Spontaneous Breathing and Imposed Work During Pediatric Mechanical Ventilation: A Bench Study

Area of Science:

• Pediatric critical care
• Respiratory physiology
• Medical device engineering

Background:

• Assessing the work of breathing is crucial for managing pediatric patients on mechanical ventilation.
• Endotracheal tube (ETT) characteristics can influence respiratory mechanics.
• The impact of ETT length and the presence of an in-situ catheter on work of breathing (WOB) in pediatric spontaneous breathing is not fully elucidated.

Purpose of the Study:

• To quantify the imposed work of breathing (iWOB) in simulated pediatric spontaneous breathing across various endotracheal tube sizes.
• To evaluate the effect of shortened endotracheal tubes on iWOB.
• To determine the influence of an intraluminal catheter on iWOB in pediatric endotracheal tubes.

Main Methods:

• An in vitro bench model simulating spontaneous breathing with sinusoidal flow was utilized.
• Imposed work of breathing was calculated by integrating tidal volume with the pressure difference across the endotracheal tube.
• Measurements were performed using endotracheal tubes ranging from 3.0 to 7.5 mm in various simulated pediatric age groups, with and without an intraluminal catheter.

Main Results:

• No significant difference in median iWOB was observed across different pediatric age groups (newborns, infants, small children, adolescents).
• Shortening endotracheal tubes led to a significant reduction in iWOB, with the greatest absolute reduction seen in small children.
• The presence of an intraluminal catheter substantially increased iWOB, ranging from a 55% increase in adolescents to over 91% in neonates.

Conclusions:

• Endotracheal tube size within the tested range does not significantly alter imposed work of breathing during simulated spontaneous breathing in pediatric patients.
• The observed low iWOB values suggest potential clinical irrelevance, supporting the use of spontaneous breathing trials without pressure support.
• Further clinical studies are warranted to confirm these findings regarding imposed work of breathing and its implications for clinical practice.