Objective: To describe the response to high-frequency jet ventilation in infants with hypoxemic respiratory failure unresponsive to high-frequency oscillatory ventilation.
Methods: This was a retrospective analysis of chart records on demographics, ventilator settings, blood gas analysis and calculated oxygenation index prior to and during the first 7 days of high-frequency jet ventilation in ten consecutive infants.
Results: Before the initiation of high-frequency jet ventilation, the ventilatory mean airway pressure (MAP; cmH2O), fraction of inspired oxygen (FiO2) and oxygenation index on high-frequency oscillatory ventilation were 14.3 +/- 1.3, 0.97 +/- 0.02 and 29 +/- 5, respectively. Three hours after the initiation of high-frequency jet ventilation, the oxygenation index improved to 18 +/- 4 (p < 0.001) and the improvement was sustained during the study period. By 6 h of high-frequency jet ventilation, the FiO2 decreased to 0.62 +/- 0.09 (p < 0.01) and, by 1-3 h of ventilation, the MAP decreased to 10.9 +/- 1.3 (p < 0.01). The improvement in FiO2 persisted for 7 days while, although the MAP remained lower throughout the study, the improvement in MAP failed to reach statistical significance after 72 h. No significant changes in pH, pCO2, or pO2 before or during high-frequency jet ventilation were noted.
Conclusion: High-frequency jet ventilation improves hypoxemic respiratory failure unresponsive to high-frequency oscillatory ventilation in infants. These findings suggest that not all high-frequency ventilatory devices yield the same clinical results.