Conceptualization and ideation of a wearable device to predict HE

Abstract

Hepatic encephalopathy (HE) is a pathology believed to be produced when the liver function is impaired and cannot adequately remove toxins from the blood, such as ammonia, which leads to a buildup of toxins in the bloodstream that can reach the brain and affect its function. Some patients that present cirrhosis may be eligible to have a TIPS (Transjugular Intrahepatic Portosystemic Shunt) implanted, which decreases the pressure in the portal vein and improves their liver condition. However, clinical evidences have shown that HE is more likely to appear in patients that have had a TIPS implanted. This work is a first stage of a project that aims to create a device able to predict the development of HE on patients that have an implanted TIPS and also study the causes of this pathology. Since ammonium is the only proven biomarker for HE, an initial study was performed to discuss which other ions or molecules could have a correlation with the development of HE. Additionally, since there is a correlation between the ammonium concentration in blood and sweat, a non-invasive sensor that measures the ammonium concentration in sweat was conceptualized and designed. Because this device is non-invasive, could be worn in daily life and it allows a simple maintenance that does not require a technician, it would present an advantage over the current diagnostic techniques since they are invasive or mainly based on psychological tests.