• Rebecca Mohr, Jörg Thomas, Vincenzo Cannizzaro, Markus Weiss, and Alexander R Schmidt.
• Department of Anaesthesia, University Children's Hospital of Zurich, Zurich, Switzerland.
• Paediatr Anaesth. 2017 Sep 1; 27 (9): 942-948.

BackgroundWork of breathing accounts for a significant proportion of total oxygen consumption in neonates and infants. Endotracheal tube inner diameter and length significantly affect airflow resistance and thus work of breathing. While endotracheal tube shortening reduces endotracheal tube resistance, the impact on work of breathing in mechanically ventilated neonates and infants remains unknown.AimThe objective of this in vitro study was to quantify the effect of endotracheal tube shortening on work of breathing in simulated pediatric lung settings. We hypothesized that endotracheal tube shortening significantly reduces work of breathing.MethodsWe used the Active-Servo-Lung 5000 to simulate different clinical scenarios in mechanically ventilated infants and neonates under spontaneous breathing with and without pressure support. Endotracheal tube size, lung resistance, and compliance, as well as respiratory settings such as respiratory rate and tidal volume were weight and age adapted for each lung model. Work of breathing was measured before and after maximal endotracheal tube shortening and the reduction of the daily energy demand calculated.ResultsTube shortening with and without pressure support decreased work of breathing to a maximum of 10.1% and 8.1%, respectively. As a result, the calculated reduction of total daily energy demand by endotracheal tube shortening was between 0.002% and 0.02%.ConclusionIn this in vitro lung model, endotracheal tube shortening had minimal effects on work of breathing. Moreover, the calculated percentage reduction of the total daily energy demand after endotracheal tube shortening was minimal.© 2017 John Wiley & Sons Ltd.

20 keywords...

hide…