Device, system and method for determining pulse pressure variation of a subject

Abstract

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.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a device, system and method for determining pulse pressure variation of a subject.BACKGROUND OF THE INVENTION[0002]Optimal circulatory volume status is important for patients in the operating room (OR) and the intensive care unit (ICU). On the one hand, hypovolemia can lead to inadequate oxygen delivery to tissues. On the other hand, hypervolemia can induce tissue edema and oxygen delivery alteration. Hemodynamic optimization, in the aim of optimal circulatory volume, has been shown to be able to improve postoperative outcome and reduce the cost of the surgery.[0003]Unfortunately, circulatory volume status cannot be assessed directly. Fluid responsiveness has been used as an indirect assessment of volume status. It answers the question if a patient's cardiac output and hence hemodynamics can be increased by giving fluid. If not, extra fluid loading may cause complications. To evaluate fluid responsiveness, static indicator...

AI Technical Summary

Benefits of technology

The present invention provides a device, system and method for more reliably determining pulse pressure variation of a subject. This is important for preventing patients from hypovolemia and hypervolemia in operating rooms and ICUs. The invention extracts the baseline from the pulse height signal and uses it as the mean PH signal to compute PPV, which involves suppressing the influence of baseline changes and avoiding generating falsely elevated or diminished PPV values. The invention also filters the de-trended pulse height signal using a band pass filter to focus on the ventilation-induced components to suppress the influence of varying phase between cardiac and ventilation cycle and irregular beats. In another embodiment, the invention computes the pulse pressure variation value in a computing window by computing the difference between the maximum value and the minimum value or between an upper threshold value and a lower threshold value of the de-trended pulse height signal. This further improves the accuracy of the computation.

Problems solved by technology

On the one hand, hypovolemia can lead to inadequate oxygen delivery to tissues.

On the other hand, hypervolemia can induce tissue edema and oxygen delivery alteration.

Unfortunately, circulatory volume status cannot be assessed directly.

If not, extra fluid loading may cause complications.

Static indicators such as central venous pressure (CVP), or left ventricular end-diastolic area have been demonstrated to have poor performance for assessing fluid responsiveness.

Further, irregular heartbeats (e.g. premature ventricular contraction or arrhythmia) greatly affect the computed PPV values.

Still further, even during situations of stable heart rhythms and no hemodynamic changes, the computation of the PPV value is intrinsically noisy.

Falsely elevated or diminished PPV values are misleading to clinicians and may lead to wrong decisions on fluid loading, resulting in patients with hypovolemia or hypervolemia.

These conditions can lead to serious complications.

The system may detect gain changes or excessive baseline modulations.

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