Clarifications and Further details

Common questions from clinicians, hospital administrators, researchers and industry partners about closed-loop anesthesia, the EasyTIVA framework and the Bissim module.

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EasyTIVA is a proprietary regulation algorithm currently embedded within a clinical application running in medical grade panel PC known as the Decision Control Module (DCM).

The clinical application continuously processes quasi real-time data streams from both the patient’s brain monitor and the connected infusion pumps. By analyzing these inputs, the EasyTIVA regulation algorithm generates a continuous assessment of the patient’s sedation dynamics.

Leveraging this precise clinical insight, the EasyTIVA algorithm determines strategies for optimal timing and infusion rates for both Propofol and Remifentanil throughout the surgery procedure. The DCM automatically transmits infusion commands (e.g., « set rate ») to the infusion pumps whenever an infusion rate adjustment is necessary.

The DCM is not an autonomous system, it’s level of automation would be best described as a Level 4 which means that the sedation regulation is supervised at all time by the anesthesiologist.

The capability to precisely calculate optimal timing and infusion rates for Propofol and Remifentanil significantly stabilizes the patient’s sedation state throughout the surgical procedure.

This stabilization is objectively demonstrated by the statistical distribution of effect-site concentration adjustments over time, which exhibit a very low variance compared to manual regulation (i.e. TCI or Weight based).

By minimizing these fluctuations, the system reduces hemodynamic volatility, thereby rendering intraoperative hemodynamic management more predictable and manageable for the anesthesiologist.

During surgical procedures, brain monitors generate a high volume of high-density data in near-real-time. To accurately decipher sedation dynamics, anesthesiologists must contextualize these instantaneous data points within the framework of historical data and underlying trends spanning several minutes.

The dataset contains subtle, complex physiological patterns that require continuous monitoring to detect. Extracting a precise, actionable information flow demands repetitive and highly accurate mathematical calculations—a task poorly suited to human cognitive processing, which is optimized for holistic decision-making rather than continuous arithmetic.

Managing this data processing burden is particularly challenging during surgery, when the clinician’s primary focus and cognitive bandwidth are occupied by immediate procedural tasks and direct patient care. Without a computerized solution monitoring the brain monitor, a fair share of the value produced and displayed by the brain monitor during surgery remains untapped and non exploited.

Feedback-driven assistive technologies are a relatively recent advancement in the medical field, particularly those relying on the integration of heterogeneous subsystems. The Operating Room provides an ideal environment for automated sedation regulation, as patients are continuously observed by trained physicians and comprehensive monitoring systems.

Consequently, any potential and residual risks associated with closed-loop sedation systems are fully mitigated by the immediate presence of expertise and support devices at the bedside.

ICUs are clearly a more challenging environment as the patient does not have a physician at the bedside. And Homecare is even a more complex and challenging environment when it comes to these PCLC based solutions.

The DCM that embeds the EasyTIVA regulation algorithm is not yet commercially available, nor has it received a CE Mark or FDA Clearance. The technology has only been approved for clinical trials under investigative device exemptions procedures.

Commercialization will materialize once B2B agreements between the key stakeholders — namely infusion pump and brain monitor manufacturers, are defined and implemented.

The current version of the DCM would qualify as TRL7 or possibly TRL8 depending upon the exact specifications sought for the commercial product. As a technology provider, Medsteer is open to work with market players such as infusion pumps or brain monitor manufacturers with the aim at reaching the commercial stage.

Further information on Technology Readiness Levels is available at: https://en.wikipedia.org/wiki/Technology_readiness_level

The Bissim module functions as a digital twin of the BIS brain monitor when used during major surgery with a patient receiving the Propofol-Remifentanil anesthetic regimen. The Bissim operation requires only basic patient demographic parameters — gender, age, weight, and height — which are provided by the anesthesiologist.

The EasyTIVA sedation regulation algorithm and the Bissim module operate as two fully separate and independent agents. While their interaction is inherently unpredictable, the combined output produces a realistic and clinically plausible series of BIS brain monitor values responding to Propofol and Remifentanil infusions.

The Bissim module is conceptually a statistical model based engine which does not pretend to reflect the entire spectrum of clinical contexts and possible dynamic events that may occur during in-vivo major surgery.

During a Bissim simulation session, the anesthesiologist interacts with various dynamic scenarios and seamlessly engage or disengage the EasyTIVA closed-loop sedation assistance at any time. When the automated feedback loop is disengaged, the system reverts to manual control allowing the clinician to select either Target-Controlled Infusion (TCI) or weight-based infusion modes.

EasyTIVA supports independent configuration for each drug, enabling the anesthesiologist to activate the automated regulation assistance for one or both agents simultaneously, while choosing the manual infusion modality best suited to the clinical context if need be. Consequently, the Bissim module delivers a high-fidelity, hands-on introduction to the operational dynamics of closed-loop sedation regulation within a operating room environment. As such, the Bissim module connected to the EasyTIVA sedation regulation assistance delivers a training environment for potential future users of the technology.

The Bissim is a standalone software module operating on Linux, designed to interface with closed-loop algorithms regulating Propofol-Remifentanil drug regimen. Integrating the Bissim module with an experimental sedation regulation algorithm yields critical preliminary insights into its anticipated performance and behavior prior to deployment in the Operating Room. As such, the Bissim module constitutes a valuable validation tool ahead of clinical trials involving human subjects.

While Bissim accelerates and streamlines the development of safe and effective sedation algorithms, it functions as a support simulation tool and does not substitute for comprehensive in-vivo clinical validation in Operating Room settings.

For further information regarding the Bissim module, please do not hesitate to contact us.

Extensive international research conducted over the past decades has consistently validated the manufacturer-recommended Bispectral Index (BIS) target range of 40–60 as both safe and effective for the depth of sedation during major surgical procedures.

When BIS Index values fall below 40, the probability of burst suppression episodes increases and becomes material. Such episodes are well-documented in the clinical literature as a source of neurological stress carrying potentially adverse consequences for patient outcomes.

Minimizing the occurrence of BIS below 40 readings therefore constitutes a critical objective in intraoperative anesthetic management and sedation regulation. Vulnerable patient populations — most notably the elderly — are disproportionately susceptible to potential post-operative complications in the hours, days, and weeks following surgery if the brain has been stressed and potentially hurt by BIS below 40 episodes during the surgery.

Unlike machine learning models, which are inherently probabilistic and susceptible to inconsistent outputs or « hallucinations, » symbolic AI is entirely deterministic. This zero-randomness paradigm ensures that identical inputs consistently yield identical outputs, making symbolic AI uniquely reliable for mission-critical operations. Built upon this framework, EasyTIVA delivers absolute determinism and complete predictability.

One of the most significant challenges in deep learning is the « black box » problem—the inherent difficulty or impossibility of tracing the exact rationale behind a neural network’s decision. Conversely, symbolic AI provides a fully transparent, step-by-step execution path. With EasyTIVA, the precise chain of rules triggered to reach a conclusion remains completely traceable. This absolute auditability is indispensable in highly regulated domains like healthcare, aviation, and defense, where software decisions must be rigorously justified on both legal and scientific grounds.

Furthermore, applying symbolic AI to closed-loop sedation regulation enables the implementation of immutable, hardcoded safety guardrails. EasyTIVA and its core dependencies integrate strict logical boundaries, physical constraints, and automated fail-safes that the system cannot violate. This architectural rigidity makes symbolic engines an ideal foundation for safety-critical system design.

Machine learning models also struggle with « long-tail » edge cases—rare clinical events underrepresented in historical training datasets. In the operating room, these anomalies are highly diverse and frequent. Because a symbolic engine does not require prior exposure to a thousand similar scenarios to act correctly, EasyTIVA’s intricate, built-in rule matrix can address these specific edge cases safely and flawlessly upon first exposure.

Finally, when medical protocols change, clinical guidelines update, or operational policies shift, machine learning models typically require extensive data aggregation and full retraining—a time-consuming process that risks introducing unintended behavioral drift. With a symbolic framework like EasyTIVA, engineers can update, validate, and deploy specific logical rules almost immediately.

For these reasons, symbolic AI represents the definitive approach to managing the inner clinical complexities and rigid contextual constraints of automated sedation regulation in the operating room.

The EasyTIVA regulation algorithm and its dependencies utilize a highly modular architecture featuring clear abstraction layers. This framework is natively engineered to interface seamlessly with any brain monitor and infusion device. Due to the complete interpretability of the source code, the system can be straightforwardly adapted to meet evolving commercial requirements or specialized clinical strategies. Consequently, the current solution serves as an open framework ready for integration into either existing or developing proprietary environments.

Furthermore, all critical software modules within the EasyTIVA framework have successfully passed rigorous MISRA C/C++ static analysis audits with exceptional compliance ratings. Key audited domains include the analysis environment, type safety, memory management, control flow, and side-effect elimination. This disciplined alignment with industry standards ensures excellent code maintainability and long-term architectural stability.

The DCM houses the EasyTIVA sedation regulation algorithm and has direct control of the pump infusion rates through a physical connection.

Infusion rates are calculated by the EasyTIVA regulation algorithm and automatically executed by the infusion pump without human intervention. On average, infusion rates are adjusted every 20 to 40 seconds in order to ensure the effect site concentrations show a low volatility and smooth dynamic over time. The amplitude of variations of effect site concentration targets is typically modest or small, typically a few 10th of a unit.

The underlying regulation mechanism can be best described as a mix of micro-boluses and shortduration basal infusions. This may appear as a paradox or counter intuitive but the high frequency of infusion rate adjustments is necessary to maximize stability of the depth of anesthesia over time

The DCM touchscreen allows the anesthesiologist to instantly activate or deactivate sedation regulation assistance at any point during surgery. User control can be applied independently or simultaneously to either drug. Deactivation is always available, activation is available when the brain monitor registers satisfactory signal quality. The sedation regulation assistance is designed to be used with the simplicity of an automated car cruise control system. Patient diversity being what it is, in a few percentage points (estimate 1 to 3% of the cases), the regulation delivered by the automated assistance may not deliver the quality usually expected by the computerized assistance. In which case, the anesthesiologist may deactivate the sedation regulation assistance and revert to a manual regulation of Propofol and Remifentanil infusions.

The EasyTIVA regulation algorithm and its dependencies utilize a highly modular architecture featuring clear abstraction layers. This framework is natively engineered to interface seamlessly with any brain monitor and infusion device. Due to the complete interpretability of the source code, the system can be straightforwardly adapted to meet evolving commercial requirements or specialized clinical strategies. Consequently, the current solution serves as an open framework ready for integration into either existing or developing proprietary environments.

Furthermore, all critical software modules within the EasyTIVA framework have successfully passed rigorous MISRA C/C++ static analysis audits with good to very good compliance ratings. Key audited domains include the analysis environment, type safety, memory management, control flow, and side-effect elimination. This disciplined alignment with industry standards ensures excellent code maintainability and long-term architectural stability.