Analysis of Contact Pressure for Monitoring Body Fluid Distribution

Fluid distribution is a key indicator for diseases that become more prevalent as we age, such as congestive heart failure (CHF) and nocturia. Current methods to monitor fluid distribution rely on infrequent and often self-report measures, which are unreliable. This thesis aims to develop and evaluate a continuous, unobtrusive, and non-invasive alternative method using pressure sensitive mats (PSM) to accurately measure fluid distribution.A series of four increasingly complex experiments were performed. The first three experiments established that PSMs are sufficiently sensitive to detect small variations in mass typical of fluid retention observed in CHF. The final experiment and corresponding algorithm aimed to differentiate when an individual exits the bed to: do nothing, void their bladder, or drink water. Based on the results from a single participant in three postures (prone, supine, and side), the system could identify bed exits associated with large voids and drinking events (p < 0.05).