Hyomental Distance Ratio Helps Predict Difficult Direct Laryngoscopy

An increase in hyomental distance of <20% with full extension of the neck predicts poor laryngoscopic view.

Hyomental distance (the distance from the hyoid bone to the mentum) sometimes is used to predict difficult direct laryngoscopy, but it is not accurate. Researchers evaluated the predictive value of the hyomental distance ratio (HMDR) — the ratio of the hyomental distances in neutral and maximal head extension positions — in 213 consecutive adult patients undergoing elective anesthesia at a single hospital in South Korea. The investigators measured hyomental distance, HMDR, thyromental distance in maximal extension, and modified Mallampati score and then compared the results to the Cormack-Lehane glottic view obtained during intubation.

Overall, 26 patients (12%) had difficult laryngoscopy (defined as a Cormack-Lehane grade III or IV view). I…

Reviewing Author

Ron M. Walls, MD, FRCPC, FAAEM

Disclosures

Speaker's bureauAirway Management Education Center, LLC

EquityAirway Management Education Center, LLC

Grant / Research supportAgency for Health Care Research and Quality

Editorial boardsManual of Emergency Airway Management; Rosen's Emergency Medicine; UpToDate; Scientific American Medicine

Leadership positions in professional societiesAssociation of Academic Chairs in Emergency Medicine (President)

Ron M. Walls, MD, FRCPC, FAAEM

Disclosures

Speaker's bureauAirway Management Education Center, LLC

EquityAirway Management Education Center, LLC

Grant / Research supportAgency for Health Care Research and Quality

Editorial boardsManual of Emergency Airway Management; Rosen's Emergency Medicine; UpToDate; Scientific American Medicine

Leadership positions in professional societiesAssociation of Academic Chairs in Emergency Medicine (President)