Ultrasound patch for detecting fluid flow
Inventors
EIBL, Joseph • Kenny, Jon-Emile S. • Demore, Christine • MUNDING, Chelsea • Brown, Jeremy • Boyes, Aaron
Assignees
1929803 Ontario Corp D/b/a/ Flosonics Medical • Daxsonics Ultrasound Inc • 1929803 Ontario Corp O/a Flosonics Medical
Publication Number
US-11109831-B2
Publication Date
2021-09-07
Expiration Date
2039-04-05
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Abstract
An ultrasound patch includes one or more transmit and receive piezoelectric transducer elements. In some embodiments, the transducer elements are positioned on a ramp on a patient pad of the patch that is configured to fit within an anatomic space between the trachea and the sternocleidomastoid muscle to orient the transducer elements toward a carotid artery. In some embodiments, a flexible phased array transducer includes a number of pillar piezoelectric elements joined by a flexible adhesive with metal electrodes deposited thereon. The phased array transducer is mounted to a flexible circuit board that allows the transducer to bend and conform to a subject's anatomy.
Core Innovation
The invention relates to an ultrasound patch device configured to non-invasively detect fluid flow in a vessel of a patient. The patch includes one or more piezoelectric transmit and receive transducer elements, which can be arranged on a ramp or as a flexible phased array transducer to direct and detect ultrasound signals at an angle with respect to the skin surface. This angulation facilitates Doppler flow measurements by orienting the ultrasound beams toward vessels such as the carotid artery. The transducers include features such as air or foam-backed piezoelectric elements and may be mounted on printed circuit boards with electrical traces for signal connection.
The problem addressed by the invention is the limitation of traditional ultrasound systems where an operator must hold a transducer at a specific angle and control the imaging system simultaneously, restricting their ability to perform other tasks. Existing dedicated flow measurement devices free the hands of caregivers but have room for design improvement, particularly in the transducers. The invention seeks to provide improved transducer designs that can be affixed to a subject for continuous or periodic flow monitoring, enabling hands-free operation and improved placement and conformability tailored to anatomical features.
Additionally, the disclosed technology addresses the need to measure flow changes and velocity in vessels, estimate vessel diameter and central venous pressure, and detect relationships between Doppler flow signals and hemodynamic pathologies such as sepsis, shock, and congestive heart failure. The invention includes novel fabrication techniques for flexible phased array transducers capable of bending to conform to patient anatomy, and structures such as patient pads with ramps that orient transducer elements optimally between anatomical landmarks (e.g., trachea and sternocleidomastoid muscle) for effective carotid velocimetry and jugular vein assessment.
Claims Coverage
The patent includes two independent claims covering two main inventive features related to ultrasound patches for fluid flow detection: one describing a patch with piezoelectric transmit and receive elements mounted on a ramped flexible engagement layer, and another describing a patch with a flexible phased array transducer composed of piezoelectric pillars connected to a flexible circuit board.
Ultrasound patch with angled ramp supporting transmit and receive piezoelectric elements
An ultrasound patch for skin application including one or more piezoelectric transmit and receive elements positioned adjacent to each other and supported by a ramp coupled to a flexible engagement layer. The ramp extends away from the housing and flexible layer toward the patient, holding the transmit and receive elements at a defined angle (e.g., about 30 degrees) relative to the bottom surface, such that ultrasound energy is transmitted toward a vessel in the patient. The ramp is sized to fit within the anatomical space between the sternocleidomastoid muscle and the trachea and can be symmetrically placed to fit either side of the neck. The transmit and receive elements may have different angular orientations, and the elements are mounted to a circuit board with an air gap behind them. The patch may include integrated ECG electrodes and circuitry to detect and transmit ECG and Doppler signals.
Ultrasound patch with flexible phased array transducer of piezoelectric pillars
An ultrasound patch comprising a flexible phased array transducer made from multiple transmit and receive piezoelectric pillars joined by flexible adhesive. The transmit and receive elements have separate common electrodes deposited on one side and connectors at either end to interface with a flexible circuit board that has an opening for ultrasound passage. The array aligns generally parallel to the patient-contacting surface of a patient pad. Transmit electronics drive the transmit elements with phased signals to produce an ultrasound beam directed at an angle relative to the patient-contacting plane. The phased array can be encapsulated with an air gap, the receive elements may have a greater width than transmit elements, and the patch may include a housing with strap-receiving openings and ECG electrodes with detection circuitry and processor for central venous pressure estimation.
The claims cover two ultrasound patch configurations: one employing piezoelectric transmit and receive elements supported on an angled ramp integrated with a flexible engagement layer to direct ultrasound toward a vessel, and another employing a flexible phased array transducer formed of piezoelectric pillars connected to a flexible circuit board that transmits beam-steered ultrasound signals at an angle. Both configurations include features for ECG integration, air backing, anatomical fit, and wireless communication for assessing fluid flow and central venous pressure.
Stated Advantages
Enables hands-free, continuous or periodic monitoring of blood flow in vessels by affixing to a patient.
Improved transducer design that mechanically or electronically angles ultrasound beams to optimize Doppler flow detection.
Flexible phased array can conform to patient anatomy, enhancing comfort and placement in various anatomical locations.
Air-backed transducers increase acoustic transmission efficiency by reflecting ultrasound forward.
Integrated ECG electrodes and signal processing improve correlation of Doppler measurements with cardiac function.
Quantitative and qualitative assessment of central venous pressure (CVP) and cardiac abnormalities via Doppler and ECG data.
Secure attachment using straps and ergonomically designed ramps fit anatomical spaces for reliable sensor positioning.
Documented Applications
Continuous or periodic measurement of blood flow velocity and volume in vessels such as the carotid artery and jugular vein.
Non-invasive estimation of central venous pressure by analyzing Doppler power comparisons between jugular vein and carotid artery.
Monitoring of fluid responsiveness, fluid tolerance, and right ventricular function via jugular venous Doppler velocity profiles.
Diagnosis and monitoring of cardiovascular hemodynamic abnormalities including sepsis, shock, congestive heart failure (CHF), tricuspid regurgitation, and pulmonary hypertension.
Measurement of cardiac function indices such as left ventricular ejection time (LVET), pre-ejection period (PEP), and PEP/LVET ratio using combined Doppler and ECG signals.
Remote or ambulatory cardiac and vascular monitoring using wireless transmission of Doppler and ECG data.
Assessment of venous waveform abnormalities and response to fluid interventions via integrated Doppler amplitude and velocity time integral measurements.
Use on anatomical locations including the neck (carotid and jugular vessels), wrist, ankle, thigh, knee, and other body sites.
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