Dataset Information

Comparison of the ventilation characteristics in two adult oscillators: a lung model study.

ABSTRACT:

Background

Two recent large randomized controlled trials did not show the superiority of high-frequency oscillatory ventilation (HFOV) in adults with ARDS. These two trials had differing results, and possible causes could be the different oscillators used and their different settings, including inspiratory time % (IT%). The aims of this study were to obtain basic data about the ventilation characteristics in two adult oscillators and to elucidate the effect of the oscillator and IT% on ventilation efficiency.

Methods

The Metran R100 or SensorMedics 3100B was connected to an original lung model internally equipped with a simulated bronchial tree. The actual stroke volume (aSV) was measured with a flow sensor placed at the Y-piece. Carbon dioxide (CO₂) was continuously insufflated into the lung model ([Formula: see text]CO₂), and the partial pressure of CO₂ (PCO₂) in the lung model was monitored. Alveolar ventilation ([Formula: see text]A; L/min) was estimated as [Formula: see text]CO₂ divided by the stabilized value of PCO₂. [Formula: see text]A was evaluated with several stroke volume settings in the R100 (IT = 50%) or several airway pressure amplitude settings in the 3100B (IT = 33%, 50%) at a frequency of 6 and 8 Hz, a mean airway pressure of 25 cmH₂O, and a bias flow of 30 L/min. Assuming that [Formula: see text]A = frequency^a × aSV^b, values of a and b were determined. Ventilation efficiency was calculated as [Formula: see text]A divided by actual minute ventilation.

Results

The relationship between aSV and [Formula: see text]A or ventilation efficiency were different depending on the oscillator and IT%. The values of a and b were 0 < a < 1 and 1 < b < 2 and were different for three conditions at both frequencies. [Formula: see text]A and ventilation efficiency were highest with R100 (IT = 50%) and lowest with 3100B (IT = 33%) for high aSV ranges at both frequencies.

Conclusions

In this lung model study, ventilation characteristics were different depending on the oscillator and IT%. Ventilation efficiency was highest with R100 (IT = 50%) and lowest with 3100B (IT = 33%) for high aSV ranges.

SUBMITTER: Yumoto T

PROVIDER: S-EPMC6419651 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Publications

Comparison of the ventilation characteristics in two adult oscillators: a lung model study.

Yumoto Tetsuya T Fujita Takahisa T Asaba Sunao S Kanazawa Shunsuke S Nishimatsu Atsunori A Yamanouchi Hideo H Nakagawa Satoshi S Nagano Osamu O

Intensive care medicine experimental 20190312 1

<h4>Background</h4>Two recent large randomized controlled trials did not show the superiority of high-frequency oscillatory ventilation (HFOV) in adults with ARDS. These two trials had differing results, and possible causes could be the different oscillators used and their different settings, including inspiratory time % (IT%). The aims of this study were to obtain basic data about the ventilation characteristics in two adult oscillators and to elucidate the effect of the oscillator and IT% on v ...[more]

PMID: 30868327

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Project description:BackgroundVolume-controlled ventilation has been suggested to optimize lung deposition during nebulization although promoting spontaneous ventilation is targeted to avoid ventilator-induced diaphragmatic dysfunction. Comparing topographic aerosol lung deposition during volume-controlled ventilation and spontaneous ventilation in pressure support has never been performed. The aim of this study was to compare lung deposition of a radiolabeled aerosol generated with a vibrating-mesh nebulizer during invasive mechanical ventilation, with two modes: pressure support ventilation and volume-controlled ventilation.MethodsSeventeen postoperative neurosurgery patients without pulmonary disease were randomly ventilated in pressure support or volume-controlled ventilation. Diethylenetriaminepentaacetic acid labeled with technetium-99m (2 mCi/3 mL) was administrated using a vibrating-mesh nebulizer (Aerogen Solo(®), provided by Aerogen Ltd, Galway, Ireland) connected to the endotracheal tube. Pulmonary and extrapulmonary particles deposition was analyzed using planar scintigraphy.ResultsLung deposition was 10.5 ± 3.0 and 15.1 ± 5.0 % of the nominal dose during pressure support and volume-controlled ventilation, respectively (p < 0.05). Higher endotracheal tube and tracheal deposition was observed during pressure support ventilation (27.4 ± 6.6 vs. 20.7 ± 6.0 %, p < 0.05). A similar penetration index was observed for the right (p = 0.210) and the left lung (p = 0.211) with both ventilation modes. A high intersubject variability of lung deposition was observed with both modes regarding lung doses, aerosol penetration and distribution between the right and the left lung.ConclusionsIn the specific conditions of the study, volume-controlled ventilation was associated with higher lung deposition of nebulized particles as compared to pressure support ventilation. The clinical benefit of this effect warrants further studies. Clinical trial registration NCT01879488.

Dataset Information

Comparison of the ventilation characteristics in two adult oscillators: a lung model study.

Background

Methods

Results

Conclusions

Publications

Comparison of the ventilation characteristics in two adult oscillators: a lung model study.

Similar Datasets

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