Table 1 Modified nasal intubation-difficulty scale (NIDS)

N1: Intubation attempts

Each additional intubation attempt after the first one adds 1 point

N2: Operators to attempt intubation

Each additional operator required to attempt intubation adds 1 point

N3: Alternative intubation techniques or change head position

Each alternative intubation technique or change head position adds 1 point

N4: Glottic exposure

0 = good visualization of vocal cords with little manipulation

1 = tools manipulated in all directions to identify the vocal cords

2 = tools extensively manipulated in all directions to identify the vocal cords

N5: Lifting force required to expose the vocal cords

0 = lifting without assistance

1 = lifting required by assistant to improve view of the vocal cords

N6: Optimize glottis exposure with BURP (backward, upward and right ward pressure)

0 = none

1 = BURP applied

N7: Techniques to aid intubation

0 = none

1 = cuff inflation or Magill forceps