Clin Exp Emerg Med.  2018 Mar;5(1):22-28. 10.15441/ceem.16.185.

Cervical collar makes difficult airway: a simulation study using the LEMON criteria

• Yuk M
• Yeo W
• Lee K
• Ko J
• Park T

• KMID: 2409815
• DOI: http://doi.org/10.15441/ceem.16.185

Abstract

OBJECTIVE
Endotracheal intubation is extremely difficult to perform in patients wearing a cervical collar for a head and neck injury. Therefore, we analyzed actual measurements using the look externally, evaluate 3-3-2, Mallampati score, obstruction, and neck mobility (LEMON) criteria before and after cervical collar application to investigate the causes of a difficult airway.
METHODS
This simulation study was performed in 76 healthy volunteers. We measured the mouth opening, modified Mallampati classification, and neck extension before and after cervical collar application.
RESULTS
The mean inter-incisor distance significantly decreased from 4.3 to 2.6 cm (P < 0.001). Fifty-seven participants classified as I and II were newly classified as III and IV according to the modified Mallampati classification after cervical collar application (16% to 91%). The angles of neck extension significantly decreased from 44° to 22° after cervical collar application (P < 0.001). Before cervical collar application, our simulations predicted that 14 of 76 participants (18%) would have a difficult airway, whereas after cervical collar application, 76 of 76 (100%) were predicted to have a difficult airway.
CONCLUSION
All values for the LEMON criteria (mouth opening, modified Mallampati classification, and neck extension) worsened significantly after cervical collar application. Additionally, a difficult airway was predicted in all participants after cervical collar application.

Keyword

Airway management; Difficult airway; Cervical collar; LEMON criteria

MeSH Terms

Airway Management
Classification
Head
Healthy Volunteers
Humans
Intubation, Intratracheal
Mouth
Neck
Neck Injuries