Clinical & Experimental Cardiology
Open Access

Abstract

Validation of EGOS-600 Near Infrared Spectroscopy to Measure Cerebral Oxygen Saturation by Comparing to NIRO-200nx In Vitro and In Vivo

Ding Han, Hui Zhang, Bai-Yu Tian, Yan Zhu, Dan Zhang, Yue Li, Yi-Chao Teng, Hong Gu, Xu Meng, Yi Luo, De-Ming Zhu* and Jia Li*

Objective: Near-infrared spectroscopy (NIRS) has been increasingly used to monitor regional cerebral oxygen saturation (rScO₂) during cardiac surgery and intensive care. NIRO-200nx (Hamamatsu Phototonics, Japan) is one of widely used NIRS devices. EGOS-600 is a new device developed by Tsinghua University in China. We validated EGOS-600 by comparing to NIRO-200nx in laboratory and clinical settings.
Materials and methods: Laboratory test : A liquid tissue model was made consisting of 40 ml of human whole blood, 25 ml intralipid-20% and 935 ml buffer solution. Oxygen saturation (SO₂) levels ranging 20-100% were made by inflating oxygen or adding sodium hydrosulfite. Eleven pairs of measures were obtained using the two oximeters.
Clinical test: 31 children (aged 0.7-61 months, median 11 months) and 20 adults (aged 18-73 years, median 59 years) were enrolled within one week after cardiac surgery. One probe of each device was sequentially placed at the middle of patient’s forehead to measure rScO₂ at 2-3 hour intervals. One hundred pairs of rScO₂ were obtained in each group. Bland-Altman method was used for data analysis.
Results: Laboratory test showed a bias of-2% and limits of agreement 20 to-24% with a trend of overestimating SO₂ by EGOS-600 when average SO₂>50% and underestimating when <50%. This trend disappeared in patients. The bias was-5.9% in children and-4.1% in adults. The limits of agreement were 1.3 to-13.1% in children, and 3.3 to-11.5% in adults.
Conclusions: EGOS-600 introduces a small underestimation of rScO₂ when compared to NIRO-200nx, with acceptable limits of agreement. The new device is applicable in clinical settings in both children and adults.