Patent Publication Number: US-2023148875-A1

Title: Devices and methods for hemorrhage detection

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority pursuant to 35 U.S.C. 119(a) to Chinese Application No. 202111369489.6, filed Nov. 18, 2021, which application is incorporated herein by reference in its entirety. 
     TECHNOLOGICAL FIELD 
     Example embodiments of the present disclosure relate generally to medical applications and, more particularly, to devices and methods for improved hemorrhage detection. 
     BACKGROUND 
     Hospitals, clinics, and other medical institutions or environments care for a variety of patients dealing with an array of differing conditions. As part of caring for patients, these institutions may rely upon various diagnostic systems, sensors, and/or the like to provide up-to-date data associated with the current condition of one or more patients. The inventors have identified numerous deficiencies with these existing technologies in the field of medical monitoring devices, the remedies for which are the subject of the embodiments described herein. 
     BRIEF SUMMARY 
     Devices, methods, systems, and associated computer program products are provided for hemorrhage detection. An example sensing device for hemorrhage detection may include a blood selective layer that includes a permeable film and an iron selective conductive circuit supported by the permeable film. The sensing device may further include a controller operably coupled with the blood selective layer. The controller may be configured to supply a current to the iron selective conductive circuit, determine an impedance (e.g., a speed of impedance change and/or time required for the impedance to change/meet an associated threshold) of the iron selective conductive circuit responsive to blood received by the blood selective layer, and determine an amount of blood received by the blood selective layer based upon the determined impedance. 
     In some embodiments, the controller may be further configured to compare the determined impedance with an alert threshold and generate an alert signal in an instance in which the determined impedance satisfies the alert threshold. 
     In some further embodiments, the alert signal may be configured to cause presentation of a user notification. 
     In other further embodiments, the alert signal is configured to modify an operating condition of one or more systems communicably coupled with the controller. 
     In some embodiments, the iron selective conductive circuit may be supported by a first surface of the permeable film. 
     In some further embodiments, the sensing device may further include an anti-penetration layer applied to a second surface of the permeable film, wherein the second surface is opposite the first surface. 
     In some embodiments, the anti-penetration layer may include a polyethylene (PE) or polypropylene (PP) microporous film configured to emit vapor to an external environment of the sensing device but preclude fluid transmission therethrough. 
     In some further embodiments, the sensing device may further include a first diversion layer defining a first surface and a second surface opposite the first surface, wherein the second surface of the first diversion layer is applied to the first surface of the blood selective layer. 
     In some embodiments, the first diversion layer may include an air through non-woven of polyethylene (PE) and polyethylene terephthalate (PET) bicomponent fibers or PE and polypropylene (PP) bicomponent fibers. 
     In some further embodiments, the sensing device may further include an absorption layer defining a first surface and a second surface opposite the first surface, wherein the second surface of the absorption layer is applied to the first surface of the first diversion layer. 
     In some embodiments, the absorption layer may include a superabsorbent polymer (SAP). In such an embodiment, one or more bicomponent fibers of the first diversion layer may be arranged along a lengthwise direction of the first diversion layer. 
     In some further embodiments, the sensing device may include a second diversion layer defining a first surface and a second surface opposite the first surface, wherein the second surface of the second diversion layer is applied to the first surface of the absorption layer. 
     In some embodiments, the second diversion layer may include an air through non-woven of polyethylene (PE) and polyethylene terephthalate (PET) bicomponent fibers or PE and polypropylene (PP) bicomponent fibers. 
     In some further embodiments, the sensing device may include a hydrophobic layer defining a first surface and a second surface opposite the first surface, wherein the second surface of the hydrophobic layer is applied to the first surface of the second diversion layer. 
     In some embodiments, the hydrophobic layer may include a spunbound nonwoven material or an air through non-woven polyethylene (PE) or polypropylene (PP) material. 
     The above summary is provided merely for purposes of summarizing some example embodiments to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above-described embodiments are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. It will be appreciated that the scope of the disclosure encompasses many potential embodiments in addition to those here summarized, some of which will be further described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having described certain example embodiments of the present disclosure in general terms above, reference will now be made to the accompanying drawings. The components illustrated in the figures may or may not be present in certain embodiments described herein. Some embodiments may include fewer (or more) components than those shown in the figures. 
         FIG.  1    illustrates an example sensing device for hemorrhage detection of the present disclosure in accordance with some example embodiments described herein; 
         FIGS.  2 A- 2 B  illustrate side and top views, respectively, of an example blood selective layer of the sensing device of  FIG.  1    in accordance with some example embodiments described herein; 
         FIG.  3    illustrates an example hydrophobic layer for use with example sensing devices described herein; 
         FIG.  4    illustrates an example second diversion layer for use with example sensing devices described herein; 
         FIG.  5    illustrates an example absorption layer for use with example sensing devices described herein; 
         FIG.  6    illustrates an example first diversion layer for use with example sensing devices described herein; 
         FIG.  7    illustrates an example anti-penetration layer for use with example sensing devices described herein; 
         FIG.  8    illustrates a schematic block diagram of an example controller that may perform various operations in accordance with some example embodiments described herein; 
         FIG.  9    illustrates an example flowchart for hemorrhage detection in accordance with some example embodiments described herein; and 
         FIG.  10    illustrates an example flowchart for alert signal operations in accordance with some example embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Some embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. Indeed, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. As used herein, terms such as “front,” “rear,” “top,” etc. are used for explanatory purposes in the examples provided below to describe the relative position of certain components or portions of components. Furthermore, as would be evident to one of ordinary skill in the art in light of the present disclosure, the terms “substantially” and “approximately” indicate that the referenced element or associated description is accurate to within applicable engineering tolerances. 
     As used herein, the term “comprising” means including but not limited to and should be interpreted in the manner it is typically used in the patent context. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. 
     As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, the particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure such that these phrases do not necessarily refer to the same embodiment. 
     As used herein, the word “example” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “example” is not necessarily to be construed as preferred or advantageous over other implementations. 
     As used herein, the terms “data,” “content,” “information,” “electronic information,” “signal,” “command,” and similar terms may be used interchangeably to refer to data capable of being transmitted, received, and/or stored in accordance with embodiments of the present disclosure. Thus, use of any such terms should not be taken to limit the spirit or scope of embodiments of the present disclosure. Further, where a first device is described herein to receive data from a second device, it will be appreciated that the data may be received directly from the second device or may be received indirectly via one or more intermediary computing devices, such as, for example, one or more servers, relays, routers, network access points, base stations, hosts, and/or the like, sometimes referred to herein as a “network.” Similarly, where a first device is described herein as sending data to a second device, it will be appreciated that the data may be sent directly to the second device or may be sent indirectly via one or more intermediary computing devices, such as, for example, one or more servers, remote servers, cloud-based servers (e.g., cloud utilities), relays, routers, network access points, base stations, hosts, and/or the like. 
     As used herein, the term “computer-readable medium” refers to non-transitory storage hardware, non-transitory storage device or non-transitory computer system memory that may be accessed by a computing device, a microcomputing device, a computational system or a module of a computational system to encode thereon computer-executable instructions or software programs. A non-transitory “computer-readable medium” may be accessed by a computational system or a module of a computational system to retrieve and/or execute the computer-executable instructions or software programs encoded on the medium. Exemplary non-transitory computer-readable media may include, but are not limited to, one or more types of hardware memory, non-transitory tangible media (for example, one or more magnetic storage disks, one or more optical disks, one or more USB flash drives), computer system memory or random access memory (such as, DRAM, SRAM, EDO RAM), and the like. 
     As described herein, the sensing device embodiments of the present disclosure reference an example sensing device for hemorrhage detection (e.g., detecting the presence or an amount of blood received by the described sensing device). The present disclosure, however, contemplates that the embodiments of the present disclosure may also be configured to determine any characteristic associated with blood such that the described “amount” may refer to a volume, density, and/or the presence of blood received by the sensing device (e.g., the detection of an amount of blood may refer to any event including but not limited to a hemorrhage of an associated patient). Additionally, the described “amount” may refer to a speed of volume change and/or a time required for the volume of blood received by the blood selective layer or the sensing device to satisfy an associated threshold. Furthermore, although described hereinafter with reference to detection of blood received by the sensing device, the present disclosure contemplates that the sensing devices described herein may be equally applicable to detection of other fluids, compounds, elements, etc. without limitation. For example, the sensing devices described herein may, additionally or alternatively, include a sodium selective layer that is reactive to sodium ions so as to determine an amount of sweat received by the sensing device. 
     Overview 
     As described above, hospitals, clinics, and other medical institutions or environments care for a variety of patients dealing with an array of differing conditions, and these institutions may rely upon various diagnostic systems, sensors, and/or the like to provide up-to-date data associated with the current condition of one or more patients. In many instances, however, traditional systems for detecting a bleeding related event (e.g., a hemorrhage or the like) rely upon ad hoc methods where individual caretakers must determine the condition of a patient. Said differently, these traditional systems fail to provide a data-driven, standardized method and device for detecting bleeding related events resulting in increased risk to patients. In many instances, such as with high risk patients, pregnant patients, and/or the like, failure to timely detect hemorrhaging of the patient may result in critical consequences. By way of a particular example, cesarean section (C-section) procedures are often associated with potential risk for bleeding events that may be dangerous to both the mother and child. As described above, traditional attempts, if any, at detecting a bleeding event associated with a C-section procedure fail to provide timely, data-driven determinations that reliably reduce the risk associated with these procedures. 
     Accordingly, the sensing devices, systems, methods, and computer program products of the present disclosure provide a mechanism for reliably detecting bleeding related events (e.g., hemorrhaging or the like) by leveraging blood selective layers with iron selective conductive circuits. For example, embodiments of the present disclosure may, via a controller or other computing device, determine an impedance of the iron selective conductive circuit (e.g., a speed of impedance change of the iron selective conductive circuit and/or a time required for the impedance to change/meet an associated threshold) responsive to blood received by the blood selective layer. The controller may further determine the presence of blood (e.g., the occurrence of a hemorrhage) and/or an amount of blood received by the blood selective layer based upon this impedance or change of impedance and generate an alert signal that notifies a user (e.g., caretaker, physician, etc.) of the bleeding event (e.g., hemorrhage or otherwise). In some embodiments, the sensing device may further form a multi-layer surgery accessory that operates to (1) ensure appropriate blood distribution for effective contact with the iron selective conductive circuits, (2) improve comfort for associated patients, and/or (3) improve cleanliness via a disposable configuration. 
     Sensing Device 
     With reference to  FIG.  1   , an example sensing device  100  (e.g., device  100 ) of the present disclosure is illustrated. As shown, the sensing device  100  may include a blood selective layer  200  that is operably coupled with a controller  300 . As described hereafter with reference to the operations of  FIGS.  9 - 10   , the controller  300  may be configured to supply a current to the blood selective layer  200  and, in response to blood received by the blood selective layer  200 , determine an impedance and/or a speed of impedance change (e.g., an electrical impedance as described herein) indicative of an amount of blood received by the blood selective layer. In some embodiments, the sensing device  100  may include only the blood selective layer  200  and the controller  300 . In other embodiments, as shown in  FIG.  1   , the sensing device  100  may be formed as a multi-layer functional fabric that comprises many different layers as described hereafter. As such, the present application contemplates that the sensing device  100  may include any number of layers in addition to the blood selective layer  200  based upon the intended application of the device  100 . 
     As detailed hereafter, the sensing device  100  of the present disclosure may be used in medical applications, such as in conjunction with a C-section procedure, in that at least a portion of the sensing device  100  may be disposed proximate a patient. For example, at least a portion of the sensing device  100  (e.g., the blood selective layer  200 ) may be position proximate an incision, wound, stitches, sutures, etc. of a patient such that any bleeding of said incision, wound, stitches, sutures, etc. may be directed to or otherwise contact the blood selective layer  200  of the sensing device  100 . As such, the blood selective layer  200  may be dimensioned (e.g., sized and shaped) so as to be positioned relative the body of a patient. 
     With reference to  FIGS.  2 A- 2 B , the blood selective layer  200  may define or otherwise be formed of a permeable film  202 . The permeable film  202  may, for example be formed of or otherwise comprise a polyurethane film through which fluid (e.g., blood) may pass. In some non-limiting embodiments, for example, the permeable film  202  may have a thickness T 1  of approximately 100 μm. The permeable film  202  may further define a first surface  208  and a second surface  206  opposite the first surface  208  such that a body having the thickness T 1  extends therebetween. Although described herein with reference to a permeable polyurethane material, the present disclosure contemplates that the permeable film  202  of the blood selective layer  200  may be formed of or comprise any permeable membrane or film based upon the intended application of the sensing device  100 . 
     The blood selective layer  200  may further include an iron selective conductive circuit  204  supported by the permeable film  202 . The iron (Fe) selective conductive circuit  204  may refer to, for example, grafted iron (Fe) selective conductive polymer screen printed or digital printed circuits that are reactive with iron (Fe). Although described herein with reference to a screen printed or digital printed circuit, the present disclosure contemplates that the iron selective conductive circuit  204  may be created by any applicable method, such as by grafting. By way of a particular example, a patient&#39;s blood may include one or more erythrocytes (e.g., red blood cells) that may be ferrous in nature. The iron (Fe) selective conductive circuit  204  may include iron (Fe) selective grafted particles configured to react with the ferrous nature of the erythrocyte of a patient&#39;s blood. The iron selective conductive circuit  204  may be grafted to the first surface  208  of the permeable film  202  such that, in operation, the iron selective conductive circuit  204  may contact blood received by the sensing device  100 . As described herein, the particles forming the iron (Fe) selective conductive circuit  204  may be configured such that the conductivity associated with the circuit  204  varies in response to blood (e.g., the iron content of erythrocyte) received by the blood selective layer  200 . For example, the blood selective layer  200  may be subjected to a current that is supplied by the controller  300  (e.g., or another element operably connected with the controller  300 ), such that a change in conductivity of the iron selective conductive circuit  204  results in a change in impedance (e.g., the combined effect of resistance and reactance) in the iron selective conductive circuit  204 . Said differently, as the iron (Fe) concentration of the iron selective conductive circuitry  204  changes, the impedance of the circuit  204  changes as a result of the increased concentration of Fe ions. 
     In addition to this reactance with iron (Fe) ions, the present disclosure contemplates that the iron selective conductive circuit  204  may be configured so as to only be influenced by the presence of iron (Fe) ions. For example, the sensing device  100  may, in operation, contact various other fluids (e.g., tissue fluid, urine, saline solutions, amniotic fluid, water, etc.) due to its relative position to a patient. These fluids, however, do not operate to influence the impedance of the iron selective conductive circuit  204 . In doing so, the embodiments described herein may be configured to accurately determine the presence and/or amount of blood while ignoring the presence of other fluids. 
     As described hereafter with reference to a determination of an amount of blood received by the blood selective layer  200 , the controller  300  may perform one or more calibration procedures in which various known amounts of blood are provided to blood selective layers (e.g., such as blood selective layer  200 ) with corresponding impedance values determined for the iron selective conductive circuit  204 . With the current supplied to the iron selective conductive circuit  204 , and the responsive impedance to known amounts (e.g., volume, density, etc.) of blood, the controller  300  may be calibrated, via leveraging one or more statistical methods, regressions, etc. In other embodiments, the controller  300  may be operably connected with one or more control systems  350  that may, for example, provide calibrated data for use in forthcoming blood amount determinations by the controller  300 . By way of example, the control systems  350  may, as described hereafter, be associated with one or more diagnostic systems, drug delivery systems, or the like for a particular patient and, as such, may include patient data indicative of the iron content of the patient&#39;s blood (e.g., via one or more iron content sensors or the like). 
     As described above, in some embodiments, the sensing device  100  may only include the blood selective layer  200  and the controller  300  operably connected thereto. In such an embodiment, the blood selective layer  200  may be housed within an exterior liner, enclosure, or the like (not shown) to prevent damage to the iron selective conductive circuit  204  disposed thereon. In such an embodiment, the controller  300  may be commonly housed within said exterior liner, enclosure, or the like (not shown) in order to provide an integrated solution. In other embodiments, the controller  300  may be housed separate from the blood selective layer  200 . For example, the controller  300  may be removably attached to the blood selective layer  200  so as to provide a disposable solution (e.g., disposing of the blood selective layer  200  following use). In other embodiments, the controller  300  may be communicably and/or operably coupled with the blood selective layer  200  via a network as described hereafter. 
     In some embodiments, as shown in  FIG.  1   , the sensing device  100  may further include one or more other layers combined with the blood selective layer  200 . For example, as shown in  FIG.  1    and  FIG.  7   , the sensing device  100  may further include an anti-penetration layer  102  applied to a second surface  206  of the permeable film  202 . The anti-penetration layer  102  as shown in  FIG.  1    may be configured to be downstream of the blood selective layer  200  in that blood (e.g., blood  112 ) leaving the blood selective layer  200  is received by the anti-penetration layer  102 . The anti-penetration layer  102  may be formed of or otherwise comprise a polyethylene (PE) or polypropylene (PP) microporous film configured to emit vapor to an external environment of the sensing device  100  but preclude fluid transmission therethrough. Said differently, the anti-penetration layer  102  may be configured to increase the comfort to the patient while preventing contamination. For example, fluid vapor may be emitted by the microporous holes defined by the anti-penetration layer  102  from the first surface  103  to an external environment of the sensing device  100  proximate the second surface  101  of the anti-penetration layer  102 . Fluid, however, may not pass therethrough so as to prevent contamination (e.g., patient blood contacting unintended surfaces, people, etc.) while improving cleanliness (e.g., a disposable solution). 
     The anti-penetration layer  102  may be dimensioned (e.g., sized and shaped) based upon the corresponding dimensions of the blood selective layer  200 . For example, the anti-penetration layer  102  may be the same size or larger than the blood selective layer  200  such that blood (e.g., blood  112 ) may be received by the anti-penetration layer  102  from the blood selective layer  200 . The anti-penetration layer  102  may be applied to the second surface  206  of the blood selective layer  200  and attached thereto, such as via an adhesive, hot melt procedure, or the like. Although described herein with reference to an adhesive, the present disclosure contemplates that any other mechanism for attaching or affixing the anti-penetration layer  102  with the blood selective layer  200  may be used. 
     With reference to  FIGS.  1  and  4   , the sensing device  100  may also include a first diversion layer  104  defining a first surface  107  and a second surface  105  opposite the first surface  107 . The second surface  105  of the first diversion layer  104  may be applied to the first surface  208  of the blood selective layer  200 . In some embodiments, the first diversion layer  104  may be formed of or otherwise comprise an air through non-woven of polyethylene (PE) and polyethylene terephthalate (PET) bicomponent fibers or PE and polypropylene (PP) bicomponent fibers. As would be evident in light of the present disclosure, in order to accurately determine the impedance associated with the blood received by the blood selective layer  200 , the blood  112  may substantially evenly distributed, disbursed, or diverted along the surface area of the blood selective layer  200 . In order to achieve this uniform or substantially uniform distribution (e.g., to prevent blood concentration at a particular location of the blood selective layer  200 ), the first diversion layer  104  may be configured to slow the flow of the blood  112 . The first diversion layer  104  may be dimensioned (e.g., sized and shaped) based upon the corresponding dimensions of the blood selective layer  200 . In some embodiments, one or more bicomponent fibers of the first diversion layer  104  may be arranged along a lengthwise direction of the first diversion layer  104  in order to improve the blood distribution operations described above. The first diversion layer  104  may be applied to the first surface  208  of the blood selective layer  200  and attached thereto, such as via an adhesive, hot melt procedure, or the like. Although described herein with reference to an adhesive, the present disclosure contemplates that any other mechanism for attaching or affixing the first diversion layer  104  with the blood selective layer  200  may be used. 
     The sensing device  100  may also include an absorption layer  106  defining a first surface  111  and a second surface  109  opposite the first surface  111 . The second surface  109  of the absorption layer  106  may be applied to the first surface  107  of the first diversion layer  104 . In some embodiments, the absorption layer  106  may be formed of or otherwise comprise a superabsorbent polymer (SAP), such as fluff pulp with sodium polyacrylate or the like. In order to control the volume of blood  112  that ultimately reaches the blood selective layer  200 , the absorption layer  106  may operate to absorb the blood  112  at a defined rate (e.g., based upon the SAP material selection or the like) such that a substantially consistent volume (e.g., a volume known to the controller  300 ) of blood may pass through the absorption layer  106 . The absorption layer  106  may be dimensioned (e.g., sized and shaped) based upon the corresponding dimensions of the blood selective layer  200  or any other layer described herein. The absorption layer  106  may be applied to the first surface  107  of the first diversion layer  104  and attached thereto, such as via an adhesive, hot melt procedure, or the like. Although described herein with reference to an adhesive, the present disclosure contemplates that any other mechanism for attaching or affixing the absorption layer  106  with the first diversion layer  104  may be used. The absorption layer  106  may comprise or be formed of a fluff pulp with an SAP material, viscus nonwovens, cotton nonwovens, and/or a combination of the above. The SAP material may include a superabsorbent resin of macromolecules containing hydrophilic groups with a crosslinked structure including one or more of a starch (e.g., graft, carboxymethylation, etc.), cellulose (e.g., carboxymethylation, graft, etc.), synthetic polymer (e.g., polyacrylic acid, polyvinyl alcohol, polyoxyethylene, etc.), among others. 
     With reference to  FIGS.  1  and  3   , the sensing device  100  may also include a second diversion layer  108  defining a first surface  115  and a second surface  113  opposite the first surface  115 . The second surface  113  of the second diversion layer  108  may be applied to the first surface  111  of the absorption layer  106 . In some embodiments, the second diversion layer  108  may also be formed of or otherwise comprise an air through non-woven of polyethylene (PE) and polyethylene terephthalate (PET) bicomponent fibers or PE and polypropylene (PP) bicomponent fibers. Similar to the first diversion layer  104 , the second diversion layer  108  may operate to substantially evenly distribute, disburse, or divert blood  112  along the surface area of one or more layers (e.g., the absorption layer  106 ) of the sensing device  100 . In order to achieve this uniform or substantially uniform distribution (e.g., prevent blood concentration at a particular location of the absorption layer  106 ), the second diversion layer  108  may be configured to slow the flow of the blood  112 . The second diversion layer  108  may be dimensioned (e.g., sized and shaped) based upon the corresponding dimensions of the blood selective layer  200  or any other layer described herein. In some embodiments, one or more bicomponent fibers of the second diversion layer  108  may also be arranged along a lengthwise direction of the second diversion layer  108  in order to improve the blood distribution operations described above. The second diversion layer  108  may be applied to the first surface  111  of the absorption layer  106  and attached thereto, such as via an adhesive, hot melt procedure, or the like. Although described herein with reference to an adhesive, the present disclosure contemplates that any other mechanism for attaching or affixing the second diversion layer  108  with the absorption layer  106  may be used. 
     With continued reference to  FIGS.  1  and  3   , the sensing device  100  may further include a hydrophobic layer  110  defining a first surface  119  and a second surface  117  opposite the first surface  119 . The second surface  117  of the hydrophobic layer  110  may be applied to the first surface  115  of the second diversion layer  108 . In some embodiments, the hydrophobic layer  110  may be formed of or otherwise comprise a spunbond nonwoven material or an air through non-woven polyethylene (PE) or polypropylene (PP) material. As described above, the sensing device  100  described herein may be positioned proximate an incision, wound, stitches, sutures, etc. of a patient such that any bleeding of said incision, wound, stitches, sutures, etc. may be directed to or otherwise contact the blood selective layer  200  of the sensing device  100 . In some embodiments, the hydrophobic layer  110  may serve as the exterior layer of the sensing device  100  and, as such, may be dimensioned (e.g., sized and shaped) so as to be positioned relative the body of a patient. The hydrophobic nature of this layer  110  may be configured to increase the comfort of a patient in contact with the hydrophobic layer  110  by providing substantially dry contact between the sensing device  100  and the patient. In some embodiments, the hydrophobic layer  110  may serve as the exterior layer and/or housing of one or more of the layers described herein of the sensing device  100  (e.g., so as to at least partially enclose one or more of the layers described herein). Although described herein with reference to an air through non-woven polyethylene (PE) or polypropylene (PP) material, the hydrophobic layer  110  may be formed of or otherwise comprise nylon 6 (P6), nylon 66 (Pa66), Terryl™ (Pa56), and/or the like. Furthermore, the hydrophobic layer  110  is not limited to woven, knitting, and/or nonwoven fabrics. 
     Example Computing Device and Control Systems 
     As shown in  FIG.  1   , the sensing device  100  may include a controller  300  that is operably or communicably coupled with blood selective layer  200 , and, in some embodiments, one or more control systems  350 . In some instances, the sensing device  100  may comprise or otherwise support the controller  300 , in whole or in part, such that the sensing device  100  is formed as a single, integrated device. In other embodiments, the controller  300  may be operably coupled with the blood selective layer  200  and/or sensing device  100  via a detachable/pluggable wired connection (not shown) or a network (not shown). 
     The controller  300  may include circuitry, networked processors, or the like configured to perform some or all of the apparatus-based processes described herein, and may be any suitable processing device and/or network server. In this regard, the controller  300  may be embodied by any of a variety of devices. For example, the controller  300  may be configured to receive/transmit data (e.g., data indicative of impedance, alert signal data, etc.) and may include any of a variety of fixed terminals, such as a server, desktop, or kiosk, or it may comprise any of a variety of mobile terminals, such as a portable digital assistant (PDA), mobile telephone, smartphone, laptop computer, tablet computer, or in some embodiments, a peripheral device that connects to one or more fixed or mobile terminals. Example embodiments contemplated herein may have various form factors and designs but will nevertheless include at least the components illustrated in  FIG.  8    and described in connection therewith. The controller  300  may, in some embodiments, comprise several servers or computing devices performing interconnected and/or distributed functions. Despite the many arrangements contemplated herein, the controller  300  is shown and described herein as a single computing device to avoid unnecessarily overcomplicating the disclosure. 
     As described above, in some instances, the controller  300  may be operably coupled with the blood selective layer  200  and/or the control systems  350  via a network. By way of example, the controller  300  may be associated with a central management system or central computing device configured to, in whole or in part, transmit instructions to or control operation of a plurality of devices. In such an embodiment, the network may include one or more wired and/or wireless communication networks including, for example, a wired or wireless local area network (LAN), personal area network (PAN), metropolitan area network (MAN), wide area network (WAN), or the like, as well as any hardware, software and/or firmware for implementing the one or more networks (e.g., network routers, switches, hubs, etc.). For example, the network may include a cellular telephone, mobile broadband, long term evolution (LTE), GSM/EDGE, UMTS/HSPA, IEEE 802.11, IEEE 802.16, IEEE 802.20, Wi-Fi, dial-up, and/or WiMAX network. Furthermore, the network may include a public network, such as the Internet, a private network, such as an intranet, or combinations thereof, and may utilize a variety of networking protocols now available or later developed including, but not limited to TCP/IP based networking protocols. In some embodiments, the network may refer to a collection of wired connections such that blood selective layer  200 , the control systems  350 , and/or the controller  300  may be physically connected, via one or more networking cables or the like. 
     As illustrated in  FIG.  8   , the controller  300  may include a processor  302 , a memory  304 , input/output circuitry  306 , and communications circuitry  308 . The controller  300  may be configured to execute the operations described below in connection with  FIGS.  9 - 10   . Although components  302 - 308  are described in some cases using functional language, it should be understood that the particular implementations necessarily include the use of particular hardware. It should also be understood that certain of these components  302 - 308  may include similar or common hardware. For example, two sets of circuitry may both leverage use of the same processor  302 , memory  304 , communications circuitry  308 , or the like to perform their associated functions, such that duplicate hardware is not required for each set of circuitry. The use of the term “circuitry” as used herein includes particular hardware configured to perform the functions associated with respective circuitry described herein. As described in the example above, in some embodiments, various elements or components of the circuitry of the controller  300  may be housed within components of the sensing device  100 . It will be understood in this regard that some of the components described in connection with the controller  300  may be housed within one or more of the devices of  FIGS.  1 - 7   , while other components are housed within another of these devices, or by yet another device not expressly illustrated in  FIGS.  1 - 7   . 
     Of course, while the term “circuitry” should be understood broadly to include hardware, in some embodiments, the term “circuitry” may also include software for configuring the hardware. For example, although “circuitry” may include processing circuitry, storage media, network interfaces, input/output devices, and the like, other elements of the controller  300  may provide or supplement the functionality of particular circuitry. 
     In some embodiments, the processor  302  (and/or co-processor or any other processing circuitry assisting or otherwise associated with the processor) may be in communication with the memory  304  via a bus for passing information among components of the controller  300 . The memory  304  may be non-transitory and may include, for example, one or more volatile and/or non-volatile memories. In other words, for example, the memory may be an electronic storage device (e.g., a non-transitory computer readable storage medium). The memory  304  may be configured to store information, data, content, applications, instructions, or the like, for enabling the controller  300  to carry out various functions in accordance with example embodiments of the present disclosure. 
     The processor  302  may be embodied in a number of different ways and may, for example, include one or more processing devices configured to perform independently. Additionally or alternatively, the processor may include one or more processors configured in tandem via a bus to enable independent execution of instructions, pipelining, and/or multithreading. The use of the term “processing circuitry” may be understood to include a single core processor, a multi-core processor, multiple processors internal to the computing device, and/or remote or “cloud” processors. 
     In an example embodiment, the processor  302  may be configured to execute instructions stored in the memory  304  or otherwise accessible to the processor  302 . Alternatively or additionally, the processor  302  may be configured to execute hard-coded functionality. As such, whether configured by hardware or by a combination of hardware with software, the processor  302  may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to an embodiment of the present disclosure while configured accordingly. Alternatively, as another example, when the processor  302  is embodied as an executor of software instructions, the instructions may specifically configure the processor  302  to perform the algorithms and/or operations described herein when the instructions are executed. 
     The controller  300  further includes input/output circuitry  306  that may, in turn, be in communication with processor  302  to provide output to a user and to receive input from a user, user device, or another source. In this regard, the input/output circuitry  306  may comprise a display that may be manipulated by a mobile application. In some embodiments, the input/output circuitry  306  may also include additional functionality including a keyboard, a mouse, a joystick, a touch screen, touch areas, soft keys, a microphone, a speaker, or other input/output mechanisms. The processor  302  and/or user interface circuitry comprising the processor  302  may be configured to control one or more functions of a display through computer program instructions (e.g., software and/or firmware) stored on a memory accessible to the processor (e.g., memory  304 , and/or the like), such as to display a user notification as described herein. 
     The communications circuitry  308  may be any means such as a device or circuitry embodied in either hardware or a combination of hardware and software that is configured to receive and/or transmit data from/to a network and/or any other device, circuitry, or module in communication with the controller  300 . In this regard, the communications circuitry  308  may include, for example, a network interface for enabling communications with a wired or wireless communication network. For example, the communications circuitry  308  may include one or more network interface cards, antennae, buses, switches, routers, modems, and supporting hardware and/or software, or any other device suitable for enabling communications via a network. Additionally or alternatively, the communication interface may include the circuitry for interacting with the antenna(s) to cause transmission of signals via the antenna(s) or to handle receipt of signals received via the antenna(s). These signals may be transmitted by the controller  300  using any of a number of wireless personal area network (PAN) technologies, such as Bluetooth® v1.0 through v3.0, Bluetooth Low Energy (BLE), infrared wireless (e.g., IrDA), ultra-wideband (UWB), induction wireless transmission, or the like. In addition, it should be understood that these signals may be transmitted using Wi-Fi, Near Field Communications (NFC), Worldwide Interoperability for Microwave Access (WiMAX) or other proximity-based communications protocols. 
     In addition, computer program instructions and/or other type of code may be loaded onto a computer, processor or other programmable circuitry to produce a machine, such that the computer, processor other programmable circuitry that execute the code on the machine create the means for implementing the various functions, including those described in connection with the components of controller  300 . 
     As described above and as will be appreciated based on this disclosure, embodiments of the present disclosure may be configured as apparatuses, systems, methods, and the like. Accordingly, embodiments may comprise various means including entirely of hardware or any combination of software with hardware. Furthermore, embodiments may take the form of a computer program product comprising instructions stored on at least one non-transitory computer-readable storage medium (e.g., computer software stored on a hardware device). Any suitable computer-readable storage medium may be utilized including non-transitory hard disks, CD-ROMs, flash memory, optical storage devices, or magnetic storage devices. 
     In some embodiments, the sensing device  100  and/or the controller  300  may be operably or communicably coupled with one or more control systems  350 . By way of example with reference to a hospital or medical implementation, the sensing device  100  of the present disclosure may integrate or otherwise communicate with various diagnostic systems, sensors, and/or the like (e.g., one or more control systems  350 ) to provide up-to-date data associated with the current condition of one or more patients. By way of a particular example, the sensing device  100  and/or controller  300  may be operably coupled with a warning or alert system, one or more drug delivery systems, or the like and may further be configured to modify or otherwise control operation thereof. As such, the one or more control systems  350  may similarly comprise circuitry components, such as those described with reference to the controller  300 , in order to perform their respective operations. 
     Example Operations 
       FIG.  9    illustrates a flowchart containing a series of operations for hemorrhage detection (e.g., method  400 ). The operations illustrated in  FIG.  9    may, for example, be performed by, with the assistance of, and/or under the control of an apparatus (e.g., controller  300 ), as described above. In this regard, performance of the operations may invoke one or more of processor  302 , memory  304 , input/output circuitry  306 , and/or communications circuitry  308 . 
     As shown in operation  402 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for supplying a current to the iron selective conductive circuit supported by the permeable film of the blood selective layer. As described above, the blood selective layer may include an iron selective conductive circuit supported by the permeable film that includes grafted iron (Fe) selective conductive polymer screen printed circuits that are reactive with iron (Fe). This iron selective conductive circuit may be supplied by an electrical current, such as via the positive (+) connection  210  and negative (−) connection  212  with the blood selective layer illustrated in  FIG.  1   . In some embodiments, the controller  300  may be in electrical communication with the blood selective layer such that the controller  300  is configured to directly supply the current to the iron selective conductive circuit (e.g., via a current source, power supply, or the like) of the controller  300 . In other embodiments, the controller  300  may be configured to cause current to be supplied to the iron selective conductive circuit, such as via transmitting instructions to a current source in electrical communication with the iron selective conductive circuit. The present disclosure contemplates that the source supplied at operation  402  may be of any kind (e.g., direct current (DC), alternating current (AC), or the like) and/or of any intensity (e.g., amperes (amps)) based upon the intended application of the sensing device  100 . 
     As shown in operation  404 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for determining an impedance of the iron selective conductive circuit responsive to blood received by the blood selective layer. As described above, a patient&#39;s blood (e.g., blood  112  in  FIG.  1   ) may include one or more erythrocytes (e.g., red blood cells) that may be ferrous in nature. The iron (Fe) selective conductive circuit may include iron (Fe) selective grafted particles configured to react with the ferrous nature of the erythrocyte of a user&#39;s blood. The iron selective conductive circuit defines a circuit through which electrical current may flow (e.g., with or without the presence of blood  112 ), such as in response to current supplied by the controller  300  as described above with reference to operation  402 . As would be evident in light of the present disclosure, the iron selective conductive is associated with an impedance (e.g., opposition to current, combined effect of resistance and reactance, etc.), and the controller  300  may be configured to, prior to contact with blood, determine an impedance associated with the iron selective conductive circuit. The impedance may be determined by Z=V/I, where V is the voltage, I is the current, and Z is impedance, a vector combination of resistance, inductive reactance, and capacitive reactance. The controller  300  may supply a current to the iron selective conductive circuit as described above with reference to operation  402  that has a determined voltage (volts) and current (amps). As such, the controller  300  may determine the impedance (Z) associated with the iron selective conductive circuit prior to operation of the sensing device  100  (e.g., prior to contact with blood). 
     In operation, the blood selective layer of the sensing device  100  may receive or otherwise contact blood, such as from a patient located proximate the sensing device  100 . As described herein, the particles forming the iron (Fe) selective conductive circuit may be configured such that the conductivity associated with the circuit varies in response to blood (e.g., the iron content of erythrocyte) received by the blood selective layer. When the blood selective layer is subjected to a current that is supplied by the controller  300  (e.g., or another element operably connected with the controller  300 ), a change in conductivity of the iron selective conductive circuit may result in a change in impedance (e.g., the combined effect of resistance and reactance) in the iron selective conductive circuit. Said differently, as the iron (Fe) concentration of the iron selective conductive circuitry changes, the impedance of the circuit changes as a result of the increased concentration of Fe ions. The controller  300  may be configured to, in some embodiments, consistently supply current to the iron selective conductive circuit at operation  402  and, in response, consistently (e.g., according to a determined sampling rate or the like) determine an impedance of the circuit. In other embodiments, the controller  300  may iteratively supply current to the iron selective conductive circuit at operation  402  and may similarly iteratively determine the impedance of the iron selective conductive circuit. In other embodiments, the controller  300  may determine an impedance of the iron selective conductive circuit at operation  404  in response to a user instruction (e.g., an operator input requesting the impedance of the iron selective conductive circuit). 
     As shown in operation  406 , the apparatus (e.g., controller  300 ) includes means, such as processor  302  or the like, for determining an amount of blood received by the blood selective layer based upon the determined impedance. As described above, the controller  300  may perform one or more calibration procedures in which various known amounts of blood are provided to blood selective layers (e.g., such as blood selective layer  200 ) with corresponding impedance values determined for the iron selective conductive circuit. With the current supplied to the iron selective conductive circuit, and the responsive impedance to known amounts (e.g., volume, density, etc.) of blood, the controller  300  may be calibrated, via leveraging one or more statistical methods, regressions, etc. In other embodiments, the controller  300  may be operably connected with one or more control systems  350  that may, for example, provide calibrated data indicative of the iron content of the patient&#39;s blood (e.g., via one or more iron content sensors or the like). As such, the controller  300  may be configured to compare the impedance determined at operation  404  with one or more calibrated impedance values in order to determine an amount of blood received by the blood selective layer. Said differently, the change in impedance of the iron selective conductive circuit may be proportional to the amount of blood received by the blood selective layer. Various regressions techniques, modeling, and/or the like may be used by the controller  300  to associate the determined impedance at operation  404  with a corresponding amount of blood at operation  406 . 
     As described above, in addition to this reactance with iron (Fe) ions, the present disclosure contemplates that the iron selective conductive circuit may be configured so as to only be influenced by the presence of iron (Fe) ions. For example, the sensing device  100  may, in operation, contact various other fluids (e.g., tissue fluid, urine, saline solutions, amniotic fluid, water, etc.) due to its relative position to a patient. These fluids, however, do not operate to influence the impedance of the iron selective conductive circuit  204 . In doing so, the embodiments described herein may be configured to accurately determine the presence and/or amount of blood while ignoring the presence of other fluids. 
     Furthermore, the amount determined at operation  406  may refer to a volume, density, and/or the presence of blood received by the sensing device  100 . In other words, the controller  300  may be configured to, in some embodiments, detect any bleeding event associated with a patient (e.g., detect the presence of blood) regardless of the amount of blood associated with the bleeding event. For example, the controller  300  may determine an impedance at operation  404  that differs from (e.g., is greater than) the impedance of the iron selective conductive circuit in the absence of blood (e.g., when a current is supplied at operation  402  and blood has yet to be received by the blood selective layer). In other embodiments, the controller  300  may be configured to determine an amount (e.g., volume, density, a speed of impedance change time required for the impedance to change/meet an associated threshold, and/or the like) that is indicative of a hemorrhaging event as described hereafter with reference to  FIG.  10   . For example, the controller  300  may leverage, define, or otherwise employ one or more thresholds against which the determined impedance may be compared. 
       FIG.  10    illustrates a flowchart containing a series of operations for alert signal operations (e.g., method  500 ). The operations illustrated in  FIG.  10    may, for example, be performed by, with the assistance of, and/or under the control of an apparatus (e.g., controller  300 ), as described above. In this regard, performance of the operations may invoke one or more of processor  302 , memory  304 , input/output circuitry  306 , and/or communications circuitry  308 . 
     As shown in operation  502 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for comparing the determined impedance with an alert threshold. As described above, in some embodiments, the controller  300  may employ one or more thresholds in order to quantify the amount or quantity of blood received by the blood selective layer and/or sensing device  100 . By way of example, during a calibration procedure or the like, one or more blood selective layers (e.g., the blood selective layer  200  or the like) may be subjected to an amount of blood indicative of a hemorrhaging event, and the controller  300  may determine the impedance of the iron selective conductive circuit in response to this amount of blood. Such a calibration procedure may be iteratively performed at various amounts of blood (e.g., based upon patient size, blood iron content, etc.) in order to determine an amount of blood that is indicative of a hemorrhaging event (e.g., the alert threshold). Said differently, the controller  300  may, for example, determine patient specific (e.g., based upon blood volume, iron content, or any other patient characteristic) thresholds against which the determined impedance may be compared at operation  502 . For example, the alert threshold may, in some embodiments, refer to a ferrous concentration of approximately 0.004%-0.006% g/ml. In any embodiment, the controller  300  may leverage various machine learning techniques (e.g., supervised learning, unsupervised learning, neural networks, etc.) in order to improved generation of the alert thresholds described herein. Furthermore, although described herein with reference to a hemorrhaging event, the present disclosure contemplates that the alert threshold(s) described herein may be used to detect any event associated with a patient based upon the intended application of the sensing device  100 . 
     Thereafter, as shown in operation  504 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for generating an alert signal in an instance in which the determined impedance satisfies the alert threshold. As described above, the determined impedance may be compared with one or more alert thresholds in order to determine the presence of blood received by the iron selective conductive circuit and/or the amount of blood received by the iron selective conductive circuit. For example, the controller  300  may iteratively supply current to the iron selective conductive circuit and iteratively determine the impedance for the iron selective conductive circuit. Given that the presence of iron in a patient&#39;s blood impacts (e.g., increases) the conductivity of the circuit, the comparison at operation  502  may be, for example, a comparison between the increase in conductivity relative an alert threshold that includes a minimum increase in conductivity. Said differently, if the impedance of the iron selective conductive circuit increases to a value that satisfies and/or exceeds the impedance value defined by the alert threshold, an alert signal may be generated. 
     In some embodiments, various alert thresholds may be used. For example, a first alert threshold may be used to detect the presence of blood received by the blood selective layer (e.g., a lower impedance increase threshold value). A subsequent or second alert threshold may be used to detect a hemorrhaging event or other hazardous condition (e.g. a larger impedance increase threshold value). In doing so, the sensing devices  100  of the present disclosure may operate to detect false positives associated with some blood contact that is prevalent in many surgeries, operations, etc. Said differently, such a first alert threshold may operate to prevent unnecessary resource diversion to a patient when blood is present, but the amount of blood isn&#39;t such that a hemorrhaging event is occurring. In this way, hospitals, clinics, etc. employing the sensing device  100  may operate to effectively prioritize emergency events. 
     In some embodiments, as shown in operation  506 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for modifying an operating condition of one or more systems (e.g., control systems  350 ) communicably coupled with the controller  300 . In some embodiments, the controller  300  may be operably connected with various control systems  350  associated with one or more diagnostic systems, drug delivery systems, or the like for a particular patient. In some embodiments, the alert signal generated at operation  504  may include instructions configured to modify, augment, or otherwise change an operating condition of these control systems  350 . For example, the sensing device  100  and/or the controller  300  may be operably connected with a drug delivery system (e.g., an example control system  350 ) that administers medication, such as anticoagulant or blood thinning agents. In response to detection of a hemorrhaging event as described above, the alert signal generated by the controller  300  may operate to halt administration of such medication by the example drug delivery system (e.g., an example control system  350 ). Although described herein with reference to anticoagulant administration, the present disclosure contemplates that the alert signal generated by the controller may be configured to cause any change associated with any control system  350  based upon the intended application of the sensing device  100 . 
     In other embodiments, as shown in operation  508 , the apparatus (e.g., controller  300 ) includes means, such as processor  302 , communications circuitry  308 , or the like, for causing presentation of a user notification. As described above, in some embodiments, the controller  300  may include one or more mechanisms for causing display of data generated by the controller  300 . For example, the controller  300  may include or otherwise be operably coupled to a display screen configured to cause presentation of a user notification in response to the alert signal. By way of a particular example, the alert signal generated at operation  504  may include instructions for causing visual and/or audible presentation of a user notification that indicates that the determined impedance satisfies the alert threshold. In doing so, the user notification may indicate to a user that either blood is presently contacting the blood selective layer of the sensing device and/or that a hemorrhaging event or other emergency event is occurring. 
       FIGS.  9  and  10    thus illustrate flowcharts describing the operation of apparatuses, methods, and computer program products according to example embodiments contemplated herein. It will be understood that each flowchart block, and combinations of flowchart blocks, may be implemented by various means, such as hardware, firmware, processor, circuitry, and/or other devices associated with execution of software including one or more computer program instructions. For example, one or more of the operations described above may be implemented by an apparatus executing computer program instructions. In this regard, the computer program instructions may be stored by a memory  304  of the controller  300  and executed by a processor  302  of the controller  300 . As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (e.g., hardware) to produce a machine, such that the resulting computer or other programmable apparatus implements the functions specified in the flowchart blocks. These computer program instructions may also be stored in a computer-readable memory that may direct a computer or other programmable apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture, the execution of which implements the functions specified in the flowchart blocks. The computer program instructions may also be loaded onto a computer or other programmable apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions executed on the computer or other programmable apparatus provide operations for implementing the functions specified in the flowchart blocks. 
     The flowchart blocks support combinations of means for performing the specified functions and combinations of operations for performing the specified functions. It will be understood that one or more blocks of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware with computer instructions.