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

Autor: Tetsuya Yumoto, Takahisa Fujita, Sunao Asaba, Shunsuke Kanazawa, Atsunori Nishimatsu, Hideo Yamanouchi, Satoshi Nakagawa, Osamu Nagano
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Intensive Care Medicine Experimental, Vol 7, Iss 1, Pp 1-10 (2019)
Druh dokumentu: article
ISSN: 2197-425X
DOI: 10.1186/s40635-019-0229-2
Popis: 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 ( V̇ $$ \dot{\mathrm{V}} $$CO2), and the partial pressure of CO2 (PCO2) in the lung model was monitored. Alveolar ventilation ( V̇ $$ \dot{\mathrm{V}} $$A; L/min) was estimated as V̇ $$ \dot{\mathrm{V}} $$CO2 divided by the stabilized value of PCO2. V̇ $$ \dot{\mathrm{V}} $$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 V̇ $$ \dot{\mathrm{V}} $$A = frequency a × aSV b , values of a and b were determined. Ventilation efficiency was calculated as V̇ $$ \dot{\mathrm{V}} $$A divided by actual minute ventilation. Results The relationship between aSV and V̇ $$ \dot{\mathrm{V}} $$A or ventilation efficiency were different depending on the oscillator and IT%. The values of a and b were 0
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