Table 1 Airway sizes and airway to cricoid ratios (ACR) at specific sites for overall and specific age groups across childhood: mean ± SD cross sectional area (CSA, mm²) and mean ± SD airway to cricoid ratios (ACR).

Overall Group

n

125

114

100

90

108

97

89

CSA mm ²

38.5 ± 8.26

29.95 ± 8.99

25.86 ± 8.70

18.54 ± 6.86

23.77 ± 8.66

16.53 ± 6.60

14.86 ± 6.35

ACR

0.85 ± 0.26

0.73 ± 0.24

0.55 ± 0.23

0.68 ± 0.27

0.48 ± 0.18

0.42 ± 0.18

Group I (age = 2.5 yrs)

n

72

67

60

50

64

56

48

CSA mm ²

34.71 ± 8.48

27.79 ± 7.48

23.98 ± 7.52

17.00 ± 5.73

23.09 ± 7.95

15 ± 6.62

12.75 ± 4.60

ACR

0.83 ± 0.23

0.71 ± 0.24

0.53 ± 0.22

0.70 ± 0.27

0.47 ± 0.20

0.37 ± 0.13

Group II (age >2.5 = 5 yrs)

n

28

28

22

21

24

22

21

CSA mm ²

36.89 ± 7.94

30.66 ± 10.07

26.80 ± 10.06

18.78 ± 6.58

22.57 ± 9.00

17.58 ± 6.53

15.64 ± 6.40

ACR

0.84 ± 0.23

0.72 ± 0.25

0.54 ± 0.20

0.64 ± 0.29

0.49 ± 0.19

0.42 ± 0.18

Group III (age >5 = 10 yrs)

n

25

19

18

19

20

19

20

CSA mm ²

37.81 ± 7.68

36.51 ± 9.31

30.98 ± 8.83

22.35 ± 8.53

27.40 ± 9.90

19.80 ± 5.54

19.10 ± 7.77

ACR

0.92 ± 0.29

0.80 ± 0.25

0.63 ± 0.26

0.66 ± 0.22

0.51 ± 0.13

0.53 ± 0.21