Miniaturization of Respiratory Measurement System in Artificial Ventilator for Small Animal Experiments to Reduce Dead Space and Its Application to Lung Elasticity Evaluation.

Homare Yoshida,Tomoshi Sugiyama,Miyoko Matsushima,Tsutomu Kawabe,Mitsuhiro Shikida,Yoshihiro Hasegawa

doi:10.3390/s21155123

Homare Yoshida, Tomoshi Sugiyama + Show 4 more

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https://doi.org/10.3390/s21155123

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Abstract

A respiratory measurement system composed of pressure and airflow sensors was introduced to precisely control the respiratory condition during animal experiments. The flow sensor was a hot-wire thermal airflow meter with a directional detection and airflow temperature change compensation function based on MEMS technology, and the pressure sensor was a commercially available one also produced by MEMS. The artificial dead space in the system was minimized to the value of 0.11 mL by integrating the two sensors on the same plate (26.0 mm × 15.0 mm). A balloon made of a silicone resin with a hardness of A30 was utilized as the simulated lung system and applied to the elasticity evaluation of the respiratory system in a living rat. The inside of the respiratory system was normally pressurized without damage, and we confirmed that the developed system was able to evaluate the elasticity of the lung tissue in the rat by using the pressure value obtained at the quasi-static conditions in the case of the ventilation in the animal experiments.

Highlights

Ventilators [1,2,3,4] are used in the medical field to assist with the maintenance of breathing as a vital activity, and they are applied to research on the respiratory system in animal experiments
To shorten the response time, the thermal airflow sensor was operated at 76.5 ◦ C by a constant temperature circuit, because it is applied to the oscillating airflow measurement by the ventilator
In we newly newly integrated integrated both both airflow airflow and and pressure pressuresensors sensorsinto intoour ourrespirarespirIn this this work, work, we atory measurementsystem system minimize artificial dead space in the ventilation during tory measurement toto minimize thethe artificial dead space in the ventilation during anianimal experiments

Summary

Introduction

Ventilators [1,2,3,4] are used in the medical field to assist with the maintenance of breathing as a vital activity, and they are applied to research on the respiratory system in animal experiments. The respiration airflow conditions, such as the tidal airflow volume and the frequency, are determined prior to the experiments, and these values are not normally changed during the experiment [5,6]. The respiratory system properties, e.g., tissue elasticity, sometimes change during the experiments depending on what kind of experiment it is. This leads to various problems when the respiration airflow conditions do not follow along with the change of the respiratory system properties. Uneven ventilations between the alveoli will be unresolved by the plateau effect [17]

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