Pulse Pressure Variation Computation Using Baseline Extraction
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Solution Overview
Problem
Existing algorithms for determining pulse pressure variation (PPV) are unreliable due to falsely elevated or diminished values during hemodynamic changes and irregular heartbeats, leading to misleading clinical decisions on fluid loading, which can result in complications such as hypovolemia or hypervolemia.
Innovation Solution
A device and method that derive a pulse height signal, extract a baseline, and compute PPV by subtracting the baseline from the pulse height signal, using a band pass filter to suppress noise and focus on ventilation-induced components, thereby improving the accuracy of PPV computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PPV algorithms are used to determine pulse pressure variation, then fluid responsiveness assessment can be performed, but the computed PPV values are falsely elevated or diminished during hemodynamic changes and irregular heartbeats, leading to unreliable results
Solution Approach 1:
The patent extracts and removes baseline components and noise from the pulse pressure signal before computing PPV values. By separating the baseline trend and irregular components from the genuine pulse pressure variations, the algorithm eliminates sources of false elevations and diminishions, thereby improving both reliability and measurement precision of PPV values during hemodynamic changes and irregular heartbeats
Solution Approach 2:
The patent introduces intermediate processing steps including baseline estimation and noise filtering as mediators between the raw pulse pressure signal and the final PPV computation. These intermediary processes act as buffers that prevent hemodynamic changes and irregular heartbeats from directly affecting the PPV calculation, thus improving reliability without sacrificing measurement accuracy
2Speed
If PPV computation is performed during hemodynamic changes such as vasoactive medication injection or rapid blood loss, then real-time fluid responsiveness monitoring is achieved, but the PPV values become falsely elevated and do not reflect true fluid responsiveness
Solution Approach 1:
The patent performs preliminary baseline estimation and noise characterization before computing PPV values during hemodynamic changes. By pre-establishing the baseline trend and identifying noise patterns, the algorithm can quickly differentiate between genuine pulse pressure variations and artifacts caused by vasoactive medication or rapid blood loss, maintaining real-time monitoring capability while improving reliability
Solution Approach 2:
The patent implements dynamic baseline tracking and adaptive noise filtering that automatically adjust to changing hemodynamic conditions. The baseline estimation continuously adapts to gradual changes while the noise filter dynamically responds to acute hemodynamic events, allowing real-time monitoring without false PPV elevations during vasoactive medication injection or rapid blood loss
3Duration of action of stationary object
If irregular heartbeats such as premature ventricular contraction or arrhythmia are present, then continuous PPV monitoring can be maintained, but the computed PPV values are greatly affected and become unreliable
Solution Approach 1:
The patent converts the harmful effect of irregular heartbeats into a detectable pattern by analyzing the timing and magnitude of pulse pressure variations. The baseline estimation and noise filtering processes identify irregular heartbeat patterns and automatically adjust the PPV calculation to exclude their influence, thereby maintaining continuous monitoring duration while preserving measurement precision even during arrhythmia or premature ventricular contractions
Data Source
AI summary
The present invention relates to a device, system and method for determining pulse pressure variation of a subject. To enable more reliably determining pulse pressure variation of a subject the device comprises a signal input (11) configured to obtain an input signal representing a hemodynamic signal of the subject, a processor (12) configured to process the input signal and compute a pulse pressure variation and a signal output (13) configured to output the computed pulse pressure variation. The pulse pressure variation is computed by deriving a pulse height signal from the input signal, deriving a pulse height baseline and a de-trended pulse height signal from the pulse height signal as the ratio between the difference between extrema of the de-trended pulse height signal and the respective value of the pulse height baseline signal, and computing the pulse pressure variation from the de-trended pulse height signal and the pulse height baseline.