Table 3.

Number (%) [95% CI] of children with correct and incorrect prediction of size of tracheal tube using the PTSP during validation phase

Age group	Correct prediction	Incorrect prediction
		Under-prediction	Over-prediction
All children (n=150)	112 (75) [67-81]	36 (24) [18-31]	2 (1) [0-4]
Younger children (1-4 years) (n=100)	88 (88) [80-93]	11 (11) [6-18]	1 (1) [0-5]
Older children (>4 years) (n=50)	24 (48) [34-62]	25 (50) [36-64]	1 (2) [0-9]

PTSP – Paediatric tube size predictor, the formula developed during the derivation phase. Correct prediction in younger vs. older children: P<0.001 (χ² test)