Validating a Wearable Bluetooth Oximeter for Infants in the Neonatal Intensive Care Unit

Oxygen is vital for life but the wrong amount of oxygen can lead to significant risk of morbidity and mortality. Preterm infants are at particular risk from both too little (hypoxia) and excess (hyperoxia) oxygen. In the neonatal intensive care unit (NICU), oxygen treatment is guided by oximetry derived from wired oximeters which are difficult to use outside of the hospital environment. We aimed to validate Bluetooth wireless oximeters in newborn infants to determine the accuracy of devices that would be more suitable for out of hospital use.

Three 20 min sets of measurements including oxygen saturations (SpO₂), heart rate (HR) and perfusion index (PI) from the post-ductal regions (left arm and lower limbs) were conducted in 21 spontaneously ventilating infants using the Masimo (1) SafetyNet and (2) Radical 7 oximeters. The wired Radical 7 oximeter was the reference. Data were downloaded onto CSV files and analysed for agreement.

Twenty-one (eight male) infants were recruited between July to September 2023. Median gestations and ages were 36 weeks and 3 days. Neither Bluetooth device (SafetyNet and wireless Radical 7) met International Organization for Standardization (ISO) standard (ARMSE ≤ 3%), Score 3.624 (wireless Rad-7) and 3.884 (SafetyNet). Both wearables consistently overestimated SpO₂, with mean biases (wired-wearable) of -1.802 (Rad-7) and -1.803 (SafetyNet), that increased at lower SpO₂ levels. Linear regression, ICC, Pearson's correlation analyses showed poor consistency.

Wireless oximeters have poor correlation with wired oximeters especially at lower SpO₂ levels but ease of use, especially in the home environment in less acutely ill patients, requires further evaluation.