Comparison of Accuracy of Ultrasound Measurement of Subglottic Diameter Versus Conventional Age Based Formula for Estimating Endotracheal Tube Size for Pediatric Surgical Patients- A Prospective Randomized Controlled Study

Abstract

Introduction: The main aim of this study is to determine if ultrasonography (USG) based measurement of subglottic diameter is the best size predictor for endotracheal tube (ETT) in pediatric surgical cases over age-based formula with micro cuff tube. Also, to test reintubation percentage and post-operative complications in children. Methodology: This research is double-blind randomized control study with 68 children undergoing elective surgery requiring general anaesthesia with micro cuff tube. They were divided into 2 groups i.e. ETT size by USG (group U) and ETT size by age-based formula group A) (with 34 children in each. Both groups ETT measurement was calculated by independent Samples t-test, and correlation of both groups with actual ET Tube was measured by Pearson’s correlation coefficient. Reintubations or post-op complications was measured by Chi-squared test. Results: Mean age of group A and U are 5.65 ± 2.77 and 5.97 ± 2.77 respectively. Mean weights were from 13.5±2.06 kgs to 27±4.63kgs. Statistical significance with a P-value (P=0.0460) is observed in group U whereas no significance was seen in group A. A strong positive correlation (R=0.960) between USG-estimated ETT size and actual ETT size is observed. The difference in reintubations and post-op complications in group U were statistically significant with P < 0.002. Conclusion: The present study concludes that the sub glottis diameter measured by USG is a good predictor for correct size of micro cuff endo tracheal tube in children.