Feasibility of Mid-Frequency Ventilation Among Infants With Respiratory Distress Syndrome

Background: Mid-frequency ventilation, a strategy of using conventional ventilators at high frequencies, may reduce lung injury but has had limited evaluation in neonates. Hence, a randomized crossover study was designed to assess the feasibility of using mid-frequency ventilation in preterm infants with respiratory distress syndrome.

Methods: Twelve preterm infants (≥500 g and ≥24 weeks gestational age) who were receiving pressure-limited conventional ventilation with frequencies ≤60 breaths/min for respiratory distress syndrome were randomized to periods of mid-frequency ventilation (conventional ventilation with the fastest frequency up to 150 breaths/min that gave complete inspiration and expiration) or conventional ventilation (frequency ≤60 breaths/min), each lasting 2 h using a crossover design. Ventilator parameters were adjusted to maintain the O₂ saturation and transcutaneous CO₂ at baseline.

Results: Mean peak inspiratory pressure (15 ± 4 cm H₂O vs 18 ± 4 cm H₂O, P < .001), Δ pressure (9.8 ± 3.3 cm H₂O vs 13.5 ± 3.9 cm H₂O, P < .001), and tidal volume (2.6 ± 0.4 mL/kg vs 4.6 ± 0.8 mL/kg, P < .001) were lower, but mean airway pressure (8.9 ± 1.9 cm H₂O vs 8.4 ± 1.6 cm H₂O, P = .02) and measured PEEP (5.1 ± 0.5 cm H₂O vs 4.4 ± 0.5 cm H₂O, P < .001) were higher with mid-frequency compared with conventional ventilation. F_IO2, gas exchange, and hemodynamic parameters were not affected.

Conclusions: Based on this small study, mid-frequency ventilation among preterm infants with respiratory distress syndrome is feasible. Further larger and longer duration trials are necessary to validate our findings. (ClinicalTrials.gov registration NCT01242462).