Retia's New Algorithm Promises ICU-Level Insight From Standard Sensors

WHITE PLAINS, NY – May 01, 2026 – A new software algorithm could soon transform standard hospital monitors into powerful tools for predicting patient decline, potentially making advanced cardiovascular surveillance ubiquitous from the emergency room to the general ward. Retia Medical today unveiled promising initial results for a non-invasive algorithm that estimates cardiac output using only the data from sensors already attached to millions of patients daily: a standard pulse oximeter and an automated blood pressure cuff.

The announcement, made at the 2026 Annual Meeting of the International Anesthesia Research Society (IARS) and the Society of Critical Care Anesthesiologists (SOCCA) in Montreal, signals a potential paradigm shift in patient monitoring. By eliminating the need for any new or specialized hardware, the technology aims to democratize access to a critical vital sign that has historically been confined to the operating room (OR) and intensive care unit (ICU).

A Software-Only Solution to a Hardware Problem

Accurate measurement of cardiac output—the amount of blood the heart pumps per minute—is fundamental for managing critically ill or high-risk surgical patients. It provides a direct window into the body's circulatory function, allowing clinicians to guide fluid and medication administration with precision. However, the tools to measure it have long presented a trade-off between accuracy and practicality.

The clinical gold standard, the pulmonary artery catheter (PAC), is highly invasive, requiring a catheter to be threaded through the heart. While accurate, it carries significant risks and is reserved for only the most complex cases. Minimally invasive alternatives, such as pulse contour analysis systems, have gained popularity but still require an arterial line, a small catheter placed in an artery, limiting their use to the OR and ICU. Other non-invasive methods exist but typically rely on specialized finger cuffs, chest electrodes, or ultrasound probes that are not part of standard hospital equipment, adding cost and complexity.

Retia Medical's innovation sidesteps this hardware dilemma entirely. By applying its patented Multi Beat Analysis® (MBA) algorithm to the photoplethysmography (PPG) signal from a simple pulse oximeter and data from a non-invasive blood pressure cuff, the company has developed a purely software-based method to derive continuous hemodynamic insights.

"These early results suggest that continuous hemodynamic monitoring could become practical far beyond the ICU or operating room, on general floors, in high-risk ward patients, anywhere deterioration can begin quietly," said Marc Zemel, Chief Executive Officer of Retia Medical, in the company's announcement. "Getting that insight earlier, without adding hardware, is how we can give clinicians earlier warning and more time to act."

Promising Data Against the Gold Standard

The results presented by Retia Biomedical Engineer Brian Nelson came from a prospective validation study involving 47 post-cardiac surgery patients. The algorithm's performance was compared head-to-head against both the invasive PAC thermodilution gold standard and an FDA-approved minimally invasive arterial line system.

Across 145 paired measurements, the non-invasive algorithm demonstrated a root mean squared error (RMSE) of 0.91 L/min compared to the PAC. This metric of accuracy was notably better than the 0.98 L/min RMSE achieved by the established, FDA-approved minimally invasive competitor in the same patient group. This suggests that the software-only approach can provide a level of accuracy comparable, or even superior, to methods that require an invasive arterial line.

The algorithm's ability to track changes in cardiac output over time, known as trending concordance, was 86%. While slightly lower than the 91% achieved by the minimally invasive comparator, this level of performance is widely considered clinically valuable, especially given the trade-off for a completely non-invasive, zero-hardware solution. Experts suggest that for broad surveillance outside the ICU, this is a more than acceptable compromise for gaining unprecedented visibility into patient status.

Democratizing Critical Care and the 'Software-Defined' Hospital

The implications of this technology extend far beyond a single data point. By unlocking advanced monitoring capabilities from ubiquitous equipment, Retia's approach could fundamentally change where and when clinicians can detect hemodynamic instability. This aligns with a growing consensus that patient deterioration often begins with subtle physiological changes that are missed by intermittent, standard vital sign checks on general hospital floors.

One leading expert in anesthesiology and medical director at a major academic medical center's eHospital, who was not involved in the study, recently commented on the value of such systems. "In high-risk patients, deterioration can begin before traditional vital signs clearly reflect it," he noted, explaining that analyzing existing monitoring data "expands visibility into patients' cardiovascular status across surgical settings and critical care units without requiring additional bedside hardware."

This vision of a "software-defined" hospital, where intelligent algorithms extract deeper meaning from routine data, is central to Retia's strategy. The company's underlying MBA algorithm, born from research at MIT and Michigan State University, has already been validated in 14 peer-reviewed publications. Its minimally invasive counterpart, the Argos Cardiac Output Monitor, is deployed in 75 hospitals and distributed by Medtronic.

The new non-invasive algorithm appears to be part of a broader platform strategy. In February 2026, the company received FDA 510(k) clearance for its Argos Infinity cardiovascular intelligence software platform, designed to analyze real-time data streams from existing hospital systems. This regulatory milestone paves the way for software-as-a-service models that integrate seamlessly into a hospital's digital infrastructure.

Economic and Clinical Imperatives Converge

The economic argument for such a system is compelling. Hospitals could expand critical monitoring without any capital expenditure on new devices or ongoing costs for proprietary disposables, which plague many current systems. This not only saves money but also removes a significant barrier to adopting better monitoring practices across an entire institution.

Furthermore, the clinical need is converging with financial incentives. Starting with the 2026 reporting period, the Centers for Medicare & Medicaid Services (CMS) will include Acute Kidney Injury (AKI)—a common and deadly complication often linked to cardiovascular instability—as a hospital harm measure that can affect reimbursement. Technologies that provide early warning of hemodynamic compromise could become essential tools for hospitals to protect both their patients and their bottom line.

While Retia Medical acknowledges that further validation in broader, more diverse patient populations is necessary to establish general applicability, the initial results represent a significant step forward. If the algorithm's performance holds up in future studies, the simple pulse oximeter clip and blood pressure cuff may soon become the sentinels that provide ICU-level vigilance for every high-risk patient, no matter where they are in the hospital.