An evaluation of a new combined SpO2/PtcCO2 sensor in very low birth weight infants

BACKGROUND: Recently, a new sensor for combined assessment of pulse oximetry oxygen saturation (Spo(2)) and transcutaneous monitoring of carbon dioxide partial pressure (PtcCO(2)) has been introduced (TOSCA 500, Radiometer basel AG, Switzerland) [corrected] We designed this study to evaluate the usability and reliability of TOSCA in neonates with birth weight <or=1500 g (very low birth weight). METHODS: In a prospective study of 22 newborns, TOSCA was tested, positioning the sensor on the ear pinna with an adhesive attachment clip. Simultaneous monitoring with TOSCA, conventional pulse oximeter (HP; Datex Ohmeda 3740), and a transcutaneous device (TINA TCM3, Radiometer, Copenhagen) was performed for 60 min. PtcCO(2) measurement from TOSCA (PtcCO(2TOSCA)) and TINA (PtcCO(2)) were compared with Pco(2) from blood samples (PCO(2EAB)) at 1 and 60 min. During the monitoring period, values of PtcCO(2TOSCA) were compared with PtcCO(2), and SatO(2) values from TOSCA with those from a pulse oximeter. Corresponding data were compared using Bland-Altman analysis. RESULTS: Bias (precision) at 1 min and at 60 min between PCO(2EAB) and PtcCO(2) values were 3.5 (12.4) mm Hg and 2.8 (10.2), respectively, whereas between PCO(2EAB) and PtcCO(2TOSCA) values were 18.3 (30.4) mm Hg and 1.8 (25) mm Hg. Bland-Altman analysis shows a better correspondence PtcCO(2)/PtcCO(2TOSCA) between 7 and 15 min. No significant differences were found between Spo(2) and SpO(2TOSCA). CONCLUSIONS: The TOSCA monitor is safe and easy to apply in very low birth weight newborns. The pulse oximeter measurements may be useful for titrating oxygen therapy. Pco(2) measurement with TOSCA is most useful as a trend and independent confirmation of arterial Pco(2) is required if an accurate value is needed.