🧒 Pediatric ETT Size & Depth
Estimate pediatric endotracheal tube size and insertion depth by age.
Clinical takeaway
Keep ± 0.5 sizes available.
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When to use
Quick airway preparation for pediatric intubation.
How it works
Uncuffed ID = age/4 + 4; cuffed = age/4 + 3.5 (mm). Depth ≈ ID × 3 (cm) or age/2 + 12. Infants < 1 y by weight.
Key points
- Keep ± 0.5 sizes available.
- Confirm position with end-tidal CO₂, auscultation and chest radiograph.
- Infants are sized by weight, not the age formula.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Age | 4 years |
|---|
→ETT internal diameteruncuffed 5 / cuffed 4.5 mm
- Uncuffed ID：5 mm (age/4 + 4)
- Cuffed ID：4.5 mm (age/4 + 3.5; some use +3, adjust by brand/clinical)
- Insertion depth：Lip ≈ ID × 3 = 15 cm; or age/2 + 12 = 14 cm
Frequently asked questions
- What is Pediatric ETT Size & Depth?
- Estimate pediatric endotracheal tube size and insertion depth by age.
- How is Pediatric ETT Size & Depth calculated? What is the core formula?
- Uncuffed ID = age/4 + 4; cuffed = age/4 + 3.5 (mm). Depth ≈ ID × 3 (cm) or age/2 + 12. Infants < 1 y by weight.
- When is Pediatric ETT Size & Depth used?
- Quick airway preparation for pediatric intubation.
- What are the key clinical points for Pediatric ETT Size & Depth?
- Keep ± 0.5 sizes available. Confirm position with end-tidal CO₂, auscultation and chest radiograph. Infants are sized by weight, not the age formula.
- What are the limits and cautions when using Pediatric ETT Size & Depth?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Pediatric ETT Size & Depth calculated in practice? Can you show a worked example?
- Inputs: Age 4 years → Result: ETT internal diameter uncuffed 5 / cuffed 4.5 mm（Uncuffed ID: 5 mm (age/4 + 4), Cuffed ID: 4.5 mm (age/4 + 3.5; some use +3, adjust by brand/clinical), Insertion depth: Lip ≈ ID × 3 = 15 cm; or age/2 + 12 = 14 cm）