2025 pediatric airway guidance
Calculate cuffed and uncuffed pediatric endotracheal tube sizes, starting oral insertion-depth estimates, adjacent backup tubes, and weight-based i-gel/LMA options for children ages 1–18.
For trained clinical professionals. This tool supplies initial equipment-preparation estimates for children 1–18 years. It does not confirm tube fit, tracheal placement, or final depth.
Pediatric airway preparation
For children 1–18 years. Age determines ETT and oral-depth estimates; weight determines device-specific SGA sizes.
Patient inputs
Height is not used because the common pediatric ETT and lip-depth equations are age-based; weight is retained for SGA manufacturer sizing.
Airway context
Tube selection
Cuffed is presented as the preferred starting setup because the 2025 AHA guideline says it is reasonable to choose cuffed ETTs over uncuffed tubes in infants and children. The uncuffed estimate remains visible for local protocol and patient-specific selection.
| Population / method | Cuffed | Uncuffed / cross-check | Preparation |
|---|---|---|---|
| 1 to <2 years | 3.5 mm | 4.0 mm | Prepare ±0.5 mm |
| ≥2 years | Age ÷ 4 + 3.5 | Age ÷ 4 + 4.0 | Round to available 0.5-mm size |
| Oral depth at lip | Age ÷ 2 + 12 cm | 3 × ETT ID | Display both; do not average disagreement |
Upper-airway narrowing, edema, croup, prior airway surgery, tube brand/external diameter, and anatomy may require a smaller size. Always prepare adjacent tubes.
Starting oral depth
The calculator shows age ÷ 2 + 12 cm and 3 × selected ETT internal diameter as separate starting estimates. A difference greater than 0.5 cm is highlighted. These values are not averaged because a mathematical midpoint has no independent validation.
Use direct cord visualization and tube depth marks, continuous waveform capnography, bilateral ventilation assessment, clinical response, securement documentation, and imaging when indicated. Reassess after movement or unexplained deterioration.
Alternative airway
The calculator reports device-specific manufacturer ranges rather than treating every SGA as interchangeable. At exact boundaries—or across overlapping i-gel bands—it displays both possible sizes and directs the clinician to the current IFU and anatomical assessment.
| LMA Supreme size | Manufacturer weight band |
|---|---|
| 1 | Up to 5 kg |
| 1.5 | 5–10 kg |
| 2 | 10–20 kg |
| 2.5 | 20–30 kg |
| 3 | 30–50 kg |
| 4 | 50–70 kg |
| 5 | 70–100 kg |
An SGA can be an important rescue interface when mask ventilation or intubation is unsuccessful, but indication, aspiration risk, device design, training, and the local difficult-airway pathway determine whether it should be used.
Frequently asked questions
For children at least 2 years old, a common cuffed estimate is age in years divided by 4 plus 3.5. The calculator uses 3.5 mm from age 1 to under 2 years, rounds available sizes to the nearest 0.5 mm, and prepares adjacent sizes.
For children at least 2 years old, a common uncuffed estimate is age in years divided by 4 plus 4. The calculator uses 4.0 mm from age 1 to under 2 years and shows the uncuffed setup beside the preferred cuffed setup.
The 2025 AHA pediatric guidelines state that choosing cuffed rather than uncuffed ETTs is reasonable. Correct size and position are essential, and cuff pressure is usually kept below 20–25 cm H2O.
Common starting estimates are age divided by 2 plus 12 cm at the lip and three times the ETT internal diameter. The calculator displays both and flags disagreement rather than averaging the methods.
Age formulas and insertion-depth estimates are less reliable in younger infants, where weight, length, manufacturer-specific tubes, and local tables become more important. Use dedicated neonatal/infant guidance below 1 year.
SGA sizing is device- and weight-specific. The calculator displays official i-gel and LMA Supreme weight bands and shows both sizes when manufacturer bands overlap at a boundary.
Evidence base
Evidence and links reviewed August 29, 2026. PulmTools is independent and does not claim endorsement by the organizations or manufacturers listed.