Vital Signs Monitor May Lower Risk of Skin Injury in NICU Babies and EB Patients

A skin-like device that measures heart rate, breathing, blood oxygen, blood pressure, and body temperature may provide a safer way to monitor vital signs of those in intensive care who have fragile skin, such as newborns and patients with epidermolysis bullosa (EB).

The technology bypasses the need for sensors that are invasive and hard-wired, and with strong adhesives that put fragile skins at risk for injury and compromise close contact between parent and child.

Preliminary tests done in newborns in intensive care units show the device is feasible to use and parallels in performance with the most advanced standard monitoring systems.

These findings were published in the report “Binodal, wireless epidermal electronic systems with in-sensor analytics for neonatal intensive care,” in the journal Science.

Existing systems for monitoring vital signs in neonatal intensive care units (NICUs) require multiple skin sensors and hard-wired connections. The hardware makes it difficult to perform basic care tasks, emergency clinical interventions, and radiological exams. Moreover, it limits skin-to-skin contact, and thus bonding, between parents and their infants. Conventional NICU monitoring systems are also a frequent cause of skin injuries and scarring, given the fragile skin of babies.

In this study, a multidisciplinary team from Northwestern University, the University of Illinois at Urbana-Champaign, and researchers from other institutions, developed a new device with the potential to overcome these challenges.

The technology, referred to as an epidermal electronic system (EES), is a wireless, battery-free, ultrathin device that gently contacts the skin in a non-invasive way. It consists of a pair of devices: one is placed on the chest and captures electrocardiograms (ECGs), and the other is mounted on the base of the foot to record photoplethysmograms (PPGs).  

PPGs are an optical, non-invasive measurement technique that has been used on several wearable devices, such as wristbands and smartwatches, for pulse monitoring.

The technology uses a source of light to illuminate the skin, and the variations in the light transmitted or reflected are used to calculate heart rate. The method is based on the principle that changes in the light sent back from skin blood vessels reflect blood volume pulsations.

The ECG-PPG system is able to transmit real-time measurements of heart rate, heart rate variability, respiration rate, blood oxygenation, and blood pressure, as well as body temperature. When used synchronously, it can measure vital signs with clinical-grade precision.

A soft and transparent coating of silicone provides a slightly adhesive surface and enables the device to operate even when immersed in water. Moreover, it enables visual inspection and medical imaging exams.

“The thin, lightweight, low-modulus characteristics of these wireless devices allow for interfaces to the skin mediated by forces that are nearly an order of magnitude smaller than those associated with adhesives used for conventional hardware in the NICU,” the researchers wrote. 

This greatly reduces the system’s potential for damaging the skin, they said.

Preliminary tests done in premature and healthy newborns, 28 weeks to full term, at two tertiary-level NICUs, successfully demonstrated the feasibility and validity of the new device, which was shown to reproduce the performance of standard systems.

In addition, it enables two other functions: temperature sensing at multiple points and continuous tracking of blood pressure.

Compared with conventional systems, the new device can be used in a mode (EEG mounted on the infant’s back) that facilitates physical contact between parent and child, which is important for stabilizing vital signs and for parental bonding.

“Comprehensive clinical studies, which are ongoing, will yield additional supporting data to verify the measurements across an increased range of age groups and ethnic backgrounds,” the researchers said.

“For clinical work, additional testing will assess the utility of these platforms in other clinical indications, including those associated with subjects who have altered skin barrier function (e.g., burn victims or patients with epidermolysis bullosa).”