Self-calibrating systems and methods for blood pressure wave form analysis and diagnostic support

Inventors

Baruch, Martin

Assignees

Caretaker Medical LLC

Abstract

Indirect, oscillometric, digital blood pressure monitoring systems and methods enabling self-calibration to obtain absolute blood pressure values using algorithmic analysis of arterial pressure pulses to establish an oscillometric profile and compensate for intervening effects on digital arterial pressure. Proper algorithmic analysis is dependent upon proper positioning and maintained engagement of a digital cuff on the digit of a user and subsequent hydraulic coupling of the cuff to the arteries within the digit.

Core Innovation

The patent describes a self-calibrating indirect oscillometric blood pressure monitoring system using a cuff with an air bladder secured to a user so the air bladder is disposed in contact with tissue adjacent at least one artery. A pump increases pressure of the air bladder, and the controller identifies an oscillometric profile as a function of the pressure of the air bladder to determine calibrated, absolute blood pressure values, including a calibrated, absolute systolic value and a calibrated, absolute diastolic value.

After identifying the oscillometric profile, the controller controls the pump to maintain the air-bladder pressure at a pressure less than a diastolic blood pressure of the user so the artery is partially unloaded and the air bladder is hydraulically coupled to the artery. While the cuff pressure is maintained below diastolic blood pressure, the controller receives pressure change data based on pulse pressure oscillations within the air bladder and uses the pressure change data to determine real-time absolute pressure measurement values by tracking changes in blood pressure relative to the calibrated, absolute blood pressure values.

The patent further refines calibration by deriving thresholds and offsets from the oscillometric profile, including preliminary thresholding, categorization into low/normal/high ranges, and slope-based features related to systolic and diastolic sides. It also includes spectral-content and slope-based correction of thresholds using features of the arterial pulse so that the resulting calibrated absolute systolic and diastolic values are consistent with ANSI/AAMI/ISO 81060-2:2013.

An alternate self-calibration embodiment is described using an additional optical oxygenation sensor to identify diastolic and systolic occlusion events during cuff inflation, and the patent includes irregularity rejection of oscillometric profiles associated with cuff positioning or scan errors.

Claims Coverage

The provided independent claims are directed to a system and a method that perform cuff pressure control below diastolic pressure after deriving a calibrated oscillometric profile, enabling real-time absolute blood pressure tracking. Across the independent claims, there are four inventive features for using an air-bladder cuff to generate an oscillometric profile, determining calibrated absolute systolic and diastolic values, maintaining hydraulic coupling under diastolic pressure, and tracking real-time absolute values from pulse-pressure-oscillation pressure change data.

The claim coverage centers on a two-phase oscillometric workflow: first, generate an oscillometric profile from cuff air-bladder pressure to derive calibrated absolute systolic and diastolic values; then, maintain cuff pressure less than diastolic to partially unload and hydraulically couple the artery, and use pulse-pressure-oscillation pressure change data to track real-time absolute pressure relative to the calibrated values. Dependent claims further refine calibration using threshold/offset/slope processing and spectral-content features, define oscillometric profile identification via an arterial pulse peak with diastolic/systolic sides and maximum amplitude, and add an optical oxygenation sensor embodiment for identifying occlusion events during cuff inflation.

Stated Advantages

Documented Applications