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exhibit the expected linear relationship (Fig. 6I). A calibration plot with a linear fit is shown in Fig. 6J. The binodal configuration of the system naturally yields not only a surrogate marker of BP but also temperatures at two different locations (trunk and limb), to improve monitoring for hypothermia and provide a noninvasive method to track peripheral perfusion. In current clinical practice, measurements of skin temperature are typically limited to a single body location because of the need to minimize wired connections and adhesive interfaces to the skin. Comparison tests of this system against FDA-cleared monitoring equipment (Dash 3000, GE Healthcare) on healthy adult volunteers (n = 3) show excellent agreement for SpO2 (mean difference = 0.3%, SD = 1.37%) as shown in Fig. 6K. Figure 6L illustrates the ability of an ECG EES and a PPG EES to capture differential skin temperature between the torso and peripheral limbs. Pilot studies in neonatal intensive care units and validation against clinical standards Preliminary testing of the EES system in both healthy neonates and premature infants in two tertiary-level NICUs demonstrates feasibility and measurement validity. Shown in Fig. 7, A to C, is a healthy term neonate with an ECG EES and a PPG EES mounted on the chest and the foot, respectively, where van der Waals forces govern the mechanical interface to the skin, with minimal mechanical, mass, or thermal load (Fig. 7A; gestational age, 38 weeks 3 days; birth weight 2.75 kg). The silicone encapsulation also enables reliable operation of the systems when completely immersed in water (fig. S1), thereby supporting compatibility with NICU incubators commonly set at humidity above 80% to maintain temperature homeostasis and prevent dehydration in premature neonates (40). Figure 7B illustrates the use in a mode that facilitates physical contact between parent and neonate, which is difficult to replicate with hardwired conventional systems. Figure 7C shows an alternative mounting location, where the ECG EES resides on the back of the neonate to facilitate chest-to-chest skin interaction, while highlighting the intimate contact with the skin, even while naturally deformed and wrinkled. In Fig. 7, D and E, the sensor system is on a neonate admitted in the NICU, highlighting intimate contact of the ECG EES to the skin, even with motion and position adjustment. An additional example of skin-to-skin contact in a chest-tochest position is shown in Fig. 7E, with the PPG EES on the upper limb to illustrate another option for placement. Representative results of continuous recordings are shown in Fig. 7F for the neonate in Fig. 7A. Calculated HR, SpO2, and RR from the experimental system are consistent with measurements obtained from gold-standard equipment operating concomitantly (Intellivue MX800, Philips).