An optimal endotracheal tube depth is ideally required for preventing the complications associated with mal-positioning of the endotracheal tube. The topographical technique of tube placement considering the individual's morphometric dimensions could help to provide optimal tube placement. hence, to evaluate the efficacy of the topographical technique in providing the optimal tube placement this study will be conducted.

The trachea is a dynamic organ and its length varies by various static and dynamic factors leading to changing the tracheal length and variable endotracheal tube tip to carina (Ti-Ca) distance. Hence, upholding optimal Ti-Ca distance during changing tracheal length is of utmost importance to prevent complications associated with endotracheal tube (ETT) mal-positioning. When the length of ETT, which is to be inserted inside the trachea, is calculated as per an individual's tracheal morphometric dimensions, the appropriate depth of placement could be achieved and tube malpositioning can be prevented. In the topographical landmark technique, an individual tracheal length is estimated by measuring the various distance from mid-thyroid level (corresponds to vocal cords) to manubriosternal joint (corresponds to carina) in the sagittal plane. After estimating the tracheal length, tip to carina distance of 3cm was deducted from the estimated length of the trachea to provide the distance of the endotracheal tube to be kept beyond the vocal cords. Hence, the investigators planned this study to find the "utility and reliability" of the topographical landmark technique compared to the conventional intubation guide mark technique in providing the appropriate depth of endotracheal tube placement.

Inclusion Criteria:

• • Age group of 18-75 years

  • ASA physical status I-III patients
  • Oral intubation for general anesthesia

Exclusion Criteria:

• • Patient with upper airway fibrosis

  • Tracheal stenosis or tracheal surgeries
  • Previous head and neck surgeries
  • Contracture neck or irradiated neck
  • Large neck swelling distorting or deviating the trachea
  • Laryngeal or tracheal tumor
  • Intubations requiring flexo-metallic tubes
  • Patient refusal

If necessary IPD data can be disclosed after patients approval.

The primary investigator will provide the information regarding the portion of endotracheal to be kept below the vocal cords to the care provider after measuring the dimensions of the trachea topographically. After tube placement, the tube tip to carina distance will be measured in both topographical and intubation guide mark technique.