Cardiac Output Decision Support System for Circulatory Compromise

The patent introduces an intermediary computational model that processes readily available physiological parameters (arterial oxygenation, haemoglobin concentration, oxygen partial pressure, oxygen consumption) to estimate mixed venous oxygen saturation and cardiac output. This intermediary calculation layer bridges the gap between simple non-invasive measurements and the need for accurate cardiac output assessment, eliminating the need for direct invasive catheter placement while maintaining measurement reliability.

The patent replaces the mechanical invasive system (PA catheter placement requiring physical insertion into pulmonary circulation) with a computational system that uses mathematical models and physiological equations. This substitution eliminates the mechanical intrusion into the patient's circulatory system while deriving cardiac output information through computational analysis of blood gas parameters and oxygen consumption data.

The patent enables the physiological monitoring system to self-assess the adequacy of cardiac output estimation by internally calculating mixed venous oxygen saturation and comparing it against physiologically plausible ranges. The system uses the Fick principle and oxygen transport equations to self-validate the consistency of estimated cardiac output with measured oxygen consumption and arterial-venous oxygen content differences, providing internal quality control without requiring invasive reference measurements.

The patent implements a feedback mechanism where the calculated mixed venous oxygen saturation is continuously compared against reference values and physiological thresholds. When the estimated SvO2 falls outside acceptable ranges or when the calculated cardiac output is inconsistent with other physiological parameters, the system generates alerts or adjusts its estimation algorithms, providing continuous validation and improving measurement reliability through iterative feedback from multiple physiological parameters.

The patent applies partial action by selectively estimating cardiac output only when clinically indicated, rather than continuously measuring in all patients. The system calculates a minimum cardiac output threshold based on measured oxygen consumption and arterial oxygen content, and only triggers full cardiac output assessment or clinical intervention when the estimated value approaches or falls below this threshold, thereby reducing unnecessary measurements while maintaining reliability for compromised patients.

The patent performs preliminary assessment by calculating the minimum cardiac output threshold and estimated mixed venous oxygen saturation using readily available physiological parameters before committing to invasive measurement procedures. This preliminary computational screening identifies which patients actually require full cardiac output measurement, allowing clinicians to prioritize interventions and avoid unnecessary invasive procedures on patients with adequate cardiac output reserves.