Aim: This study was conducted with the aim of determining the optimal depth of ET placement in Indian adult population and its relation with vertebral column, height, weight, arm span length.

Materials and Methods: This was a prospective study which was carried out in 100 ASA grade I and II adult patients who were planning to undergo elective surgery which required orotracheal intubation during general anaesthesia.

Results: The airway distance from lip to carina was 22.38±2.59 cms in males and 20.92±3.55 cms in females; airway distance from lip to cricotracheal membrane was 13.67 ±0.59 cms in males and 11.99±1.66 cms in females; airway distance from cricotracheal membrane to carina was 9.10±6.58cms in males and 9.37±0.22cms in females; airway distance from endotracheal tube tip-carina was 3.21±1.11 cms in males and 2.22±2.58 cms in females; airway  distance from lip to endotracheal tube tip was 21.29±1.08 cms in males and 18.39 ±3.33 cms in females. The various airway distances in males and females were correlated with patient factors separately. The total airway length (L-C), lower airway length (CT-C) were significantly correlated with height, arm span, vertebral column length (P<0.05), but the correlation with upper airway length (L-CT) was not statistically significant. In females, both total and upper airway length was significantly correlated with height, arm span, vertebral column length. In case of BMI and airway distances, it was statistically insignificant in both males and females. It was found that the total and upper airway length correlated significantly with height, arm span and vertebral column length (P<0.01), when the various patient factors were correlated with airway lengths in all patients (males and females together). The coefficient of correlation was much less suggesting a poor correlation, the lower airway length was also found to have a statistically significant correlation with height, arm span and vertebral column length. BMI and airway distances were not found to be correlated.

Conclusion: The patient’s height correlates the best with the length of the airway. In Indian population, the mean airway distances were smaller so that the average depth of fixation was easier from right angle of mouth.