Validation of a New Transcutaneous tcPO2/tcPCO2Sensor with an Optical Oxygen Measurement in Preterm Neonates

Abstract

Introduction: Traditional transcutaneous oxygen (tcPO 2) measurements are affected by measurement drift, limiting accuracy and usability. The new potentially drift-free oxygen fluorescence quenching technique has been combined in a single sensor with conventional transcutaneous carbon dioxide (tcPCO 2) monitoring. This study aimed to validate optical tcPO 2 and conventional tcPCO 2 against arterial blood gas samples in preterm neonates and determine measurement drift. Methods: In this prospective observational study, during regular care, transcutaneous measurements were paired to arterial blood gases from preterm neonates aged 24-31 weeks of gestational age (GA) with an arterial catheter. Samples were included based on stability criteria and stratified for sepsis status. Agreement was assessed using the Bland-Altman analysis. Measurement drift per hour was calculated. Results: Sixty-eight premature neonates were included {median (interquartile range [IQR]) GA of 26 4/7 [25 3/7-27 5/7] weeks}, resulting in 216 stable paired samples. Agreement of stable samples in neonates without sepsis (n = 38) and with suspected sepsis (n = 112) was acceptable for tcPO 2 and good for tcPCO 2. However, in stable samples of neonates with sepsis (n = 66), tcPO 2 agreement (bias and 95% limits of agreement) was -32.6 (-97.0 to 31.8) mm Hg and tcPCO 2 agreement was 4.2 (-10.5 to 18.9) mm Hg. The median (IQR) absolute drift values were 0.058 (0.0231-0.1013) mm Hg/h for tcPO 2 and 0.30 (0.11-0.64) mm Hg/h for tcPCO 2. Conclusion: The accuracy of optical tcPO 2 in premature neonates was acceptable without sepsis, while electrochemically measured tcPCO 2 remained accurate under all circumstances. Measurement drift was negligible for tcPO 2 and highly acceptable for tcPCO 2.