Bridging Brain Science and Medical Engineering: An Interview with Li Yue, CEO of EnginMed

Cerebral Oxygen Saturation: An Indicator Reflecting the Dynamic Balance Between Oxygen Supply and Oxygen Consumption in Brain Tissue.

The adult brain accounts for less than 2% of total body weight. However, it receives 15–20% of cardiac output and consumes 20% of the body’s total energy.

If cerebral blood and oxygen supply are interrupted, loss of consciousness occurs within 8–15 seconds; brain tissue glucose is depleted within 2–4 minutes, and ATP is exhausted within 4–5 minutes. Beyond 5 minutes, neuronal damage becomes irreversible, potentially leading to brain death.

These irreversible effects underscore the critical role of cerebral oxygen saturation monitoring in fields such as anesthesiology, emergency and critical care, neonatal intensive care units (NICU), neurosurgery, and cardiovascular and cerebrovascular medicine.

Among the various technical approaches to cerebral oxygen monitoring,Near-Infrared Spectrometer (NIRS)It holds a significant position due to its non-invasive, rapid, real-time, continuous, and sensitive characteristics.

In the field of NIRS technology, there is a startup team spun off from the research achievements of the School of Biomedical Engineering at Tsinghua University. Leveraging over 20 years of accumulated technical expertise, the team has deeply cultivated the industry and provided clinical services.

In 1994, China had just established the Medical Device Product Certification Committee and the Medical Device Quality Certification Center; universities had just independently developed the first CT research prototype; and the first central monitoring system had just appeared on the market.

During the nascent stage of the medical device industry,One of the Founders of Biophotonics in China—Professor Ding HaishuGrantThe research team led by him undertook the research task of non-invasive monitoring of tissue oxygenation using near-infrared spectroscopy (NIRS).

In 2000, Li Yue joined the research group, embarking on more than two decades of exploration at the intersection of medicine and engineering, integrating industry, academia, and research.

In 2005, through the long-term research and development efforts of the entire team, the research group from the Department of Biomedical Engineering at Tsinghua University School of Medicine successfully developed the TSAH-100 near-infrared tissue oxygenation non-invasive monitor, which possesses fully independent intellectual property rights.

This achievement marks the emergence of China’s only original R&D team in the field of cerebral oximetry. The team’s technical standards have not only reached a world-leading level but also made China the third country, after Japan and the United States, capable of manufacturing such products.

In the subsequent years, the team completed the productization of the engineering prototype, obtained regulatory approvals, and conducted clinical trials. Leveraging several invention patents and utility model patents, the team achieved the commercialization of scientific and technological achievements, becoming one of the early successful case studies of technology transfer at Tsinghua University.

In 2011, Li Yue, representing the Tsinghua University team, successfully launched the cerebral oxygen monitoring project in Suzhou. Aegean Medical was established and secured successful financing. Three years later, the company achieved mass production with its fifth-generation prototype, thereby realizing the commercialization of the cerebral oxygen monitoring project.

Today, Aegean Medical’s products have been deployed in more than 400 Grade IIIA hospitals across China, and are widely used in anesthesia, cardiac surgery, neurosurgery, pediatrics, and critical care, capturing over 60% of the domestic market share.

Looking back on the path of scientific research translation taken by Li Yue and Aegean Medical, everything seems to have fallen into place.

Undertake research projects, conduct scientific research, develop prototypes, secure patent grants, perform clinical studies, establish the registration entity, submit for regulatory approval, iterate product development, execute marketing strategies, and install equipment in hospitals.

Yet, Li Yue and his team navigated this path—now regarded as a textbook model for scientist-led startups—by feeling their way forward without any prior experience.

After completing the R&D of the first three generations of products, and in response to the requirements of clinical experts as well as a key component in advancing scientific research projects, the team obtained Class II registration approval in 2005 through a laser equipment manufacturer.Achieved true commercialization.

The initial excitement of researchers entering the market had not yet fully subsided when the first signs of problems began to emerge.

It has been widely recognized that there is no necessary correlation between a product’s quality and its marketability.

Although the laser equipment manufacturer partnering for certification possesses sufficient qualifications and experience in production and sales of its own products, it lacks corresponding channels in the primary application scenarios for cerebral oxygen saturation monitoring, such as anesthesiology, pediatrics, and intensive care. Before even discussing sales volume, the ability to reach the correct departments must be built from scratch.

Recalling the situation at that time, combined with years of subsequent reflection, Li Yue realizedFrom Productization to Commercialization, a gap that was entirely unforeseen. Productization can be largely achieved with engineers and regulatory affairs personnel, whereas industrialization requires more than just product development or market access approval,“Successful commercialization is purely a matter of clinical acceptance.”

Since there are no ready-made channels, we will develop them ourselves.

At that time,The Gap in Clinical Installed Base Between the Chinese Market and the European and American Markets, which is the breakthrough point for Li Yue and Aegean Medical.

According to Li Yue’s research, over half of cardiac surgeries in the United States utilize cerebral oximetry monitors, with such monitoring being universally applied in complex cardiac procedures involving major blood vessels. In contrast, the adoption rate of cerebral oximetry in China remains below 10%. Meanwhile, the configuration rate of cerebral oximetry devices in Chinese ICU beds falls far short of the mature ratios observed in European and American countries.

As awareness of the importance of cerebral oximetry monitoring has grown within the industry, and driven by the genuine needs of doctors returning from overseas training—particularly experts specializing in cardiopulmonary bypass for cardiac surgery—Aegean Medical has gradually established its clinical reputation.

From basic application guidance to the interpretation of abnormal indicators, and further to tracing the physiological significance of these metrics in academic discussions, Aegean Medical has made tremendous efforts. Ultimately, this has indirectly facilitated the inclusion of cerebral oxygenation monitoring technology in multiple expert consensus statements and clinical guidelines.

Aegean Medical also has a unique approach in scientific research iteration and medical-engineering integration.。

Thanks to their fully proprietary algorithms, Li Yue and his team had already accumulated a substantial volume of cerebral oxygenation data by the time they obtained registration certification in 2005. One of the indicators,THI Tissue Hemoglobin Index, nearly overlooked amidst the vast amount of data. As a team with backgrounds in engineering, our understanding of the clinical definition of THI was limited at the time, and we had even less knowledge about the clinical significance reflected by its variations in clinical scenarios. Therefore, we temporarily set it aside during the registration process.

In experiments conducted over the subsequent years, the team gradually discovered that the THI index exhibited changes consistent with clinical expectations during cardiopulmonary bypass procedures involving hemodilution, thereby fulfilling the corresponding indications.

In 2012, in experiments conducted with Beijing Anzhen Hospital and Fuwai Hospital, the team observed that during cardiopulmonary bypass surgery, there were not only changes in cerebral oxygenation but also changes in THI, and they determined that THI can reflect changes in hemoglobin concentration in the blood.

In 2020, in collaboration with the First Affiliated Hospital of Tsinghua University, the team noted the relationship between the THI index and vascular resistance, as well as how it can reflect the reactivity of microvessels to systemic hemodynamic changes, leading to a novel interpretation.

As an entrepreneur with an engineering background, Li Yue, when reviewing the application of THI, believes that the implementation of medical-engineering integration sometimes“It is not only necessary to innovate in principle, that is, to calculate the indicators accurately; more importantly, those who develop the principles and algorithms need to engage in in-depth communication with clinical physicians. Both parties should jointly explore the physiological significance of the indicators and their clinical applications.”

Li Yue also shared his observations on the future trends in technology and applications for cerebral oxygen monitoring.

At the level of the original algorithm, Li Yue believes that the development of the THI index has approached the theoretical limit of near-infrared cerebral oximetry technology. With the algorithm remaining unchanged,Innovations in the Application of Cerebral Oxygen Saturation and THIIt is a most promising direction. What is the relationship between THI and vascular resistance? How can microcirculation be assessed by monitoring its changes? How should cerebral oxygenation be dynamically applied in patients with hemodynamic instability, such as those in shock, and so on?

Another direction,is a fusion algorithm for cerebral oxygenation and other indicators, such as fusion algorithms involving mean arterial pressure, hemodynamic parameters, and electroencephalography.

A more back-to-basics direction isRevisiting the fundamentals of optics to explore whether they can detect concentrations of other chromophores that reflect tissue hypoxia and metabolism. These developments have raised higher requirements for information collection.

Li Yue and his team have already laid the groundwork for pioneering this new phase.

In 2019, Aegean Medical exclusively represented a domestic NIRS brand in participating in the “Phase III International Multicenter Clinical Study on Brain Protection in Extremely Preterm Infants”The project involves nearly 50 hospitals across more than 20 countries worldwide;

In 2020, Aegean Medical andNational Research Center for Rehabilitation Technical AidsCollaborated on the research project “Application of Cerebral Oxygenation Assessment in Cognitive Impairment among the Elderly,” with findings published in Frontiers in Aging Neuroscience in 2022;

In 2021, Aegean Medical andDepartment of Anesthesiology, Beijing HospitalLaunched the project “Development of a Prediction System for Perioperative Neurological Complications Using Artificial Intelligence and Multimodal Cycle Monitoring.” In the same year, the findings were published in *Annals of Translational Medicine*;

In 2022, Aegean Medical represented domestic NIRS brands in participating inChinese Critical Care Ultrasound Study Group (CCUSG)"Visualized Multimodal Base Based on the Hemodynamic Management System" Project.

As one of the paradigmatic institutions for the integration of medicine and engineering in China, Tsinghua University has delivered numerous successful cases to both academia and industry. These successful projects and their commercialization have not only generated corresponding returns for the university and its researchers but also provided valuable experience for other stakeholders in the sector.

Looking back on the more than 20-year journey of Aegean Medical and Li Yue, these experiences serve as a guide left by a seasoned mentor for newcomers, helping researchers in brain science and many other fields who are committed to translating their achievements into marketable products avoid unnecessary detours and setbacks.