Effects of changes in frequency and inspiratory time on arterial oxygenation and CO2 elimination during high-frequency jet ventilation in a child with laryngotracheal papillomata

An 11-yr-old female without any pulmonary disorders underwent laser resections of laryngotracheal tumors using high-frequency jet ventilation (HFJV) 6 times over a period of 17 months at our institute. In this series of surgeries, we studied the effects on PaO2 and PaCO2 during HFJV of changes of either frequency or inspiratory time. Increasing the frequency from 100 to 400/min decreased the PaO2 and increased the PaCO2. Decreasing the inspiratory time from 30% to 20% increased the PaCO2, although it did not affect the PaO2. All the procedures were uneventfully carried out without critically impairing gas exchange during HFJV. In this patient with normal lung function, CO2 elimination during HFJV appeared to be facilitated by either decreasing the frequency or increasing the inspiratory time. Arterial oxygen tension during HFJV was higher at lower frequencies.