What’s new in High Frequency Oscillatory Ventilation in Neonates?

Abstract

High Frequency Oscillatory (HFO) ventilation, mostly used as a rescue strategy in neonates with worsening of respiratory failure on conventional mechanical ventilation, is also proposed as a lung protective strategy due to its generation of low tidal volumes and supraphysiological frequencies that facilitate gas exchange. Most of the studies have failed to show any advantage of HFO ventilation over conventional ventilation, probably due to the large fluctuations of tidal volumes produced in HFO ventilation. Modes for targeting tidal volumes in HFO ventilation are currently available in the newer ventilators. The effects of volume targeting in HFO ventilation were reviewed from the literature. Six studies were identified as eligible for this review. Targeting tidal volumes in HFO ventilation seemed feasible and offered some stability of ventilation parameters like high frequency tidal volumes (VTHf) delivered, minute ventilation (MV) produced, partial pressure of carbon dioxide (pCO2) in blood, and diffusion coefficient of carbon dioxide (DCO2) in preterm infants ventilated for respiratory distress. Better stability of oxygen saturation (SpO2) levels was also reported in one of the studies. None of the reviewed studies could however demonstrate better stability of haemodynamic parameters including heart rate, perfusion index, pleth variability index and mean arterial blood pressure levels. Follow-up data were also not available in any of the studies reviewed. The quality of evidence from the papers reviewed based on their study designs, study quality and directness in judging the quality of evidence is very low and the strength of the evidence is considered weak. However, this mode of ventilation appears promising and needs to be evaluated in well-designed future trials.