The present technology is generally related to ultrasound devices and associated systems and methods. In particular, several embodiments are directed to ultrasound devices and associated methods for measuring carotid blood flow.
Conventional techniques for blood flow monitoring during time-sensitive medical emergencies, such as cardiac arrest, suffer from several drawbacks. For example, to determine the need for cardiopulmonary resuscitation (“CPR”) in the setting of a cardiac arrest, lay persons and emergency personnel typically attempt to palpate a major artery (e.g., the carotid or femoral artery) for the presence or absence of a pulse. In many cases, however, such approaches are undesirable and/or inaccurate because the patient can be violently and/or abruptly moving. As a consequence, potentially life-saving CPR may be withheld from those individuals who could have benefitted from CPR but were not recognized as being in cardiac arrest. In addition, many existing non-invasive blood flow monitoring devices require application to the chest wall, which is likely to interfere with attempted CPR.
To address the challenges associated with non-invasive blood flow monitoring methods, several invasive monitoring devices and approaches exist, such as pulmonary artery catheters and lithium dilution. Such techniques, however, are generally not suitable for application during emergency cardiac arrest because (1) the insertion of an invasive device necessarily interrupts ongoing CPR; (2) invasive blood flow monitoring comes with an increased risk of vascular injury, infection or other adverse events; and (3) invasive monitors that require a wire- or catheter-based technology may be sensitive to movement so that even subtle changes in position (such as those occurring during chest compressions) can result in inaccurate readings because the device is inadvertently moved from the proper position to measure blood flow.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure. Furthermore, components can be shown as transparent in certain views for clarity of illustration only and not to indicate that the illustrated component is necessarily transparent.
The present technology is generally directed to devices, systems, and methods for non-invasively measuring blood flow. In one embodiment, for example, a blood flow measuring system includes a patient assembly configured to be rapidly positioned and stabilized at an external location proximate to a major artery of a human patient while the patient is experiencing cardiac arrest. The system can measure blood flow, for example, to identify the onset of cardiac arrest before it occurs, verify the presence or absence of cardiac arrest, guide CPR efforts during cardiac arrest, to achieve specific hemodynamic or physiologic targets, and/or assess cardiac arrest prognosis during or immediately after cardiac arrest.
Specific details of several embodiments of the present technology are described herein with reference to
For ease of reference, throughout this disclosure identical reference numbers are used to identify similar or analogous components or features, but the use of the same reference number does not imply that the parts should be construed to be identical. Indeed, in many examples described herein, the identically-numbered parts are distinct in structure and/or function.
Generally, unless the context indicates otherwise, the terms “distal” and “proximal” define a position or direction with respect to the treating clinician or clinician's control device (e.g., an ultrasound device). “Distal” or “distally” can refer to a position distant from or in a direction away from the clinician or clinician's control device. “Proximal” and “proximally” can refer to a position near or in a direction toward the clinician or clinician's control device.
As described in greater detail below, the system 100 can also include a controller 106 configured to measure, analyze, and/or indicate the patient's blood flow velocity and/or blood pressure in real time to guide CPR efforts during cardiac arrest and/or assess the patient's prognosis. In some embodiments, measurements obtained by the patient assembly 101 can be mapped to electrocardiographic (“EKG”) recordings so that the presence of a perfusing cardiac rhythm can be differentiated from pulseless electrical activity. In further embodiments (and as mentioned below) the controller 106 can determine the blood pressure via ultrasound measurements measured at two proximate locations in the targeted artery. Additionally or alternatively, in some embodiments, the vessel diameter can be measured, and the vessel diameter measurements and blood velocity measurements can be used to derive an estimate of blood pressure in the vessel.
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The controller 106 can include memory (not shown), storage devices (e.g., disk drives), one or more output devices (e.g., a display), one or more input devices (e.g., a keyboard, a touchscreen, etc.) and processing circuitry (not shown). The memory and storage devices are computer-readable storage media that may be encoded with non-transitory, computer-executable instructions. In addition, the instructions, data structures, and message structures may be stored or transmitted via a data transmission medium, such as a signal on a communications link and may be encrypted. Various communications links may be used, such as the Internet, a local area network, a wide area network, a point-to-point dial-up connection, a cell phone network, Bluetooth, RFID, and other suitable communication channels. Aspects of the system can also be practiced in distributed computing environments where tasks or modules are performed by remote processing devices, which are linked through a communications network, such as a Local Area Network (LAN), Wide Area Network (WAN), Storage Area Network (SAN), Fibre Channel, or the Internet. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
In some embodiments, the controller 106 can provide real-time feedback to the HCP via an indicator (not shown). Such indicators can include one or more display(s), user interface(s), LEDs, speaker(s), and/or other similarly communicative devices. For example, the controller 106 may include a graphical user interface that can receive HCP input and/or provide blood flow information to the HCP. The feedback can guide an HCP in administering CPR and/or determine the effectiveness of any ongoing CPR or medical efforts.
Additionally, the controller 106 can be in communication with a wired or wireless network 110 so that blood flow measurements can be remotely available in real-time to HCPs. For example, the network 110 can actively communicate information from the controller 106 to other devices 108 on the network 110, such as personal computers in the doctor's lounge, nurse's station, etc. In particular embodiments, the controller 106 and/or network 110 can communicate with a server 116 (e.g., via the Internet) so that ultrasound data can be available outside of the network 110. For example, ultrasound data can be available on a home computer, a smart phone, a tablet, a personal computer within another network (e.g., at a different medical care center), and/or other remote devices. In these and other embodiments, blood flow measurements can be stored in a central database and accessed later for analysis. Further, it will be appreciated that other configurations and communication channels can be used to provide remote access and/or monitoring.
In operation, when the ultrasound transducer 102 (
1. A system for monitoring blood flow of a human patient during cardiac arrest, the system comprising:
a hand-held ultrasound transducer;
an interface element configured to be removably attached to the patient's skin at a target site proximate to a carotid artery of the patient, wherein the adhesive member includes one or more reference indicia corresponding to anatomical landmarks associated with a desired position of the ultrasound transducer relative to the carotid artery,
wherein the ultrasound transducer is configured to be positioned in contact with the interface element at the target site; and
a controller operably coupled to the ultrasound transducer and configured to—
2. The system of example 1 wherein the reference indicia correspond to a projected position and orientation of the carotid artery within the patient.
3. The system of example 1 wherein the system further comprises an indicator operably coupled to the controller, and wherein the indicator is configured to provide audio, visual, and/or haptic feedback regarding the blood flow velocity to a user.
4. The system of example 1 wherein the ultrasound transducer is a first ultrasound transducer and the interface element is a first interface element, and wherein the system further comprises a second ultrasound transducer operably coupled to the controller and a second interface element, and further wherein, during operation, the first interface element and first ultrasound transducer are configured for placement proximate a left carotid artery of the patient, and the second interface element and second ultrasound transducer are configured for placement proximate a right carotid artery of the patient.
5. A method for measuring blood flow within a carotid artery of a human patient during a cardiac arrest event, the method comprising:
positioning an adhesive member on skin of the patient at a target location proximate the carotid artery;
positioning an ultrasound transducer in contact with the adhesive member such that at least a portion of the adhesive member is between the ultrasound transducer and the skin of the patient; and
determining a blood flow measurement within the carotid artery of the patient via the ultrasound transducer.
6. The method of example 5 wherein positioning the adhesive member on skin of the patient comprises positioning the adhesive member proximate to a left carotid artery of the patient.
7. The method of example 5 wherein positioning the adhesive member on skin of the patient comprises positioning the adhesive member proximate to a right carotid artery.
8. The method of example 5 wherein the adhesive member is a first adhesive member positioned at a first target location proximate a left carotid artery of the patient, the ultrasound transducer is a first ultrasound transducer, and determining a blood flow measurement comprises determining the blood flow within the left carotid artery via the first ultrasound transducer, and wherein the method further comprises:
positioning a second adhesive member on skin of the patient at a second target location proximate a right carotid artery of the patient;
positioning a second ultrasound transducer in contact with the second adhesive member; and
determining a blood flow measurement within the right carotid artery of the patient via the second ultrasound transducer.
9. The method of example 8 wherein determining the blood flow measurement within the left carotid artery via the first ultrasound transducer and determining the blood flow measurement within the right carotid artery via the second ultrasound transducer occur simultaneously.
10. The method of example 8 wherein determining the blood flow measurement within the left carotid artery via the first ultrasound transducer and determining the blood flow measurement within the right carotid artery via the second ultrasound transducer occur in sequence.
11. The method of example 5, further comprising transmitting the determined blood flow measurements to a remote device.
12. The method of example 5, further comprising providing audio, visual, and/or haptic feedback to a health care provider regarding the blood flow measurement.
13. The method of example 5, further comprising determining a blood pressure of the patient based, at least in part, on the determined blood flow measurement.
14. The method of example 5, further comprising:
determining a diameter of the artery; and
determining a blood pressure of the patient based, at least in part, on the determined blood flow measurement and the determined artery diameter.
15. An interface element for use with an ultrasound transducer, the interface element comprising:
a body portion including—
a first adhesive material at the distal surface;
a second adhesive material at the proximal surface;
one or more reference indicia at the proximal surface, wherein the indicia correspond to (a) an anatomical landmark associated with a projected position and/or orientation of the major artery of the patient, and (b) a desired orientation for placement of the ultrasound transducer relative to the major artery.
16. The interface element of example 15 wherein the reference indicia comprise at least one of a marking, bump, groove and/or cut in the interface element.
17. The interface element of example 15 wherein the reference indicia correspond to the carotid artery.
18. The interface element of example 15 wherein the reference indicia correspond to the femoral artery.
19. The interface element of example 15 wherein the reference indicia correspond to the temporal artery.
20. The interface element of example 15 wherein the reference indicia correspond to the brachial artery.
The above detailed descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.
Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
This application claims the benefit of U.S. Provisional Patent Application No. 61/718,845, filed Oct. 26, 2012, which is incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2013/066976 | 10/25/2013 | WO | 00 |
Number | Date | Country | |
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61718845 | Oct 2012 | US |