Validation of a new combined transcutaneous tcPCO(2) and tcPO(2) sensor in children in the operating theater

BACKGROUND: Arterial blood gas analysis is the gold standard for monitoring of P(a)CO(2) and PaO(2) during mechanical ventilation. However, continuous measurements would be preferred. Transcutaneous sensors continuously measure blood gases diffusing from the locally heated skin. These sensors have been validated in children mostly in intensive care settings. Accuracy in children during general anesthesia is largely unknown. AIMS: We conducted a study in children undergoing general anesthesia to validate the use and to determine the accuracy of continuous transcutaneous measurements of the partial pressures of PCO(2) (tcPCO(2)) and PO(2) (tcPO(2)). METHODS: A prospective observational study in a tertiary care pediatric hospital in The Netherlands, from April to October 2018, in children aged 0–18 years undergoing general anesthesia. Patients were included when endotracheally intubated and provided with an arterial catheter for regular blood sampling. Patients with a gestational age <31 weeks, burn victims, and patients with skin disease were excluded. TcPCO(2) and tcPO(2) measurements were performed with a SenTec OxiVenT(™) sensor (SenTec AG). Accuracy was determined with an agreement analysis between arterial and transcutaneous PCO(2) and PO(2) values, and between arterial and endtidal PCO(2) (etCO(2)) values, according to Bland and Altman, accounting for multiple measurements per subject. RESULTS: We included 53 patients (median age 4.1 years, IQR 0.7–14.4 years) and retrieved 175 samples. TcPCO(2)‐P(a)CO(2) agreement analysis provided a bias of 0.06 kPa (limits of agreement (LOA) −1.18 to 1.31), the etCO(2)‐P(a)CO(2) agreement showed a bias of −0.31 kPa (LOA −1.38 to 0.76). Results of the tcPO(2)‐PaO(2) agreement showed a bias of 3.40 to 0.86* (mean tension) kPa. CONCLUSIONS: This study showed good agreement between P(a)CO(2) and tcPCO(2) in children of all ages during general anesthesia. Both transcutaneous and endtidal CO(2) measurements showed good accuracy. TcPO(2) is only accurate under 6 months of age.