The statements that correctly describe proper delivery of two ventilations to a child or infant during CPR are those specifying: open the airway with head-tilt/chin-lift (avoiding hyperextension in infants), deliver each breath over about 1 second, give just enough volume to make the chest visibly rise, use a barrier device or bag-mask when available, and allow the chest to deflate between breaths. For a lone rescuer without a barrier device, current guidance also permits compression-only CPR if unwilling or unable to ventilate.
The physiology that dictates every ventilation rule
Every procedural rule for pediatric ventilation traces back to one mechanical fact: a child's functional residual capacity is small relative to oxygen consumption. An infant's oxygen consumption per kilogram is roughly double an adult's, and the chest wall is highly compliant. That combination means oxygen desaturation during apnea is fast and lung overdistension is easy. The rescuer is working inside a narrow window between too little and too much.
The 1-second inspiratory time is a compromise between two failure modes. Faster delivery risks inadequate tidal volume and higher peak airway pressures. Slower delivery wastes time in a low-flow state and, in trained two-rescuer settings, delays the next compression cycle. One second is long enough for gas to distribute through small airways yet short enough to keep interruptions minimal.
Visible chest rise is the only bedside confirmation most rescuers have that gas actually entered the lungs. It simultaneously rules out two failures: an obstructed or poorly sealed airway (no rise) and overinflation (excessive, abrupt rise). Volume is judged by effect rather than by number because pediatric tidal volume scales with body size, and rescuers cannot estimate milliliters reliably in the field. This is why the guidance says "just enough to make the chest rise" rather than naming a volume.
Excessive volume matters more in children than adults. Overdistension raises intrathoracic pressure, which impedes venous return to a heart that may already be outputting poorly. It also raises gastric insufflation risk, and a distended stomach pushes the diaphragm upward, further reducing the volume the lungs can accept on the next breath. Excessive ventilation during CPR is a recognized cause of worsened hemodynamics. The proper-procedure statements are, at bottom, a set of rules for staying inside the safe window.
Quantified context: ratios, timing, and the interruption budget
Pediatric resuscitation guidance from major societies gives compression-to-ventilation ratios of 30:2 for a lone rescuer and 15:2 for two trained rescuers, with the two-rescuer ratio applying from infancy through puberty. The logic is arithmetic. At 15:2 with compressions at 100 to 120 per minute, ventilations consume a smaller fraction of each minute, so the rescuer delivers more compressions per cycle while still oxygenating.
| Element | Infant | Child | Adult reference point |
|---|---|---|---|
| Compression:ventilation (1 rescuer) | 30:2 | 30:2 | 30:2 |
| Compression:ventilation (2 rescuers) | 15:2 | 15:2 | 30:2 |
| Breath duration | About 1 second | About 1 second | About 1 second |
| Head position | Neutral, sniffing position | Head-tilt/chin-lift | Head-tilt/chin-lift |
| Ventilation route | Mouth-to-mouth-and-nose or mouth-to-mouth | Mouth-to-mouth | Mouth-to-mouth |
| Primary arrest cause | Asphyxia | Asphyxia | Often cardiac |
| Advanced airway | 1 breath every 2–3 seconds | 1 breath every 2–3 seconds | 1 breath every 6 seconds |
The adult column explains why pediatric rules differ at all. Pediatric arrest is disproportionately asphyxial, so ventilation is not optional physiology: restoring oxygen delivery is part of reversing the arrest. Adult arrest is more often primary cardiac, which is why adult guidance tolerates compression-only CPR far more readily.
Time matters quantitatively. High-quality CPR aims for compressions delivered at 100 to 120 per minute with minimal interruption. Pauses for ventilations should be short. When an advanced airway is in place, the ratio model changes to continuous compressions with one breath every 2 to 3 seconds, which eliminates the pause entirely. That threshold matters because it is the point where the question shifts from "how do I time two breaths" to "how do I ventilate without stopping compressions."
Where the procedure changes: infants, obstructive causes, and rescuer limits
Infant anatomy modifies the airway step more than any other. An infant's head is proportionally large and the neck is short, so tilting the head back fully can flex the neck and occlude the airway. The proper maneuver is a neutral or slightly sniffing position. Rescuers should also know that the airway seal for an infant is formed by the rescuer's mouth covering both the infant's mouth and nose, or by a properly sized bag-mask.
Obstructive arrest changes the priority order. If the arrest followed choking, the rescuer should clear the obstruction per standard foreign-body airway protocols before relying on ventilations to succeed. A breath that fails to produce chest rise despite a good seal and a repositioned airway should be treated as possible obstruction, not repeated blindly.
Rescuer skill and equipment define the fallback. Without a barrier device, a lone rescuer faces a real choice, and current guidance permits compression-only CPR if the rescuer is unwilling or unable to provide rescue breaths; compressions still circulate whatever oxygen remains. With a bag-mask device, the two-person technique (one rescuer seals with both hands, the other squeezes) produces more reliable chest rise than a one-handed seal. The counterintuitive professional caveat is that a rescuer who is unsure of technique may do more good with uninterrupted compressions and rapid defibrillation than with fumbled ventilations, because each hesitation costs perfusion.
Misconceptions that persist in thin explainers
The most common wrong statement is that breaths to a child or infant should be delivered forcefully, as in a deep adult breath. The correct framing is volume to the chest-rise threshold, and no more. A second frequent error is describing the infant head position identically to the adult: full head-tilt is wrong for infants.
A third misconception is that the two initial breaths must be interposed somewhere other than the standard cycle. Two ventilations are delivered after the first set of 30 compressions in the standard sequence, not as a standalone ritual at some arbitrary moment. A fourth is the idea that a pulse check and two breaths substitute for the cycle; the two breaths belong inside the compression-ventilation rhythm, not in place of it.
Red flag: repeating failed breaths without repositioning the airway or checking the seal. Red flag: delivering rapid, forceful breaths that make the chest rise abruptly or the abdomen distend. Red flag: pausing compressions for long stretches to "get the breaths right." Red flag: hyperextending an infant's neck during the head-tilt step. Red flag: assuming a single rescuer must ventilate even without a barrier device.
Practical actions: the sequence in order
Reconcile the thresholds this way: the 30:2 and 15:2 ratios govern when no advanced airway is present; once an advanced airway is placed, the ratio disappears and one breath every 2 to 3 seconds applies. The 1-second breath duration and the chest-rise endpoint apply in every case. These thresholds do not conflict; they mark different stages of the resuscitation.
Position the child supine and open the airway with head-tilt/chin-lift, using a neutral position for an infant. Form a seal with a barrier device, bag-mask (two-person preferred), or directly for an infant, covering mouth and nose. Deliver one breath over about 1 second and watch for visible chest rise. Deliver a second breath the same way, allowing full deflation between breaths. If chest rise is absent, reposition the airway and reattempt once before treating as possible obstruction. Resume compressions immediately, maintaining the appropriate compression-to-ventilation ratio.
The time-course table below shows how the procedural moments map onto the larger resuscitation sequence.
| Stage | Typical timing | What the rescuer does |
|---|---|---|
| Recognition and activation | Immediate | Confirm unresponsiveness, call for help and an AED |
| First compression cycle | 0–20 seconds | 30 compressions at 100–120 per minute |
| First two ventilations | After first cycle | Two 1-second breaths with visible chest rise |
| Subsequent cycles | Ongoing | Repeat ratio (30:2 or 15:2) |
| AED arrival | As soon as available | Apply and follow prompts with minimal interruption |
| Advanced airway placement | When trained personnel arrive | Switch to continuous compressions with 1 breath every 2–3 seconds |
Practical thresholds to hold in mind: compressions 100 to 120 per minute, depth about one-third of chest diameter, full recoil between compressions, and short pauses for ventilations. If any step cannot be performed safely, prioritize uninterrupted compressions.
Limitations: what the statements cannot guarantee
Chest rise is a proxy, not a measurement. A rescuer can achieve visible rise with gas that partially enters the stomach, and can fail to see rise despite adequate ventilation if the chest wall is stiff or the rescuer's observation angle is poor. This is why the proper-procedure statements describe observable actions rather than outcomes. Similarly, scene conditions, rescuer training, and equipment availability legitimately alter which correct statement applies at a given moment. No list of proper-procedure statements substitutes for hands-on training with a manikin, where seal, timing, and volume judgment are actually rehearsed.
This article is general educational information about CPR technique, not a diagnosis, treatment plan, or substitute for certified training. It does not promise any outcome from performing or omitting any step. For emergencies, call local emergency services immediately; for CPR certification, consult a qualified local instructor or your national resuscitation council.