Table 1.

Age-wise distribution of mean height, weight, actual ETT OD, ETT OD based on formula 1 and 2, and ultrasound-measured subglottic diameter

Patient characteristics	Age (y)
	2-3	>3-4	>4-5	>5-6
Number of patients	26	6	5	4
Weight (kg)	12.4±1.7	16.5±2.0	17.75±2.0	18.84±4.1
Height (cm)	87.6±6.3	98.2±3.1	105±8.7	103±14.6
Actual ETT OD (mm)	6.0±0.4	6.4±0.4	6.9	7.2±0.3
US-measured subglottic diameter (mm)	7.5±0.4	7.9±0.5	8.2±0.2	8.5±0.2
Age-based formula 1 ETT OD (mm)	6.2	6.9	6.9	7.5
Age-based formula 2 ETT OD (mm)	5.9±0.4	6.7±0.4	6.9	7.5

ETT – Endotracheal tube; OD – Outer diameter; US – Ultrasound. All values are as numbers or mean±SD