A method for determining a flow rate and/or a concentration of particles of a fluid flowing in a chamber, which includes the steps of: producing an ultrasound beam of a given frequency with a first transducer such that all fluid components traveling through an intersection region between the ultrasound beam and the chamber are insonated by the first transducer; receiving Doppler-shifted ultrasound signals generated by the fluid components in the insonated region of the chamber with a second transducer; acquiring the ultrasound signals received by the second transducer during an acquisition time; obtaining a Doppler Power Spectrum of the acquired ultrasound signals; and determining the flow rate and/or the concentration of particles of the fluid by adjustment between, on the one hand, the obtained Doppler Power Spectrum and, on the other hand, a model of the Doppler Power Spectrum.

A control system in a blood line (12) of a cardiopulmonary bypass perfusion system (1) comprises a flow sensor (26) to determine a flow value indicative of the flow rate, a controller configured to process the flow value, and an adjustable restriction (28) responsive to the controller, to reduce the flow rate in the venous blood line (12) to maintain a flow rate to the venous blood reservoir that does not exceed a restriction threshold. As the adjustable restriction (28) is responsive to the flow sensor (26), this provides a closed loop control mechanism that avoids restricting the blood line (12) of the perfusion system (1) more than intended.

A portable device for monitoring vascular access status is disclosed. The portable device comprises a measurement device and a monitoring module. The measurement device senses vibration data induced by blood flow over certain part of a vascular access of a subject via a vibration-sensing module, and sends the sensed data to outside via its communication module. The monitor module controls an electronic device to receive the sensed data and determines a vibration evaluation index corresponding to a status of the part of the vascular access. The portable device for monitoring vascular access status of the present disclosed example has advantages of small size, easy to carry, low cost, and so on, so as to be applicable to home vascular access status monitor.

A device and method for monitoring an access to a patient, an extracorporeal blood circuit and/or a dialyzing fluid system includes a centrifugal pump for conveying blood or dialyzing fluid instead of an occluding pump. Centrifugal pumps bring about a large change in flow rate by even a small change in pressure difference across the pump. The device includes a measuring unit for measuring the flow rate of blood or dialyzing fluid conveyed by the centrifugal pump, and a control and computing unit configured to determine an incorrect vascular access or malfunction if a change in measured flow rate Q is more than a predetermined amount. For example, a small drop in pressure in the venous blood line leads to a marked increase in the flow rate of the centrifugal pump, which is used as a basis for the detection of an incorrect vascular access.

A cardiac function measuring system 200 includes a flowmeter 70 that measures a flow rate waveform of blood from a human body while the blood is circulating outside the body in an extracorporeal circulator. A control unit 100 acquires a pulsation waveform 62 (waveform 60) which is a flow rate fluctuation waveform of blood included in a flow rate waveform measured by the flowmeter 70. A display unit 30 displays a pulsation waveform indicating a cardiac function of a human body in response to a command from the control unit 100.

Provided are a flowmeter that can measure a flow rate of a liquid with high accuracy and that is easy to carry and handle, and a dialysis machine and a medicinal solution injection device that employ the flowmeter. A flowmeter includes a tube connection member and a measurement instrument body. The tube connection member includes a tube-shaped body, a plurality of resonators that are arranged with gaps there between on an inner wall surface of the body, resonator-side antennas that are connected to the plurality of resonators and a heating element that is arranged between the pluralities of resonators. The measurement instrument body includes measurement-instrument-side antennas, temperature measurement units that are connected to the measurement-instrument-side antennas and measure a temperature, and a flow rate calculation unit that calculates a flow rate on the basis of the temperatures measured by the temperature measurement units.

A fluid flow sensing and bubble detecting apparatus, comprising: housing provided with a cavity configured to receive a tube through which conductive fluid flows; a fluid flow sensing and bubble detecting electrical sensor assembly supported by the housing and configured to sense the flow of the fluid flowing through the tube and to detect bubbles in the fluid; andan electrically grounded Electro-Magnetic Interference (EMI) shielding arranged between at least a part of the sensor assembly and the cavity such that the EMI shielding protects the sensor assembly from unwanted EMI emanating from a tube received within the cavity, which might otherwise cause the fluid flow sensing and bubble detecting apparatus to generate false bubble detection signals.

A control system controlling the blood flow rate in a blood supply system (1) in which a pump (18) transports blood from a reservoir (10) toward multiple outlets (30, 26, 26a) of which one or more outlets are openable to permit flow and closable to block flow, wherein the control system comprises a monitoring arrangement (22, 32, 32a) to determine the flow rate through a first outlet (30), and a controller responsive to the monitoring arrangement and controlling the pump (18) to maintain the flow rate through the first outlet (30) at a pre-determined level. This allows a flow rate through the first outlet to be maintained independently of any active blood diversions.

A device and method for monitoring an access to a patient, an extracorporeal blood circuit and/or a dialyzing fluid system includes a centrifugal pump for conveying blood or dialyzing fluid instead of an occluding pump. Centrifugal pumps bring about a large change in flow rate by even a small change in pressure difference across the pump. The device includes a measuring unit for measuring the flow rate of blood or dialyzing fluid conveyed by the centrifugal pump, and a control and computing unit configured to determine an incorrect vascular access or malfunction if a change in measured flow rate Q is more than a predetermined amount. For example, a small drop in pressure in the venous blood line leads to a marked increase in the flow rate of the centrifugal pump, which is used as a basis for the detection of an incorrect vascular access.

A renal therapy apparatus including at least two feedback controls is disclosed. Each control includes an estimated volume calculator to calculate an estimated volume based on a set flow, a comparator to compare the estimated volume with a measured volume, a volume deviation determining means to determine a volume deviation based on the comparison, a correction calculator to calculate a correction based on the volume deviation, a flow control generator to generate a flow control signal based on the calculated correction amount and the set flow, and a feedback control output to output the controlled flow control signal to a pump associated with each feedback control. A flow correction distributor includes an input to receive correction signals from the correction calculator, a limited correction signal calculator to calculate a limited correction signal for the input correction required signals, and an output to output each calculated limited correction signal to the feedback control from which its underlying correction required signal has been received.