Table 2.

Correlation between age-based ETT (formula 1, 2) OD and US-measured subglottic diameter with final ETT OD

Parameter	R2	P
Formula-1-based OD	0.6	<0.001
Formula-2-based OD	0.7	<0.001
US-measured-subglottic diameter-based OD	0.7	<0.001
Age	0.7	<0.001
Height	0.3	<0.001
Weight	0.4	<0.001

ETT – Endotracheal tube; OD – Outer diameter; US – Ultrasound