When giving chest compressions to an infant you should use two fingers (the two-finger technique) placed on the lower half of the breastbone, or the two-thumb encircling-hands technique if you have been trained and have a second rescuer. Both deliver compressions at a rate of 100 to 120 per minute, to a depth of about 1.5 inches (4 cm), allowing full chest recoil between pushes. For a lone rescuer, two fingers are the practical default; for two trained rescuers, thumbs are preferred.
The mechanics of an infant chest compression
An infant's chest is not a scaled-down adult chest. The rib cage is cartilaginous and compliant, the heart sits relatively higher, and the lungs are small and easily over-ventilated. Compressions work by two mechanisms acting together: direct cardiac squeeze and a thoracic pump effect, where rhythmic pressure changes intrathoracic pressure and moves blood. In infants, the compliant chest makes the thoracic pump relatively more influential, which is one reason technique and hand placement matter so much.
The two-finger technique uses the index and middle fingers of one hand, with the other hand supporting the back or head. The two-thumb encircling-hands technique wraps both hands around the chest, with both thumbs pressing on the lower sternum. Thumbs are shorter and stiffer than fingers, so they transmit force more consistently and fatigue more slowly. That mechanical advantage is why guidelines favor thumbs when two trained rescuers are present.
Depth targets exist because too shallow a compression fails to generate forward flow, and too deep a compression risks injury to a small, soft chest. The target of about 1.5 inches (4 cm) reflects roughly one-third of the anterior-posterior chest diameter in a typical infant. Allowing full recoil lets the chest refill and the heart refill between beats. Leaning on the chest between compressions quietly defeats the whole cycle.
Quantified context: rate, ratio, and depth
The numbers are tightly specified because they are the difference between effective and ineffective resuscitation. Compression rate is 100 to 120 per minute for infants, the same target as adults and children. The compression-to-ventilation ratio for a lone rescuer is 30:2; for two rescuers it is 15:2, because infants desaturate quickly and need more frequent breaths relative to compressions.
Depth is about 1.5 inches (4 cm), or approximately one-third of the chest's front-to-back dimension. These figures come from major resuscitation consensus guidelines and are stable recommendations rather than dated measurements. High-quality CPR also means minimizing interruptions: pauses should be kept under about 10 seconds, and rescuers should switch roles roughly every 2 minutes to limit fatigue-driven decay in depth and rate.
The 15:2 ratio for two rescuers is the counterintuitive detail. Intuition says more compressions mean more circulation, so why ventilate more often in infants? Because an infant's oxygen reserve is small and the cause of arrest is often respiratory. More breaths per cycle correct the underlying problem faster, and the two-rescuer setup makes the extra breaths feasible without long pauses.
Technique comparison
| Technique | Rescuers | Hand position | Main advantage | Main drawback |
|---|---|---|---|---|
| Two-finger | One or two | Index and middle fingers, lower sternum | Simple, fast to start solo | Shallower depth, faster fatigue |
| Two-thumb encircling-hands | Two (preferred) | Both thumbs, lower sternum | Consistent depth, less fatigue | Requires a second rescuer and training |
| One-hand (older child style) | Not for infants | Whole hand | — | Inappropriate for infant chest size |
| Adult two-hand | Never for infants | Both hands | — | Excessive force, injury risk |
The table clarifies a common confusion: the one-hand and two-hand techniques belong to children and adults, not infants. Using adult force on an infant chest can cause rib fractures, liver injury, and ineffective compressions.
Timeline of an infant resuscitation
| Time from collapse | Action | Target |
|---|---|---|
| 0–10 seconds | Confirm unresponsiveness, check breathing | Recognize arrest |
| 10–30 seconds | Start compressions, call for help | Begin high-quality CPR |
| First 2 minutes | 30:2 solo or 15:2 with two rescuers | Establish circulation |
| Every ~2 minutes | Switch compressor roles | Limit fatigue decay |
| After AED arrival | Apply pediatric pads or attenuator | Early defibrillation if indicated |
| Until EMS or recovery | Continue cycles | Sustain perfusion |
The timeline matters because the first minutes set the trajectory. Bystander CPR that starts within the first minute or two substantially improves survival odds compared with delayed initiation. Each minute of delay without compressions reduces the chance of a good outcome.
Edge cases and special situations
Newborns in the delivery room are a distinct category. For a newborn immediately after birth, the compression-to-ventilation ratio is 3:1, reflecting the dominance of respiratory causes and the very high breathing rate needed. This is different from the infant CPR ratio outside the delivery room, and mixing them up is a real error.
Infants with a tracheostomy, congenital heart disease, or recent chest surgery need individualized guidance from their care team. A rescuer should not hesitate to start compressions because of a medical history; the default technique still applies until professional help arrives. Suspected foreign-body airway obstruction follows its own sequence, with back blows and chest thrusts before compressions if the infant is conscious.
The professional caveat: guideline numbers are population targets, not calibration for one baby. A very small premature infant and a large 11-month-old differ enough that "one-third of chest depth" and "about 1.5 inches" can diverge. Rescuers should aim for the depth that produces visible chest movement without excessive force, and follow dispatcher guidance when available.
Common misconceptions
The most persistent misconception is that two fingers are always the "correct" infant technique. Guidelines actually favor two thumbs when two trained rescuers are available, because thumb compressions achieve more consistent depth. Two fingers are the right call for a lone rescuer who needs a free hand to manage the airway and call for help.
Another misconception is that compressions alone are enough. For infants, rescue breaths matter because respiratory arrest often precedes cardiac arrest. Compression-only CPR is better than nothing, but the 30:2 or 15:2 cycles with breaths are the recommended standard when a rescuer is trained and willing.
A third error is pressing too fast and too shallow. Rate and depth trade off under fatigue: rescuers who rush often lose depth. The fix is deliberate recoil and role switching, not speed. A fourth is placing fingers too high on the sternum, which reduces effectiveness and raises injury risk; the lower half of the breastbone is the target. Finally, some rescuers lean between compressions, which prevents refilling and quietly reduces output.
Practical actions and red flags
Start by confirming the infant is unresponsive and not breathing normally, then call emergency services or direct someone to call. Begin compressions immediately at 100 to 120 per minute. Use two fingers if you are alone; switch to two thumbs if a trained second rescuer arrives. Give 30 compressions to 2 breaths alone, or 15 to 2 with two rescuers. Push about 1.5 inches (4 cm), let the chest come fully back up, and minimize pauses. Use an AED as soon as one is available, with pediatric pads or a dose attenuator when provided. Continue until EMS takes over or the infant shows signs of life.
Red flags that demand immediate professional help and continued CPR:
The infant is unresponsive, limp, or not breathing normally. Breathing is gasping, irregular, or absent. Skin is pale, bluish, or mottled. Compressions are not producing chest movement. You are exhausted, alone, or unsure of technique; call for help early. The infant has a known heart condition or tracheostomy and deteriorates.
Limitations and what the evidence cannot settle
Technique recommendations rest on consensus guidelines and physiological reasoning more than on large randomized trials in infants, which are ethically and practically hard to run. The two-thumb preference is supported by studies showing better depth and blood pressure, but the size of the survival benefit is uncertain. Depth targets are approximations, not precise calibration for every body size. The best a rescuer can do is follow the trained technique, aim for visible chest movement, and keep interruptions short. Training and refresher courses remain the strongest predictor of correct technique under stress.
This article is general educational information about CPR technique, not a diagnosis or a treatment plan for any specific infant. It does not replace hands-on training or the guidance of a qualified local clinician or emergency dispatcher. If an infant is unresponsive, not breathing, or in immediate danger, call your local emergency number and follow dispatcher instructions while starting CPR.