s shoulder and shout, “Are you okay?”
- Check breathing: Look for normal breathing for no more than 10 seconds. Gasping or irregular breathing is not normal.
- Call for emergency help: If unresponsive and not breathing normally, call 911 yourself or ask someone nearby to call.
- Get an AED if available: Automated external defibrillators can deliver a shock to restart the heart and improve survival.
- Place the person on their back on a firm surface: This helps chest compressions be effective. If they are on a soft surface, move them to the floor carefully.
- Begin chest compressions immediately: Place your hands on the center of the chest and start pressing firmly.
Following these steps ensures you provide prompt and proper care.
How does CPR compression technique differ for children and infants?
CPR technique varies based on age and size to avoid injury and improve effectiveness.
| Age Group | Compression Depth | Compression Method | Compressions to Breaths Ratio |
|---|---|---|---|
| Adults | At least 2 inches (5 cm) | Two hands on center chest | 30 compressions : 2 breaths |
| Children | About 2 inches or 1/3 chest depth | One or two hands depending on size | 30:2 (one rescuer), 15:2 (two rescuers) |
| Infants (<1 year) | About 1.5 inches (4 cm) | Two fingers on center chest | 30:2 (one rescuer), 15:2 (two rescuers) |
For infants, use two fingers instead of full hands to avoid injury. When two rescuers are present for children and infants, the ratio changes to 15 compressions followed by 2 breaths to improve oxygen delivery. Always allow the chest to fully recoil between compressions.
What related terms do people often confuse with CPR compressions?
Understanding related terms helps avoid confusion during emergency response:
- Chest Compressions: The physical pressing on the chest that pumps blood out of the heart. This is the main action in CPR.
- Rescue Breaths: Breaths given mouth-to-mouth to supply oxygen to the lungs.
- CPR: The full procedure combining chest compressions and rescue breaths.
- Heart Massage: An older name sometimes used for chest compressions but not commonly used today.
- Automated External Defibrillator (AED): A device that analyzes heart rhythm and delivers an electric shock to restart the heart, used alongside CPR.
Some people may mistakenly think CPR means only giving breaths or only compressions. Both chest compressions and breaths are important unless performing hands-only CPR.
Frequently asked questions
How deep should chest compressions be during CPR?
For adults, compress about 2 inches deep; for children, about 2 inches or one-third the chest depth; for infants, about 1.5 inches. Proper depth is key to effective circulation.
Can CPR be done without giving rescue breaths?
Yes. Hands-only CPR (continuous chest compressions without breaths) is recommended for untrained rescuers or if you are unwilling or unable to give breaths. This still helps circulate oxygenated blood.
How can I tell if my rescue breaths are effective?
Effective breaths cause the chest to visibly rise. Give each breath slowly over about 1 second while watching the chest. If the chest doesn’t rise, reposition the head and try again.
What if I get tired performing CPR compressions?
If another trained person is available, switch every 2 minutes to maintain high-quality compressions. If alone, continue as best you can until help arrives or the person recovers.
When should I stop performing CPR?
Stop when emergency medical personnel take over, the person starts breathing normally, you are physically unable to continue, or a trained professional tells you to stop.
How do I maintain the correct compression rate?
Counting aloud at a steady pace or thinking of the beat of a song with about 100 to 120 beats per minute can help keep your compressions on target.