Non-invasive high-frequency oscillatory ventilation in neonates: review of physiology, biology and clinical data

Abstract

Non-invasive high-frequency oscillatory ventilation (NHFOV) consists of the application of a bias flow generating a continuous distending positive pressure with superimposed oscillations, which have constant frequency and active expiratory phase. NHFOV matches together the advantages of high-frequency ventilation (no need for synchronisation, high efficacy in removing CO 2 ) and nasal continuous positive airway pressure (CPAP) (non-invasive interface, increase in functional residual capacity allowing oxygenation to improve). There is enough clinical expertise demonstrating that NHFOV may be tried in some selected cases, in whom CPAP or conventional non-invasive ventilation have failed. Nonetheless, there are no clear data about its clinical usefulness and there is a need for randomised controlled studies. Our purpose is to review the physiology and biological effects of NHFOV, to present the current clinical evidence on its use, to provide some guiding principles to clinicians and suggest directions for further research.

Early noninvasive high‐frequency oscillatory ventilation in the primary treatment of respiratory distress syndrome

“…To our knowledge, the CNO device generates oscillations by periodical interruption of the drive flow and is only designed to deliver nHFOV amplitudes of up to 10(‐12) cmH 2 O, even when lower nHFOV frequencies are set. However, experimental and clinical observational data, using other nHFOV devices than the CNO, suggest the need for much higher amplitudes at a frequency of 10 Hz to have a clinically relevant effect on pCO 2 . As pCO 2 levels were not reported in the present study, the reader can only assume that the pCO 2 may have been lower during nHFOV, as there were fewer intubations due to respiratory acidosis in the nHFOV group, compared to the nCPAP group (2 vs 8).…”

Mechanics of nasal mask‐delivered HFOV in neonates: A physiologic study

“…During our previous mechanical studies on nasal prongs‐delivered NHFOV, we used slightly different ventilatory parameters, thus, the data comparison may partially be inaccurate. However, the knowledge and clinical experience on NHFOV has meanwhile increased, and, in the present study, we tested the combination of ventilatory parameters that we use in clinical practice and that seems preferable according to the best current knowledge of the topic . We acknowledge that a comparative study with the previously used type of nasal prongs would have been theoretically sound.…”

“…These protocols have been designed to separately study the effect of the different parameters, as already done for mechanical studies on invasive high frequency oscillatory ventilation . Parameters boundaries have been chosen according to values commonly used when applying NHFOV in our unit . The same parameters have been used to ventilate the control model with ETT.…”

“…Nasal masks have recently become widely available in neonatology and seem superior to other interfaces in terms of clinical efficiency and patients’ comfort . So far, NHFOV has been applied in neonates only using binasal short prongs or nasopharyngeal cannulae …”

Non‐invasive high‐frequency oscillatory ventilation for preterm newborns: The time has come for consideration

“…Non‐invasive high‐frequency oscillatory ventilation (NHFOV) is a new and exciting strategy that could redefine respiratory support of the preterm infant. Theoretical reasons for using NHFOV, as well as a number of case reports and observational studies reporting positive effects in human neonates and animal models, have been the focus of recent reviews . NHFOV is viewed as a gentler method of delivering mechanical ventilation.…”