Abstract

Background: Difficult airway is a condition in which a trained anaesthesiologist has
trouble with complications. Risk factors associated with difficult airway are failure or delay
identifying at risk patients and poor planning. Objectives: To study predictors of difficult
airway intubation in patients undergoing general anaesthesia.
Materials & Methods:Single centre, prospective observational study in which patients
scheduled for surgery were included. In addition to patient’s demographic information,
indication for surgery, modified Mallampati grading, inter incisor distance, neck
circumference was noted. Patients were monitored intraoperatively.
Results: Mean Age was 35.9 ± 14.2 years, majority were of ASA status I (65.5%). Mean
sternomental distance was 15.1 ± 2.1 cm, mean thyromental distance was 6.1 ± 1.1 cm &
ratio of height to thyromental distance (RHTMD) was 23.1 ± 5.1. Mallampati class 3/4 in
supine position were 28.25%, class 3/4 sitting were 19.25%, other significant features were
short muscular neck (10.5%), neck movement <80˚ (4%), inter incisor distance ≤3.5 cm
(4%) & limited mandibular protrusion (2.25 %). Difficult intubation was noted in 8%.
Significant factors associated with difficult intubation were Mallampati class 3/4 (sitting),
increased sternomental distance, increased thyromental distance, increased ratio of height
to thyromental distance (RHTMD), short neck, snoring history, neck movement <80˚, short
inter‑ incisor distance, cervical spondylosis & limited mandibular protrusion.
Conclusion: Significant factors associated with difficult intubation were Mallampati class
3/4 (sitting), more sternomental distance, more thyromental distance, increased ratio of
height to thyromental distance (RHTMD), short neck, snoring history, neck movement
<80˚, inter‑ incisor distance ≤3.5 cm, cervical spondylosis & limited mandibular
protrusion. Predicting difficult intubation during the preoperative assessment is a key
challenge, as no single clinical predictor is sufficiently valid for predicting the outcomes.