A Formula for the Determination of Appropriate Chest Tube Size and Length of Insertion in Children

Introduction: Chest tubes are inserted regularly in clinical practice. It is a life-saving therapeutic procedure. But there can be complications if the appropriate size or length of insertion is not considered carefully. There are charts that guide, but there is no clear mathematical relationship between the age and body surface area (BSA), and the appropriate size and length of insertion. We carried out this study to develop a formula that provides a more precise guide using the child’s age or BSA. Additionally, in the absence of a chart, the clinician can easily remember the formula to determine the most appropriate size and length. Patients and methods: Children aged 12 years and below who had chest tube insertion at the National Cardiothoracic Centre from July 2015 to August 2016 were retrospectively enrolled into the study. The inclusion criteria was those who had the chest tube data recorded in their notes. This was the derivative cohort. The chest tube type used was SURUCATH ULTRA®. The BSA was calculated using the Mosteller formula. The statistical analysis was performed using Microsoft excel 2013. Formulae were developed from the data of the derivative cohort, and used to determine the appropriate chest tube size and length of insertion on a validation cohort from January 2021 to April 2022. Results: In the derivative cohort, there were 50 children, 34.0% being males. The mean age was 4.2 ± 2.9 years. The weight ranged from 3.5 – 50 kg, the height ranged from 50 – 159 cm and the body surface area ranged from 0.2 – 1.5 m2. In the validation cohort, there were 56 children, 48.0% being males. The mean age was 4.4 ± 2.8. The weight ranged from 5 – 40 kg, the height ranged from 54 – 152 cm and the body surface area ranged from 0.3 – 1.3 m2. The outcome of the validation was good. The chest tubes functioned well and there were no chest tube-associated complications. The formulae obtained were S (FG) = A + 16, L (cm) = 0.3A + 3.5, S (FG) = 6B + 16, L (cm) = 3.5B + 3, where S is the size of the chest tube, A is the age in years, L is the length of insertion and B is the body surface area. Conclusion: A formula can be developed to guide in determining the most appropriate chest tube size and length of insertion in children, using the age and body surface area.