Clinical evaluation of nares-vocal cord distance and its correlation with various external body parameters

BACKGROUND AND AIMS: The optimal visualisation of vocal cords during fibreoptic intubation may be utilised for the nares-vocal cord distance (NVD) estimation. The present study was conducted to measure NVD and to correlate with various external body parameters. METHODS: This study was conducted on 50 males and 50 females. We measured NVD and analysed its relationship with height, nares to tragus of ear distance (NED), nares to angle of mandible distance (NMD), sternal length (SL), thyro-mental distance (TMD), sterno-mental distance (SMD) and arm span (AS). RESULTS: The mean NVD of the males was 18.5 ± 1.5 cm, and that of the females was 15.9 ± 1.1 cm. The relationship between the NVD and body height (males P = 0.001, r = 0.463, females P = 0.000, r = 0.555), SL (males P = 0.000, r = 0.463, females P < 0.000, r = 0.801) or AS (males P = 0.000, r = 0.561, females P = 0.000, r = 0.499) showed a significant correlation but NED, NMD, TMD, SMD did not. After combining male and female groups, (n = 100), the correlation of NVD with external body parameters is as follows SL (r = 0.887), height (r = 0.791), AS (r = 0.769), weight (r = 0.531), SMD (r = 0.466), NED (r = 0.459), NMD (r = 0.391), TMD (r = 0.379). CONCLUSION: The relationship of NVD to external body parameters had strong correlation in all parameters in the combined group; whereas when gender was taken into consideration NVD correlated significantly only with SL, height and AS.