Department of Electrical Engineering, Federal University of Piauí (UFPI), Teresina 64049-550, Brazil.
Computer Science Department, State University of Londrina (UEL), Londrina 86057-970, Brazil.
Sensors (Basel). 2024 Feb 24;24(5):1481. doi: 10.3390/s24051481.
Respiratory diseases are among the leading causes of death globally, with the COVID-19 pandemic serving as a prominent example. Issues such as infections affect a large population and, depending on the mode of transmission, can rapidly spread worldwide, impacting thousands of individuals. These diseases manifest in mild and severe forms, with severely affected patients requiring ventilatory support. The air-oxygen blender is a critical component of mechanical ventilators, responsible for mixing air and oxygen in precise proportions to ensure a constant supply. The most commonly used version of this equipment is the analog model, which faces several challenges. These include a lack of precision in adjustments and the inspiratory fraction of oxygen, as well as gas wastage from cylinders as pressure decreases. The research proposes a blender model utilizing only dynamic pressure sensors to calculate oxygen saturation, based on Bernoulli's equation. The model underwent validation through simulation, revealing a linear relationship between pressures and oxygen saturation up to a mixture outlet pressure of 500 cmHO. Beyond this value, the relationship begins to exhibit non-linearities. However, these non-linearities can be mitigated through a calibration algorithm that adjusts the mathematical model. This research represents a relevant advancement in the field, addressing the scarcity of work focused on this essential equipment crucial for saving lives.
呼吸系统疾病是全球主要死因之一，COVID-19 大流行就是一个突出的例子。传染病等问题影响着大量人群，并且根据传播方式的不同，可能会在全球迅速传播，影响成千上万的人。这些疾病有轻有重，严重的患者需要通气支持。空气-氧气混合器是机械呼吸机的关键组成部分，负责将空气和氧气按精确比例混合，以确保稳定供应。这种设备最常用的版本是模拟模型，但它存在几个挑战。这些挑战包括调整和氧气吸入分数的不精确性，以及随着压力下降，钢瓶中的气体浪费。该研究提出了一种仅使用动态压力传感器来根据伯努利方程计算氧饱和度的混合器模型。该模型通过模拟进行了验证，结果表明压力和氧饱和度之间存在线性关系，直到混合出口压力达到 500 cmHO。超过这个值，关系开始呈现非线性。然而，这些非线性可以通过校准算法来缓解，该算法可以调整数学模型。这项研究是该领域的一个重要进展，解决了在这个对拯救生命至关重要的基本设备方面工作稀缺的问题。
