Description

Multivariate analysis of the variables affecting difficult tracheal intubation allows development of a risk index which can be used to assess patients prior to intubation. The 7 variables identified are independent predictors of difficulty with tracheal visualization.


Variable

Finding

Points

mouth opening

>= 4 cm

0

 

< 4 cm

1

thyromental distance

> 6.5 cm

0

 

6.0 - 6.5 cm

1

 

< 6.0 cm

2

Mallampati score

I

0

 

II

1

 

III

2

neck movement

> 90°

0

 

80 - 90°

1

 

< 80°

2

ability to prognath

yes

0

 

no

1

body weight

< 90 kilograms

0

 

90 - 110 kilograms

1

 

> 110 kilograms

2

history of difficult intubation

none

0

 

questionable

1

 

definite

2

 

risk index score =

= (points for mouth opening) + (points for thyromental distance) + (points for Mallampati score) + (points for neck movement) + (points for ability to prognath) + (points for body weight) + (points for history of difficult intubation)

 

Interpretation:

• minimum score: 0

• maximum score: 12

 

Index Score

Tracheal Intubation

< 4

unlikely to be difficult

>= 4

likely will be difficult

 


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