Size marked on bronchoscope (I.D in mm) | External diameter (in mm) | Age range |
2.5 | 4 | Premature/Neonate |
3 | 5 | 4 weeks - 3 months |
3.5 | 5.7 | 4 - 12 months |
4 | 7 | 12 - 36 months |
5 | 7.8 | 3 - 9 years |
6 | 8.2 | Over 9 years |