Patent Application
20220192917
The present invention relates generally to medical devices, and more particularly to a cardiopulmonary resuscitation (CPR) device that uses blood flow cardiopulmonary resuscitation value feedback for improving the outcome of cardiopulmonary resuscitation.
Cardiopulmonary Resuscitation (CPR) is a very established medical procedure for reviving a patient who has suffered a medical emergency that has rendered their heart unable to pump blood. In such a situation, chest compressions are performed by an emergency medical worker to establish blood perfusion such that blood flows to vital organs and the brain with subsequent restoration of heart rhythm. Cardiopulmonary Resuscitation (CPR) is thus a life saving technique that must be performed immediately and with proper technique in order to save the life of the patient. Proper technique includes timing of the chest compression, force applied to the chest during the chest compression, location of the chest compression, as well as the amount of compressive travel during each chest compression. Unfortunately there is currently no way for the emergency medical worker to obtain feedback on the effectiveness of each chest compression, thus leaving a very undesirable element of chance to such a critical medical procedure. To make matters that much more difficult, the physiological makeup of each patient is different, and thus necessitates slightly different chest compression techniques for each patient. For example, overweight and underweight patients present very different requirements for compressive force and placement of each chest compression.
What is needed is a way to provide real time feedback on the effectiveness of chest compression being provided by an emergency medical worker such that the emergency medical worker can modify their chest compression technique so that it provides optimal blood perfusion.
What is also needed is a way to provide real time feedback on the effectiveness of chest compression being performed by a mechanical chest compression device to that mechanical chest compression device such that chest compressions being performed by the mechanical chest compression device are optimal for blood perfusion.
What is also needed is a way to provide real time information on the effectiveness of chest compressions during cardiopulmonary resuscitation to emergency medical workers and also to provide information from other sources to emergency medical workers or a mechanical chest compression device so that the chest compressions are optimal for blood perfusion.
The present invention and the various embodiments described and envisioned herein provide for such unmet needs.
In accordance with the present invention, there is provided a cardiopulmonary resuscitation (CPR) device that improves the outcome of cardiopulmonary resuscitation (CPR). The device uses a non-invasive blood flow sensor to determine cardiopulmonary function during CPR and in turn provides real-time feedback to the individual performing CPR on a patient. Cardiopulmonary functions may include heart rate, blood velocity, blood volume, blood pressure, and blood oxygenation. Real-time feedback is provided to the individual performing CPR by way of an audible or visual signal. A change in the characteristics of the signal (for example, with an audible signal, change in volume or frequency of the audible signal) indicates how effective or ineffective each chest compression is, and alerts the CPR provider to either continue with their course of action or change it (change placement of the chest compression, timing, depth or force of the chest compression).
In some embodiments, the blood flow sensor provides a signal to a mechanical chest compression device which in turn adjusts the chest compression or placement of the chest compressor on the patient. The mechanical chest compression device may have an X-Y rail arrangement for moving the location of the chest compressor in response to information from the blood flow sensor.
In some embodiments, the cardiopulmonary resuscitation (CPR) device is a wearable device that contains a non-invasive blood flow sensor and is capable of providing event data to an event recorder and also an alert through a network.
The foregoing has been provided by way of introduction, and is not intended to limit the scope of the invention as described by this specification, claims, and the attached drawings.
The invention will be described by reference to the following drawings, in which like numerals refer to like elements, and in which:
The present invention will be described in connection with a preferred embodiment, however, it will be understood that there is no intent to limit the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by this specification, claims, and drawings attached hereto.
As will be further described herein, a cardiopulmonary resuscitation device with blood flow cardiopulmonary resuscitation value feedback is disclosed.
The cardiopulmonary resuscitation device monitors blood flow non-invasively, and provides real time feedback during and/or after an emergency medical procedure. The real time feedback includes a cardiopulmonary resuscitation value that is derived from a measured blood flow value and in turn provides feedback to emergency medical personnel regarding the adequacy of their cardiopulmonary resuscitation actions. The feedback may come in a variety of forms, including audible, visual, tactile, or in some embodiments as an electronic feedback signal to a mechanical chest compression device instructing the mechanical chest compression device to take certain actions or modify certain actions. The cardiopulmonary resuscitation value is derived from a measured blood flow value as well as other patient specific parameters to provide real time feedback to emergency medical personnel resulting in optimal chest compressions. This optimization would not be possible with blood flow monitoring alone, and will be described in further detail below by reference to the drawings.
Turning first to
A blood flow sensor 107 is applied to a patient non-invasively through a cuff, a strap, a band or a similar arrangement that provides skin contact over a blood vessel. There may be a plurality of blood flow sensors configured as a strap, cuff or similar wearable arrangement. The blood flow sensors may employ photo acoustics, doppler, ultrasound, duplex doppler ultrasonography, electromagnetics, optics, laser doppler, fiber optics or the like. In addition, the blood flow sensor 107 may include pulse oximetry for determining blood oxygen saturation. In one preferred embodiment, photoacoustic doppler is used for the blood flow sensor 107.
Placement of the blood flow sensor 107 would, in one embodiment, preferably be on the brachial artery. The blood flow sensor 107 may include a clear or partially clear cuff, strap or band such that the sensors are visible to an emergency medical provider during placement, ensuring correct placement of the blood flow sensor 107 during an extremely time sensitive procedure. The blood flow sensor 107 provides rate of flow and flow velocity in real time for subsequent downstream processing. Flow velocity can also be used to determine blood pressure which is in turn provided to the computer system 101 for subsequent determination of cardiopulmonary resuscitation values. While the blood flow sensor 107 may provide an analog signal representative of blood flow velocity or volume, an analog to digital converter 105 may be employed to convert the analog signal to digital signals that are sent to the computer system 101 through an interface 103. The interface 103 may simply be a communications interface such as RS-232, RS-422, RS-485, other serial or parallel interfaces, or may employ a wireless or encrypted standard.
A computer system 101 can be seen that has a processor, memory, and access to computer readable media. The computer system 101 receives blood flow data from the interface 103 for subsequent conversion to a cardiopulmonary resuscitation value. Within the computer system 101, a computer/processor 111 executes a computer program 113 that executes the steps of retrieving a binary representation of the blood flow sensor output; converting the binary representation of the blood flow sensor output to a blood flow value; assigning the blood flow value to a cardiopulmonary resuscitation value; converting the cardiopulmonary resuscitation value to a user feedback value; and providing the user feedback value to a sensory indicator 119. In some embodiments of the present invention, the blood flow value is converted to a cardiac output value. The cardiac output value is calculated by the computer program 113 using blood flow values with sensed heart rate and estimated stroke volume. In one embodiment of the present invention, the cardiac output value is determined with Fick's Formula. The sensory indicator 119 may be an audible indicator such as a tone or a signal that changes in amplitude, frequency, or duration/cadence as the emergency medical responder performs chest compressions that are more conforming or less conforming to an optimal value as defined by cardiopulmonary resuscitation values that are provided in real time or near real time to the emergency medical responder. The sensory indicator may also provide a visual indicator for user feedback. In some embodiments the visual indicator is a light or a computer display. The computer system 101 may also send or receive remote diagnostics 117 such as, for example, medication status, medical records, archival or historical cardiovascular data, and the like.
The system may also, in some embodiments, determine blood pressure, heart rate, temperature, respiratory rate, end tidal CO2, pH/blood gas, heart rhythm, oxygen saturation, blood glucose, and the like. In some embodiments, the system of the present invention can take an action when a value of a sensed function is exceeded or goes below a certain value.
In some embodiments the system integrates with electronic medical records, providing ease of charting and order entry. This would allow anyone involved in the patient's care to have real time updates on the patient's vitals. It would also allow ease of determining the timing of interventions such as medications, CPR, oxygen administration, defibrillation, and the like. The system may also, in some embodiments, provide medical alerts to providers when critical changes in vitals occur so that treatment is provided promptly when needed.
In its simplest form, the cardiopulmonary resuscitation is directly and linearly correlated to a blood flow value. For example, decreased blood flow results in a lower (or in some embodiments a higher) cardiopulmonary resuscitation value, which in turn relates to a lower (or in some embodiments a higher) user feedback value. Since the user feedback value is provided to a sensory indicator 119, a lower blood flow may result in a lower sensory indication (for example, a lower volume audio signal) and alternatively, a higher blood flow would result in a higher sensory indication (for example, a higher volume audio signal). The sensory indicator may also provide feedback in the form of slower or faster cadence, higher or lower pitch (sound frequency), and the like. The cardiopulmonary resuscitation value may also contain a value that corresponds to placement of the hand during compression, depth of the compression, force of the compression, and the like, and may provide user feedback for these variables as another sensory indicator (for example, light or haptics), or as a multi-dimensional audio or visual signal (where, for example, in an audio signal amplitude (volume) represents blood flow, frequency represents force of the chest compression, and cadence represents hand placement during each compression).
In some embodiments, the cardiopulmonary resuscitation value is adjusted or modified based on patient specific parameters. Patient specific parameters include, but are not limited to, patient age, patient weight, patient height, patient age, patient medication history, patient medical history, and patient cardiovascular history. With an adjusted or modified cardiopulmonary resuscitation value, the user feedback value is also modified or adjusted accordingly. While the American Heart Association recommends chest compressions at a rate of 100-120 per minute and to a depth of at least two inches, and not greater than 2.4 inches, these figures may vary based on the patient. Also, and very importantly, with current CPR procedures, there is no way for the provider of CPR to know if they are performing chest compressions properly at all.
While a sensory indicator embodiment is valuable in a majority of CPR cases, a wearable device that provides blood flow feedback may provide additional or enhanced life saving utility.
Turning now to
Historical or archival data from past blood flow data collections may be used to improve patient outcomes by helping to define patient specific parameters.
While the blood flow sensor is essential for beginning the process of providing user feedback to a provider of cardiopulmonary resuscitation during a medical emergency, it is essential that blood flow values from the blood flow sensor are ultimately converted to meaningful signaling, whether that signaling is a sensory indicator or instructions provided to a mechanical chest compression device. This conversion process is software based, and performed with a processor/computer. Hemodynamics is a complex topic, and the use of software to not only convert blood flow values to useful outputs but also to modify those useful output values based on patient centric values provides for an optimal instruction set for improved patient outcome. While in its simplest form, sensing blood flow or lack of blood flow and alerting the emergency medical provider to this binary condition is a fundamental and basic component of the present invention, optimizing blood flow during cardiopulmonary resuscitation not only improves patient outcome but also reduces complications associated with lack of blood flow. Blood flow velocity can be expressed as:
V=Q/A
Where V is blood flow velocity (cm/s), Q is blood flow (ml/s) and A is cross sectional area (cm2). Blood flow can vary based on the smoothness of the vessels and other factors, thus making optimal blood flow patient specific. A preferred placement of the blood flow sensor of the present invention is the brachial artery. A blood flow value (BFV) may be expressed in ml/s or ml/min. For example, brachial artery blood flow may be 600-800 ml./min. This value is then converted to a cardiopulmonary resuscitation (CPR) value, which may be, in some embodiments, the same as the initial blood flow value (for example, a blood flow value of 800 ml/min may be assigned a CPR value of 800. This CPR value may then be acted on or modified by a variety of parameters such as patient parameters to ensure that a feedback value that indicates optimal blood flow for a given chest compression is the same regardless of the patient and differences in their hemodynamic characteristics. For example, a CPR value of 800 may indicate that optimal blood flow is occurring in patient A, whereas optimal blood flow for patient b in the brachial artery may be 700 ml/min. Thus, a CPR value for patient A may be 800 who has an optimal blood flow value of 800 ml/min. and the CPR value for patient B may also be 800 where patient B has an optimal blood flow value of 700 ml/min. For simplicity of this example, if a CPR value of 800 indicates optimal blood flow, the User Feedback Value would be greatest (for example, greatest amplitude of a tone being indicative of optimal blood flow) at a CPR value of 800. Thus, if the amplitude (volume) of a sensory indicator is greatest at a CPR value of 800, and the maximum volume of the sensory indicator is a 10 (of course these decimal numbers are arbitrary and would most likely be represented in binary as part of the computer program of the present invention), then a CPR value of 800 would be assigned a user feedback value of 10. While these numbers are arbitrary, the data flow and data conversion of this example would apply to a variety of situations of the present invention.
With this example in mind, an example of data flow of the present invention is provided by way of
In some embodiments, a mechanical chest compression device (automated CPR machine) is included with the device for improving the outcome of cardiopulmonary resuscitation.
In step 603, the CPR Value (CPRV) is converted to a chest compression value (CCV) and provided to a mechanical chest compression device in step 605. By providing CPR Values (CPRVs) to a mechanical chest compression device customized chest compressions and ventilation periods can be determined based on blood flow values and other inputs that may have been used to determine CPR Values. A digital interface is preferably provided that converts the stream of CPR Values being calculated in real time or near real time to digital representations (digital numerical values and perhaps additional information to supplement the CPR Values such as machine control information) that are in turn received by the mechanical chest compression device and used to modify key physical parameters such as stroke depth, stroke rate, ventilation interval and timing, and the like. In the embodiment described by way of
Turning now to
Mechanical chest compression device functionality, which includes a blood flow sensor and related software and processor, may be integrated with a mechanical chest compression device or may, in some embodiments, be a detachable peripheral that is connected to the electronic unit of the mechanical chest compression device by way of a cable or a wireless interface.
Lastly,
Having described and illustrated the principles, components and methods of the present invention by reference to one or more preferred embodiments, it should be apparent that the preferred embodiment(s) described and envisioned herein may be modified in arrangement and detail without departing from the spirit and broad scope of the present invention, and that these modifications and variations are to be considered and construed as being included in the present application and invention described herein.
This application claims priority to U.S. Patent Application Ser. No. 63/126,716 filed on Dec. 17, 2020 entitled “Medical Device”, and U.S. Patent Application Ser. No. 63/173,887 filed on Apr. 12, 2021 entitled “Self-Adjusting Mechanical Chest Compression Device”, the entire disclosures of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63173887 | Apr 2021 | US | |
| 63126716 | Dec 2020 | US |
