FEEDBACK-CONTROLLED PRESSURE MONITORING SYSTEM FOR LIMB-STABILIZING MEDICAL PRESSURE SPLINTS

Feedback-controlled pressure monitoring system for limb-stabilizing medical pressure splints are described herein. In one embodiment, a limb-stabilizing system, includes: a pressure splint; a pressure sensor operatively coupled with the pressure splint; a controller configured to receive a first signal from the pressure sensor and to send a second signal to a pump; and the pump operatively coupled to the pressure splint. The pump is configured to adjust a pressure of air inside the pressure splint based on the second signal received from the controller.

BACKGROUND

Management of a variety of musculoskeletal conditions requires the use of a cast or splint. Splints are generally understood as immobilizers that can accommodate swelling. This attribute makes splints useful for managing a variety of acute musculoskeletal conditions in which swelling is anticipated, such as acute fractures or sprains, or for initial stabilization of reduced, displaced, or unstable fractures before orthopedic intervention.

In contrast with splints, casts are circumferential immobilizers. Therefore, casts provide superior immobilization, but are less forgiving, have higher complication rates, and are generally reserved for complex and/or definitive fracture management.

Selection of a specific cast or splint varies based on the area of the body being treated, and on the acuity and stability of the injury. To maximize benefits while minimizing complications, the use of casts and splints is generally short term. However, even when using a splint for a relatively short time (for example, several hours) the condition of the immobilized limb may sufficiently change through, for example, swelling, different outside pressure, position of the patient body, etc., to make the splints uncomfortable to the patient. Accordingly, systems and methods are needed for making splints more comfortable and/or more functional as the conditions affecting the patient change.

SUMMARY

Briefly, the inventive technology is directed to air splints that sense pressure inside the splint and regulate the pressure to stabilize the splint. In some embodiments, the splint includes a feedback loop for regulating the pressure to a predetermined target point. Such feedback loops may operate in real time to increase/decrease pressure in response to fluid leaking out of or into the splint, limb swelling, changes in ambient pressure or temperature, etc. In some embodiments, a pressure in the splint is maintained by a 2-way pump. The inventive technology may be suitable for pressurized splints and for vacuum-based splints.

DETAILED DESCRIPTION

FIG. 1is a partially schematic drawing of an air splint10in accordance with an embodiment of the present technology. The air splint10may partially or completely house a patient's limb5. When properly inflated, the air splint10supports and immobilizes the limb5.

In some embodiments, the air splint10includes a pump20that is configured to add or remove air from the air splint10. The operation of the pump20(e.g., turning the pump and off) may be controlled by a controller22based on, at least in part, sensing the pressure inside the splint by a pressure sensor24. In some embodiments, proper functioning of the sensor24may be verified by comparing a pressure readout of this sensor to a pressure readout of an ambient pressure sensor25. For example, such a verification may take place before the air splint10is pressurized since both sensors25and28should read close to atmospheric pressure at such time. In some embodiments, the air splint includes a relief valve28(e.g., a safety valve) that depressurizes the air splint10when a predetermined pressure threshold is reached. In different embodiments, the above described elements of the limb support system may be carried by the air splint itself or may be configured separately from the air splint10. Furthermore, the pump20, controller22and/or pressure sensors24,25may be energized by a source of power26. In some embodiments, the source of power26is a battery.

In operation, the air splint10may lose pressure or may become over pressurized. In response to the pressure inside the air splint10falling outside of a predetermined range, the pressure sensor24provides pressure signal to the controller22, which in turn may activate the pump20to bring the pressure back within the predetermined range. The communication between the controller22and the pressure sensors24,25and the pump20may be through conductive wires or wireless (e.g., Bluetooth or other wireless communication).

FIG. 2is a partially schematic drawing of a vacuum splint11in accordance with an embodiment of the present technology. In the context of this specification, the vacuum splint11and the air splint10are collectively referred to as pressure splints. In operation, the vacuum splint11is maintained at a below-atmospheric pressure, and the air splint10is maintained at an above-atmospheric pressure.

The vacuum splint11may contain stiffening elements15that add stiffness to the splint and help to immobilize the limb. In some embodiments, the stiffening elements15may be configured inside the vacuum splint to stabilize or give shape to the vacuum splint.

Some non-exclusive examples of such stiffening elements are rigid sticks or other shapes, granular material (e.g., sand), hemming at the vacuum splint edges, etc. The illustrated vacuum splint11partially encloses the limb, however, in other embodiments patient's limb may be completely enclosed.

In operation, the pressure (vacuum) inside the vacuum splint11may drift away from its predetermined range. Analogously to the operation of the air splint10, the pressure sensor24provides pressure signal to the controller22, which in turn may activate the pump20to bring the pressure back within the predetermined range.

In some embodiments, a chiller40can cool the patient's limb while being immobilized inside the vacuum splint11or air splint10. In different embodiments, the chiller40may be attached to the pressure splint by suitable coolant hoses, or the chiller may be directly attached to the pressure splint.

FIG. 3is an isometric drawing of a pump20in accordance with an embodiment of the present technology. In some embodiments, the pump20is a 2-way pump that can pressurize the attached pressure splint through an outlet132or depressurize the pressure splint through an inlet134. The operation of the pump20may be controlled by a controller. In some embodiments, the pressure sensor24, the controller22and the source of power26may be integrated into the pump20. In different embodiments, the pump20may be a centrifugal pump or a volumetric pump.

FIG. 4is a schematic diagram of a system in accordance with an embodiment of the present technology. In operation, the pressure sensing system (e.g., the pressure sensor24) senses the pressure inside the pressure splint (e.g., air splint10or vacuum splint11). The pressure control system (e.g., the controller22) receives input signal from the pressure sensing system, and in turn provides signal to the air pump to turn on or off. Based on this feedback-controlled pressure monitoring, pressure inside the pressure splint is maintained within a predetermined range, therefore maintaining required limb immobility and comfort of the patient. In some embodiment the controller22may an Arduino board Mega 2560. In some embodiments, the pressure sensors24,25may be piezoresistive transducers, for example Honeywell ABP MPxx5010 transducers.

FIG. 5is a flowchart of a method500for operating a splint in accordance with an embodiment of the present technology. In some embodiments, the method may include additional steps or may be practiced without all steps illustrated in the flow chart.

The method starts in block505. In block510, the pressure splint is positioned over the limb that requires immobilization. In block515, the pressure splint is inflated or vacuumed to its initial set point by, for example, the pump20. In block520, pressure in the pressure splint is measured by, for example, a pressure sensor24. The pressure measurement data may be provided to the controller22.

In block525, the controller22ascertains whether the target pressure is achieved. The target pressure may correspond to a predetermined pressure range or to a single pressure value. If the target pressure is achieved, the pressure inside the pressure splint is measured again in block520. If the target pressure is not achieved, that is, the measured pressure is outside the predetermined pressure range, the controller activates the pump in block515. For example, if the measured pressure is below the target pressure, the pump20may add air into the pressure splint thus, for example, further increasing pressure inside the air splint. Conversely, if the measured pressure is above the target pressure, the pump20may remove air from the pressure splint, thus, for example, further increasing vacuum inside the vacuum splint.

In block530, the pressure splint is removed. The method ends in block535.

The present application may also reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present application. Also in this regard, the present application may use the term “plurality” to reference a quantity or number. In this regard, the term “plurality” is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms “about,” “approximately,” etc., mean plus or minus 5% of the stated value.

Many embodiments of the technology described above may take the form of computer- or controller-executable instructions, including routines executed by a programmable computer or controller. Those skilled in the relevant art will appreciate that the technology can be practiced on computer/controller systems other than those shown and described above. The technology can be embodied in a special-purpose computer, controller or data processor that is specifically programmed, configured or constructed to perform one or more of the computer-executable instructions described above. Accordingly, the terms “computer” and “controller” as generally used herein refer to any data processor and can include Internet appliances and hand-held devices (including palm-top computers, wearable computers, cellular or mobile phones, multi-processor systems, processor-based or programmable consumer electronics, network computers, mini computers and the like).

From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the disclosure. Moreover, while various advantages and features associated with certain embodiments have been described above in the context of those embodiments, other embodiments may also exhibit such advantages and/or features, and not all embodiments need necessarily exhibit such advantages and/or features to fall within the scope of the technology. Accordingly, the disclosure can encompass other embodiments not expressly shown or described herein.