High Performance CPR (2025)

In this lesson, we'll cover one of the most important concepts in resuscitation—something called chest compression fraction, otherwise known as CCF.

What is CCF exactly? It's the percentage of time during a cardiac arrest that chest compressions are actually happening. And here’s what really matters: the more time you spend compressing the chest properly, the better the patient’s chances of survival.

So what causes low CCF anyway? Interruptions in compressions—particularly during rhythm analysis and defibrillation.

When we’re providing ventilations, we have specific time requirements for giving those effective breaths if we don’t have an advanced airway in place. That is one second per breath, and then two seconds between those. It’s important to make sure that breaths are effective, but we must minimize the delay in chest compressions. Although an advanced airway is best practice in an arrest for protecting the airway, inserting one may not always be an option, so we look for other places that we can increase the time with compressions being applied to the chest.

The other action we perform that may affect the CCF is rhythm checks. But how can we possibly check a rhythm without delaying cardiac compressions? The goal is to complete rhythm analysis and deliver a shock—if needed—in 10 seconds or less. In order to do this well, the whole team needs to anticipate what's coming next, stay coordinated, and execute specific strategies before, during, and after the pulse check.

The following is a breakdown of the latest ECC Guidelines for working in concert with a resuscitation or CODE team.

Precharging the Defibrillator

Precharging the defibrillator is one of those simple habits that makes a huge difference. It eliminates delays and keeps your pauses in compressions as brief as possible.

One example of how this can be accomplished is 15 seconds before you hit the 2-minute mark on CPR compressions, have the team member in charge of the defibrillator set its proper joule setting and then precharge. If ventricular fibrillation or pulseless ventricular tachycardia is identified during the rhythm analysis, you can deliver the shock immediately—thereby saving tons of time.

Pulse Check Timing & Technique

To optimize your pulse check routine and keep your CCF high, focus on these critical coordination strategies:

• Consistency Wins: Pick one person to check the pulse and keep them there for the entire code whenever possible. Using the same provider, same position, and same technique reduces hesitation and wasted movement. Fewer variables means faster, cleaner pauses.
• Locate the Site Early: Locate the femoral site before the pause. Don’t wait until compressions stop to start searching for the femoral artery. While compressions are ongoing, place two fingers in the groin crease—just below the ligament, about halfway between the hip bone and the pubic area. Use your fingertips (never your thumb, which has its own pulse). You’re not making a decision yet—you’re just finding your spot so you’re ready to go.
• Hold the Location: If allowed, consider marking the pulse location with an accurate medical marker. Once you’ve found the artery, stay there. Light contact is key—enough to keep your place, but not so much that you collapse the vessel. You’ll confirm during the pause, but you don’t want to search for that location every single time you cycle through.
• Set the Team Before the Check: As you approach the end of the compression cycle, the leader should cue the team so everyone is in their place. The compressor should be finishing strong, the monitor must be visible, the defibrillator charged if needed, and the pulse checker already in position.

Look at the whole picture, not just your fingers. Don’t rely on touch alone, as tactile feel can easily error in high-stress situations. Check the monitor, watch for patient movement, and pay close attention to capnography trends. A sudden rise in the ETCO2 on a monitor displaying an organized rhythm can support what you’re feeling—but none of it replaces a quick, decisive assessment. If you don't feel a pulse, get right back to compressions. We’ve got 10 seconds or less, and if a pulse isn’t clearly there, it just isn’t there.

Compressions are going to restart immediately. After a shock is delivered, go straight back to compressions with no hesitations. Never pause to check a pulse immediately following a shock; every unnecessary delay costs perfusion and pulse pressures.

Additionally, do not force the femoral site if it’s not working. Sometimes it can be a difficult location to access due to the physique of the patient, positioning, or environmental issues. If you can’t get a reliable answer quickly, switch to a site you can assess better. Finally, use better tools when they are available. If capnography, an arterial line, or ultrasound are available, utilize them—they provide highly accurate and reliable information. However, this should never come at the expense of extending or wasting time. The priority never changes: keep compressions going and keep interruptions minimal.

Compressor Positioning During Pauses

What your compressor does during a compression pause matters more than we realize. When compressions pause for any reason, the compressor should maintain their position, hovering directly over the chest in the right location.

Hovering serves two critical purposes: it doesn't interfere with the rhythm analysis, and it allows compressions to resume immediately—whether that's after a rhythm check, following the delivery of a shock, or after any other necessary pause.

Advanced Airways & Medication Delivery

Current guidelines and best practices state that we should start with a basic airway unless there's a clear and immediate reason to lead with an advanced airway. Whether you're using basic or advanced options, placing capnography or capnometry while using a bag-valve mask remains best practice.

The priorities of high-performance CPR must follow this specific order:

• High-quality compressions first
• Monitoring
• Defibrillation
• IV/IO access
• Medication administration

Once those steps are initiated, advanced airways like intubation or supraglottic devices can be considered. If defibrillation is initially delayed, be sure ventilations are performed after the first 30 compressions whenever possible.

Keep in mind that guidelines explicitly state compressions should not stop while placing an advanced airway. Once an advanced airway (such as an LMA, laryngeal tube, or i-gel) is in place, switch to continuous compressions with asynchronous ventilations at a rate of one breath every six seconds. When the patient is intubated, the 30:2 ratio is no longer used. Studies have shown that continuous compressions alone increase your CCF by over 10 percent.

For medication delivery, guidelines state to administer medications right after rhythm checks. This method naturally aligns with the algorithm and keeps medication timing perfectly on track. The sequence flows smoothly: compressions resume immediately after the rhythm check, the team identifies the correct medication, and the medications are administered. Following this process ensures that medications are delivered approximately every two minutes, or as needed, minimizing wasted time while maximizing accuracy and efficiency.