Comparison of Ultrasonographic Estimation of Endotracheal Tube Size with Age-Based Formula and Diameter of Little Finger in Pediatric Patients

Maintaining a patent airway is the first principle of resuscitation and life support. Successful intubation with the appropriate size endotracheal tube (ETT) is more difficult in children than adults. Use of inappropriate size of ETT can cause significant morbidity and mortality. Visualization of the pediatric airway diameter with the help of ultrasound can enable anesthesiologist to better predict ETT size and it will prevent unnecessary tube changes and airway trauma. Hence, we undertook this study to assess accuracy of USG guided tracheal diameter measurement in predicting ETT size in pediatric patients and its comparison with that determined by age-based formula and diameter of little finger. A total of 50 patients aged between 2 and 6 years were included in this study from July 2017 to June 2018. Agreement between actual ETT inserted and ETT estimation by diameter of little finger, age-based formula and ultrasonography was calculated by using kappa statistics. ETT measurement by diameter of little finger shows an agreement percentage of only 20% (kappa value of 0.05) while the agreement with age-based formula was 56 % (kappa value 0.42). The best agreement was seen between ETT estimated by USG and actual ETT inserted with a kappa value of 0.87 (very good agreement). USG may be considered as a reliable tool for ETT estimation in pediatric patients when compared to age-based formula & diameter of little finger. Age based formula should be preferred over diameter of little finger for ETT estimation when USG is not available.