To investigate the efficiency of neck circumference to thyromental distance ratio in prediction of diffucult intubation on patients under intratracheal general anesthesia

The aim of this study is to determine the correlation of diffucult intubation which is determined by using IDS score and NC/TMD ratio in general population, obeses and OSAS patients and to compare this ratio with indicators which were defined before such as MO, NC, TMD, SMD, MS and WRS. ASA 1-2 class, over the age of 18, 280 patients were included to this study. Age, height and weight values were registered as demographic data. Patients who have positive OSAS history and obese patients whose BMI is ≥ 30 kg/m were categorized. Predictor tests for predetermining diffucult intubation such as MO, NC, TMD, SMD, NC/TMD, NC/SMD and NC/BMI were measured, MS and WRS tests were applied and registered. Diffucult intubation were determined by using IDS score. It was compared the prediction ability of NC/TMD on diffucult intubation with other tests on general population, obeses and OSAS patients. According to IDS score, diffucult intubation rate was found as 11,1% on general population, 17,7% on obeses, 27,7% on OSAS patients. It was determined statistical significant correlation between NC/TMD ratio and diffucult intubation on each three population. It was determined significant correlation between NC/BMI and diffucult intubation only on obese patients. Addition to this, it was not found significant correlation between MS and diffucult intubation on OSAS patients. On applied ROC analysis it was determined NC / TMD ratio as the most effective test on each population and it was determined 5,2 on general population, 5,8 on obeses and OUAS patients as cut off value. NC/TMD ratio is a better method than other established bedside tests for predicting diffucult intubation. Also NC / SMD and NC/BMI ratio on obeses can be better predictors for predicting diffucult intubation.