Unmet Need: Measuring Urinary Output in premature infants
Urinary output (UO) is an important metric in the diagnosis, monitoring and treatment of many disorders including kidney disease, heart failure, dehydration, and shock. Premature infants suffer from several factors that make them especially vulnerable to fluid and electrolyte imbalances. Thus, they undergo routine fluid and electrolyte management including close monitoring of input and UO. UO is such a critical element in the care of these infants that it has been identified as a predictor of mortality in the newborn intensive care unit (NICU).The current measurement for UO involves diaper removal, movement to a common area for weighing, zeroing the scale with an unused diaper, and weighing of used diaper. The clinician documents the output, date, and time, and then cleans the common area, including the scale with a disinfecting agent. Infants in the NICU undergo diaper changes every 3-6 hours. In a 30-bed NICU, this process is conducted on average 140 times/day. This repetitive and monotonous task is associated with lapses in judgement and errors. In addition, the handling of dirty diapers is unhygienic and requires frequent disinfecting with potentially toxic chemicals. Furthermore, the presence and possible spread of bacteria and other pathogens poses a considerable threat to vulnerable babies.
The Technology: Self-weighing, self-powered “Smart Diaper”
Researchers at Washington State University’s College of Nursing, School of Electrical Engineering, and Department of Apparel, Merchandising, Design & Textiles have developed a wearable microelectronic system to sense fluid volume inside a diaper and automatically record it via a base station.
The system consists of a “smart diaper” and a recording station to automatically weigh and record UO at the bedside. This innovative system is made up of a low-cost, textile-based, flexible sensor to accurately measure UO volume by sensing material expansion; accompanied by a highly energy-efficient, non-battery dependent ambient-powered chip, a radio-frequency identification (RFID)-based custom-silicon tag, an RFID reader base station to passively power the tag and readout sensor, and a low-loss omnidirectional antenna with a small footprint embedded in the textile base.
Advantages of this technology include the ability to quickly and cheaply measure UO while significantly decreasing the possibility of human error, the spread of pathogens and the use of chemicals. Furthermore, the sensing material as an underpad application (e.g. a “chux”) provides the advantage of being able to measure UO without removing the pad prematurely (i.e. if there is no UO). This prevents both unnecessary repositioning of patients who are sensitive to movement, such as cardiac patients. This also greatly reduces the need for a urinary catheterization and its associated clinical risks such as catheter-associated urinary tract infections. This system will improve both adherence to and accuracy of measurement and documentation, prevent complications associated with current practice, and decrease the number of steps involved in current UO measurement.
• Quickly and cheaply measure UO while significantly decreasing the possibility of human error
• Greatly reduces the need for a urinary catheterization and its associated clinical risks such as catheter-associated urinary tract infections
• Ability to measure UO without removing the pad prematurely
PCT patent application filed