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Non-invasive high-frequency oscillatory ventilation in preterm infants: a randomised controlled cross-over trial
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  • Published on:
    Response to the letter to the editor by Zhu et al regarding “Non-invasive high-frequency oscillatory ventilation in preterm infants”
    • Daniel Klotz, Consultant Neonatology Center for Pediatrics, Department of Neonatology, Medical Center/Faculty of Medicine - University of Freiburg, Germany
    • Other Contributors:
      • Hans Fuchs, Consultant Neonatology

    Dear Editor

    We appreciate the comments of Zhu and Shi on our crossover trial comparing nHFOV (nasal high frequency oscillatory ventilation) and nCPAP (nasal continuous positive airway pressure) in preterm infants <32 weeks gestational age after extubation from invasive ventilation for respiratory distress syndrome or after less invasive surfactant therapy.1

    The aim of our study was to evaluate the efficacy of an oscillatory pressure waveform superposed to CPAP in spontaneously breathing preterm infants suffering from hypercarbia. In our trial, patients received a CPAP of 5 – 8 cmH2O, which represents standard of care in our unit and is in line with the clinical practice within many neonatal centers.2 Individual CPAP levels were the same before (adjusted according to standard of care) and within the study periods.
    We agree with Zhu et al that increasing the CPAP level in addition to oscillations may enhance lung recruitment and ventilation. However, the effect of oscillations can hardly be differentiated from elevated CPAP levels in this scenario. Other factors than increased lung recruitment might contribute to increased CO2 clearance (e.g. increased leak flow, increased pharyngeal washout or the infants’ respiratory response). In conclusion, we cannot speculate on the effect of increased CPAP levels when testing nHFOV in our trial, but we would advise against testing differing opening pressures when comparing nHFOV to CPAP respiratory support.

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    Conflict of Interest:
    None declared.
  • Published on:
    Non-invasive high-frequency oscillatory ventilation in preterm infants
    • Xingwang Zhu, neonatologist Department of Neonatology JiulongpoPeople's Hospital
    • Other Contributors:
      • Yuan Shi, neonatologist

    To the editor:
    We appreciate the work by Klotz et al., published in this journal1, who presented a randomized controlled cross-over trial to determine whether noninvasive high-frequency oscillatory ventilation (nHFOV) decreases CO2 partial pressure(pCO2) in premature infants more effectively than non-invasive continuous positive airway pressure(nCPAP). In this trial, they assigned 26 premature infants of less than 28 weeks’gestational age (GA) to receive either nHFOV or nasal continuous positive airway pressure (nCPAP) immediately after extubation or non-invasive
    surfactant treatment. The authors could not etablish an increased
    carbon dioxide clearance applying nHFOV compared with
    nCPAP in this cohort of preterm infants. The result is in contrast
    to previous reports where nHFOV was applied at higher airway
    levels compared with nCPAP. Although the author provided brief information about the trial in the paper, we have the following questions about the details of the trial.
    1. How was the mean airway pressure (MAP) titrated in the two sequences?
    According to the paper, the range of MAPs applied in the two sequences were (5-8cmH2O)and (5-7cmH2O)respectively. The authors emphasized that the MAPs applied to nHFOV and nCPAP are equal, but it is not clear how was the MAP titrated (within the range) in the two sequences. Similar to what is done in invasive high frequency oscillatory ventilation, The MAP applied in nHFOV should be tit...

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    Conflict of Interest:
    None declared.