ULTRASOUND ASSESSMENT OF SUBGLOTTIC LARYNGEAL DIAMETER FOR ESTIMATION OF APPROPRIATE ENDOTRACHEAL TUBE SIZE IN PAEDIATIRIC PATIENTS – A PROSPECTIVE RANDOMIZED STUDY

ABSTRACT

Background and Aim: The appropriate size of endotracheal tube for children are traditionally selected based on their age, height and or weight by using formulas. The ultrasound guided measurement of subglottic laryngeal diameter can be used to appropriate selection of endotracheal tube. The endotracheal tube is selected based on the nearest external diameter corresponding to the measured subglottic region. The aim of the study is to compare the appropriateness of uncuffed endotracheal tube selection based on age based formula with that of ultrasound assessment of subglottic diameter in children. A prospective randomised parallel group study involving 60 children Materials and Methods: of age 2-6years undergoing elective surgeries under general anaesthesia were selected for study. They are divided into two groups as Group A – Endotracheal tube selection based on ultrasound assessment of diameter of subglottic region and Group B – Endotracheal tube selection based on age based formula which is (Age /3)+ 3.5mm ID. The noted parameters were internal diameter (ID) and external diameter (OD) of the predicted ETT by the two methods, ID and OD of the appropriate size ETT used and the ultrasound assessed subglottic diameter. The incidence of ETT size predicted by ultrasound assessment of Results: subglottic diameter was 83.33% while with age based formula it is 53.34%. The linear regression equation model in Group A showed R²= 0.694, P = 0.001 which was statistically signicant. While in Group B it was R²=0.258., p=0.001. There Conclusion: was a strong correlation between the outer diameter of clinically used uncuffed ETT and the subglottic diameter assessed with ultrasound examination in paediatric patients. Hence USG assessment of the subglottic diameter is a better tool in predicting the appropriate uncuffed ETT in paediatric patients undergoing elective surgeries under general anaesthesia than the age- based formula