Abstract: The present disclosure relates to pulse oximetry measurements and, more particularly, relates to a combined sensor that includes a pulse oximetry (SpO2) sensor component and a continuous non-invasive blood pressure (CNIBP) sensor component. The combined sensor can be positioned such that the SpO2 sensor component is located over tissues where pulsatility is weak while the CNIBP sensor component may be located over tissues where pulsatility is strong. A second separate CNIBP sensor may be used to together with the CNIBP sensor component of the combined sensor in order to detect the differential pressure pulse transit time from the heart to two different locations on the body. A pulse signal detected by the CNIBP sensor component of the combined sensor can be used to trigger the SpO2 measurement from the SpO2 sensor component in order to improve SpO2 measurement fidelity.