Pediatric Endotracheal Tube (ETT) Size Calculator
Pediatric Endotracheal Tube Size Calculator
Calculate the appropriate ETT size and insertion depth for pediatric patients
About Pediatric Endotracheal Tube Sizing
Selecting the appropriate endotracheal tube (ETT) size is crucial for effective ventilation in pediatric patients. Unlike s, children require specific ETT sizes based on their age and development to ensure proper fit and function.
Formulas
Several formulas are used to estimate the appropriate ETT size for pediatric patients:
Uncuffed ETT size (mm): (Age in years / 4) + 4
Cuffed ETT size (mm): (Age in years / 4) + 3.5
Depth of insertion (cm): ETT size (mm) × 3
Note: These formulas are applicable for children over 1 year of age. For infants and neonates, different guidelines apply.
Recommended ETT Sizes by Age
| Age | Uncuffed ETT Size (mm) | Cuffed ETT Size (mm) |
|---|---|---|
| Premature | 2.5 | Not recommended |
| Term newborn | 3.0-3.5 | Not recommended |
| 6 months | 3.5-4.0 | 3.0-3.5 |
| 1-2 years | 4.0-4.5 | 3.5-4.0 |
| 3-5 years | 4.5-5.0 | 4.0-4.5 |
| 6-7 years | 5.0-5.5 | 4.5-5.0 |
| 8-10 years | 5.5-6.0 | 5.0-5.5 |
| 11-12 years | 6.0-6.5 | 5.5-6.0 |
| 13-14 years | 6.5-7.0 | 6.0-6.5 |
| 15-16 years | 7.0-7.5 | 6.5-7.0 |
Clinical Considerations
- Always have ETT sizes one size larger and one size smaller than the calculated size available
- The calculated size is an estimate; clinical judgment is essential
- Cuffed tubes are increasingly preferred in pediatric patients due to improved technology and reduced need for tube changes
- Depth of insertion should be confirmed by clinical assessment and chest X-ray
- For emergency situations, the little finger size of the child can approximate the appropriate ETT size
Limitations
The formulas provide estimates and may not be accurate for all children, especially those with:
- Congenital airway abnormalities
- Growth or developmental delays
- Syndromes affecting the airway or facial structure
- History of prolonged intubation or tracheostomy
References
- Khine HH, et al. Comparison of cuffed and uncuffed endotracheal tubes in young children during general anesthesia. Anesthesiology. 1997;86(3):627-631.
- Motoyama EK, et al. Smith's Anesthesia for Infants and Children. 8th ed. Mosby; 2010.
- Weiss M, et al. Cuffed endotracheal tubes in children: when, which, why. Paediatr Anaesth. 2004;14(2):117-118.
- American Heart Association. Pediatric Advanced Life Support Provider Manual. 2020.