What Researchers Did
Researchers mechanically ventilated four types of heat and moisture exchange devices (HMEs) and three endotracheal tubes (ETTs) at various minute ventilation volumes in a hyperbaric chamber to measure added work of breathing.
What They Found
Peak pressure increased from 2 cm H₂O at 1 ATA to 6 cm H₂O at 6 ATA with an HME alone, and work of breathing rose from 0.2 J/L to 1.2 J/L at 6 ATA with high minute ventilation. Connecting an HME to an ETT, especially smaller diameters (7.5 mm), significantly increased peak pressure up to 27.7 cm H₂O and work of breathing to 3.76 J/L at 6 ATA, exceeding critical thresholds.
Canadian Relevance
This study has no direct Canadian connection or authors.
Study Limitations
A limitation of this study is that it was conducted using mechanical ventilation models in a hyperbaric chamber rather than on actual human patients.