7.2 Compression-Ventilation Ratios

Ratios Without an Advanced Airway

Until a cuffed or uncuffed tracheal tube (or other advanced airway per protocol) is placed and confirmed, coordinate compressions and ventilations in cycles. The ratio depends on how many rescuers are performing CPR and the patient’s pediatric vs post-pubertal status.

Exam-critical ratio table

Why 15:2 for two-rescuer pediatric CPR? Children more often have respiratory causes of arrest; more frequent ventilation better matches that physiology when a second person can manage the airway without destroying compression quality. Single rescuers use 30:2 because leaving the chest too often for breaths creates excessive interruptions when only one person is available.

Delivering the breath portion

• Open the airway; use a mask that covers nose and mouth.
• Deliver each breath over about 1 second with just enough volume for visible chest rise.
• Avoid stacked, forceful breaths that cause gastric inflation.
• Resume compressions immediately after the second breath—do not reassess for a full set of vitals between every cycle.

Cycle timing and compressor switches

Perform about five cycles of 15:2 (two-rescuer) or the equivalent ~2-minute block before a planned rhythm/pulse check, aligning with defibrillator prompts when an AED/manual defibrillator is attached. Switch compressors during these planned pauses so quality stays high.

With an Advanced Airway: Continuous Compressions + Timed Breaths

Once an advanced airway is in place and position is confirmed (continuous waveform capnography is preferred when available):

1. Deliver continuous chest compressions at 100–120/min without pausing for each breath.
2. Give 1 breath every 2–3 seconds (about 20–30 breaths per minute)—use the higher end of that range for younger infants when protocol emphasizes age-appropriate rates within the 20–30 band.
3. Do not hyperventilate. Excessive rate is a common error after intubation.
4. Watch for chest rise and ETCO2 waveform; troubleshoot tube dislodgement, obstruction, pneumothorax, and equipment failure if ETCO2 is suddenly lost (Chapter 7.3 and airway chapters).

Asynchronous ventilation means the compressor does not stop while the airway provider ventilates. That design protects chest compression fraction. If the advanced airway attempt itself is prolonged, pause the attempt, resume bag-mask with 15:2 or 30:2 as appropriate, and retry with better preparation—do not sacrifice minutes of compressions for a difficult intubation.

Link to bag-mask before the tube

Effective bag-mask with correct ratios is not a "failure." Many pediatric arrests are successfully managed with high-quality BMV until ROSC or until a skilled operator places an advanced airway under controlled conditions.

Pulse Present, Breathing Inadequate: Rescue Breathing Rates

Not every critically ill child needs chest compressions. If a definite pulse is present (≥60/min with adequate perfusion signs) but respiratory effort is absent or inadequate:

• Deliver 1 breath every 2–3 seconds (20–30 breaths/min).
• Use oxygen and proper airway opening; reassess pulse and perfusion frequently.
• If heart rate remains <60/min with signs of poor perfusion despite adequate oxygenation and ventilation, start CPR (compressions) per the pediatric bradycardia with poor perfusion pathway—even if a pulse is still faintly palpable. This is a classic PALS decision point: bradycardia plus cardiopulmonary compromise is treated with CPR, not endless observation.

Do not confuse rescue breathing (pulse present) with CPR ratios (pulseless or HR <60 with poor perfusion despite support).

C-A-B Sequence and the ≤10-Second Pulse Check

For the unresponsive, non-breathing (or only gasping) child, healthcare providers follow a C-A-B emphasis for arrest care:

1. C — Circulation: Begin high-quality chest compressions promptly once arrest is recognized (start CPR within 10 seconds of recognition).
2. A — Airway: Open the airway for breaths.
3. B — Breathing: Deliver ventilations coordinated by ratio or continuous compressions once advanced airway is placed.

Pulse check rules for healthcare providers

• Check the pulse for no more than 10 seconds (brachial in infants; carotid or femoral in children, per training).
• If no definite pulse is felt in that window, start compressions—do not extend the search hoping for a maybe-pulse.
• Simultaneous scanning for breathing/gasping and a brief pulse check is appropriate; do not spend separate long intervals for each.

Lay rescuers are often taught to begin CPR based on unresponsiveness and abnormal breathing without a formal pulse check; PALS-level testing assumes the HCP pulse-check discipline above.

AED with Pediatric Attenuator — Early

Attach a monitor/defibrillator or AED as soon as it is available. For infants and children, use a pediatric dose attenuator and pediatric pads when available so delivered energy is appropriate. Key points:

• Do not delay CPR while waiting for the AED to arrive—compress first, apply pads as soon as possible.
• If a pediatric attenuator is not available, use the standard AED rather than withholding defibrillation for a shockable rhythm; follow device prompts.
• Resume compressions immediately after a shock (or after a no-shock prompt) with minimal pause.
• Manual defibrillation energy doses (2 J/kg then 4 J/kg, etc.) are covered in the cardiac arrest chapter; this BLS section emphasizes early AED application with pediatric attenuation when available.

Clinical scenario (synthesis)

Two nurses find a 2-year-old pulseless and apneic in a clinic hallway. Rescuer A starts compressions; Rescuer B opens the airway and they use 15:2. A third person brings the AED with pediatric attenuator pads and applies them without stopping CPR longer than needed for pad placement. After two minutes, they pause <10 seconds for the AED analysis, deliver a shock if advised, and immediately resume 15:2. When EMS places an advanced airway later, they switch to continuous compressions and 1 breath every 2–3 seconds. If instead the child had a strong pulse of 90/min with only gasping respirations, they would provide rescue breaths every 2–3 seconds without compressions, reassessing continuously.

Know single vs two-rescuer ratios, advanced-airway rates, rescue-breathing rates, C-A-B with brief pulse checks, and early attenuated AED use cold—these facts appear throughout skills testing and the written exam.