80 results about "Cuff pressure" patented technology

The invention relates to the field of physiological signal detection, and discloses a blood pressure measurement system based on brachial artery cuff pressurization and finger PPG detection, which comprises a pressure control module, a PPG acquisition module and a central processing unit. The central processing unit is configured to extract a multi-dimensional PPG feature vector from the PPG signal in real time; dynamically adjusting the change mode of the cuff pressure applied by the pressure control module in a closed-loop manner based on the change of the PPG feature vector; constructing a dynamic response map based on the synchronously recorded cuff pressure and PPG feature vector; and determining a blood pressure value based on the overall analysis of the dynamic response map. Determining the blood pressure value specifically includes identifying a systematic distorted phase transition point in the atlas to determine systolic pressure. Through closed-loop adaptive excitation and global trajectory analysis, blood pressure determination is established on the basis of hemodynamic state transition, dependence on isolated event points is avoided, and measurement robustness and accuracy are improved.

This invention, which offers the advantage of an automatic repetitive blood pressure measurement that minimizes discomfort for the subject while continuously measuring blood pressure regardless of the subject's movement, thereby enhancing the reliability of the measurement results, which leads to the development of an automatic repetitive blood pressure measurement device and method for a smart blood pressure monitor, relates to blood pressure measurement technology, involving periodically repeating the inflation and deflation of a cuff a set number of times upon receiving a single operation signal input. The method includes the steps of detecting arterial wall vibrations when the cuff pressure is between the systolic and diastolic pressures of the artery during cuff inflation and deflation, recognizing the point where maximum vibration is detected as the systolic blood pressure based on the detection results, recognizing the diastolic blood pressure if the vibration decrease exceeds a threshold, and providing measurement results sequentially, including the recognized systolic and diastolic blood pressure values during the repeated inflation and deflation of the cuff a set number of times.

A method of estimating the reliability of cardiac output (CO) measurements obtained using an arterial waveform analysis (AWA) technique calibrated using thermodilution. During thermodilution calibration: (i) initiating inflation of a cuff that is at a location on the subject, (ii) obtaining a first cuff pressure signal comprising measurements of pressure inside the cuff during inflation, (iii) analyzing the first cuff pressure signal to derive a relationship between oscillations in arterial volume beneath the cuff and pressure in the arteries, and (iv) estimating a first arterial compliance of the arteries for a range of cuff pressures based on the determined relationship, (b) during a second time period that is after the first time period, repeating steps (i)-(iv) to estimate a second arterial compliance of the arteries, and (c) using a result of a comparison of the first arterial compliance and the second arterial compliance to determine a reliability of CO measurements.

The invention provides a blood pressure measurement system and method for identifying oscillatory wave characteristics by using an elastic template method, and relates to the technical field of wearable medical health monitoring, the blood pressure measurement system comprises a pressure control module, a data preprocessing module, a data quality evaluation module and a waveform analysis and matching module; the method comprises the following steps: acquiring cuff pressure control and an original oscillation wave signal of a to-be-identified sample, and preprocessing the acquired original oscillation wave signal; then carrying out quality evaluation on the preprocessed oscillatory waves, wherein the quality evaluation comprises data quality evaluation of the oscillatory waves and data quality evaluation related to inflation and deflation blood pressure measurement; and finally, performing blood pressure estimation based on a dynamic time warping (DTW) algorithm, fusing an amplitude coefficient method in an oscillography, oscillatory waves and changes of characteristic wave bands of the oscillatory waves, and estimating the blood pressure based on a waveform template matching method.

The present invention relates to a device, system and method for calibrating a blood pressure, BP, surrogate for use in monitoring a subject's blood pressure. The device comprises a BP input (51), a sensor input (52) and a processing unit (53) that is configured to compute a control signal for controlling the pressure-delivery system (10) to repeatedly inflate its cuff in directly consecutive partial inflations up to a cuff pressure equal to or below the subject's mean BP, compute pulse-related values from the first and second time-dependent sensor signals, measured during the repeated directly consecutive partial inflations of the cuff, using a first feature in the first time-dependent sensor signal and a second feature in the second time-dependent sensor signal, the pulse-related values being pulse arrival time, PAT, values or pulse transit time, PTT, values, and compute a calibration parameter for a BP surrogate from the BP measurement value and pairs of the pulse-related values and corresponding cuff pressure values, computed from the first and second time-dependent sensor signals measured during the repeated directly consecutive partial inflations of the cuff, a pair comprising a pulse-related value and a corresponding, temporally related cuff pressure value.

The embodiment of the invention provides equipment, a method and a device for measuring blood pressure based on a boosting process. The equipment comprises a cuff with an inflatable air bag, a pressure signal acquisition unit, a piezoelectric signal acquisition unit and a processor, the piezoelectric signal acquisition unit is arranged on the side, attached to the arm, of the cuff, and the pressure signal acquisition unit acquires pressure signals in the cuff in the air bag inflation stage when the equipment is used for measuring blood pressure; the piezoelectric signal acquisition unit is used for synchronously acquiring piezoelectric signals generated by brachial artery pulsation in an air bag inflation stage; and the processor is used for processing the piezoelectric signal to obtain the signal position of the effective Korotkoff sound signal, and obtaining a blood pressure measurement result based on the signal amplitude of the pressure signal at the signal position. In the blood pressure measurement process, the air bag can be inflated slowly and evenly, pressurization is stopped immediately when it is detected that the pressure reaches a target value, the use comfort of the device is improved, meanwhile, Korotkoff sound is accurately detected, and the blood pressure measurement accuracy is improved.

The present invention comprises a cuff (20), a cuff pressure adjustment unit (32, 33), and a pressure sensing unit (31) that senses cuff pressure. During a pressure release process, the time at which a waveform feature point of a pulse beat was generated for each pulse of a pulse wave indicated by an artery passing through a measurement target site is recorded. During the pressure release process, a memory (51) is caused to sequentially store, as a data pair, the time at which the waveform feature point of the pulse beat was generated and the cuff pressure at that time. The cuff pressure is displayed on an indicator (50).In the pressure release process, an observer listening for a Korotkoff sound with a stethoscope while observing the cuff pressure displayed on indicator (50) operates an operating unit (52B) and inputs a time signal indicating the time at which the observer judged that the generation of the Korotkoff sound had ceased. A data pair corresponding to one pulse beat preceding a data pair corresponding to the time is specified, and a cuff pressure contained within the specified data pair is recorded as a corrected diastolic blood pressure value.

A blood pressure measuring device includes: a cuff to be wrapped around a measurement target site; a pressure sensing unit configured to detect cuff pressure; a pressure control unit configured to control the cuff pressure; a blood pressure calculation unit configured to perform blood pressure calculation processing based on the cuff pressure;and a winding strength determination unit configured to perform winding strength determination processing to determine a winding strength of the cuff at the target measurement location, wherein the pressure control unit performs constant pressure control to maintain the cuff pressure at a constant target pressure value from the start of an increase in cuff pressure until the end of the winding strength determination processing, and performs constant rate pressurization control to increase the cuff pressure at a constant rate to calculate the blood pressure after completion of the winding strength determination processing, and wherein the winding strength determination unit determines the winding strength during the constant pressure control.

The invention provides a blood pressure measurement system and method based on oscillatory wave intelligent simplification and transmission, and relates to the technical field of wearable medical health monitoring. Comprising a pressure sensing module, a data preprocessing module, a signal quality evaluation module, a waveform simplification module, an availability evaluation module and an information processing module. The method comprises the following steps: continuously acquiring cuff pressure data on an arm of a user in real time through a cuff pressure sensor, acquiring real-time cuff pressure, and acquiring a real-time value of cuff pressure oscillatory waves; an air pressure sensor is arranged on an air pipe of a sphygmomanometer cuff, a voltage comparator is additionally arranged in the air pressure sensor to monitor the pressure change in the cuff, a serial port chip converts data transmitted by a chip SOC and serial port data mutually, and through a 4G / 5G antenna, a GPS / GNSS antenna and an identity recognition module which are integrated, the pressure change in the cuff is monitored. Transmitting the output simplified oscillation wave waveform signal, the cuff pressure signal, the real-time position information and the personal information of the testee to a health cloud system, and establishing a personal blood pressure monitoring database.

Electronic blood pressure monitor (1), which comprises: a cuff (20) which can be worn at a measuring location; a pressure adjustment unit (51, 52) which adjusts the pressure within the cuff (20) by increasing or decreasing pressure; a pressure detection unit including a plurality of pressure sensors (321, 322) and configured to detect the cuff pressure within the cuff (20) based on the pressure information output from the plurality of pressure sensors; a blood pressure calculation unit (112) which calculates a blood pressure based on the change in cuff pressure, which is detected by the pressure detecting unit at a time of blood pressure measurement; a maintenance unit (111) which maintains the cuff pressure at a predetermined pressure at the time of blood pressure measurement; and an abnormality detection unit (113) which, in a state in which the maintenance unit maintains the cuff pressure at a predetermined pressure, detects whether an abnormality has occurred in at least one of the plurality of pressure sensors (321, 322), based on the pressure information output by the plurality of pressure sensors (321, 322).

Various patient monitoring systems, devices, and methods are disclosed for monitoring physiological parameters of a patient. A noninvasive blood pressure monitor can include an inflatable cuff, a pressure transducer, an air pump, and a plurality of air paths connecting the inflatable cuff, the pressure transducer, and the air pump. The monitor can also include an acoustic filter provided along at least one of the air paths. In some cases, the monitor can include first and second air pumps, as well as a processor to independently control operating characteristics of the air pumps. The processor can also control the air pumps so as to provide a first inflation rate for the inflatable cuff during a non-measurement portion of an inflation phase and a second, higher inflation rate during a measurement portion of the inflation phase.

A blood purification device (10) comprises: a measurement unit (44) that uses a cuff (54) for pressurizing a blood vessel of a patient undergoing blood purification treatment to measure the patient's blood pressure values and the patient's pulse wave amplitude values corresponding to cuff pressures; and a prediction unit (50) that receives, as input, time-series data including the blood pressure values and the pulse wave amplitude values measured in the blood purification treatment, and outputs the patient's blood pressure prediction value.

The utility model relates to a tracheal catheter capable of monitoring air bag pressure, which comprises an air guide tube, an air bag sleeved outside the air guide tube, an inflation tube used for inflating and deflating the air bag and a pressure measuring device capable of monitoring the air bag pressure, and the pressure measuring device comprises a pressure indicating bag arranged outside the air bag and a liquid storage bag sleeved outside the pressure indicating bag. The pressure indication bag is communicated with the air bag through an inflation tube, and indication liquid used for displaying expansion and contraction changes of the pressure indication bag is arranged in the liquid storage bag. After the technical scheme is adopted, the liquid storage bag is arranged outside the air bag, the liquid storage bag is located outside the human body during use, safety is higher, risks caused by accidental leakage are avoided, the pressure indicating bag and the liquid storage bag are used for monitoring the pressure change of the air bag, simplicity and intuition are achieved, and even if the pressure change is small, the liquid storage bag can not be used. The liquid level sensor has the advantage of being convenient to monitor.

The invention relates to the field of intelligent wearing and blood pressure detection, in particular to a novel blood pressure detection method combining photoelectric pulse waves and a wrist cuff. The system comprises a wrist cuff, an air pump, a barometer, an analog-to-digital conversion module, a photoelectric pulse wave detection module, an MCU calculation unit, a display module and a cloud data module. The cuff pressurization process is started, and meanwhile photoelectric pulse wave detection is started, that is to say, blood pressure data in the cuff pressurization process can be obtained, and data of photoelectric pulse waves can also be obtained at the same time. Particularly, a photoelectric pulse wave detection module needs to be placed behind a cuff pressurization physical blocking line, and the purpose is to solve the problems that a wrist type cuff is small, pressurization saturation is fast, and once the volume of the cuff is full, the pressure value of the cuff is not in linear correlation. For people with hypertension, blood flow cannot be linearly blocked, a blood pressure value cannot be accurately calculated, photoelectric pulse wave data are increased to solve the problem that hypertension cannot be accurately measured due to the fact that a wrist cuff is small, and meanwhile the blood pressure measuring range of the wrist cuff is increased.

Blood pressure measuring device (1), which has: a cuff (40) which, when worn on a blood pressure measuring area, pressurizes an artery in the measuring area at the pressure of a fluid in the cuff (40); a piezoelectric pump (31) which increases the pressure within the cuff (40); an air outlet unit (32) which reduces the pressure within the cuff (40); a pressure detection unit (33) which detects the cuff pressure, which is the pressure content of the cuff (40); and a control unit (20) wherein the control unit (20) includes: a determining device which determines a control amplitude and determining a control frequency of a voltage applied to the piezoelectric pump (31) (step S111 to step S114, step S131 to step S134); an applied voltage control means which carries out the control so that a voltage at the control amplitude and control frequency determined by the determining means is applied to the piezoelectric pump (31) (step S121, step S122); and a blood pressure measuring device which calculates a blood pressure value based on the cuff pressure detected by the pressure detecting unit during inflation when the cuff pressure is increased by the piezoelectric pump (31) (step S123), and wherein the applied voltage control means can control the amplitude of the voltage in predetermined steps and, in a predetermined order, applies a voltage having an amplitude which is a value above the control amplitude by at least one step and a voltage having an amplitude which is a value below the control amplitude by at least one step, so that the discharge of the piezoelectric pump (31) is approximately the same as when a voltage at the control amplitude determined by the determining means is applied (step S111, step S112, step S121, step S122, step S131 to step S133).

The invention relates to a blood pressure measuring method and device, computer equipment and a storage medium, and the method comprises the steps that a cuff pressurizing module is started, and an air pump assembly is used for inflating the cuff pressurizing module until the pressure of the cuff pressurizing module exceeds the systolic pressure of a measured person; in the process that the air pump assembly inflates the cuff pressurization module based on the preset inflation rate, cuff pressure data detected by the pressure sensor and PPG data collected by the PPG sensor module are obtained; and performing fusion calculation on the cuff pressure data and the PPG data by using a preset blood pressure calculation model to obtain a blood pressure measurement result. The blood pressure measuring precision and the air inflation rate can be improved, the measuring time is shortened, and then the problem that in the air inflation process, a measured person is pressed by the cuff for a long time, and consequently discomfort is caused can be solved.

The present invention discloses a training method, application method, device, and medium for a blood pressure measurement network. The method includes: obtaining a pulse wave signal and a cuff pressure signal for blood pressure measurement and determining the mean pressure position; shearing the original signal according to the mean pressure position to obtain a blood pressure correction training sample set; constructing a blood pressure recognition training sample set using the signals corresponding to the systolic pressure sampling position and the diastolic pressure sampling position; downsampling the blood pressure training sample set using a preset position information expansion method to obtain a target blood pressure recognition training sample set; and determining a fully trained first recognition model, a second recognition model, a third recognition model, and a correction model. The present invention solves the technical problem in the prior art of using directly obtained pulse wave signals as input to a blood pressure prediction network, which results in a large workload and inaccurate measurement results.

A blood pressure measurement device for estimating a blood pressure value using pulse wave data, having: a cuff for compressing a part under measurement; a sensor that detects the pressure of the cuff; a pulse wave acquisition unit that acquires pulse wave data from an output signal from the sensor; an index estimation unit that, at a prescribed periodicity, performs index estimation processing to estimate an index on the basis of the pulse wave data acquired up to the present time while the cuff is gradually pressurized, said index expressing the position of the present time with respect to a predicted envelope that is predicted to be obtained if the pressurization of the cuff is continued; and a pressurization control unit that stops the pressurization of the cuff when the value of the index estimated by the index estimation processing reaches a predetermined threshold.

The invention discloses a pneumatic pressurization control method and system for an electronic sphygmomanometer and a related device, which are used for improving the comfort of a tested person and the measurement safety and improving the measurement efficiency of a blood pressure measurement process on the whole. The method comprises the following steps: carrying out component separation on a photoelectric volume pulse wave signal to obtain a pulsation component reflecting the periodic change of arterial blood flow, and constructing an amplitude feature sequence updated along with a pressurization process; calculating the attenuation rate of the amplitude feature sequence relative to the reference sequence in the current pressure interval; constructing a nonlinear response trend model of the pulse amplitude to the pressurization process; whether the far-end artery blood flow enters a blocking critical state or not is judged in combination with a preset background noise base; if yes, the cuff is controlled to stop continuous pressurization, and the self-adaptive pressurization upper limit parameter measured this time is determined according to the cuff pressure at the corresponding moment; and controlling the sphygmomanometer to be switched from the pressurization control process to the deflation measurement process based on the self-adaptive pressurization upper limit parameter.

Provided is a sphygmomanometer capable of achieving high-precision blood pressure measurement even with a small amount of teacher data. This sphygmomanometer is provided with: a cuff wound around the arm of a person to be measured; a control unit for controlling the pressure of the cuff on the arm; a detection unit that detects a cuff pressure applied to the cuff from the arm; a measuring unit for measuring the blood pressure of the subject by oscillography using the time-series change in the cuff pressure; a correction model, which is constructed by machine learning for a plurality of subjects, and which has, as an explanatory variable, waveform information relating to a time-series change in the cuff pressure, and which has, as a target variable, an error in the blood pressure measured by the measurement unit with respect to the blood pressure used as a true value; a correction unit that corrects the blood pressure measured by the measurement unit on the basis of an error output by the correction model by inputting, to the correction model, the information of the waveform relating to the time-series change in the cuff pressure detected by the detection unit; and an output unit that outputs the blood pressure corrected by the correction unit.

A biological information measuring device includes: a blood pressure measuring section that measures blood pressure of a subject, the blood pressure measuring section having a cuff that compresses a measured site of the subject, a pump that supplies gas into the cuff, an exhaust valve that adjusts discharge of the gas from the cuff, a pressure detecting section that detects a cuff pressure as a pressure in the cuff, a cuff pressure control section that controls the pump and the exhaust valve, and a blood pressure operation section that calculates the blood pressure of the subject; an electrocardiogram measuring section that measures an electrocardiogram waveform by processing an electrical signal acquired by a plurality of electrodes, the plurality of electrodes including an electrode provided on a side of the measured site of the cuff and capable of contacting a skin of the subject; and an electrocardiogram storage section that stores information of the measured electrocardiogram waveform in association with time, the biological information measuring device including an interval specifying section that specifies an interval of the information of the electrocardiogram waveform from the information of the electrocardiogram waveform stored in the electrocardiogram storage section based on a progress of the measurement of the blood pressure of the subject in parallel with the measurement of the electrocardiogram waveform.

An endotracheal tube or tracheostomy tube with a cuff assembly comprises a cuff pressure regulator and a leak detection system. A pressure sensor monitors and measures the tracheal wall pressure and the pressure within the cuff assembly. When the measured value of the pressure sensor is abnormal, the cuff pressure adjustment process is initiated. The leak detection system detects air leakage from the seal between the cuff assembly and the tracheal wall. A scented film with a predetermined scent is placed on the lower portion of the cuff assembly distal to the seal with the tracheal wall. If a predetermined scent is detected in the air within the trachea proximal to the cuff assembly, it indicates an air leak. An air circulation device can generate an air flow within the trachea and sample and inspect a new batch of air. When an air leak is detected, the cuff pressure adjustment process is initiated.

The invention belongs to the technical field of hemostasis instruments, and provides a method for measuring blood vessel locking pressure by an orthopedic surgery hemostasis instrument, which comprises the following steps of: inflating a cuff wound on a limb until a blood vessel is completely locked, and controlling the cuff to release pressure at a constant speed, the pressure sensor and the independent pulse vibration sensor synchronously and independently collect a cuff pressure value and a pulse wave signal, the pulse wave signal is processed to obtain the trend that the amplitude of the pulse wave signal changes along with the pressure, and the amplitude is converted from a stable baseline state representing vascular atresia to the corresponding cuff pressure when the amplitude continuously rises for the first time. And the critical opening pressure of the blood vessel is accurately judged and is used as an individualized blood vessel locking pressure measurement value. The invention also discloses steps for carrying out hemostasis operation by using the method and a hemostasis instrument for realizing the method. The problem that in the prior art, measurement is not accurate due to the fact that pressure or pressure pulsation signals depend on experience is solved, and accurate measurement of the vascular locking pressure is achieved.

The present invention relates to device, system and method for calibrating a blood pressure, BP, measurement function. The device comprises a pressure input (51) configured to obtain time-dependent cuff pressure values during inflation and / or deflation of a cuff (11) of a pressure-delivery system (10) attached to a subject's body part; a sensor input (52) configured to obtain a first time-dependent sensor signal and a second time-dependent sensor signal, both related to the subject's heartbeat and measured during the inflation and / or deflation of the cuff; and a processing unit (53) configured to calibrate the blood pressure measurement function based on a reference BP value, a computed pulse-related value and a computed derivative value of the derivative of the fitting function at the reference BP value.

According to one aspect, there is provided a method of estimating the reliability of a cardiac output, CO, measurement obtained for a subject using an arterial waveform analysis, AWA, technique. The AWA technique is calibrated using a CO measurement obtained using a thermodilution CO measurement technique. The method comprises: (a) during a first time period in which a first CO measurement is obtained for the subject using the thermodilution CO measurement technique: (i) initiating (203) inflation of a cuff at a first location on the subject; (ii) obtaining (205) a first cuff pressure signal comprising measurements of pressure inside the cuff during inflation; (iii) analysing (207) the first cuff pressure signal to derive a relationship between oscillations in the volume of an artery under the cuff and pressure in the artery; and (iv) estimating (209) a first arterial compliance of the artery for a range of cuff pressures based on the determined relationship; (b) during a second time period after the first time period, repeating (211) steps (i)-(iv) to estimate a second arterial compliance of the artery; and (c) using (213) the results of a comparison of the first arterial compliance and the second arterial compliance to determine the reliability of a CO measurement obtained during the second time period using the AWA technique.

The invention relates to a multi-parameter analysis method integrated with arteriosclerosis assessment and a health monitoring system, and the method comprises the steps: determining a pressure oscillatory wave signal based on a cuff pressure signal through synchronously collecting the cuff pressure signal and electrocardiosignals and photoelectric volume pulse wave signals of two-side finger tips; calibrating a blood pressure analysis process of the pressure oscillatory wave signal based on a systolic pressure calibration reference determined by the photoelectric volume pulse wave signal, and determining a blood pressure value; calculating a vascular function evaluation result including the arteriosclerosis degree based on a heartbeat time sequence reference determined by the electrocardiosignal, the cuff pressure signal and the photoelectric volume pulse wave signal; performing multi-parameter correlation analysis on the blood oxygen signal and the electrocardiosignal extracted from the photoelectric volume pulse wave signal to obtain a multi-parameter analysis result; the blood pressure value, the blood vessel function evaluation result and the multi-parameter analysis result are integrated, and a comprehensive health evaluation report is generated; according to the invention, integration of multi-parameter acquisition, accurate calculation and deep analysis can be realized, and comprehensive and reliable health assessment support is provided.

The invention provides a medical inflation device. The medical inflation device comprises an air storage chamber, a constant pressure chamber, a pressure detection module and a plurality of airflow control modules. The air inlet end of the constant pressure chamber is connected with the air outlet end of the air storage chamber through a first controllable flow path, and the air outlet end of the constant pressure chamber is a cuff air supply outlet; the gas inlet end of the gas storage chamber is connected with various gas sources through a second controllable flow path; the air outlet end of the constant pressure chamber is also connected with external atmosphere through a third controllable flow path; airflow control modules are arranged on the first controllable flow path, the second controllable flow path and the third controllable flow path; the airflow control module is used for regulating and controlling airflow on-off and flow; the system has the functions of multi-gas-source redundancy, real-time detection and correction and gas safety guarantee, and the pressure of the cuff can be automatically adjusted in real time through pressure feedback.

The present invention suppresses the occurrence of noise associated with switching of control and acquires a clean pressure pulse wave from a low pressure. This blood pressure measurement device comprises a cuff that is wound around a measurement site, a pressure detection unit that detects the cuff pressure in the cuff, a pressure control unit that controls the cuff pressure, a blood pressure calculation unit that performs a blood pressure calculation process for calculating the blood pressure of a subject on the basis of the detected cuff pressure, and a winding strength determination unit that performs a winding strength determination process for determining the winding strength with which the cuff is wound around the measurement site. The pressure control unit performs uniform rate pressurization control in which the cuff pressure is increased at a uniform rate through the winding strength determination process performed after the increasing of the cuff pressure is started and the blood pressure calculation process performed after the end of the winding strength determination process.

The present disclosure relates to a method and corresponding system for a non-invasive determination of a physiological parameter, the method (400) comprising: applying (410) a first pressure cuff (150) to a limb of a living subject, in particular of a human being; applying (420) a second pressure cuff (104) distally to the first pressure cuff (150) to the limb of the subject; inflating (430) the first pressure cuff (150) to a pressure value exceeding a first threshold value; monitoring (440) a pressure signal of the second pressure cuff (104) after the step of inflating the first pressure cuff (150); deriving (450) a measure indicative of mean systemic filling pressure, MSFP, from the monitored pressure signal of the second pressure cuff (104).