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Mallampati class, obesity, and a novel airway trajectory measurement to predict difficult laryngoscopy
Author(s) -
Lee Scott L.,
Hosford Clint,
Lee Quyen T.,
Parnes Steve M.,
Shapshay Stanley M.
Publication year - 2015
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.24829
Subject(s) - laryngoscopy , body mass index , medicine , intubation , surgery
Objectives/Hypothesis To determine whether Mallampati class correlates with Cormack‐Lehane grade in obese adults, and investigate a novel airway trajectory measurement (ATM) to anticipate difficult laryngoscopy. Study Design Retrospective cohort plus a pilot study. Methods One hundred eighty‐four nonobese and 160 obese adults underwent laryngoscopy. Spearman correlations, gamma coefficients (G), and Kendall's τ investigated body mass index (BMI):Mallampati, BMI: Cormack‐Lehane, and Mallampati:Cormack‐Lehane. A z test compared the two groups. Twenty‐six volunteers had neck x‐rays taken in the sniffing position to examine trajectories to the larynges (ATM). Results Positive predictive value of high Mallampati for difficult laryngoscopy was 8.57%. BMI did not correlate with Mallampati ( r = 0.055 [nonobese], r = −0.056 [obese]) or Cormack‐Lehane [ r = −0.014 [nonobese], r = −0.022 [obese]). Among nonobese adults, gamma coefficients for BMI:Mallampati was 0.039 ( P = .63), for BMI:Cormack‐Lehane was 0.02 ( P = .85), and for Mallampati:Cormack‐Lehane was 0.43 ( P = .004). Among obese adults, gamma coefficients for BMI:Mallampati was −0.127 ( P = .16), for BMI:Cormack‐Lehane was 0.014 ( P = .88), and for Mallampati:Cormack‐Lehane was 0.365 ( P = .01). Kendall's τ were comparable to gamma coefficients in all analyses. When comparing gamma coefficients for Mallampati:Cormack‐Lehane among the nonobese and obese, z = 0.04 ( P = .98). In the ATM study, only Mallampati and upper lip bite test had a significant relationship (G = 1.00, P < .001). Conclusions Mallampati correlates poorly with Cormack‐Lehane, regardless of BMI. Pilot data suggest that ATM is feasible. Level of Evidence 4. Laryngoscope , 125:161–166, 2015