This paper presents a special designed artificial blood circulatory (ABC) for studying gaseous embolism based on detection of gaseous emboli and their sizing using ultrasound (US) spectral Doppler. Blood mimicking fluid (BMF) was used in the circulatory to get valid results without using human blood. The additional necessary degassing circulatory shows a promising effect of decontaminating the BMF from air bubbles. This offers the base for detecting and sizing microemboli using special algorithms and finally leads to reliable calculations of dangerous embolism and its air volume. Standard US probes at an integrated tissue model and a new 8-MHz central catheter ultrasound (CCUS) probe inside a superior vena cava model (SVCM) are used and deliver the Doppler spectrogram as input for automatic emboli detection and further signal analysis. First results using the newly developed 8-MHz CCUS probe inside the SVCM and its Doppler spectrogram characteristics show promising results but need more detailed studies.