Aims: The aim was to conduct a clinical investigation protocol for non-invasive pulse oximeter testing according to ISO standard 80601-2-61:2019 Particular requirements for basic safety and essential performance of pulse oximeter equipment. To prove that the device is accurate also on low oxygen saturation levels, the pulse oximeter testing must be done on human beings since there are no reference materials to ensure correct operation. The accuracy of the investigational pulse oximeter can be measured by comparing the readings of a secondary standard pulse oximeter equipment. Invasive blood gas analyses are not required to demonstrate the performance and were therefore not included in this protocol. The protocol was used to test a wearable patient monitoring device Pamo manufactured in Tampere University, Finland. Pamo consists of SpO2, ECG and impedance pneumography measurements.
Methods: The desaturation was implemented with a Hypoxico Everest II device designed for high altitude simulation training in sports. GE Carescape B450 patient monitor and Masimo RAD-97 pulse oximeter were used to obtain reference data. Study subjects were exposed to gradually lowered oxygen levels inside a tent covering their upper body. During the measurements, blood oxygen saturation levels were decreased as low as 70%. Subjects were recruited from Tampere University and aeroplane pilot training program of Patria company, and the measurements took place in Tampere University's premises.
Results: This study protocol enabled a fluent, non-invasive execution of desaturation measurements for pulse oximeter performance testing. In the proposed protocol, subjects' safety was ensured in a comprehensive manner by prior health checks, vital sign monitoring during desaturation, preparedness for medical emergencies and the presence of medical professionals. After 21 desaturation measurements major adverse events were not observed.