Length of the middle finger of hand as a simple and reliable predictor of optimal size of uncuffed endotracheal tube in paediatric patients: An observational study

Abstract

Background and Aims: A recent study suggested middle finger length-based formula as a better predictive guide compared with age-based formula for selecting uncuffed endotracheal tubes (ETTs) in children. But that study did not meet sample size requirement. Thus, we primarily aimed to determine the accuracy of formula using length of the middle finger to determine the internal diameter of the uncuffed ETT and to compare its accuracy with the Cole's formula. As a secondary objective, we desired to compare its accuracy with some commonly used length and weight-based formulae. Methods: This prospective observational study included children aged up to 12 years posted for elective surgery under general anaesthesia. The length of the middle finger on the palmar aspect of the hand was measured in the preoperative period and the characteristics of the airway used were noted. A predefined criterion of optimal size of the uncuffed ETT was used. Results: A total of 139 patients were included in the final analysis. It was observed that the formula based on middle finger length can predict the optimal size of uncuffed ETT within an error of 0.5 mm in more than 90% instances and its predictive performance is better than Cole's formula. As a secondary outcome, we also observed that its accuracy is better than other formulae under evaluation. Conclusion: Formula based on middle finger length can be used as a predictor of optimal size of uncuffed ETT in paediatric patients and it is a better predictor than Cole's formula.