可量測高壓氣囊受壓變形的投影式疊紋法系統開發 - 提升氣囊式智能座墊系統之預防壓瘡效能

Abstract

壓瘡是對需使用輪椅行動的脊髓損傷患者常見且嚴重的問題之一，除了本身對患者造成生理及經濟上的負擔之外，對照護資源的需求也是相當可觀，且對於整個醫療體系更為一大挑戰。為了能在根本上解決壓瘡的問題，本研究團隊發展出一具有氣囊陣列之智能型氣囊式座墊，以提供區域性減壓及加壓之功能，並提供量測病人體量之功能，提供醫師診斷之依據。為了能將氣囊與病人的資訊連結，本篇論文發展可量測高壓氣囊受壓變形的投影式疊紋法系統，以探討智能型座墊上的氣囊受壓後行為表現，得到氣囊之特性曲線，以做為控制智能型氣囊式座墊之根據，並藉此有效提升壓瘡的預防效能。 以投影式疊紋法量測大變形技術，可量測出氣囊受壓前後的表面輪廓以及大變形，並在不同施加重量量測下，依照截面曲線分析方式得知氣囊的體積、高度、膨脹量等等物理量和相關性趨勢，並且在二維的觀測角度之下，以二元四次多項式方程擬合出氣囊膨脹所形成的橢圓截面積，證實氣囊在不同重量下的膨脹行為。再搭配有限元素模擬，針對氣囊的材料表面受壓分佈、側邊形變位移量以及內部氣壓的計算做分析，並與投影式疊紋法測得的數據作比較，驗證出模擬結果與光學量測結果的相符程度，最後應用Arduino控制器操控單顆氣囊充氣與放氣，並且以持續施壓作重量測試，提供智能型座墊量測乘坐者體重的依據；這種新開發的智能座墊具有選擇性地減少局部臀部組織受壓的能力，此外，還可以藉由量測出病人體重，提供醫務人員臨床診斷資訊，使醫務人員可以依照患者身體重量指數提供正確的藥物劑量，並有效治療甚至預防壓瘡的產生。

Pressure ulcer is one of the common problems for wheelchair patients with spinal cord injury. It has become not only a physical and economic burden on wheelchair patients, but also a big challenge to health care system. In order to fundamental overcome this problem, we developed a smart air cushion system made by air-cell array. By providing the capability to adjust pressure of each air cell, localized stress can be decreased dynamically. To identify the characteristic profile of air cell and use it for controlling air cell function, we develop a Fringe Projection System to measure the large deformation of a compressed air cell. Thus, the characterized performance of air cell and internal pressure can be correlated. This characteristic curve will be used as a reference to operate the smart air cushion system and provide weight value for diagnostic purposes. Thus, the purpose of this study is to understand the behavior of the air cell of a smart air cushion system. . Fringe projection method is used to measure the surface profile of a air cell, the large deformation under different applied weight is measured. Physical parameters of air cells volume, height and amount of expansion are studied to correlated to specific trends in cross section analysis. Under the two-dimensional measurement, it is confirmed that the expanded behavior of the air cell under different weights has an elliptical deformation and is fitted by a bivariate quartic polynomial equation. Subsequently, COMSOL multiphysics is used to perform finite element method to simulate surface pressure distribution of an air cell and deformation of the sidewall. In addition, by comparing with fringe projection measured data, the results of the optical measurement and consistency are verified. Finally, using an open access Arduino controller to control a single air cell inflation and deflationfor studying the performance of the air call under different loading. Based on the quantified characteristic curve, it can be applied to selectively reduce the local buttock tissue pressure by using the smart air cushion system. In addition, it can take a patient’s weight measurement for diagnosing purposes.