Neonatal Chest Compressions: The 3:1 Ratio Explained

Neonatal resuscitation compresses at 3:1, not the 30:2 most clinicians know from adult BLS. That difference isn't arbitrary: it reflects a different underlying problem. Adult cardiac arrest is usually a primary cardiac event; neonatal compromise is almost always a respiratory one that secondarily drops heart rate. The ratio is built to keep ventilation dominant even while compressions are running.

When compressions start

Chest compressions begin when heart rate stays below 60 bpm despite 30 seconds of ventilation that is visibly moving the chest, ideally through an ETT or laryngeal mask, since effective compressions depend on effective ventilation already being in place. Starting compressions before ventilation is actually working just circulates poorly oxygenated blood.

Technique

Hand position: two thumbs, side by side or overlapping on smaller chests, on the lower third of the sternum, just below an imaginary line between the nipples. Hands encircle the torso, fingers supporting the back.
Why two-thumb over two-finger: the encircling two-thumb technique generates higher, more consistent peak pressure and causes less rescuer fatigue over a prolonged resuscitation. NRP prefers it whenever team size allows the encircling position.
Depth: approximately one-third of the anterior-posterior diameter of the chest, allowing full chest recoil between compressions.
Avoid the xiphoid. Compressing over it risks liver laceration.

The 3:1 rhythm, in practice

Three compressions and one breath make one cycle, delivered at a combined rate that works out to 90 compressions and 30 breaths per minute, 120 events per minute total. Most teams count it out loud as "one-and-two-and-three-and-breathe," with the compressor and the ventilator staying on the same spoken cadence rather than each tracking their own count separately.

FiO₂ goes to 100% at this point Once compressions start, increase FiO₂ to 100% for the duration. This is one of the few points in the algorithm where oxygen titration to preductal SpO₂ targets is set aside in favor of maximizing delivery during a critical, low-flow state.

Reassessment

Check heart rate after 60 seconds of coordinated compressions and ventilation, not sooner. Interrupting compressions every 10 or 15 seconds to feel for a pulse or recheck a monitor breaks the rhythm and reduces effective coronary perfusion; the algorithm is built around a full minute of uninterrupted work before reassessing.

If heart rate remains below 60 bpm at that reassessment, this is the point where epinephrine is indicated, and where the team should already be moving to secure UVC or IO access if it isn't in place.

Common mistakes

Compressing too shallow because the provider is worried about rib fracture, a real complication, but under-compression is a more common failure than over-compression in practice.
Losing the 3:1 count under stress and drifting toward a faster, shallower rhythm that doesn't match either compressions or breaths to target.
Checking heart rate too frequently, which interrupts perfusion without changing the plan.

Studying for NRP or board exams?

Practice the full compression-to-epinephrine sequence.

PediaSuite's clinical case simulator scores your timing on compressions, reassessment, and medication, not just whether you knew the ratio.

See the NRP module ($29)