Patent Description:
The commercial state-of-the-art medical device for IO access is a small, drill-like device built around a relatively primitive electric motor for effectuating IO access by drilling with a needle assembly of the IO-access medical device. Some medical devices for IO access utilize linear springs to provide rotational energy for drilling, while some other IO-access medical devices even rely on a manual means for providing the rotational energy for the drilling. No matter what means for drilling a clinician uses for IO access, the clinician needs to be able to control the IO-access medical device under any circumstance and interrupt the drilling at any time for any reason. In addition, there is a need to prevent accidental triggering of IO-access medical devices while handling an IO-access medical device, before the needle assembly of an IO-access medical device is properly positioned for IO access, or even while the IO-access medical device is stored, for example, in an emergency bag. <CIT> relates to drilling devices, and more particularly to medical drilling devices, such as may be used, for example, for drilling into bone. <CIT> relates to a device for surgery, and more particularly, for accessing bone marrow for enhancement of tissue repair.

Claim <NUM> defines the invention and dependent claims disclose embodiments. No surgical methods are claimed. Disclosed herein are various operating mechanisms for IO-access medical devices and exemplary methods thereof that address the foregoing needs. In addition, constant-torque IO access devices and methods thereof are disclosed that significantly reduce design and manufacturing complexity of the small, drill-like devices that are currently the state-of-the-art for IO access.

Disclosed herein is an IO access device including, in some embodiments, a constant-torque spring assembly, a drive shaft, an IO needle, and an interlock mechanism. The constant-torque spring assembly is disposed in a housing, and the drive shaft extends from the housing. The drive shaft is coupled to the constant-torque spring assembly. The IO needle is coupled to the drive shaft. The IO needle is configured for drilling through bone and providing IO access to a medullary cavity of a patient. The interlock mechanism is configured to prevent rotation of the IO needle and the drilling therewith until the interlock mechanism is disengaged.

In some embodiments, the constant-torque spring assembly includes a metal ribbon reversely wound onto an output spool. The output spool has an axial channel. The metal ribbon is configured to wind onto a storage spool with a constant torque when the output spool is released.

In some embodiments, spindles of the output spool and the storage spool are coupled together by at least one elastomeric loop to prevent any timing-related errors between the output spool and the storage spool.

In some embodiments, the interlock mechanism includes a trigger configured to release a lock pin disposed between the trigger and the output spool. A pressure-based trigger mechanism of the IO device is configured to require the interlock mechanism to be disengaged before activation of the pressure-based trigger mechanism for rotation of the IO needle.

In some embodiments, the interlock mechanism includes a rotatable lock pin configured to block axial movement of an extension pin disposed in the axial channel of the output spool between the lock pin and the drive shaft. A pressure-based trigger mechanism of the IO device is configured to require the interlock mechanism to be disengaged before activation of the pressure-based trigger mechanism for rotation of the IO needle.

In some embodiments, the interlock mechanism includes a trigger pivotally mounted on a transversely oriented pin having trigger teeth configured to interlock with those of a distal-end portion of the output spool. A pressure-based trigger mechanism of the IO device is configured to require the interlock mechanism to be disengaged before activation of the pressure-based trigger mechanism for rotation of the IO needle.

In some embodiments, the interlock mechanism includes a spring-loaded trigger mounted in an exterior channel of the housing including an extension channel configured to allow the drive shaft to extend from the axial channel into the extension channel when the extension channel and the axial channel are aligned. A pressure-based trigger mechanism of the IO device is configured to require the interlock mechanism to be disengaged before activation of the pressure-based trigger mechanism for rotation of the IO needle.

In some embodiments, the interlock mechanism includes a pressure-based trigger configured to release a detent from a bore of the output spool. A pressure-based trigger mechanism of the IO device is configured to allow the interlock mechanism to be disengaged either before or after activation of the pressure-based trigger mechanism for rotation of the IO needle.

In some embodiments, the pressure-based trigger mechanism includes a set of housing teeth around an aperture of the housing from which the drive shaft extends, as well as a set of complementary drive-shaft teeth around the drive shaft opposing the set of housing teeth. The set of housing teeth and the set of drive-shaft teeth are engaged in an inactive state of the IO access device by a compression spring between a back side of the set of drive-shaft teeth and the output spool.

In some embodiments, the drive shaft is slidably disposed in the axial channel of the output spool such that force applied to a distal end of the IO needle simultaneously compresses the compression spring and inserts the drive shaft deeper into the axial channel. The force applied to the distal end of the IO needle disengages the set of drive-shaft teeth from the set of housing teeth and initiates an active state of the IO access device in which rotation of the IO needle is effectuated by the output spool of the constant-torque spring assembly on the drive shaft.

In some embodiments, the compression spring is configured to relax when the force applied to the distal end of the IO needle is removed. The set of drive-shaft teeth reengages with the set of housing teeth and reinitiates the inactive state of the IO access device when the force applied to the distal end of the IO needle is removed.

In some embodiments, the IO access device is configured such that entry of the IO needle into the medullary cavity of the patient automatically removes the force applied to the distal end of the IO needle.

In some embodiments, the IO access further comprises a braking system. The braking system is configured to act on the output spool to slow the metal ribbon from winding onto the storage spool.

In some embodiments, the IO needle is configured to separate from the IO access device subsequent to achieving IO access to the medullary cavity of the patient.

In some embodiments, the IO needle includes an obturator removably disposed in a cannula. The cannula has a lumen configured for at least IO infusion upon removal of the obturator.

Also disclosed herein is a method of an IO access device including, in some embodiments, a device-obtaining step, an interlock-disengaging step, a needle-inserting step, a force-applying step, and a drilling step. The device-obtaining step includes obtaining the IO access device. The interlock-disengaging step includes disengaging an interlock mechanism configured to prevent rotation of an IO needle and drilling therewith until the interlock mechanism is disengaged. The needle-inserting step includes inserting a distal end of the IO needle through skin at an insertion site of a patient. The force-applying step includes applying force to bone at the insertion site with the distal end of the IO needle. The force-applying step activates a pressure-based trigger mechanism and starts winding a metal ribbon of a constant-torque spring assembly from an output spool onto a storage spool. The winding of the metal ribbon from the output spool onto the storage spool starts rotation of the IO needle by way of a drive shaft coupled to the constant-torque spring assembly. The drilling step includes drilling through the bone until the IO needle enters a medullary cavity of the patient. IO access is achieved upon entering the medullary cavity of the patient with the IO access device.

In some embodiments, the interlock-disengaging step includes triggering a trigger to release a lock pin disposed between the trigger and the output spool. The pressure-based trigger mechanism is configured to require the interlock-disengaging step before the force-applying step to activate the pressure-based trigger mechanism.

In some embodiments, the interlock-disengaging step includes rotating a lock pin configured to block axial movement of an extension pin disposed in an axial channel of the output spool between the lock pin and the drive shaft. The pressure-based trigger mechanism is configured to require the interlock-disengaging step before the force-applying step to activate the pressure-based trigger mechanism.

In some embodiments, the interlock-disengaging step includes triggering a trigger pivotally mounted on a transversely oriented pin having trigger teeth configured to interlock with those of a distal-end portion of the output spool. The pressure-based trigger mechanism is configured to require the interlock-disengaging step before the force-applying step to activate the pressure-based trigger mechanism.

In some embodiments, the interlock-disengaging step includes triggering a spring-loaded trigger mounted in an exterior channel of a housing including an extension channel configured to allow the drive shaft to extend from an axial channel of the output spool into the extension channel when the extension channel and the axial channel are aligned. The pressure-based trigger mechanism is configured to require the interlock-disengaging step before the force-applying step to activate the pressure-based trigger mechanism.

In some embodiments, the interlock-disengaging step includes triggering a pressure-based trigger configured to release a detent from a bore of the output spool. The pressure-based trigger mechanism is configured to require the interlock-disengaging step either before or after the force-applying step to activate the pressure-based trigger mechanism.

In some embodiments, the method further includes a force-ceasing step. The force-ceasing step includes ceasing to apply the force to the bone with the distal end of the IO needle. The force-ceasing step stops the rotation of the IO needle.

In some embodiments, the force-ceasing step is manually initiated by a clinician after feeling a change in tissue density upon entering the medullary cavity of the patient. Alternatively, the force-ceasing step is automatically initiated by the pressure-based trigger mechanism after the change in the tissue density upon entering the medullary cavity of the patient.

In some embodiments, the method further includes a needle-detaching step, an obturator-removing step, a cannula-confirming step, a cannula-securing step, and an infusion-starting step. The needle-detaching step includes detaching the IO needle from a remainder of the IO access device. The obturator-removing step includes removing from the IO needle an obturator removably disposed in a cannula. The cannula-confirming step includes confirming the cannula is disposed in the medullary cavity by aspirating bone marrow through a syringe. The cannula-securing step includes securing the cannula to the patient. The infusion-starting step includes starting IO infusion as boluses with a same or different syringe.

With respect to "proximal," a "proximal portion" or a "proximal-end portion" of, for example, a catheter includes a portion of the catheter intended to be near a clinician when the catheter is used on a patient. Likewise, a "proximal length" of, for example, the catheter includes a length of the catheter intended to be near the clinician when the catheter is used on the patient. A "proximal end" of, for example, the catheter includes an end of the catheter intended to be near the clinician when the catheter is used on the patient. The proximal portion, the proximal-end portion, or the proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, the proximal-end portion, or the proximal length of the catheter need not include the proximal end of the catheter. That is, unless context suggests otherwise, the proximal portion, the proximal-end portion, or the proximal length of the catheter is not a terminal portion or terminal length of the catheter.

With respect to "distal," a "distal portion" or a "distal-end portion" of, for example, a catheter includes a portion of the catheter intended to be near or in a patient when the catheter is used on the patient. Likewise, a "distal length" of, for example, the catheter includes a length of the catheter intended to be near or in the patient when the catheter is used on the patient. A "distal end" of, for example, the catheter includes an end of the catheter intended to be near or in the patient when the catheter is used on the patient. The distal portion, the distal-end portion, or the distal length of the catheter can include the distal end of the catheter; however, the distal portion, the distal-end portion, or the distal length of the catheter need not include the distal end of the catheter. That is, unless context suggests otherwise, the distal portion, the distal-end portion, or the distal length of the catheter is not a terminal portion or terminal length of the catheter.

As set forth above, there is a need to prevent accidental triggering of IO-access medical devices while handling an IO-access medical device, before the needle assembly of an IO-access medical device is properly positioned for IO access, or even while the IO-access medical device is stored, for example, in an emergency bag. Disclosed herein are various operating mechanisms for IO-access medical devices and methods thereof that address the foregoing needs.

In addition to the foregoing, there is a need to significantly reduce design and manufacturing complexity of the small, drill-like devices that are currently the state-of-the-art for IO access. Also disclosed herein are constant-torque IO access devices and methods thereof that significantly reduce design and manufacturing complexity of the small, drill-like devices that are currently the state-of-the-art for IO access.

Various embodiments of the constant-torque IO access devices are initially described below. Various operating mechanisms such as a pressure-based trigger mechanism and a number of different interlock mechanisms for the constant-torque IO access devices are subsequently described below. Some of the various operating mechanisms are described below with respect to particular embodiments of the of the constant-torque IO access devices; however, this is for expository expediency in conveying certain concepts of the various operating mechanisms. A particular operating mechanism described with respect to a particular embodiment of a constant-torque IO access device should not be construed as being limited to the particular embodiment of the constant-torque IO access device. And while the various operating mechanisms are described in the context of constant-torque access devices, it should be understood the various operating mechanisms are not limited thereto.

<FIG> illustrate a first IO access device <NUM> in accordance with some embodiments. <FIG> illustrate a second IO access device <NUM> in accordance with some embodiments. <FIG> illustrate a third IO access device <NUM> in accordance with some embodiments. <FIG> illustrates a constant-torque spring assembly <NUM> in accordance with some embodiments.

As shown, the IO access device <NUM>, <NUM>, or <NUM> includes the constant-torque spring assembly <NUM>, <NUM>, or <NUM> disposed a housing <NUM>, <NUM>, or <NUM>, a drive shaft <NUM> extending from the housing <NUM>, <NUM>, or <NUM> and an IO needle assembly <NUM> coupled to the drive shaft <NUM> configured to provide IO access to a medullary cavity of a patient.

The housing <NUM>, <NUM>, or <NUM> houses components of the IO access device <NUM>, <NUM>, or <NUM>. While the components of the IO access devices <NUM>, <NUM>, and <NUM> are largely the same in terms of function, the components can be physically different in order to accommodate a particular form factor. For example, the IO access device <NUM> has a form factor for holding the IO access device <NUM> in a way that permits the IO needle assembly <NUM> to access a medullary cavity of a patient with a stabbing motion. In contrast, the IO access device <NUM> has a form factor for holding the IO access device <NUM> in a way that permits the IO needle assembly <NUM> to access a medullary cavity of a patient with in a more traditional drilling motion. The housing <NUM>, <NUM>, or <NUM> is molded of a medically acceptable polymer such that sagittal halves of the housing <NUM>, <NUM>, or <NUM> can be snapped or bound (e.g., mechanically fastened with fasteners, chemically bonded by adhesive, etc.) together around the components of the IO access device <NUM>, <NUM>, or <NUM>.

The constant-torque spring assembly <NUM>, <NUM>, or <NUM> includes a metal ribbon (e.g., a stainless-steel ribbon) <NUM>, at least a portion of which is reversely wound onto an output spool <NUM> and correctly wound onto a storage spool <NUM> with respect to a bias of the metal ribbon <NUM>. The metal ribbon <NUM> is configured to wind onto the storage spool <NUM> or into a storage cavity with a constant torque across a range of revolutions-per-minute ("RPMs") when the output spool <NUM> is released or otherwise allowed to do so.

The constant-torque spring assembly <NUM>, <NUM>, or <NUM> is unique in that stresses associated with deflection of the metal ribbon <NUM> are not cumulative over an entire length of the metal ribbon <NUM>. The stresses are temporary and apply to only a short length (e.g., the exposed length) of the metal ribbon <NUM> at any given time. In addition, the metal ribbon <NUM> can be tuned with respect to any characteristic selected from its thickness, width, number of winds around the output spool <NUM>, and the like for configuration of the constant-torque spring assembly <NUM>, <NUM>, or <NUM> with an optimal rotary action of the IO needle assembly <NUM> for IO insertion.

Each spool of the output spool <NUM> and the storage spool <NUM> optionally includes a spindle co-incident with an axis of the spool for mounting the spool in the housing <NUM>, <NUM>, or <NUM>. Such a spindle can be on one side of the spool or both sides of the spool. For example, the constant-torque spring assembly <NUM> of the IO access device <NUM> includes spindle <NUM> and spindle <NUM> of the output spool <NUM> and spindle <NUM> and spindle <NUM> of the storage spool <NUM>. Likewise, the constant-torque spring assembly <NUM> of the IO access device <NUM> includes spindle <NUM> and spindle <NUM> of the output spool <NUM> and spindle <NUM> and spindle <NUM> of the storage spool <NUM>. The constant-torque spring assembly <NUM> of the IO access device <NUM> includes analogous spindles as well; however, reference number for the spindles are omitted for clarity.

Alternatively or additionally to the foregoing spindles, each spool of the output spool <NUM> and the storage spool <NUM> optionally includes an axial channel co-incident with the axis of the spool, which can be for mounting the spool in the housing <NUM>, <NUM>, or <NUM>, driving another component (e.g., the drive shaft <NUM>) of the IO access device <NUM>, <NUM>, or <NUM>, etc. Such an axial channel can be in one side of the spool, both sides of the spool, or extending from one side of the spool to the other side of the spool. For example, the constant-torque spring assembly <NUM>, <NUM>, or <NUM> of the IO access device <NUM>, <NUM>, or <NUM> includes an axial channel <NUM>, which, in at least this case, includes a hexagonal shape to drive the hexagonal proximal-end portion of the drive shaft <NUM>. (See <FIG> and <FIG>. ) If the output spool <NUM> or the storage spool <NUM> includes a spindle on a side of the spool <NUM> or <NUM> and an axial channel in the same side of the spool <NUM> or <NUM>, the spindle has an outer diameter large enough to accommodate an inner diameter of the axial channel as shown in <FIG> by the spindle <NUM> and the axial channel <NUM>.

As shown in <FIG>, same-side spindles such as the spindles <NUM> and <NUM>, respectively of the output spool <NUM> and the storage spool <NUM> of the constant-torque spring assembly <NUM>, can be coupled together by at least one elastomeric loop <NUM> (e.g., an 'O'-ring) to prevent any timing-related errors between the output spool <NUM> and the storage spool <NUM>. Such timing-related errors are possible if the metal ribbon <NUM> winds onto the storage spool <NUM> more slowly than the metal ribbon <NUM> winds off the output spool <NUM> - or vice versa. As shown, the elastomeric loop <NUM> includes a half twist such that it crosses over itself to match the rotational motion of both the output spool <NUM> and the storage spool <NUM>.

Notwithstanding the foregoing, the constant-torque spring assembly <NUM>, <NUM>, or <NUM> can alternatively be configured as a constant-power spring assembly including a constant-power spring or a torsion spring assembly including a torsion spring. Like the constant-torque spring assembly <NUM>, <NUM>, or <NUM> such a constant-power spring assembly or torsion spring assembly can be disposed in the housing <NUM>, <NUM>, or <NUM> for driving the drive shaft <NUM> coupled to the IO needle assembly <NUM> to provide IO access to a medullary cavity of a patient.

The IO needle assembly <NUM> is configured to separate from the IO access device <NUM>, <NUM>, or <NUM> subsequent to achieving IO access to a medullary cavity of a patient. While not shown, the IO needle assembly <NUM> includes an obturator removably disposed in a cannula. The cannula has a lumen configured for at least IO infusion upon removal of the obturator.

<FIG> illustrates the constant-torque spring assembly <NUM> in combination with a pressure-based trigger mechanism <NUM> for activating rotation of the IO needle assembly <NUM> in accordance with some embodiments. <FIG> illustrates an inactive state and an active state of the pressure-based trigger mechanism <NUM> in accordance with some embodiments.

As shown, the pressure-based trigger mechanism <NUM> for activating rotation of the IO needle assembly <NUM> includes the drive shaft <NUM> slidably disposed in the axial channel <NUM> of the output spool <NUM>, a set of drive-shaft teeth <NUM> around the drive shaft <NUM>, a set of opposing but complementary housing teeth <NUM> around an aperture of at least the housing <NUM> from which the drive shaft <NUM> extends, and a compression spring <NUM> between a back side of the set of drive-shaft teeth <NUM> and the output spool <NUM>.

In the inactive state of at least the IO access device <NUM>, a spring force is exerted on the back side of the set of drive-shaft teeth <NUM> by extension of the compression spring <NUM> between the back side of the set of drive-shaft teeth <NUM> and the output spool <NUM>. Extension of the compression spring <NUM> keeps the drive shaft <NUM> pushed out of the axial channel <NUM>, which also keeps the set of drive-shaft teeth <NUM> thereof away from the output spool <NUM> such that the set of drive-shaft teeth <NUM> and the set of housing teeth <NUM> are engaged with each other. Each set of teeth of the set of drive-shaft teeth <NUM> and the set of housing teeth <NUM> can include sawtooth-shaped teeth. When such sets of teeth are engaged with each other as in the inactive state of the IO access device <NUM>, rotation of the drive shaft <NUM> and, thus, the rotation of the IO needle assembly <NUM> is prevented.

In the active state of at least the IO access device <NUM>, the spring force exerted on the back side of the set of drive-shaft teeth <NUM> by the extension of the compression spring <NUM> is overwhelmed by force applied to a distal-end portion of the drive shaft <NUM> by way of a distal end of the IO needle assembly <NUM>. Compression of the compression spring <NUM> keeps the drive shaft <NUM> pushed into the axial channel <NUM>, which also keeps the set of drive-shaft teeth <NUM> thereof close to the output spool <NUM> such that the set of drive-shaft teeth <NUM> and the set of housing teeth <NUM> are disengaged with each other. When such sets of teeth are disengaged with each other as in the active state of the IO access device <NUM>, rotation of the drive shaft <NUM> and, thus, the rotation of the IO needle assembly <NUM> is allowed.

In a transition between the inactive state and the active state of at least the IO access device <NUM>, force applied to the distal-end portion of the drive shaft <NUM> by way of, for example, engaging bone with the distal end of the IO needle assembly <NUM>, simultaneously inserts the drive shaft <NUM> deeper into the axial channel <NUM> and compresses the compression spring <NUM> between the back side of the set of drive-shaft teeth <NUM> and the output spool <NUM>. Inserting the drive shaft <NUM> deeper into the axial channel <NUM> disengages the set of drive-shaft teeth <NUM> from the set of housing teeth <NUM> to initiate the active state of the IO access device <NUM>, in which state rotation of the IO needle assembly <NUM> is effectuated by the output spool <NUM> of the constant-torque spring assembly <NUM> on the drive shaft <NUM>.

In a transition between the active state and the inactive state of at least the IO access device <NUM>, force removed from the distal-end portion of the drive shaft <NUM> by way of, for example, disengaging the distal end of the IO needle assembly <NUM> from bone, allows the compression spring <NUM> between the back side of the set of drive-shaft teeth <NUM> and the output spool <NUM> to relax, which pushes the drive shaft <NUM> out of the axial channel <NUM> away from the output spool <NUM>. Pushing the drive shaft <NUM> out of the axial channel <NUM> reengages the set of drive-shaft teeth <NUM> with the set of housing teeth <NUM> to initiate the inactive state of the IO access device <NUM>, in which state rotation of the IO needle assembly <NUM> is by the output spool <NUM> of the constant-torque spring assembly <NUM> on the drive shaft <NUM> is prevented.

The transition between the active state and the inactive state of at least the IO access device <NUM> can be automatically initiated by the IO access device <NUM>. In such an IO access device, the compression spring <NUM> is configured by way of its material, construction, or both to have a spring constant and a compressible length proportional to a spring force greater than an average force that can be applied on the distal end of the IO needle assembly <NUM> by marrow in a medullary cavity of a patient. Entry of the IO needle assembly <NUM> into the medullary cavity of the patient automatically replaces the force applied on the distal end of the IO needle assembly <NUM> by compact bone, which force is greater than the foregoing spring force, with the force applied on the distal end of the IO needle assembly <NUM> by the marrow in the medullary cavity, which force is less than the foregoing spring force, thereby allowing the compression spring <NUM> to push the drive shaft <NUM> out of the axial channel <NUM> away from the output spool <NUM> to initiate the transition to the inactive state of the IO access device <NUM>. Notwithstanding the foregoing, the transition between the active state and the inactive state can be manually initiated by a clinician after feeling a change in tissue density upon entering the medullary cavity from compact bone.

While the pressure-based trigger mechanism <NUM> is described for the IO access device <NUM>, it should be understood that any IO access device selected from the IO access devices <NUM>, <NUM> and <NUM> can include the pressure-based trigger mechanism <NUM>, optionally as part of an interlock mechanism. Notably, the IO access devices <NUM> and <NUM> are not shown with the set of drive-shaft teeth <NUM> or the complementary set of housing teeth <NUM> of the pressure-based trigger mechanism <NUM>. Without such teeth, rotation of the IO needle assembly <NUM> must be effectuated by or in combination with another rotation-activating means set forth herein for activating rotation of the IO needle assembly <NUM>. Notwithstanding that, the compression spring <NUM> remains a useful component to a clinician for feeling the change in tissue density upon the distal end of the IO needle assembly <NUM> entering the medullary cavity from compact bone, thereby signaling drilling should be stopped. Indeed, regardless of whether the IO access device <NUM> or <NUM> includes the set of drive-shaft teeth <NUM> and the set of housing teeth <NUM>, the compression spring <NUM> is still configured to push the drive shaft <NUM> out of the axial channel <NUM> away from the output spool <NUM> upon the distal end of the IO needle assembly <NUM> entering the medullary cavity from compact bone, which provides an immediate palpable signal to a clinician to stop drilling.

As shown in <FIG> for at least the IO access device <NUM>, a combination of an extension pin <NUM> disposed in the axial channel <NUM> of the output spool <NUM> between the drive shaft <NUM> and a molded piece <NUM> within the housing <NUM> is configured to stop over insertion of the drive shaft <NUM> into the axial channel <NUM> of the output spool <NUM> during the transition between the inactive state and the active state of the IO access device <NUM>. In addition to stopping the over insertion of the drive shaft <NUM> into the axial channel <NUM> of the output spool <NUM>, the combination of the extension pin <NUM> and the molded piece <NUM> provides a decoupling mechanism configured to decouple the force applied to the distal end of the IO needle assembly <NUM> from the constant-torque spring assembly <NUM>. That is, any further force applied to the distal end of the IO needle assembly <NUM> than that needed for the transition between the inactive state and the active state of ate least the IO access device <NUM> is applied to the molded piece <NUM> of the housing <NUM> by the extension pin <NUM> instead of the constant-torque spring assembly <NUM>. Minimization of bearing surface area and reduction of extraneous moment-arm lengths further decouple the force applied to the distal end of the IO needle assembly <NUM> from the constant-torque spring assembly <NUM>.

<FIG> illustrates a cross section of the IO access device <NUM> having a first interlock mechanism <NUM> in accordance with some embodiments.

As shown in <FIG>, the interlock mechanism <NUM> of the IO access device <NUM> includes a trigger <NUM> and a lock pin <NUM> disposed between the trigger <NUM> and the output spool <NUM> in the inactive state of the IO access device <NUM>. The interlock mechanism <NUM> must be disengaged before the pressure-based trigger mechanism <NUM> can be activated for rotation of the IO needle assembly <NUM>, thereby providing a safety mechanism for the IO access device <NUM>. The trigger <NUM> can be pressed with a clinician's fingers, web of his or her hand, or the like such as by gripping the IO access device <NUM>. When the trigger <NUM> is pressed in toward the housing <NUM>, the trigger <NUM> is configured to release the lock pin <NUM>. Once released, the lock pin <NUM> is free to move in a proximal direction when a force is applied to the distal end of the IO needle assembly <NUM> that simultaneously compresses the compression spring <NUM> and inserts the drive shaft <NUM> deeper into the axial channel <NUM>.

<FIG> illustrates a cross section of the IO access device <NUM> having a second interlock mechanism <NUM> in accordance with some embodiments.

As shown, the interlock mechanism <NUM> includes a lock pin <NUM> configured to rotate such that the lock pin <NUM> does not block axial movement of the extension pin <NUM> in the axial channel <NUM> of the output spool <NUM>, thereby allowing activation of the pressure-based trigger mechanism <NUM>. This is shown on the right-hand side of <FIG>, wherein the lock pin <NUM> is no longer engaged with the extension pin <NUM>.

<FIG> illustrates a cross section of the IO access device <NUM> having an interlock mechanism <NUM> in accordance with some embodiments.

As shown in <FIG>, the interlock mechanism <NUM> of the IO access device <NUM> includes a trigger <NUM> pivotally mounted on a transversely oriented pin <NUM> disposed in the housing <NUM> adjacent the output spool <NUM>. Both an internal-end portion of the trigger <NUM> and a distal-end portion of the output spool <NUM> have interlocking teeth that are interlocked in the inactive state of the IO access device <NUM>. The interlock mechanism <NUM> must be disengaged before the pressure-based trigger mechanism <NUM> can be activated for rotation of the IO needle assembly <NUM>, thereby providing a safety mechanism for the IO access device <NUM>. When an external-end portion of the trigger <NUM> is pressed in toward the housing <NUM>, the trigger <NUM> is configured to pivot about the pin <NUM> and withdraw the interlocking teeth of the internal-end portion of the trigger <NUM> away from those of the output spool <NUM>, thereby allowing a force applied to the distal end of the IO needle assembly <NUM> to simultaneously compress the compression spring <NUM> and insert the drive shaft <NUM> deeper into the axial channel <NUM> for rotation of the IO needle assembly <NUM>.

<FIG> illustrates a cross section of the third IO access device <NUM> having a first interlock mechanism <NUM> in accordance with some embodiments.

As shown on the left-hand side of <FIG>, the pressure-based trigger mechanism <NUM> of the IO access device <NUM> is activated, but a detent <NUM> coupled to a spring-mounted trigger <NUM> of the interlock mechanism <NUM> is engaged with a bore of the output spool <NUM> preventing rotation of the IO needle assembly <NUM>. This is mechanistically different than any interlock mechanism of the interlock mechanisms <NUM>, <NUM>, and <NUM>, which require the interlock mechanism <NUM>, <NUM>, or <NUM>, to be disengaged before the pressure-based trigger mechanism <NUM> can even be activated. Indeed, the IO access device <NUM> is configured such that either the interlock mechanism <NUM> or the pressure-based trigger mechanism <NUM> can be activated first, but both the pressure-based trigger mechanism <NUM> and the interlock mechanism <NUM> need to be activated for rotation of the IO needle assembly <NUM>. When the trigger <NUM> is pressed in toward the housing <NUM>, the detent <NUM> is configured to withdraw from the bore of the output spool <NUM>, thereby allowing - if a force is already applied to the distal end of the IO needle assembly <NUM> - the applied force to simultaneously compress the compression spring <NUM> and insert the drive shaft <NUM> deeper into the axial channel <NUM> for rotation of the IO needle assembly <NUM>. The IO access device with the interlock mechanism is configured such that rotation of the IO needle assembly <NUM> can be interrupted at any time by removing the pressure applied to the distal end of the IO needle assembly <NUM> or releasing the trigger <NUM>, which relaxes the spring of the spring-loaded trigger <NUM> returning the trigger to its default position.

<FIG> illustrates a cross section of the third IO access device <NUM> having a second interlock mechanism <NUM> in accordance with some embodiments.

As shown in <FIG>, the interlock mechanism <NUM> of the IO access device <NUM> includes a spring-loaded trigger <NUM> slidably mounted in an exterior channel of the housing <NUM> proximal of the output spool <NUM>. The trigger <NUM> includes an extension channel of the axial channel <NUM>. When the trigger <NUM> is activated and properly aligned, the drive shaft <NUM> can extend into the extension channel of the trigger <NUM> upon application of force to the distal-end portion of the drive shaft <NUM> in accordance with activation of the pressure-based trigger mechanism <NUM>. When the trigger <NUM> is not activated or not properly aligned, the drive shaft <NUM> cannot extend into the extension channel of the trigger <NUM>, which precludes activation of the pressure-based trigger mechanism <NUM>. That is, the interlock mechanism <NUM> must be disengaged before the pressure-based trigger mechanism <NUM> can be activated for rotation of the IO needle assembly <NUM>, thereby providing a safety mechanism for the IO access device <NUM>.

As an additional preventing means to the foregoing interlock mechanisms <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> for preventing accidental activation of the pressure-based trigger mechanism <NUM> of an IO access device by dropping or handling the IO access device, a needle cover can be included to cover the IO needle assembly <NUM>. While not shown, the needle cover is configured to cover the IO needle assembly <NUM> and prevent accidental activation of the pressure-based trigger mechanism <NUM> by way of providing a spatial buffer around the IO needle assembly <NUM>. Until the needle cover is removed from around the IO needle assembly <NUM>, a clinician is also prevented from touching the IO needle assembly <NUM>, thereby enhancing sterility of the IO needle assembly <NUM>.

While not shown, the IO access device <NUM>, <NUM>, or <NUM> can further include a hand-actuated braking system configured to act on the output spool <NUM> to slow the metal ribbon <NUM> from winding onto the storage spool <NUM>. The braking system can be initiated at a start of the winding of the metal ribbon <NUM> onto the storage spool <NUM> or at any time throughout the winding.

Methods of the IO access device <NUM>, <NUM>, or <NUM> include at least a method of using the IO access device <NUM>, <NUM>, or <NUM>.

A method of using the IO access device <NUM>, <NUM>, or <NUM> includes at least a device-obtaining step. The device-obtaining step includes obtaining the IO access device <NUM>, <NUM>, or <NUM>.

The method can also include a skin-preparing step. The skin-preparing step includes preparing skin of a patient with an antiseptic (e.g., iodopovidone) at an insertion site of the patient. The insertion site can be about the proximal tibia, the distal tibia, or the distal femur.

The method can also include an interlock-disengaging step. The interlock-disengaging step includes disengaging an interlock mechanism set forth herein configured to prevent rotation of an IO needle and drilling therewith until the interlock mechanism is disengaged. In an example, the interlock-disengaging step can include triggering the trigger <NUM> to release the lock pin <NUM> disposed between the trigger <NUM> and the output spool <NUM>. In another example, the interlock-disengaging step can include rotating the lock pin <NUM> configured to block axial movement of the extension pin <NUM> disposed in the axial channel <NUM> of the output spool <NUM> between the lock pin <NUM> and the drive shaft <NUM>. In yet another example, the interlock-disengaging step can include triggering the trigger <NUM> pivotally mounted on the transversely oriented pin <NUM> having trigger teeth configured to interlock with those of a distal-end portion of the output spool <NUM>. In yet another example, the interlock-disengaging step can include triggering the spring-loaded trigger <NUM> mounted in the exterior channel of the housing <NUM> including the extension channel configured to allow the drive shaft <NUM> to extend from the axial channel <NUM> of the output spool <NUM> into the extension channel when the extension channel and the axial channel <NUM> are aligned. The pressure-based trigger mechanism <NUM> is configured to require the foregoing interlock-disengaging step before the force-applying step to activate the pressure-based trigger mechanism. That said the pressure-based trigger mechanism <NUM> can be configured to require the interlock-disengaging step either before or after the force-applying step to activate the pressure-based trigger mechanism. Indeed, the interlock-disengaging step can include triggering the pressure-based trigger <NUM> configured to release the detent <NUM> from the bore of the output spool <NUM>.

The method can also include a needle-inserting step. The needle-inserting step includes inserting the distal end of the IO needle of the IO needle assembly <NUM> through the skin at the insertion site.

The method can also include a force-applying step. The force-applying step includes applying force to bone at the insertion site with the distal end of the IO needle of the IO needle assembly <NUM> to activate the pressure-based trigger mechanism <NUM>. In accordance with force-applying step, the drive shaft <NUM> is inserted deeper into the axial channel <NUM> of the output spool <NUM> of the constant-torque spring assembly <NUM>, <NUM>, or <NUM>, which compresses the compression spring <NUM> between the back side of the set of drive-shaft teeth <NUM> and the output spool <NUM>. Compressing the compression spring <NUM> disengages the set of drive-shaft teeth <NUM> from the opposing set of housing teeth <NUM> around the aperture of the housing <NUM>, <NUM>, or <NUM>. Further in accordance with the force-applying step, the metal ribbon <NUM> of the constant-torque spring assembly <NUM>, <NUM>, or <NUM> starts winding from the output spool <NUM> onto the storage spool <NUM>, thereby starting rotation of the IO needle assembly <NUM> and the IO needle thereof by way of the drive shaft <NUM> coupled to the constant-torque spring assembly <NUM>, <NUM>, or <NUM>.

The method can also include a drilling step. The drilling step includes drilling through the bone until the IO needle assembly <NUM> enters a medullary cavity of the patient. IO access is achieved upon entering the medullary cavity of the patient with the IO access device <NUM>, <NUM>, or <NUM>.

The method can also include a force-ceasing step. The force-ceasing step includes ceasing to apply the force to the bone with the distal end of the IO needle assembly <NUM> or the IO needle thereof. The force-ceasing step removes at least a portion of the drive shaft <NUM> from the axial channel <NUM> of the output spool <NUM>, relaxes the compression spring <NUM>, and reengages the set of drive-shaft teeth <NUM> with the set of housing teeth <NUM> to stop the rotation of the IO needle assembly <NUM>. The force-ceasing step can be automatically initiated by the IO access device <NUM>, <NUM>, or <NUM> after experiencing a change in tissue density (e.g., compact bone to marrow) upon entering the medullary cavity of the patient. Alternatively, the force-ceasing step can be manually initiated by a clinician after feeling the change in tissue density upon entering the medullary cavity of the patient.

The method can also include a needle-detaching step. The needle-detaching step includes detaching the IO needle assembly <NUM> from a remainder of the IO access device <NUM>, <NUM>, or <NUM>.

The method can also include an obturator-removing step. The obturator-removing step includes removing from the IO needle assembly <NUM> the obturator removably disposed in a cannula.

The method can also include a cannula-confirming step. The cannula-confirming step includes confirming the cannula is disposed in the medullary cavity by aspirating bone marrow through a syringe.

The method can also include a cannula-securing step. The cannula-securing step includes securing the cannula to the patient with a dressing.

The method can also include an infusion-starting step. The infusion-starting step includes starting IO infusion as boluses with a same or different syringe.

Claim 1:
An intraosseous access device, comprising:
a constant-torque spring assembly (<NUM>, <NUM>, <NUM>) disposed in a housing (<NUM>, <NUM>, <NUM>);
a drive shaft (<NUM>) extending from the housing (<NUM>, <NUM>, <NUM>), the drive shaft (<NUM>) coupled to the constant-torque spring assembly (<NUM>, <NUM>, <NUM>);
an intraosseous needle coupled to the drive shaft (<NUM>) configured for drilling through bone and providing intraosseous access to a medullary cavity of a patient; and
an interlock mechanism (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to prevent rotation of the intraosseous needle and the drilling therewith until the interlock mechanism (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is disengaged.