Description

Kheterpal et al developed a score for predicting impossible mask ventilation in a patient undergoing anesthesia. This can help to identify a patient who may require more aggressive management. The authors are from the University of Michigan at Ann Arbor.


Impossible mask ventilation is Grade 4 on the Mask Ventilation Scale of Han et al (above). It is often associated with difficult intubation.

 

Parameters:

(1) radiation changes over the neck

(2) gender

(3) beard

(4) sleep apnea

(5) Mallampati class (modified with 4 classes)

 

Parameter

Finding

Points

radiation changes over neck

absent

0

 

present

6

gender

female

0

 

male

4

beard

absent

0

 

present

2

sleep apnea

absent

0

 

present

3

Mallampati class

I or II

0

 

III or IV

2

 

where:

• A beard usually indicates that the patient is male unless the patient is a bearded lady.

• Radiation change to the neck is equivalent to 2 of the other risk factors in the score.

 

total risk score =

= SUM(points for all 5 parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 17

• The higher the score the greater the risk of impossible mask ventilation.

• The presence of 4 or 5 of the risk factors was a high odds ratio for impossible mask ventilation.

 

Performance:

• The area under the ROC curve is 0.80.


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