Correlation of ratio of neck circumference to thyromental distance for predicting difficult intubation in non obese patients.

I want to conduct an observational study to "correlate the ratio of neck circumference to thyromental distance for predicting difficult intubation in non obese patients" for my MD Anesthesia Thesis.

Aim:- This study aims to assess the ability to predict and evaluate the risk of difficult endotracheal intubation using neck circumference to thyromental distance ratio in non obese patients undergoing surgical procedure.

Objective:- To determine a sensitive reliable specific predictor for difficult to intubation preoperatively.

1. To determine the incidence of difficult intubation in non obese patients.

2. To assess the correlation between the NC/ TM distance ration for determining intubation difficult score in patient undergoing general anesthesia.

Details of the study

Study Design- Prospective Observational study.

Study Place- Bharat Ratna Late Shri Atal Bihari Vajpayee Memorial Medical College and Hospital Rajnandgaon Chhattisgarh.

STUDY APPROVAL: Institutional Scientific and Ethics Committee.

STUDY DURATION: 01/04/2024 to 01/06/2025

STUDY POPULATION: Non obese patient scheduled for major surgeries under general anesthesia.

DATA COLLECTION: Preformed Pretested Proforma.

METHODOLOGY: This prospective observational study aims to investigate the correlation b/w the ration of NC/TM ratio and the difficulty of intubation in non-obese patients undergoing general anesthesia.

ETHICAL CONSIDERATIONS: This study will be conducted after obtaining approval from the institutional scientific and ethics committee.

Informed written consent will be obtained from all participating patients.

DATA COLLECTION:

Preoperative assessment- Demographic data, BMI, height, and airway assessment variables will be recorded:

NC- measured at the level of cricoid cartilage.

TM- measured from the thyroid notch to the mentum with the neck fully extended.

Interimcisor Gap-  measured with maximum mouth opening.

Mallampati Score- classified into four grades based on the visibility of oral structure.

Intraoperative assessment-

Intubation difficulty will be assessed using the intubation difficulty scale (IDS), which includes seven variables:

• Number of intubation attempts

• Number of additional operators

• Number of alternative intubation techniques used

• Laryngoscopic view ( Cormack and Lehane grade)

• Lifting force applied during laryngoscopy

-Need for external laryngeal pressure

• Position of the vocal cords at intubation

• A total IDS score will be calculated, with scores ≥5 indicating difficult intubation.

• Standard anesthesia monitoring will be implemented.

• After preoxygenation, general anesthesia will be induced.

• Laryngoscopy will be performed by an independent Anesthetist using a Macintosh laryngoscope. Laryngoscopy will be performed by senior contestant who has atleast five years of experience or trainee doctor who has 2 years of experience.

BURP maneuver ( Backward, Upward, Rightward Pressure) may be used to improve glottic visualisation.

The NC/TM ratio will be calculated, with a cutoff point of ≥5.0 for predicting difficult intubation.

STATISTICAL ANALYSIS

The relationship b/w the NC/TM ratio and the IDS will be analysed to determine the predictive value of the NC/TM ratio for difficult intubation in non-obese patients.

This study will provide valuable insights into clinical utility of the NC/TM ratio as a predictor of difficult intubation, potentially aiding in the identification of patients at increased risk guiding the choice of airway management strategies.