Complete CPR Technique Guide for Durham: Depth, Rate & Best Practices

CPR technique matters because chest compressions only help when they are deep enough, fast enough, and steady enough to move blood. Most people remember the idea of pushing on the chest. The harder part is knowing where to place your hands, how far to press, how fast to go, when breaths matter, and what to do when fatigue or an AED interrupts the rhythm. Those details decide whether CPR is only motion or a real attempt to keep blood reaching the brain.

Technique details matter because a Durham rescuer may be kneeling on a gym floor, carpeted office, clinic hallway, or living-room rug. Depth, rate, recoil, and switching rescuers are not trivia; they are what keep compressions useful. That could be a Duke clinic hallway, Durham Public Schools gym, RTP office, or living room where the rescuer has to make compressions count.

How to Perform CPR on Adults

Before starting compressions, confirm the scene is safe, then check responsiveness: tap the person’s shoulders firmly and call out to them. If they don’t respond, check for breathing, look for chest rise and listen for normal breath sounds for no more than ten seconds. Agonal breathing (gasping, snoring, or gurgling sounds) is not normal breathing. If the person is unresponsive and not breathing normally, start CPR.

Call 911 before beginning, or direct someone specific to call while you start compressions. If you’re alone with no phone, shout for help, then begin compressions.

Positioning: place the person flat on their back on a firm surface. Kneel beside them at the level of their chest. Place the heel of one hand on the center of the chest, directly on the lower half of the breastbone (sternum). Place your second hand on top of the first and interlace your fingers, keeping them off the chest. Lock your elbows and position your shoulders directly above your hands. This geometry lets your body weight do most of the work rather than your arm muscles alone.

Compressions: push down hard and fast, then allow the chest to fully recoil before the next compression. The compression-to-recoil ratio should be roughly 50/50, equal time compressing and releasing. Don’t lean on the chest between compressions; full recoil allows the heart to refill with blood.

CPR Compression Rate: How Fast Should You Go?

The AHA recommends a compression rate of 100 to 120 compressions per minute for adults, children, and infants. Below 100 is too slow to maintain adequate blood flow. Above 120 per minute, depth often suffers because there is not enough time to press fully and let the chest rise before the next compression.

100 to 120 beats per minute is slightly faster than most people expect. Songs often used as pacing guides include “Stayin’ Alive” by the Bee Gees and “Another One Bites the Dust” by Queen, both run at approximately 100 beats per minute. In training, you’ll also hear “push hard, push fast” as a rhythmic cue. Whatever mental metronome you use, the target range is the same.

Counting compressions aloud or using a mental count while performing them helps maintain pace and track cycles. After 30 compressions in CPR with rescue breaths, give 2 rescue breaths, then return to compressions. In hands-only CPR, you simply continue compressions without stopping for breaths.

CPR Compression Depth for Adults

For adults, the AHA recommends compressions of at least 2 inches (5 cm) deep, but no more than 2.4 inches (6 cm). The “at least 2 inches” standard reflects research showing that shallower compressions generate insufficient blood flow. The 2.4-inch upper limit reflects evidence that compressions beyond that depth can cause injury without improving outcomes.

Two inches is deeper than most untrained bystanders push. When people compress at what feels like a firm push, they’re typically reaching only 1 to 1.5 inches, not enough. The compression that reaches 2 inches feels forceful and may feel uncomfortable to deliver. This is one reason hands-on training matters: until you’ve pushed a mannequin to the correct depth and felt what that takes, the verbal instruction doesn’t fully translate.

Ribs can fracture during proper adult CPR, particularly in older adults. A rib injury can happen even when compressions are being done correctly, because meaningful blood flow requires real force. Continue CPR if you feel or hear ribs crack.

CPR Compression Depth for Children

For children aged one to puberty, the AHA recommends compressions approximately 2 inches deep (5 cm), or about one-third of the chest diameter, whichever is less. The anatomical difference from adults is that children’s chests are proportionally smaller, so the fraction-of-chest-diameter rule prevents over-compression even as the absolute depth is similar to the adult standard.

Hand positioning for children depends on the child’s size. For most school-age children, one or two hands placed on the lower half of the breastbone work effectively. For smaller children, a single hand may be sufficient. The principle is the same: heel of the hand on the lower sternum, compress to appropriate depth, allow full recoil.

The compression rate for children is the same as for adults: 100 to 120 per minute. If you are alone and no one has called 911, give 5 cycles of CPR, about 2 minutes, before stopping to call. Pediatric arrests are more often respiratory in origin than adult sudden cardiac arrests, so that brief period of CPR before the call can matter.

CPR Compression Depth for Infants

For infants under one year old, the recommended compression depth is approximately 1.5 inches (4 cm), or about one-third of the chest diameter. The technique also differs from older ages: use two fingers (typically the middle and ring fingers) placed on the center of the infant’s chest, just below the nipple line. For two-rescuer CPR on an infant, the two-thumb-encircling-hands technique, where both thumbs are placed on the sternum while the hands wrap around the torso, generates better blood flow than the two-finger method and is used when a second rescuer is available.

The rate for infant CPR remains 100 to 120 compressions per minute. The compression-to-breath ratio is 30:2 for a single rescuer and 15:2 when two trained rescuers are present. Infant CPR requires gentle but firm compressions. The chest is small and fragile, but insufficient depth is still the more common error.

When Rescue Breaths Matter in CPR

For adults who collapse suddenly from suspected cardiac arrest, hands-only CPR, continuous compressions without rescue breaths, is as effective as CPR with rescue breaths in the first several minutes. The blood circulating at the time of collapse still contains enough oxygen to sustain the brain briefly. The AHA endorses hands-only CPR for untrained bystanders responding to adult cardiac arrest because it removes the barrier of mouth-to-mouth contact and keeps the focus on immediate compressions.

Rescue breaths become more important in specific circumstances. For children and infants, most cardiac arrests follow respiratory failure rather than sudden electrical malfunction, oxygen depletion is often the underlying cause. In these cases, rescue breaths are part of the standard protocol from the start. For drowning victims of any age, oxygen depletion is the cause of arrest, and rescue breaths are recommended immediately. For adults who have been in arrest for several minutes without CPR, ventilations become more important as oxygen reserves deplete.

When rescue breaths are part of the protocol, tilt the head back, lift the chin, pinch the nose closed, and give a breath over one second. Give enough air to produce visible chest rise, but not more. Excessive ventilation is a common error that increases chest pressure and reduces blood flow from compressions.

Common CPR Mistakes to Avoid

The most common CPR error is shallow compressions. The needed depth feels more forceful than most people expect, especially during the first class practice. If you are unsure whether you are pressing deep enough on an adult, push harder. Compressions that feel uncomfortable to deliver are far better than shallow ones that barely move blood.

Speed is the next common problem. Below 100 compressions per minute, blood flow drops below the level needed to support the brain. If you are counting slowly, pick up the pace. The rhythm should feel urgent without becoming frantic.

Incomplete chest recoil. Leaning on the chest between compressions, even slightly, prevents the heart from refilling with blood between beats. Allow the chest to fully rise after each compression before the next one begins. This is harder to maintain as fatigue sets in, which is why rotation between rescuers matters in prolonged CPR.

Interrupting compressions too often or for too long. Every pause in compressions reduces cerebral perfusion. Keep interruptions to less than ten seconds whenever possible. If using an AED, minimize the gap between the last compression and the shock delivery.

Excessive ventilation. Over-ventilating increases chest pressure and reduces the effectiveness of compressions. If giving rescue breaths, keep each breath to one second and avoid the instinct to breathe in more air than needed to produce visible chest rise.

When to Stop CPR

Continue CPR until one of the following occurs: the person shows obvious signs of life (spontaneous breathing, movement, opening eyes), a trained rescuer or EMS personnel take over, an AED is attached and provides a prompt, or you become physically unable to continue due to exhaustion.

Stopping CPR to check for a pulse is generally discouraged for lay rescuers because it interrupts compressions and the check is unreliable. A person in cardiac arrest may have a faint pulse that an untrained rescuer cannot detect. Unless the person begins breathing normally and moving, assume arrest continues and keep going.

One situation requires a brief interruption: when an AED becomes available. Stop compressions to apply the pads, allow the AED to analyze the rhythm, and deliver the shock if advised. Immediately resume compressions after the shock, don’t wait to see if the person wakes up. Resume CPR for the full two-minute cycle and let the AED advise the next rhythm check.