Evaluation of performance of two high-frequency oscillatory ventilators using a model lung with a position sensor

Iguchi, Naoya; Hirao, Osamu; Uchiyama, Akinori; Mashimo, Takashi; Nishimura, Masaji; Fujino, Yuji

doi:10.1007/s00540-010-1032-0

Cited by 6 publications

(6 citation statements)

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“…In the previous studies that measured aSV with the 3100B oscillator, a pneumotachometer or a hot-wire anemometer was used with a data sampling rate of 1000 Hz [ 12 , 13 ]. Iguchi et al measured aSV with two adult oscillators (3100B and R100) using a position sensor placed on the lung model with a data sampling rate of 667 Hz [ 14 ]. Although the aSV measurements were steady and stable in our study, the data sampling rate of 200 Hz might not be adequate for the frequency of 8 Hz.…”

Section: Discussionmentioning

confidence: 99%

Bias flow rate and ventilation efficiency during adult high-frequency oscillatory ventilation: a lung model study

Nagano

Yumoto

Nishimatsu

et al. 2018

ICMx

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BackgroundBias flow (BF) is essential to maintain mean airway pressure (MAP) and to washout carbon dioxide (CO2) from the oscillator circuit during high-frequency oscillatory ventilation (HFOV). If the BF rate is inadequate, substantial CO2 rebreathing could occur and ventilation efficiency could worsen. With lower ventilation efficiency, the required stroke volume (SV) would increase in order to obtain the same alveolar ventilation with constant frequency. The aim of this study was to assess the effect of BF rate on ventilation efficiency during adult HFOV.MethodsThe R100 oscillator (Metran, Japan) was connected to an original lung model internally equipped with a simulated bronchial tree. The actual SV was measured with a flow sensor placed at the Y-piece. Carbon dioxide (CO2) was continuously insufflated into the lung model (CO2), and the partial pressure of CO2 (PCO2) in the lung model was monitored. Alveolar ventilation (A) was estimated as CO2 divided by the stabilized value of PCO2. A was evaluated by setting SV from 80 to 180 mL (10 mL increments, n = 5) at a frequency of 8 Hz, a MAP of 25 cmH2O, and a BF of 10, 20, 30, and 40 L/min (study 1). Ventilation efficiency was calculated as A divided by the actual minute volume. The experiment was also performed with an actual SV of 80, 100, and 120 mL and a BF from 10 to 60 L/min (10 L/min increments: study 2).ResultsStudy 1: With the same setting SV, the A with a BF of 20 L/min or more was significantly higher than that with a BF of 10 L/min. Study 2: With the same actual SV, the A and the ventilation efficiency with a BF of 30 L/min or more were significantly higher than those with a BF of 10 or 20 L/min.ConclusionsIncreasing BF up to 30 L/min or more improved ventilation efficiency in the R100 oscillator.Electronic supplementary materialThe online version of this article (10.1186/s40635-018-0176-3) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Bias flow rate and ventilation efficiency during adult high-frequency oscillatory ventilation: a lung model study

Nagano

Yumoto

Nishimatsu

et al. 2018

ICMx

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“…This probably had little effect, as in studies on model lungs using both ventilators the 1 : 1 ratio that the R100 uses caused greatest gas movement. 125 However, the R100 did have the facility to perform conventional ventilation, which made protocol design and training considerably easier, and it was this that largely determined our choice of ventilator.…”

Section: Chapter 6 Discussionmentioning

confidence: 99%

A randomised controlled trial and cost-effectiveness analysis of high-frequency oscillatory ventilation against conventional artificial ventilation for adults with acute respiratory distress syndrome. The OSCAR (OSCillation in ARDS) study

Lall

Hamilton

Young

et al. 2015

Health Technology Assessment

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BackgroundPatients with the acute respiratory distress syndrome (ARDS) require artificial ventilation but this treatment may produce secondary lung damage. High-frequency oscillatory ventilation (HFOV) may reduce this damage.ObjectivesTo determine the clinical benefit and cost-effectiveness of HFOV in patients with ARDS compared with standard mechanical ventilation.DesignA parallel, randomised, unblinded clinical trial.SettingUK intensive care units.ParticipantsMechanically ventilated patients with a partial pressure of oxygen in arterial blood/fractional concentration of inspired oxygen (P : F) ratio of 26.7 kPa (200 mmHg) or less and an expected duration of ventilation of at least 2 days at recruitment.InterventionsTreatment arm HFOV using a Novalung R100®ventilator (Metran Co. Ltd, Saitama, Japan) ventilator until the start of weaning.Control arm Conventional mechanical ventilation using the devices available in the participating centres.Main outcome measuresThe primary clinical outcome was all-cause mortality at 30 days after randomisation. The primary health economic outcome was the cost per quality-adjusted life-year (QALY) gained.ResultsOne hundred and sixty-six of 398 patients (41.7%) randomised to the HFOV group and 163 of 397 patients (41.1%) randomised to the conventional mechanical ventilation group died within 30 days of randomisation (p = 0.85), for an absolute difference of 0.6% [95% confidence interval (CI) −6.1% to 7.5%]. After adjustment for study centre, sex, Acute Physiology and Chronic Health Evaluation II score, and the initial P : F ratio, the odds ratio for survival in the conventional ventilation group was 1.03 (95% CI 0.75 to 1.40;p = 0.87 logistic regression). Survival analysis showed no difference in the probability of survival up to 12 months after randomisation. The average QALY at 1 year in the HFOV group was 0.302 compared to 0.246. This gives an incremental cost-effectiveness ratio (ICER) for the cost to society per QALY of £88,790 and an ICER for the cost to the NHS per QALY of £78,260.ConclusionsThe use of HFOV had no effect on 30-day mortality in adult patients undergoing mechanical ventilation for ARDS and no economic advantage. We suggest that further research into avoiding ventilator-induced lung injury should concentrate on ventilatory strategies other than HFOV.Trial registrationCurrent Controlled Trials ISRCTN10416500.FundingThis project was funded by the NIHR Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 19, No. 23. See the NIHR Journals Library website for further project information.

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“…As shown previously, [6][7][8]14 the principal factors influencing the mechanical performance of HFOV ventilators are frequency, inspiratory time, and load charge. Although all ventilators delivered lower V T with increasing frequencies, there were marked differences in the extent of V T decrease between ventilators at an oscillatory frequency of 15 Hz.…”

Section: Discussionmentioning

confidence: 99%

New Generation Neonatal High Frequency Ventilators: Effect of Oscillatory Frequency and Working Principles on Performance

2014

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Increasing the frequency proportionally decreased the V T for all the ventilators, although the magnitude of the decrease was highly variable between ventilators. At 15 Hz and a pressure amplitude of 60 cm H 2 O, the delivered V T ranged from 3.5 to 5.9 mL between devices while simulating pre-term infant conditions and from 2.6 to 6.3 mL while simulating term infant conditions. Activating the volume-targeted mode in the 3 machines that offer this mode allowed the V T to remain constant over the range of frequencies and with changes of lung mechanical properties, for pre-term infant settings only while targeting a V T of 1 mL. CONCLUSIONS: These new generation neonatal ventilators were able to deliver adequate V T under pre-term infant, but not term infant respiratory system conditions. The clinical relevance of these findings will need to be determined by further studies.

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Evaluation of performance of two high-frequency oscillatory ventilators using a model lung with a position sensor

Abstract: Because it is able to deliver comparably greater V(T), R100 may be a better choice for HFOV in critical ARDS patients. Better proportionality may be a result of more effective amplitude titration for adjusting PaCO₂ during oscillation.

Cited by 6 publications

References 21 publications

Bias flow rate and ventilation efficiency during adult high-frequency oscillatory ventilation: a lung model study

Bias flow rate and ventilation efficiency during adult high-frequency oscillatory ventilation: a lung model study

A randomised controlled trial and cost-effectiveness analysis of high-frequency oscillatory ventilation against conventional artificial ventilation for adults with acute respiratory distress syndrome. The OSCAR (OSCillation in ARDS) study

New Generation Neonatal High Frequency Ventilators: Effect of Oscillatory Frequency and Working Principles on Performance

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