Research ArticleOriginal Research

Oscillation Transmission of Modern High-Frequency Neonatal Ventilators Under Different Lung Mechanics Conditions

Roberta Centorrino, Valentina Dell'Orto, Charlotte Boussard, Agathe Debray, Rafik Ben-Ammar and Daniele De Luca
Respiratory Care July 2022, 67 (7) 850-856; DOI: https://doi.org/10.4187/respcare.09721

Abstract

BACKGROUND: High-frequency oscillatory ventilation (HFOV) is widely used in neonatal critical care, and several modern ventilators using different technologies are available to provide HFOV. These devices have different technical characteristics that might interact with patient lung mechanics to influence the effectiveness of ventilation. To verify this, we studied the oscillation transmission of 5 neonatal oscillators in a lung model mimicking the mechanical patterns commonly observed in neonatal practice.

METHODS: This was a benchtop, in vitro, physiological, pragmatic study using a model mimicking airways and lung of a 1-kg preterm neonate and the following patterns: normal (compliance: 1.0 mL/cm H2O, resistance: 50 cm H2O/L/s), restrictive (compliance: 0.3 mL/cm H2O, resistance: 50 cm H2O/L/s), and mixed mechanics (compliance: 0.3 mL/cm H2O, resistance: 250 cm H2O/L/s). Several permutations of HFOV parameters (variable mean airway pressure or amplitude or frequency protocols) were tested. Oscillations were measured with a dedicated pressure transducer validated for use during HFOV, and oscillatory pressure ratio (OPR) was calculated to estimate the oscillation transmission.

RESULTS: Overall OPR (calculated on all experiments) was significantly different between ventilators and the mechanical patterns (both P < .001). Different ventilators and patterns accounted for 35.6% and 20.6% of the variation in oscillation transmission, respectively. Sub-analyses per changing amplitude or frequency protocols and multivariate regressions showed that VN500 (standardized β coefficient [St.β]: 0.548, P < .001) and Fabian HFO (St.β: 0.421, P < .001; adjusted R2: 0.615) provided the best oscillation transmission. Fabian HFO also delivered oscillations with the lowest variability when increasing amplitude.

CONCLUSIONS: In an experimental setting mimicking typical neonatal lung disorders, the oscillation transmission was more dependent on the ventilator model than on the mechanical lung conditions at equal HFOV parameters. Fabian HFO and VN500 provided better oscillation transmission overall, and when increasing amplitude, Fabian HFO delivered oscillations with the lowest variability.

Introduction

High-frequency oscillatory ventilation (HFOV) is a well-known respiratory support technique whose physiological principles are quite different from conventional ventilation.1 Short- and long-term benefits have been suggested for HFOV-treated preterm neonates with respiratory distre-ss syndrome (RDS), although these are not consistently reported in every trial.2,3 Given the accumulated experience and its relative simplicity, HFOV has also been used as rescue therapy for other types of respiratory failure in more mature and in severely ill neonates.4 Despite some negative results in adult subjects,5,6 HFOV is still commonly used in neonates,7 has also been introduced in noninvasive mode,8 and several industries have recently produced modern ventilators providing HFOV with different technologies. These second-generation oscillators provide electronic monitoring of the delivered volume, friendlier interfaces, and less noise compared to the first-generation devices. They also differ for the mechanisms producing the oscillation, the controlling algorithms, and the technical characteristics of waveforms.

Clinical trials have shown that the effectiveness of HFOV depends on its technical characteristics and on the optimization of its application.9 Bench studies showed that reduced lung compliance negatively affects the volume delivery in some ventilators, and not all devices were able to provide adequate ventilation in bench models mimicking full-term neonates.10 Consistently, testing certain ventilators under several frequency and amplitude permutations, a plateau in the actually transmitted oscillation was observed.11 These data, however, did not consider all the possible lung mechanics patterns typically encountered in neonatal critical care. It is reasonable to think that the technical characteristics of the various ventilators might interact with lung mechanics of each patient and influence the effectiveness of ventilation.

Neonates with respiratory failure usually present with a restrictive pattern (low compliance, normal resistance) or a mixed obstructive-restrictive pattern (low compliance, high resistance). The former are represented by neonates affected by RDS or neonatal ARDS12; the latter are typically those with evolving bronchopulmonary dysplasia (BPD),13 with or without superimposed acute event (acute-on-chronic respiratory failure), and might be more difficult to ventilate. The term evolving BPD refers to preterm babies needing ongoing respiratory support after the first days of life, albeit not yet qualifying for BPD as they did not reach 36 or 40 weeks' postmenstrual age. They do not suffer anymore from RDS due to primary surfactant deficiency or from any other acute form of respiratory failure but have augmented airway resistances leading to decreased lung aeration, particularly from the second week of life, and may show increasing respiratory need.14 This phenomenon is due to the impaired alveolarization occurring over time and can continue beyond the 36 or 40 weeks' time point so as to be described as chronic pulmonary insufficiency of prematurity.15 Considering these patterns are needed to clarify the performance of modern oscillators, particularly for the more severe cases, where HFOV may represent the last rescue therapy.

We performed a benchtop, in vitro, physiological, pragmatic study to investigate the oscillation transmission of several second-generation oscillators in lung models mimicking mechanical conditions commonly observed in neonatal practice. We hypothesized that mean oscillation transmission would significantly vary between different brands of second-generation oscillators in this experimental setting.

QUICK LOOK

Current Knowledge

Several modern neonatal ventilators provide high-frequency oscillatory ventilation (HFOV) with different technology and performance. These characteristics might interact with lung mechanics of patients and influence the effectiveness of ventilation.

What This Paper Contributes to Our Knowledge

In experimental bench models mimicking the mechanics of typical neonatal lung disorders, oscillation transmission was more dependent on the ventilator model than on lung mechanical conditions at equal HFOV parameters. Fabian HFO and VN500 provided greater oscillation transmission, and Fabian HFO delivered oscillations with the lowest variability when increasing amplitude.

Methods

Devices and Materials

We studied 4 second-generation neonatal ventilators providing HFOV (the VN500 [Dräger, Lübeck, Germany], the Fabian HFO [Vyaire, Mettawa, Illinois], the SLE5000 [SLE, Croydon, United Kingdom], and the Leoni [Löwenstein, Rheinland-Pfalz, Germany]). As previously done,10 we used the SensorMedics SM3100A (SM) (Vyaire) as reference device. One device for each ventilator model was tested, and all were routinely used in our unit, while subjected to regular maintenance.16 The same device was always used for every permutation and measurement according to the protocol described below. Full names and details of these devices are described in eTab.1 (see related supplementary materials at http://www.rc.rcjournal.com): these devices differ for several technical characteristics that might influence their performance. With the exception of SM (that was used with its proprietary circuit), these ventilators were connected to a routinely single-use neonatal respiratory circuit (Evaqua 2, RT265; Fisher & Paykel, Auckland, New Zealand). The humidifier was kept in line but left empty and turned off. In all cases, the circuit was connected to a lung model ideal to mimic that of a 1-kg preterm neonate (Iwaki, Tokyo, Japan) (volume: 45 mL, compliance: 1 mL/cm H2O, resistance: 50 cm H2O/L/s; the lung model includes a small “trachea” [inner diameter: 2.5 mm, length: 5 cm]17), similar to what has been used in previous studies.18,19

Experimental Setup

A simple experimental setup was prepared based on that used by Grazioli et al.10 Ventilators were connected to the lung model mimicking various mechanical conditions in order to reproduce patterns of clinical interests (see below). Before any experiment, compliance and resistance of the lung model were measured on all the 4 tested ventilators using their pressure and flow sensors in controlled conventional ventilation (as done for common clinical use). To measure pressure oscillation amplitude at the lung model, a respiratory function monitor (Florian, Acutronic Medical Systems, Hirzel, Switzerland) specifically validated for the use during HFOV20 and incorporating an in-built pressure transducer (measurement accuracy ± 8%) was connected and sealed to the bottom of the test lung using a low-compliance tubing, as previously described.18,19 For ventilators requiring them (all devices expect SM), pressure and flow transducers were placed at the Y-piece before the lung model, as done for common clinical use. Devices were calibrated and tested according to manufacturer's recommendations before any experiment. The experimental setup is sketched in Figure 1. To limit possible external sources of inaccuracy, all experiments were performed in the same laboratory adjacent to the neonatal ICU at constant temperature and humidity.

Fig. 1.
Fig. 1.

Experimental setup.

Experimental Protocol

Three experimental patterns with different lung mechanics were created:

  1. a normal pattern (no lung disease; compliance: 1.0 mL/cm H2O, resistance: 50 cm H2O/L/s),

  2. a restrictive pattern (compliance: 0.3 mL/cm H2O, resistance: 50 cm H2O/L/s),21

  3. a mixed pattern (compliance: 0.3 mL/cm H2O, resistance: 250 cm H2O/L/s).14,22

Compliance was reduced by making the lung externally stiffer, and resistance was increased by applying an airway resistor on the newborn lung trachea. The 2 pathological patterns were chosen to mimic lung mechanics of a 1-kg preterm neonate affected by a restrictive respiratory failure (restrictive pattern, such as RDS or neonatal ARDS) or evolving BPD with acute-on-chronic respiratory failure (mixed pattern). For each of these patterns, HFOV parameters were changed using 3 protocols consisting of the following permutations:

  1. Variable mean airway pressure (Embedded Image) protocol: Embedded Image was sequentially set at 10, 12, 14, 16, 20, 22, 24, 26, and 28 cm H2O, whereas amplitude and frequency were fixed at 45 cm H2O and 10 Hz, respectively.

  2. Variable amplitude protocol: Amplitude was sequentially set at 30, 35, 40, 45, 50, 55, 60, 65, 70, and 75 cm H2O, whereas Embedded Image and frequency were fixed at 15 cm H2O and 10 Hz, respectively.

  3. Variable frequency protocol: Frequency was sequentially set at 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16 Hz, whereas Embedded Image and amplitude were set at 15 and 45 cm H2O, respectively.

These protocols were chosen following previous studies about HFOV mechanics,23 and to be comprehensive, boundaries were selected using values slightly beyond those usually applied in clinical care. Bias flow was automatically adjusted (VN500) or fixed (SLE5000 [8 L/min] and Leoni [7 L/min]) or manually set (Fabian HFO and SM [both 20 L/min]). Inspiratory time and FIO2 were fixed at 33% (1:2) and 0.4, respectively, for all experiments. Volume guarantee mode was never used.

Before any experiment, a leak test was performed, and leaks were continuously monitored for 10 min. If leaks were not constantly < 5%, the lung model and circuit were tightened, and the test was restarted. Subsequently, the actual measurement phase was started, and the oscillation amplitude at the lung model was measured by the Florian pressure transducer. Ventilators were left functioning in these conditions for 15 min per each permutation. After this stabilization period, 2 investigators (RC, VDO) manually recorded the amplitudelung for each experiment by averaging 10 measurements obtained over 1 min. The oscillatory pressure ratio (OPR) was used to estimate the amount of oscillation reaching the lung model: OPR was calculated as amplitudelung/amplitude (where amplitude was the oscillation amplitude set at the ventilator), as previously reported.24

Statistics

Data were tested for normality with Kolmogorov-Smirnov test and expressed as mean (SD). OPR was compared between different ventilators and lung mechanics patterns using 2-way ANOVA followed by Bonferroni post hoc test where appropriate. Data were first analyzed for the whole experimental data set, and then subgroup analyses were performed for the variable amplitude or frequency protocols, as these two are known to be the variables more directly influencing the oscillation transmission (subgroup analyses were performed using data from restrictive and mixed patterns only). Variability of oscillation transmission was summarized by calculating the coefficient of variation (CV) of each ventilator for the data obtained with changing amplitude or frequency protocols. Multivariate linear regression with forward method was performed on the whole data set to confirm the factors more strongly associated to the oscillation transmission (expressed as OPR); covariates inserted in the model were the ventilator type, the lung mechanics pattern, the frequency, and the amplitude set at the ventilator. Results were expressed as standardized β coefficients (St.β), and model goodness of fit was expressed with adjusted R2 values. Analyses were performed with SPSS 27 (IBM, Armonk, New York), and P < .05 was considered to be statistically significant.

Results

Figure 1 illustrates the experimental setup. Figure 2 shows that overall oscillation transmission is significantly different between ventilators (P < .001) and between the 3 tested patterns (P < .001). Different ventilators and patterns account for 35.6% and 20.6% of the variation in oscillation transmission, respectively. Post hoc differences are shown in eTab.2 (see related supplementary materials at http://www.rc.rcjournal.com).

Fig. 2.
Fig. 2.

Overall oscillation transmission for 5 devices according to different lung mechanics patterns. Oscillation transmission is expressed as oscillatory pressure ratio (OPR), that is, the ratio between the amplitude measured at the lung model and the amplitude set at the ventilator. Columns and T-bars represent means and SDs, respectively. Post hoc differences are shown in online supplement. Data are obtained on the whole data set considering all lung patterns and protocols. NLD: no lung disease.

Figure 3 and eTab.3 (see related supplementary materials at http://www.rc.rcjournal.com) show the results of the sub-analysis per changing amplitude protocol. OPR is significantly different between ventilators (P < .001 both for the restrictive and mixed pattern). VN500 and Fabian HFO provided greater oscillation transmission than the other ventilators, and Fabian HFO presented the least variable OPR (CV: 17.3% and 15.5%, for the restrictive and mixed pattern, respectively) compared with the other ventilators (VN500: 31.7% and 31.9%; SLE5000: 31.5% and 39.7%; SM3100A: 45.6% and 125%; Leoni: 31.8% and 35.1%, for the restrictive and mixed pattern, respectively).

Fig. 3.
Fig. 3.

Oscillation transmission: sub-analysis per changing amplitude protocol. Findings of the restrictive (A) and mixed (B) patterns, respectively. Horizontal T-bars indicate means and SDs. Vertical dashed line indicates the absence of oscillation transmission. Post hoc differences are shown in online supplement.

Figure 4 and eTab.4 (see related supplementary materials at http://www.rc.rcjournal.com) show the results of the sub-analysis per changing frequency protocol. OPR is significantly different between ventilators (P < .001 both for the restrictive and mixed pattern). VN500 and Fabian HFO provide greater oscillation transmission than the other ventilators, and all ventilators approximately presented a similar OPR variability (CV Fabian HFO: 42.8% and 50.3%; VN500: 39.4% and 39.5%; SLE5000: 37% and 46.2%; Leoni: 63% and 46.2%, for the restrictive and mixed pattern, respectively) with the exception of SM (CV: 75% and 82.7%, for the restrictive and mixed pattern, respectively).

Fig. 4.
Fig. 4.

Oscillation transmission: sub-analysis per changing frequency protocol. Findings of the restrictive (A) and mixed (B) patterns, respectively. Horizontal T-bars indicate means and SDs. Vertical dashed line indicates the absence of oscillation transmission. Post hoc differences are shown in online supplement.

Multivariate analysis on the whole data set showed that VN500 (St.β: 0.548, P < .001) and Fabian HFO (St.β: 0.421, P < .001) were the ventilators more strongly associated with higher OPR, followed by SLE5000 (St.β: 0.246, P < .001) and Leoni (St.β: −0.081, P = .033); model goodness of fit was good (adjusted R2: 0.615 at the last regression step).

Discussion

Our results show that modern neonatal ventilators providing HFOV have relevant differences in terms of oscillation transmission. The delivery of the oscillatory waveform is more dependent on the ventilator model than on the mechanical conditions of the lung being ventilated at equal HFOV parameters. In fact, the overall OPR variability is due to the different ventilator model and mechanical patterns in about 35% and 20% of cases, respectively. Consistently, the mean OPR of each ventilator is approximately the same, in restrictive and mixed lung patterns, as shown by sub-analyses per variable amplitude or frequency protocols. Under these experimental conditions, Fabian HFO and VN500 seem to provide the best oscillation transmission overall, as this is shown both at the univariate and multivariate analyses. Fabian HFO also delivers oscillations with the lowest variability, at least when using it by increasing amplitude at a fixed frequency.

We performed a bench study with the intent to pragmatically investigate oscillation transmission provided under experimental lung mechanics conditions mimicking the typical patients ventilated in neonatal practice. This study can contribute to provide a practical guidance for clinicians at the bedside. Our findings confirm the relevant variability already observed about the mechanical performance of first-generation oscillators.25–27 Direct comparisons between these devices and newer ventilators are unfeasible, but, clearly, this variability has not been eliminated. Our data expand some previously published on fewer devices28 and are important since, even in the current era, the output of neonatal oscillators remains variable; and therefore, HFOV parameters should be individually set for each device in order to optimize their use. Whereas other advantages have been made available in modern ventilators (such as electronic control of oscillation, display of derived parameters, or volume guarantee during HFOV), our findings identify an area for improvement, since a steadier oscillation transmission is suitable. This, in fact, could provide a safer and more controlled CO2 clearance and allow more informed decisions by clinicians at the bedside.

Our findings were partially consistent with those reported by Grazioli et al,10 as they studied volume delivery, which is linked to the oscillation transmission. We both reported that the performance was significantly influenced by the type of device and, to a lesser extent, by the lung mechanics patterns. Tingay et al11 also reported similar variability between ventilators without studying restrictive or mixed lung models. They also confirmed the direct relationship between endotracheal tube diameter and oscillation transmission, which we did not study and which had already been described for first-generation oscillators.23 These 2 studies reported a particularly worse performance for VN500, and this could be explained with the different experimental setup and protocols. Moreover, we did not simulate a term lung, for which VN500 has been demonstrated to be less performant, owing to the technology used to generate the oscillations.10,11 Our data, and particularly the results of multivariate analysis, provide a pragmatic description of the performances of these devices on a whole picture of mechanical conditions and ventilatory parameters that may be commonly encountered in neonatal ICUs.

We believe that these findings can be useful to further improve neonatal ventilators, to choose the best device on a case-by-case basis. In fact, they increase our knowledge in the field, as they made evident that the most important factors influencing oscillation transmission are the type of ventilator and, secondarily, the mechanical properties of the lung being ventilated. Nonetheless, we must remember that less oscillation dampening and variability may ameliorate gas exchange but do not necessarily translate in a more protective ventilation. Wider oscillations transmitted to small airways may deliver larger volumes and greater energy, whose safe thresholds are unknown. Whereas volume measurement is now available in second-generation oscillators, energy is more difficult to measure since the mechanical power concepts cannot be directly applied to HFOV. Along the same line, recent data seem to support the use of higher frequency to distally deliver smaller volumes (that is, narrower oscillation amplitude).29,30 Moreover, the tested ventilators generate different flow waveforms (eTab.1), and a squared waveform may be associated with greater energy transmitted to the lung.31 These data need to be considered on the whole to better understand what the optimal strategy is in order to balance the need to wash out CO2 and to be as gentle as possible.

Whereas it contributes to the knowledge in the field, this study also has some limitations that prevent to completely reproduce what happens in vivo and to directly apply results to the clinical setting without careful interpretation of mechanical conditions of each clinical case. As it is a bench in vitro study, it cannot reproduce the complexity of in vivo gas exchange. We did not connect an external CO2 source to the lung model; thus, we cannot evaluate the effect of varying OPR on actual ventilation. Nonetheless, we know that the oscillation transmission is directly linked to the delivery of oscillatory volume, which is, in its turn, the main determinant for alveolar ventilation.1 We did not consider the resistance of the tube used for pressure measurements at the bottom of the test lung: whereas this can theoretically influence results, it should have equally affected all studied patterns and permutations. We used the same circuit for all ventilators, except for SM, as we wanted to be pragmatic since the same circuit is used for all devices in our unit. However, the circuit may significantly impact ventilator performance, and this choice also represents another difference compared to previous studies.11 The best circuit for each of the tested ventilators remains to be determined. We did not use any humidification, and we did not analyze the characteristics of the pressure waveform generated by each device. The bias flow was different for every oscillator, and we did not change it, nor did we vary the inspiratory time, as this, compared to other HFOV parameters, is less frequently changed in clinical practice. The impact of all these factors on the mechanical performances of these devices deserves dedicated studies.

We only tested one device per each ventilator brand. We did not test those devices that are not used in our clinical practice and not subjected to routine maintenance in order to be pragmatic and provide information as close as possible to the clinical field. This, however, prevented testing other oscillators that are marketed in other countries or areas. Finally, the manual recording of measurements could have affected our accuracy, although particular care was applied to record values only when the signal was stable and averaging them on several measurements in order to further reduce their variability.18,19

Conclusions

In an experimental setting mimicking the typical neonatal lung disorders ventilated with HFOV, the oscillation transmission was more dependent on the ventilator model than on the mechanical conditions of the lung being ventilated at equal HFOV parameters. Fabian HFO and VN500 provided greater oscillation transmission overall, and Fabian HFO also delivered oscillations with the lowest variability when increasing amplitude.

Acknowledgments

The authors are grateful to Herman Groepenhoff PhD, for the statistical guidance and help in the preparation of figures.

Footnotes

  • Correspondence: Daniele De Luca MD PhD, Service de Pédiatrie et Réanimation Néonatale, Hôpital A. Béclère, GHU Paris Saclay, APHP, 157 rue de la Porte de Trivaux, 92140 Clamart, France. E-mail: dm.deluca{at}icloud.com

  • Supplementary material related to this paper is available at http://rc.rcjournal.com.

  • Dr De Luca discloses relationships with Getinge, Vyaire, and Medtronic. Drs Centorrino and Dell'Orto disclose relationships with Vyaire. The remaining authors have disclosed no conflicts of interest.

References

  1. 1.↵
    1. Boynton BR,
    2. Hammond MD,
    3. Fredberg JJ,
    4. Buckley BG,
    5. Villanueva D,
    6. Frantz ID
    . Gas exchange in healthy rabbits during high-frequency oscillatory ventilation. J Appl Physiol (1985) 1989;66(3):1343–1351.
    OpenUrlPubMed
  2. 2.↵
    1. Cools F,
    2. Offringa M,
    3. Askie LM
    . Elective high-frequency oscillatory ventilation versus conventional ventilation for acute pulmonary dysfunction in preterm infants. Cochrane Database Syst Rev Mar 19 2015(3):CD000104.
  3. 3.↵
    1. Zivanovic S,
    2. Peacock J,
    3. Alcazar-Paris M,
    4. Lo JW,
    5. Lunt A,
    6. Marlow N,
    7. et al
    . Late outcomes of a randomized trial of high-frequency oscillation in neonates. N Engl J Med 2014;370(12):1121–1130.
    OpenUrlCrossRefPubMed
  4. 4.↵
    1. Jaballah NB,
    2. Mnif K,
    3. Khaldi A,
    4. Bouziri A,
    5. Belhadj S,
    6. Hamdi A
    . High-frequency oscillatory ventilation in term and near-term infants with acute respiratory failure: early rescue use. Amer J Perinatol 2006;23(7):403–411.
    OpenUrl
  5. 5.↵
    1. Young D,
    2. Lamb SE,
    3. Shah S,
    4. MacKenzie I,
    5. Tunnicliffe W,
    6. Lall R,
    7. et al
    ; OSCAR Study Group. High-frequency oscillation for acute respiratory distress syndrome. N Engl J Med 2013;368(9):806–813.
    OpenUrlCrossRefPubMed
  6. 6.↵
    1. Ferguson ND,
    2. Cook DJ,
    3. Guyatt GH,
    4. Mehta S,
    5. Hand L,
    6. Austin P,
    7. et al
    . High-frequency oscillation in early acute respiratory distress syndrome. N Engl J Med 2013;368(9):795–805.
    OpenUrlCrossRefPubMed
  7. 7.↵
    1. van Kaam AH,
    2. Rimensberger PC,
    3. Borensztajn D,
    4. De Jaegere AP
    ; Neovent Study Group. Ventilation practices in the neonatal intensive care unit: a cross-sectional study. J Pediatr 2010;157(5):767–771.
    OpenUrlCrossRefPubMed
  8. 8.↵
    1. De Luca D,
    2. Dell'Orto V
    . Noninvasive high-frequency oscillatory ventilation in neonates: review of physiology, biology, and clinical data. Arch Dis Child Fetal Neonatal Ed 2016;101(6):F565–70.
    OpenUrlAbstract/FREE Full Text
  9. 9.↵
    1. Froese AB,
    2. Kinsella JP
    . High-frequency oscillatory ventilation: lessons from the neonatal/pediatric experience. Crit Care Med 2005;33(3 Suppl):S115–21.
    OpenUrlCrossRefPubMed
  10. 10.↵
    1. Grazioli S,
    2. Karam O,
    3. Rimensberger PC
    . New-generation neonatal high-frequency ventilators: effect of oscillatory frequency and working principles on performance. Respir Care 2015;60(3):363–370.
    OpenUrlAbstract/FREE Full Text
  11. 11.↵
    1. Tingay DG,
    2. John J,
    3. Harcourt ER,
    4. Black D,
    5. Dargaville PA,
    6. Mills JF,
    7. Davis PG
    . Are all oscillators created equal? In vitro performance characteristics of eight high-frequency oscillatory ventilators. Neonatology 2015;108(3):220–228.
    OpenUrlCrossRefPubMed
  12. 12.↵
    1. De Luca D,
    2. van Kaam AH,
    3. Tingay DG,
    4. Courtney SE,
    5. Danhaive O,
    6. Carnielli VP,
    7. et al
    . The Montreux definition of neonatal ARDS: biological and clinical background behind the description of a new entity. Lancet Respir Med 2017;5(8):657–666.
    OpenUrlPubMed
  13. 13.↵
    1. Loi B,
    2. Vigo G,
    3. Baraldi E,
    4. Raimondi F,
    5. Carnielli VP,
    6. Mosca F,
    7. et al
    . Lung ultrasound to monitor extremely preterm infants and predict BPD: multi-center longitudinal cohort study. Am J Respir Crit Care Med 2021;203(11):1398–1409.
    OpenUrlCrossRefPubMed
  14. 14.↵
    1. Loi B,
    2. Casiraghi C,
    3. Catozzi C,
    4. Storti M,
    5. Lucattelli M,
    6. Bartalesi B,
    7. et al
    . Lung ultrasound features and relationships with respiratory mechanics of evolving BPD in preterm rabbits and human neonates. J Appl Physiol 2021;131(3):895–904.
    OpenUrl
  15. 15.↵
    1. Steinhorn R,
    2. Davis JM,
    3. Göpel W,
    4. Jobe A,
    5. Abman S,
    6. Laughon M,
    7. et al
    ; International Neonatal Consortium. Chronic pulmonary insufficiency of prematurity: developing optimal end points for drug development. J Pediatr 2017;191:15–21.
    OpenUrlCrossRefPubMed
  16. 16.↵
    1. Ottaviani V,
    2. Veneroni C,
    3. Dell'Orto V,
    4. Lavizzari A,
    5. Ventura ML,
    6. Tossici M,
    7. et al
    . Accuracy of volume and pressure delivery by mechanical ventilators in use in neonatal intensive care units: a quality-control study. Pediatr Pulmonol 2020;55(8):1955–1962.
    OpenUrl
  17. 17.↵
    1. De Luca D,
    2. Shankar-Aguilera S,
    3. Centorrino R,
    4. Fortas F,
    5. Yousef N,
    6. Carnielli VP
    . Less invasive surfactant administration: a word of caution. Lancet Child Adolesc Health 2020;4(4):331–340.
    OpenUrl
  18. 18.↵
    1. De Luca D,
    2. Carnielli VP,
    3. Conti G,
    4. Piastra M
    . Noninvasive high-frequency oscillatory ventilation through nasal prongs: bench evaluation of efficacy and mechanics. Intensive Care Med 2010;36(12):2094–2100.
    OpenUrlCrossRefPubMed
  19. 19.↵
    1. De Luca D,
    2. Piastra M,
    3. Pietrini D,
    4. Conti G
    . Effect of amplitude and inspiratory time in a bench model of noninvasive HFOV through nasal prongs. Pediatr Pulmonol 2012;47(10):1012–1018.
    OpenUrlCrossRefPubMed
  20. 20.↵
    1. Scalfaro P,
    2. Pillow JJ,
    3. Sly PD,
    4. Cotting J
    . Reliable tidal volume estimates at the airway opening with an infant monitor during high-frequency oscillatory ventilation. Crit Care Med 2001;29(10):1925–1930.
    OpenUrlCrossRefPubMed
  21. 21.↵
    1. Choukroun ML,
    2. Llanas B,
    3. Apere H,
    4. Fayon M,
    5. Galperine RI,
    6. Guenard H,
    7. et al
    . Pulmonary mechanics in ventilated preterm infants with respiratory distress syndrome after exogenous surfactant administration: a comparison between two surfactant preparations. Pediatr Pulmonol 1994;18(5):273–278.
    OpenUrlPubMed
  22. 22.↵
    1. Shepherd EG,
    2. Clouse BJ,
    3. Hasenstab KA,
    4. Sitaram S,
    5. Malleske DT,
    6. Nelin LD,
    7. et al
    . Infant pulmonary function testing and phenotypes in severe bronchopulmonary dysplasia. Pediatrics 2018;141(5):e20173350.
    OpenUrlCrossRefPubMed
  23. 23.↵
    1. Van de Kieft M,
    2. Dorsey D,
    3. Morison D,
    4. Bravo L,
    5. Venticinque S,
    6. Derdak S
    . High-frequency oscillatory ventilation: lessons learned from mechanical test lung models. Crit Care Med 2005;33(3 Suppl):S142–147.
    OpenUrlPubMed
  24. 24.↵
    1. van Genderingen HR,
    2. Versprille A,
    3. Leenhoven T,
    4. Markhorst DG,
    5. van Vught AJ,
    6. Heethaar RM
    . Reduction of oscillatory pressure along the endotracheal tube is indicative for maximal respiratory compliance during high-frequency oscillatory ventilation: a mathematical model study. Pediatr Pulmonol 2001;31(6):458–463.
    OpenUrlCrossRefPubMed
  25. 25.↵
    1. Jouvet P,
    2. Hubert P,
    3. Isabey D,
    4. Pinquier D,
    5. Dahan E,
    6. Cloup M,
    7. et al
    . Assessment of high-frequency neonatal ventilator performances. Intensive Care Med 1997;23(2):208–213.
    OpenUrlCrossRefPubMed
  26. 26.
    1. Hatcher D,
    2. Watanabe H,
    3. Ashbury T,
    4. Vincent S,
    5. Fisher J,
    6. Froese A
    . Mechanical performance of clinically available, neonatal, high-frequency, oscillatory-type ventilators. Crit Care Med 1998;26(6):1081–1088.
    OpenUrlCrossRefPubMed
  27. 27.↵
    1. Pillow JJ,
    2. Wilkinson MH,
    3. Neil HL,
    4. Ramsden CA
    . In vitro performance characteristics of high-frequency oscillatory ventilators. Am J Respir Crit Care Med 2001;164(6):1019–1024.
    OpenUrlPubMed
  28. 28.↵
    1. John J,
    2. Harcourt E,
    3. Davis P,
    4. Tingay D
    . Dräger VN500's oscillatory performance has a frequency-dependent threshold. J Paediatr Child Health 2014;50(1):27–31.
    OpenUrlPubMed
  29. 29.↵
    1. Zannin E,
    2. Dellaca' RL,
    3. Dognini G,
    4. Marconi L,
    5. Perego M,
    6. Pillow JJ,
    7. et al
    . Effect of frequency on pressure cost of ventilation and gas exchange in newborns receiving high-frequency oscillatory ventilation. Pediatr Res 2017;82(6):994–999.
    OpenUrl
  30. 30.↵
    1. Solís-García G,
    2. González-Pacheco N,
    3. Ramos-Navarro C,
    4. Rodríguez Sánchez de la Blanca A,
    5. Sánchez-Luna M
    . Target volume-guarantee in high-frequency oscillatory ventilation for preterm respiratory distress syndrome: low volumes and high frequencies lead to adequate ventilation. Pediatr Pulmonol 2021;56(8):2597–2603.
    OpenUrl
  31. 31.↵
    1. Harcourt ER,
    2. John J,
    3. Dargaville PA,
    4. Zannin E,
    5. Davis PG,
    6. Tingay DG
    . Pressure and flow waveform characteristics of eight high-frequency oscillators. Pediatr Crit Care Med 2014;15(5):e234–40.
    OpenUrl
Back to top

In this issue

 

Print
Download PDF
Article Alerts
Email Article
Citation Tools

Jump to section

Related Articles

Cited By...

Keywords