Comparison of "15 Degrees" vs "30 Degrees" Table Inclination on Intubation Parameters in Young Adults

Background and Aims: Proper alignment of the oral, pharyngeal, and laryngeal axes is critical for successful endotracheal intubation. While the traditional approach uses head positioning, tilting the operating table may also aid glottic visualization. Conflicting evidence exists regarding the optimal table tilt: some studies suggest a "15 degrees" head-up tilt improves intubation speed and ease, while others report benefits with a "30 degrees" incline. This randomised study compared the impact of "15 degrees" vs "30 degrees" table inclination on intubation parameters in young adults. Methods: 120 adult patients (age 18-40) requiring elective intubation under general anaesthesia were randomly assigned to one of three table positions: "0 degrees" (flat supine), "15 degrees" head-up, or "30 degrees" head-up. Standardised induction and direct laryngoscopy with a Macintosh blade were performed by experienced anaesthesiologists, with patients in the sniffing position on the assigned table tilt. Pre-intubation airway status was evaluated by Modified Mallampati Grade (MPG I-IV). Outcome measures included the Cormack-Lehane (CL) laryngoscopic view grade, time to intubation (TI), ease of intubation, need for any rescue manoeuvres (such as changing position or applying external laryngeal pressure), and hemodynamic responses at 30 seconds and 1minute post-intubation. Data were analyzed with appropriate statistical tests (Kruskal-Wallis test for categorical/ordinal outcomes like CL grade, rescue; ANOVA or Kruskal-Wallis for continuous variables like TI and vital signs), with p<0.05 considered significant. Results: Patient groups were similar in age (mean 32-33 years) and baseline characteristics (no significant differences in age or MPG distribution between groups, p>0.5). Overall intubation success was 100% in all groups, with comparable first-pass intubation rates. Median CL grade did not differ significantly between "0 degrees", "15 degrees", and "30 degrees" groups when all patients were considered together (p=0.58). Similarly, median intubation time was not significantly different among the three positions (overall median ~13-15 seconds, p=0.31). The ease of intubation was statistically similar as well (p=0.15). Hemodynamic responses showed no difference in blood pressure at 30 s or 1 min post-intubation between groups (p>0.1); however, heart rate at 1 minute was slightly higher in the "15 degrees" group compared to "0 degrees" and "30 degrees" (p=0.033). Crucially, in the subset of patients with anticipated difficult airways (MPG IV), the "30 degrees" head-up position yielded a significantly better glottic view (lower CL grades) and shorter intubation time than "15 degrees". For MPG IV patients, mean intubation time at "30 degrees" was ~17 s vs ~44 s at "15 degrees" (p<0.01), and many who were predicted to have CL grade 3-4 views had improved CL grades (I-II) when intubated at "15 degrees", avoiding the need for rescue maneuvers. Patients in the 30 degree group required fewer rescue interventions compared to the 15 degree group (p = 0.045). Conclusion: A "15 degrees" head-up tilt did not significantly outperform the flat supine position for routine intubations. However, a "30 degrees" incline of the table markedly improved intubation conditions in patients with difficult airway anatomy (MPG III-IV), leading to better laryngeal visualization and faster, easier intubation. These findings support the use of moderate head-up table positioning (especially "30 degrees") to facilitate intubation in anticipated difficult airways, without adverse effects on hemodynamics. Future studies should confirm these benefits in broader populations and evaluate operator comfort at different inclinations.