Field of the Inventions
[0001] The inventions described below relate to emergency medical devices and methods and
the resuscitation of cardiac arrest patients.
Background of the Inventions
[0002] Cardiopulmonary resuscitation (CPR) is a well-known and valuable method of first
aid used to resuscitate people who have suffered from cardiac arrest. CPR requires
repetitive chest compressions to squeeze the heart and the thoracic cavity to pump
blood through the body. Artificial respiration, such as mouth-to-mouth breathing or
a bag mask apparatus, is used to supply air to the lungs. When a first aid provider
performs manual chest compression effectively, blood flow in the body is about 25%
to 30% of normal blood flow. However, even experienced paramedics cannot maintain
adequate chest compressions for more than a few minutes.
Hightower, et al., Decay In Quality Of Chest Compressions Over Time, 26 Ann. Emerg.
Med. 300 (Sep. 1995). Thus, CPR is not often successful at sustaining or reviving the patient. Nevertheless,
if chest compressions could be adequately maintained, then cardiac arrest victims
could be sustained for extended periods of time. Occasional reports of extended CPR
efforts (45 to 90 minutes) have been reported, with the victims eventually being saved
by coronary bypass surgery. See
Tovar, et al., Successful Myocardial Revascularization and Neurologic Recovery, 22
Texas Heart J. 271 (1995).
[0003] In efforts to provide better blood flow and increase the effectiveness of bystander
resuscitation efforts, various mechanical devices have been proposed for performing
CPR. In one variation of such devices, a belt is placed around the patient's chest
and the belt is used to effect chest compressions. Our own patents, Mollenauer et
al.,
Resuscitation device having a motor driven belt to constrict/compress the chest,
U.S. Patent 6,142,962 (Nov. 7, 2000); Sherman, et al.,
CPR Assist Device with Pressure Bladder Feedback,
U.S. Patent 6,616,620 (Sep. 9,2003); Sherman et al.,
Modular CPR assist device,
U.S. Patent 6,066,106 (May 23, 2000); and Sherman et al.,
Modular CPR assist device,
U.S. Patent 6,398,745 (Jun. 4, 2002), and our application
09/866,377 filed on May 25, 2001, show chest compression devices that compress a patient's chest with a belt. Each
of these patents is hereby incorporated by reference in their entirety.
[0004] Since seconds count during an emergency, any CPR device should be easy to use and
facilitate rapid deployment of the device on the patient. Our own devices are easy
to deploy quickly and do increase the patient's chances of survival. Nevertheless,
a novel compression belt cartridge has been designed to facilitate deployment, use
and maintenance of chest compression devices.
Summary
[0005] The devices and methods shown below provide for a belt cartridge for use in devices
that perform chest compressions. The cartridge has a belt, a compression pad attached
to the belt, a cover plate through which the belt is threaded, a belt spline for attaching
the belt to a drive spool of a belt drive platform, and belt guards rotatably attached
to the cover plate. During use, the cover plate and belt guards are removably attached
to the housing of the belt drive platform. In turn, the belt extends out of the housing
and is secured around the patient.
[0006] The belt itself is a single band of material that has a non-uniform width. The belt
has two portions, with each portion of the belt having shared pull-straps that are
narrow, a load distribution section that is wide and a trapezoid-shaped transition
section between the pull straps and load distribution sections. The transition sections
of the belt are provided with reinforcing plates that strengthen the belt. The load
distribution sections of the belt are provided with hook and loop fasteners so that
the belt can be secured around the patient. In addition, a peg in the center of one
load distribution section fits into a corresponding eyelet in the other load distribution
section, thereby providing a means for registering the belt with the center of the
patient's sternum. The compression pad is disposed beneath the load distribution sections
and facilitates chest compressions.
[0007] The cover plate is provided with curved extensions such that the belt cartridge fits
within only selected belt drive platforms. The cover plate is also provided with snap
latches and hooks so that the cover plate attaches securely to the belt drive platform
in a pre-determined orientation. Crossbars and reinforcing beams are provided to the
cover plate so that the cover plate may be made from a thin, lightweight plate of
plastic. The entire chest compression cartridge is low cost, lightweight and disposable.
[0008] The belt cartridge is attached to the belt drive platform via the cartridge cover
plate. The belt itself is attached to a drive spool via a belt spline. The belt spline
fits into a slot provided in the drive spool. The spline is provided with bosses or
catches and the slot is provided with a corresponding shape so that the spline fits
securely into the slot. A guide plate disposed around one end of the drive spool slot
serves as a guide for inserting the spline. After the spline is inserted into the
slot, the guide plate is adjusted to further secure the spline within the slot. Once
the spline and belt are secured to the drive spool, the cover plate is attached to
the housing of the belt drive platform.
[0009] Snap latches and hooks provided on the cover plate fit into corresponding detents
and apertures in the housing of the belt drive platform so that the cover plate is
secured to the housing. Belt guards disposed on the lateral ends of the cover plate
are then closed around spindles disposed on the belt drive platform. The belt guards
further secure the cover plate to the belt drive platform and protect the patient,
rescuer and belt during use. In addition to the belt guards, labels are provided on
the housing, cover plate and belt to indicate to the user the correct method of attaching
the cartridge to the belt drive platform and on the correct method of wrapping the
belt around the patient.
[0010] The safety mechanisms include a breakable link, liner socks, belt guards and a rapid-release
connector. The breakable link is attached near the transition section of the belt.
The breakable link prevents an unsafe amount of tension from developing in the belt
by breaking at a pre-selected load threshold. The liner socks protect the patient
from friction and contain the breakable link. The liner socks cover the belt so that
the belt slides against the liner socks and not against the patient. If the link breaks,
then the link remains inside a sock. The belt guards protect foreign objects from
entering the belt drive platform. Thus, articles of clothing, tools, fingers, other
body parts, or other foreign objects are less likely to interfere with the belt drive
platform. Similarly, the patient and rescuer are less likely to be injured by the
device since the belt guards protect the moving parts of the belt drive platform.
The rapid-release connector allows the belt to be removed safely even during compressions.
The rapid release connector is placed on the load distribution sections of the belt.
The connector is a combination of hook and loop fasteners and a peg disposed within
an eyelet.
Brief Description of The Drawings
[0011]
Figure 1 shows the chest compression belt fitted on a patient.
Figure 2 shows a bottom view of a chest compression device that uses a belt to perform
compressions.
Figure 3 shows a top (anterior) view of a belt cartridge used with a belt drive platform.
Figure 4 shows a bottom (posterior) view of a belt cartridge used with the belt drive
platform.
Figure 5 shows a superior view of a belt cartridge used with the belt drive platform.
Figure 6 shows the belt used in the belt cartridge of Figures 3 through 5.
Figure 7 shows a close-up view of the cover plate used in the belt cartridge of Figures
3 through 5.
Figure 8 illustrates a method of attaching the compression belt to the drive spool.
Figure 9 shows a close-up view of the spline, the belt and the drive spool.
Figure 10 illustrates a method of attaching the belt cartridge to the belt drive platform.
Figure 11 illustrates a method of attaching a belt guard to a spindle of the belt
drive platform.
Figure 12 shows a close-up view of the compression belt cartridge.
Figure 13 shows a cross-section of the belt, liner socks and breakable link.
Figure 14 shows the belt attached to the breakable link.
Figure 15 shows another cross-section of the breakable link.
Detailed Description of the Inventions
[0012] Figure 1 shows the chest compression belt fitted on a patient
1. A chest compression device
2 applies compressions with the belt
3, which has a right belt portion
3R and a left belt portion
3L. The chest compression device
2 includes a belt drive platform
4 and a compression belt cartridge
5 (which includes the belt). The belt drive platform includes a housing
6 upon which the patient rests, a means for tightening the belt, a processor and a
user interface disposed on the housing. The means for tightening the belt includes
a motor, a drive train (clutch, brake and/or gear box) and a drive spool upon which
the belt spools during use. Various other mechanisms may be used to tighten the belt,
including the mechanisms shown in Lach et al.,
Resuscitation Method and Apparatus,
U.S. Patent 4,774,160 (Sep. 13, 1988) and in Kelly et al.,
Chest Compression Apparatus for Cardíac Arrest,
U.S. Patent 5,738,637 (Apr. 14, 1998). The entirety of these patents is hereby incorporated by reference.
[0013] In use, the patient is placed on the housing and the belt is placed under the patient's
axilla (armpits), wrapped around the patient's chest, and secured. The means for tightening
the belt then tightens the belt repetitively to perform chest compressions.
[0014] The compression belt
3 shown in Figure 1 is provided with a structure that aids in performing compressions
effectively and efficiently. Specifically, the belt is shaped like a double-bladed
oar. The wider load distribution sections
16 and
17 of the belt are secured to each other over the patient's chest and apply the bulk
of the compressive load during use. The narrow pull straps
18 and
19 of the belt are spooled onto the drive spool of the belt drive platform to tighten
the belt during use. The trapezoid-shaped transition sections
20 and
21 reinforce the belt and transfer force from the pull straps to the load distribution
sections evenly across the width of the load distribution sections. The narrow end
of a trapezoid faces the pull strap and the wide end of a trapezoid faces a corresponding
load distribution section.
[0015] The pull straps
18 and
19 of the belt are narrow so that the chest compression device may perform compressions
more efficiently, thus saving battery power and prolonging the ability of the device
to perform compressions. The narrow pull straps of the belt reduce the mass of the
belt and reduce the torque necessary to tighten the belt around the patient's chest,
particularly when the means for tightening the belt tightens the belt by spooling
it around a drive spool. In addition, by using narrow pull straps, the belt may fit
within a narrow channel beam in the belt drive platform. This reduces the weight and
size of the belt drive platform and increases the strength of the platform by allowing
a narrower channel beam (see item 45 of Figure 2) to be used with the platform.
[0016] The load distribution sections
16 and
17 of the belt are wider than the pull straps to allow the chest compression device
to perform compressions more effectively and more safely. The wider portions of the
belt compress more of the chest, increasing blood flow and thus performing compressions
more effectively. In addition, the wider portions of the belt allow more force to
be applied to the patient by evenly distributing pressure on the patient's chest,
thus increasing blood flow while making chest compressions safer for the patient.
[0017] The transition sections
20 and
21 of the belt transfer the tension from the pull straps to the load distribution sections
and reinforce the belt. Thus, the transition sections narrow along the lateral portion
of the belt.
[0018] The right load distribution section
16 and left load distribution section
17 of the belt are provided with hook and loop fasteners so that the belt may be secured
to the patient's chest. (Securing the right and left load distribution sections to
each other secures the belt around the patient's chest.) Preferably, the hook side
of the hook and loop fastener is located on the anterior load distribution section
of the belt (in this illustration, the left side is anterior to and superficial to
the right load distribution section) so that the hooks do not contact carpet or other
materials when the belt is open and splayed on the ground, though the hook and loop
fasteners may be located anywhere on the load distribution sections of the belt. A
handle
32 (more clearly shown in Figure 2) is provided on the left end of the belt to aid in
placing and removing the belt. The handle and user interface are located on the same
side of the belt drive platform to make applying and removing the belt an ergonomic
motion.
[0019] An eyelet
33 is provided in the left load distribution section of the belt and a corresponding
registration peg
34 is provided in the right load distribution section of the belt. (The peg, eyelet
and hook and loop fasteners may be disposed on either load distribution section.)
To secure the belt to the patient, the left load distribution section is laid over
the right load distribution section and the eyelet is aligned with the peg. (The peg
fits within the eyelet.) The eyelet and peg assist the rescuer to properly register
the load distribution sections with respect to each other and the patient, and thereby
properly position the belt on the patient. The eyelet and peg are also long relative
to the superior/inferior direction of the patient and are located in the center of
the assembled load distribution sections. Thus, the eyelet and peg help the rescuer
place the center of the load distribution sections over the center of the patient's
sternum. In addition, since the right and left load distribution sections tend to
pull away from each other when the belt is tensioned, the peg and eyelet further secure
the load distribution sections of the belt to each other by resisting shear forces
that tend to pull the sections apart.
[0020] In addition, the peg and eyelet enable the rescuer to repeatably release the belt
and then secure the belt around the patient such that the belt has the same length
each time the belt is secured around the patient. (During use the rescuer may need
to release the belt and re-secure the belt around the patient without replacing the
cartridge.) Since the belt maintains the same length, the chest compression device
is much more likely to achieve the same depth of chest compressions after the belt
has been re-secured as compared to before the belt has been re-secured.
[0021] The combination of hook and loop fasteners and the eyelet/peg fastener provides for
a means for securing the belt around the patient. The same combination allows a rescuer
to rapidly and easily release the belt. The rescuer may release the belt, even during
compressions, by grasping the left end of the belt and lifting the left load distribution
section from the right load distribution section. Thus, the securing mechanism is
also an emergency release mechanism. To further enhance safety, the eyelet may be
provided with an electrical contact switch, optical sensor or other electrical or
mechanical means for determining whether the peg is inserted into the eyelet. Thus,
a chest compression device with the appropriate software or hardware can sense whether
the peg is fully inserted into the eyelet. If the peg is not in the eyelet, then the
chest compression device will not perform compressions. The system will alert the
operator if proper registration is not detected so that the operator may re-fit the
belt.
[0022] Figure 2 shows a bottom view of the belt drive platform
4 and shows the housing
6, a belt cartridge
5 attached to the housing and a means for tightening the belt disposed within the belt
drive platform. The means for tightening the belt may comprise a drive spool
42 attached to the belt and to a motor. The drive spool is shown in phantom to indicate
its position beneath the cover plate. The motor and associated components are located
within the belt drive platform.
[0023] The belt drive platform is provided with a control system that controls how the belt
is wrapped around the drive spool. For example, the drive spool is controlled so that
some of the belt is left wrapped around the drive spool between compressions. When
the means for tightening has loosened the belt around the patient, just before beginning
the next compression, a length of the belt corresponding to one revolution of the
drive spool is left wrapped around the drive spool. Thus, the belt will maintain its
curled shape, reducing the chance of causing folds in the belt during compressions
and increasing the efficiency of spooling the belt around the drive spool.
[0024] The housing serves as a support for the patient. Handles
43 provide for easy transport of the housing and of the patient while on the housing.
The belt cartridge has a cover plate
44 that fits within a channel beam
45 in the belt drive platform, thus securing the belt cartridge
41 to the belt drive platform
4. Labels
46 are placed on the housing and cover plate to indicate the proper alignment of the
cover plate. The cover plate is secured to and aligned within the channel beam by
the use of retainer clips or snap latches
47, 48, 49 and
50 which fit between corresponding paired bosses or detents in the housing. Tabs integrally
formed with the snap latches extend into slots disposed in the housing of the belt
drive platform. The cover plate is also aligned and secured within the channel beam
by the use of hooks
51, 52, 53 and
54 which fit into corresponding apertures in the housing. In addition, the cover plate
is also provided with additional labeling
55 to provide warnings, manufacturer information, trademarks or advertising.
[0025] Figures 3, 4 and 5 show the belt cartridge
41. The belt cartridge is disposable so that there is no need to clean the belt, or other
elements of the cartridge, after use. Thus, the belt cartridge reduces the exposure
of subsequent patients and users to bodily fluids or other contaminants. If necessary,
the cartridge may be replaced while the patient is still on the belt drive platform.
In addition, since the belt cartridge is disposable the belt may be made of materials
that readily conform to the shape of an individual patient, but have a shorter service
life.
[0026] The cartridge includes a belt
3, a compression pad
65 attached to the belt, a belt clip, key or spline
66 for attaching the belt to a drive spool, a cover plate
44 and belt guards
67 and
68 rotatably attached to the cover plate via hinges
69 and
70. The belt guards are removably secured over spindles that are attached to the belt
drive platform. A liner, sleeve or sock is disposed over the belt, as shown in Figure
5. The belt is threaded through slots
71 and
72 disposed in the belt guards
67 and
68. With regard to the belt
3, the right portion
3R and the left portion
3L of the belt share pull straps
18 and
19 and each have a load distribution section
16 and
17 and a transition section
20 and
21. Each load distribution section of the belt is provided with hook and loop fasteners
so that the belt may be secured around the patient's chest. Additionally, as described
above, an eyelet
33 is provided in the left load distribution section and a corresponding peg
34 is provided in the right load distribution section (see Figure 5). Preferably, the
pull strap sections comprise a single strap.
[0027] The pull straps of the belt are secured to the drive spool of the belt drive platform
with the spline
66, which is attached to the pull straps of the belt. The spline fits within a slot provided
in the drive spool. When the drive spool rotates, the pull straps spool around the
drive spool. The compression belt then tightens and is pulled onto the patient's chest,
thereby accomplishing compressions.
[0028] The pull straps
18 and
19 of the belt are threaded through the belt guards
67 and
68 which are rotatably attached to the cover plate
44. The belt guards and cover plate are fashioned from a lightweight but strong plastic.
The cover plate and belt guards are designed to allow the belt cartridge to be removably
attached to the belt drive platform and to protect the belt during use. Specifically,
the cover plate is provided with snap latches
47, 48, 49 and
50 that fit between corresponding paired bosses or detents on the housing. Integral
tabs extend from the snap latches and fit into corresponding slots in the housing.
The cover plate is also provided with hooks
51, 52, 53 and
54 that fit into corresponding apertures in the housing of the belt drive platform.
The snap latches and hooks are designed so that the cover plate is removably attached
to the belt drive platform without the use of tools. The snap latches and hooks may
have a variety of shapes and forms. The snap latches and hooks may also be asymmetrical
with respect to the cover plate, thus making it possible to fit the cover plate on
the belt drive platform in only one orientation. To increase the ease of use of the
cartridge, the cover plate is provided with labels
46 to indicate the desired orientation of the cover plate with respect to the belt drive
platform.
[0029] Below the load distribution sections of the belt is a compression pad
65 that affects the distribution of compression force and assists in performing chest
compressions. An example of a chest compression pad may be found in our application
10/192,771, filed July 10, 2002. In one embodiment the compression pad is a three-sectioned bladder filled with foam.
The compression pad is located on the belt so that it is centered over the patient's
chest when the belt is in use. The compression pad is disposed below the load distribution
sections of the belt and is removably attached to the belt with double-stick tape,
hook and loop fasteners or comparable fastening means. The compression pad is also
disposed inside the liner sock.
[0030] Additional safety features may be provided with the compression belt cartridge
41. For example, spreader bars or reinforcing plates
87 may be attached to the transition sections of the belt with stitches
88. (The reinforcing plates may be attached to the transition sections of the belt by
any suitable method.) The reinforcing plates reinforce the transition sections of
the belt and help prevent the transition and load distribution sections from twisting,
bending, folding or otherwise deforming with respect to the pull straps, except in
regard to the ability of the belt to wrap around the patient's chest. The reinforcing
plates are made of a hard plastic or other non-resilient, though flexible material.
[0031] The belt also may be provided with one or more breakable couplings or breakable links
89 on one or both sides of the load distribution or belt transition sections. The breakable
link
89 or links are interposed between sequential portions of the belt such that the belt
separates if a link breaks. The link is designed to break at a predetermined tension.
If the belt experiences an unsafe amount of tension, then a link breaks, the belt
separates and the patient is thereby protected from excessive forces. What constitutes
an unsafe amount of tension or excessive force varies, depending on the patient and
the device and belt used, but is in the range of about 200 pounds to about 500 pounds
as measured in the area of the belt to the side of the patient. Preferably, the link
is designed to break under about 300 pounds of tension as measured in the area of
the belt to the side of the patient. In addition, the link may be designed to reattach
to itself or to a clip or other mating fastener after failure. Thus, in the event
of link failure, the belt may be re-attached quickly and compressions may be restarted
with minimal delay.
[0032] To prevent the load distribution sections from twisting relative to the other sections
of the belt, the links may be designed to also serve as swivel joints, or the belt
may be provided with additional swivel joints along the belt. The swivel joints connect
the pull straps to the belt transition sections. The swivel joints allow the load
distribution sections to twist relative to the pull straps, about the longitudinal
axis of the belt, without twisting the pull straps themselves.
[0033] Another safety feature is a liner sock
90 for the belt (see Figure 5). The liner sock surrounds the portions of the pull straps,
as well as the compression pad, that contact the patient thereby protecting the patient
from friction as the belt moves during compressions. The liner socks are attached
to the belt guards around the belt guard slots so that hair, other body parts or other
foreign objects cannot become caught in the belt guard slots. On the other end, the
socks are disposed around and are attached to the load distribution sections of the
belt.
[0034] In use, the belt spline is inserted into the drive spool of the belt drive platform.
The cover plate of the cartridge is then inserted into the channel beam of the belt
drive platform and fixed into place via the hooks and snap latches. The belt is wrapped
around the patient, with the load distribution sections secured over the patient's
chest. Thus, the chest compression device performs compressions by repetitively tightening
the belt.
[0035] Figure 6 shows the belt
3 used in the belt cartridge of Figures 3 through 5. When laid out, the belt has the
shape of a double-sided oar or paddle. As described above in reference to Figures
3 through 5, the right portion
3R and the left portion
3L of the belt each have a load distribution section
16 and
17, a transition section
20 and
21 and pull straps
18 and
19. The pull straps are narrow with respect to the load distribution sections. The load
distribution sections are disposed opposite each other, and each load distribution
section of the belt is provided with hook and loop fasteners
96 so that the belt may be secured to the patient's chest. An eyelet
33 is provided in the left load distribution section and a corresponding peg
34 is provided in the right load distribution section to further secure the belt around
the patient. (The peg and eyelet may comprise a variety of shapes and sizes; for example,
the peg may be a post and the eyelet a round grommet.) In addition, a spline
66 is attached to the belt by any suitable manner. The spline fits within a slot provided
in the drive spool of the belt drive platform. Thus, when the drive spool rotates,
the pull straps will spool around the drive spool.
[0036] The transition sections
20 and
21 of the belt are disposed opposite each other and are provided with corresponding
thin (1/16 inch) reinforcing plates
97 and
98 of flexible plastic that reinforce the belt. (The plates may comprise different materials
and may be thicker or thinner, or even of varying thickness, depending on the material
used and the desired stiffness of the transition sections; however, plates with a
thickness of about 1/4 inch or less are preferred.) The reinforcing plates mitigate
the effects of stress concentrations in the belt, stress voids in the belt, belt creasing,
belt wadding and other problems caused by using a compression belt that has a non-uniform
width. The reinforcing plates are attached to the transition sections of the belt
and the shape of the reinforcing plates conforms to the shape of the transition sections
of the belt. (The reinforcing plates may be attached to the transition sections by
any suitable means and may be located above, below or within the transition sections.)
The reinforcing plates also bend to conform to the shape of the patient's torso during
compressions. As the plates bend around the patient, the bending stiffness of the
plates along the other axes of the plates increases. To provide smooth compressions
along the patient's chest, one or more edges of the reinforcing plates may be bent
outwards and away from the patient (like ski tips).
[0037] The belt material of the pull straps, the load distribution sections and the transition
sections has a constant thickness of about 0.010 inches and is made of a custom, fiber-reinforced
material that can be manufactured by a number of belt manufacturers. Our belt is a
material made from unidirectional layers of high-strength fibers held together with
a resin. (The fibers are Spectra 2000 fibers available from Allied Signall, Inc.,
but may also be carbon, Kevlar™ and other fibers.) Our custom belts do not stretch
or break under heavy loads, and are resistant to bodily fluids, aging, humidity and
temperature.
[0038] The belt may also be made of a flat metal or rounded metallic cable, nylon, sail
cloth or other strong and flexible materials. The belt material may also include layers
of additional materials such as Tyvek™ (high-density, spun bonded polyethylene) or
Teflon™ (polytetrafluoroethylene) directly bonded to the primary belt material.
[0039] The custom belts used with the belt cartridge have 4 laminated layers of fibers oriented
at 0, 90, 6 and -6 degree angles with respect to the long axis of the belt. Placing
at least some of the layers obliquely with respect to the long axis of the belt improves
belt performance and longevity. The resin holding the fibers together is about 60%
to 70% of the volume of the material. An additional layer is laminated on the outside
of the belt to improve water resistance and lessen friction during use. A belt designed
with laminated fibers at different orientations with respect to the long axis of the
belt is less likely to stretch during compressions. The above belt has an average
stiffness of about 77,000 pounds per inch per one-inch length of belt, as measured
along the longitudinal axis of the belt, and thus does not stretch during compressions.
[0040] The belt (or cable) may be pre-conditioned before distribution or sale. The cartridge
and belt may be disposed on a test platform and the cartridge and belt tested before
being sold. This process pre-conditions the belt. Pre-conditioning the belt deforms
the belt to the shape of the spool shaft, which allows for more efficient spooling
of the belt during compressions. Preconditioning also helps prevent the belt from
deforming during use. Thus, preconditioned belts will perform consistently during
use. In addition, the belt is at least partially spooled around the drive spool during
storage so that the pull straps are set to the shape of the drive spool prior to use.
[0041] The overall belt and belt cartridge are sized and dimensioned to be used with 95%
of all body sizes. (Only extremely small or large patients may have difficulty benefiting
from a device that includes the compression belt cartridge.) The pull straps are about
2 inches wide (along the superior-inferior dimension of the patient, as indicated
by the direction of arrows
99) and about 40 inches long (along the medial-lateral dimension of the patient, as indicated
by the direction of arrows
100). The load distribution sections of the belt are about 8 inches wide and about 12 inches
long. The transition sections of the belt are about 6 inches long and taper gradually
between the pull straps and a load distribution section; thus, the transition sections
have a trapezoidal shape. All sections of the belt material have a constant thickness
of about 0.010 inches, with a tolerance of 0.001 inches. The belt may be thinner to
reduce the weight of the cartridge and the overall device, though the belt may be
as thick as 0.25 inches.
[0042] Because the belt is thin, the overall weight of a compression device is kept to a
minimum. Using a thin belt also spools less material onto a drive spool during use.
This reduces the overall diameter of the drive spool plus belt material, thereby reducing
the amount of torque necessary to operate the chest compression device. Thus, using
a thin belt also saves energy, thereby increasing the life of a battery used to power
a chest compression device.
[0043] Figure 7 shows a close-up view of the cover plate
44 used in the belt cartridge of Figures 3 through 5. As already described, the cover
plate is designed to allow the belt cartridge to be removably attached to the belt
drive platform and to protect the belt during use. Specifically, the cover plate is
provided with hooks
51 and
52 that fit within apertures provided in the housing. The cover plate is also provided
with snap latches
47 and
48 which fit securely between corresponding paired bosses or detents that extend from
slots disposed in the housing. Tabs integrally formed with the snap latches extend
into the slots when the cover plate is secured to the housing.
[0044] To reduce weight, the cover plate is fashioned from a thin plate of plastic. To increase
strength, the cover plate is provided with intersecting reinforcing ribs
106 (also shown in Figure 3) that reinforce the cover plate and help the cover plate
to resist the force of compressions. Additional aluminum reinforcement braces
107 (also shown in Figure 3) are provided to further reinforce the cover plate. The reinforcement
braces span the height of the cover plate to provide the cover plate with additional
strength. The reinforcement braces also brace the channel beam, thereby protecting
the belt drive platform from deforming under high forces.
[0045] The cover plate is provided with opposing curved extensions
108 and
109 so that the cover plate fits precisely within the belt drive platform. The curved
extensions, as well as the overall size and dimensions of the cover plate, prevent
the belt cartridge from being used with devices not designed to receive the belt cartridge.
Thus, the cover plate also helps ensure that the cartridge will be used safely.
[0046] Rotatably attached to the curved extensions of the cover plate are belt guards
67 and
68 that protect the user, belt drive platform and belt when the chest compression device
is in use. The belt guards are removably secured around the spindles during use. The
belt guards are wider than the belt, and the pull straps are threaded through slots
71 and
72 disposed in the belt guards. Thus, during use, the belt slides within the belt guards
and over the spindles. The spindles, in turn, rotate within the belt drive platform.
The spindles also rotate underneath the belt guards, sliding against the belt guards
where the belt guards are disposed against the spindles.
[0047] On each end of the cover plate, fingers or pawls
110 and
111 hook around corresponding catches or ratchets
112 and
113. The ratchets are attached to corresponding hinges
69 and
70, though may be attached to the corresponding belt guards. The pawls are attached to
the cover plate and prevent the belt guards from curling away from the cover plate.
However, a user may (preferably without tools) apply a force sufficient to pull the
ratchets away from the pawls as the hinges rotate, thereby allowing belt guards more
freedom to rotate outwardly, away from the cover plate. The user may also re-engage
the pawl and ratchet so that the belt guards are once again prevented from curling
outwardly.
[0048] The various components of the belt cartridge may be differently oriented with respect
to each other. For example, the compression pad may be disposed beneath the liner
sock instead of inside the liner sock. In other embodiments, if the geometry of the
belt drive platform changes, then the compression belt cartridge may be changed accordingly.
For example, if the drive spool is located to one side of the belt drive platform,
then the spline would be located outside the belt guards (instead of between them)
and the rest of the cartridge would be adjusted to fit to the housing and belt drive
platform. The belt may have other shapes; for example, the belt may have more than
one narrow region. (If the belt drive platform uses more than one drive spool then
the belt may have more than one set of pull straps.) In addition, other means for
tightening the belt may be used, such as multiple motors and drive spools, pistons,
scissors mechanisms or other mechanical actuators.
[0049] Figures 8 through 11 illustrate devices and methods for operably inserting the belt
cartridge into the housing of the belt drive platform. Figure 8 illustrates a user
124 inserting the belt spline
66 into the slot
125 in the drive spool
42. The user sets aside the cover plate
44 and inserts the front end
127 of the spline into the drive spool slot
125 in the direction indicated by arrow
128. The user then fits the back end
129 of the spline into a guide slot
130 disposed in a guide plate
131, which serves to further secure the spline in place, and secures the back end of the
spline into the drive spool slot. The user then secures the cover plate over the channel
beam
45. After securing the cover plate in the channel beam, the belt guards
67 and
68 attach to opposing rods, rollers or spindles
132 fixed to the sides of the belt drive platform. The spindles decrease friction as
the belt travels along the spindles.
[0050] Figure 9 shows a close-up view of the spline
66, the guide plate
131 and the drive spool slot
125. The spline is provided with a particular shape so that the spline will fit more securely
within the drive spool slot. The shape of the spline also discourages the use of splines
not designed by the manufacturer and discourages placement of the spline in an incorrect
orientation. Thus, the spline is keyed to the drive spool slot.
[0051] Specifically, the spline
66 is provided in the form of a rectangular rod or bar made of a hard plastic or a metal.
The front end
127 of the spline is provided with a protruding foot, boss or catch
143 shaped to fit into the front end
144 of the drive spool slot. Likewise, the back end
129 of the spline is provided with a second protruding foot, boss or catch
145 shaped to fit into the back end
146 of the drive spool slot. (The spline may have other shapes to accommodate differently
shaped slots in the drive spool.)
[0052] The drive spool slot is provided with corresponding recesses
147 and
148 to accommodate the front and back catches on the spline respectively. Thus, the spline
resembles a key and can function in a similar manner with respect to the use of the
chest compression device. In addition to the catches, slots and recesses shown, the
spline is further held in place with one or more detents in the belt drive platform
that engage the front or back catches on the spline. The detents also serve as catches
inside the belt drive platform that prevent the drive spool from rotating when the
spline is not inserted in the drive spool slot. Thus, the device will not operate
unless the spline is correctly inserted into the drive spool slot. In addition, the
front end of the spline engages an electromechanical switch when inserted into the
slot. When the spline engages the switch, a signal is generated (or interrupted) that
informs the control system that the clip is present and properly engaged. Additionally,
the belt drive platform may be provided with hardware or software that detects whether
the spline is correctly inserted and informs the user of incorrect insertion and prompts
the user to re-insert the spline if the spline is not correctly inserted.
[0053] The spline, cover plate or belt drive platform may be provided with a means for ensuring
that a particular compression belt cartridge will only be used once (that is, used
on only one patient during one rescue attempt). For example, the spline may be provided
with a breakaway or deformable tab that, on insertion into the drive spool slot, renders
the spline unusable after the spline has been removed from the spool shaft slot. Additionally,
the spline may have a means for identifying whether the spline was produced by an
approved manufacturer or whether the spline previously had been attached to the drive
spool slot of a belt drive platform. For example, an RF identification tag or other
wireless communication mechanism could be attached to the spline, wherein the RF tag
transmits data corresponding to a unique identifying number. A magnetic strip may
also be attached to the spline that stores a unique identifying number. A given belt
drive platform will operate only if the identifying number corresponds to a number
provided to the platform by the manufacturer and only if that number has not been
used with the belt drive platform in the past. If the belt drive platform is connected
to a network, then any belt drive platform connected to the network may be programmed
to recognize when a particular belt cartridge has been used with any other belt drive
platform. Moreover, the belt drive platform may be programmed to alter the identifying
number on the spline, thereby rendering the cartridge unusable with any other belt
drive platform. If this feature is implemented, the belt drive platform may be accompanied
by an over-ride feature that allows a used cartridge to be used again. Thus, in the
unusual situation where multiple heart attack victims are encountered or where a used
cartridge is the only available cartridge, the cartridge may be used again.
[0054] To further secure the spline within the drive spool slot, a collar or guide plate
131 is provided around one or both ends of the drive spool
42. The guide plate is provided with a guide plate slot
130 through which the back end of the spline is inserted. After the spline is inserted,
the guide plate is adjustable to firmly secure the spline within the drive spool slot.
A user may manually move the guide plate sufficiently to insert the spline into and
remove the spline from the slot.
[0055] The guide plate may be spring loaded and pushed into the wall of the channel beam
to make room for inserting the spline, or the guide plate may be rotated (or rotated
and pushed) to secure the back end of the spline within the drive spool slot. If the
guide plate is spring loaded, the spring comprises a means for providing a biasing
force to the guide plate; however, other means for biasing the guide plate may be
used, such as a flexible tab. In any case, the guide plate may be disposed in relation
to the drive spool such that the spline may not be inserted into or removed from the
drive spool slot unless the guide plate or the drive spool is moved. This ensures
that the spline will remain secured to the drive spool during use and during storage
(while the drive spool is rotating and while the drive spool is stationary).
[0056] In use, the spline is inserted into the drive spool slot as shown by arrows
149 and
150. When the drive spool rotates, the belt
3 wraps or spools around the drive spool, thereby tightening the belt. As the belt
is tightened the patient's chest is compressed. The patient's chest is decompressed
as the drive spool rotates in the opposite direction, thereby allowing the belt to
unwind and relax. After use, the process of inserting the belt may be reversed to
detach the belt cartridge from the belt drive platform. Thus, the belt cartridge may
be replaced after each use of the belt drive platform. Preferably, all of the attachment
mechanisms are releasable, as described above, so that the operator can replace the
belt without the use of special tools.
[0057] Figure 10 illustrates a method of attaching the belt cartridge to the housing of
the belt drive platform. The belt cartridge cover plate
44 is attached to the channel (established by beam
45) in the belt drive platform. Labels
46 allow the user to easily align the cover plate within the channel beam. Hooks
53 on the cover plate fit into corresponding apertures
158 in the belt drive platform. Belt guards
67 are removably disposed around spindles
132. (The spindle is shown in phantom to indicate its position underneath the belt guard
and within the belt drive platform). In addition, snap latches
47 fit within paired detents that extend from the edges of slots
159 in the belt drive platform. Tabs extending from the snap latches fit within the slots
themselves.
[0058] The labels include an arrow
160 disposed in a recess
161 in the belt drive platform and an arrow
162 disposed in a recess
163 on the cover plate
44. The cover plate is correctly aligned within the channel beam when the arrow on the
belt drive platform is pointing at the arrow on the cover plate. The hooks and snap
latches on the cover plate then fit within corresponding apertures and slots within
the belt drive platform.
[0059] The snap latches are designed so that an audible click is heard when a snap latch
is fully inserted into a corresponding slot. The snap latches may be designed so that
they bend as they fit between the detents. When fully inserted, a flange on the end
of the snap latch slips with respect to the detents, making an audible click when
the flange strikes the edge of the slot. In addition, the hooks and snap latches may
be aligned so that the belt cartridge only fits in one orientation with respect to
the belt drive platform. For example, the snap latches or hooks may be spaced asymmetrically
with respect to cover plate so that if the cover plate is incorrectly oriented the
cover plate will not fit into the channel beam.
[0060] Figure
11 shows a method of attaching a belt guard
68 to a spindle
132 of the belt drive platform
4. The cover plate
44 has already been secured to the belt drive platform, though the hinges
70 allow the belt guard to rotate with respect to the belt drive platform and cover
plate. The belt guards are provided with a hook-shape so that they securely attach
around the spindles
132 fixed to the belt drive platform. The user may secure the belt guards around the
spindles, as indicated by arrow
173.
[0061] In use, the belt guards protect the patient, rescuer, belt, belt cartridge and belt
drive platform. The belt guards prevent foreign objects from entering the belt drive
platform and becoming caught in the channel beam. Thus, a user's fingers or clothes,
patient's clothes or body parts, or debris located near the site of emergency cannot
enter the belt drive platform and damage the patient, the rescuer or the various parts
of either the belt drive platform or the belt cartridge.
[0062] Figure 12 shows a close-up view of the compression belt cartridge
41. Instructions
174 on how to deploy the compression belt cartridge or the belt drive platform are printed
on the outer surface of the belt
3, belt liner, cover plate, compression pad or any other component of the compression
belt cartridge. Specifically, indicia including pictorial instructions and written
instructions (including Braille) show the rescuer how to correctly secure the compression
belt around the patient.
[0063] Markings
175 on the outside of the belt liner indicate when the belt straps have been twisted.
The markings may be lines that are oblique or skew to the longitudinal axis of the
belt or belt liner, but may also be areas of solid colors on one side of the belt
or belt liner. Preferably, less than the entire surface of one side of the belt liner
is painted or marked. (Excessive ink, dye, transfer or adhesive elements, such as
stickers, cause the liner to become too stiff, thereby significantly increasing the
chances that the belt liner will wear prematurely.) The markings
175 may also serve as a means for identifying the manufacturer; for example, the markings
may show the manufacturer name or other advertising information.
[0064] In addition, markings are provided to show a rescuer how to correctly align the compression
belt and the belt drive platform with the patient. A yellow or other brightly colored
orientation line is disposed along the superior edge of the load distribution sections
of compression belt, parallel to the longitudinal axis of the compression belt. When
the compression belt is correctly placed on the patient the yellow line will line
up with the patient's axilla (armpits). Furthermore, the yellow line also lines up
with a corresponding yellow strip disposed on the housing of the belt drive platform.
Thus, a rescuer can easily visualize when the belt and belt drive platform are correctly
oriented with respect to the patient and to each other. (Other marking schemes may
also be used in relation to other anatomical landmarks such that the placement of
the orientation lines may be varied.)
[0065] Similarly, the alignment peg on the load distribution section indicates that the
patient should be aligned on the center of the belt drive platform and that the load
distribution sections should be aligned on the center of the patient's chest. Thus,
when the belt is placed correctly, the peg lies over the center of the patient's sternum.
Preferably, the peg is long relative to the superior-inferior direction such that
the longitudinal axis of the peg lies directly over and parallel to a superior-inferior
line in the center of the patient's sternum.
[0066] The instructions, alignment arrows and cartridge components are color coded (or otherwise
uniquely marked) to be easier to read and understand, or to indicate the purpose of
the instructions. For example, the eyelet
33 and peg
34 are colored yellow (or otherwise uniquely colored or marked) to indicate that they
mate. The belt cartridge also may be provided with colored warning or instruction
labels
176 (multiple colors and color schemes may be used). Examples of warning or instruction
labels include: "Align the armpits onto the yellow line," "LifeBand straps 90 degrees
to platform," "Do not cut," "Do not twist" or "Single patient use do not reuse." Each
warning may be assigned a different color, such as red, blue, black and gray.
[0067] The devices and methods shown above in reference to the figures may be modified.
For example, the spline may be a hemisphere and attach to a corresponding hemisphere
on the drive spool. The slot in the drive spool may extend through the drive spool
and the belt threaded through the slot. The spline may also be provided with arms
that clip around the drive spool and thereby secure the spline to the drive spool.
The spline may be provided with magnets, a collar, detents or other latching features
to ensure that the spline remains attached to the drive spool during use. In the case
of a magnet, the wrapped portion of the belt around the drive spool holds the belt
in place when the load becomes large.
[0068] The hook and loop fasteners may be replaced with buckles. The cartridge may be provided
with a processor and a speaker, with the processor programmed to give audio instructions
to the user. In addition, other means for tightening the belt may be used, such as
multiple motors and drive spools, pistons, scissors mechanisms or other mechanical
actuators.
[0069] Similarly, the drive spool or drive spools may have different shapes. If so, then
the connection between the pull straps and the drive spool may have to be altered
to accommodate the new drive spool shape. For example, a drive spool may have a conical
shape and the pull straps replaced with pull cables or with pull straps made of a
material without resin. In this case, the belt or cables may be fixedly attached to
the drive spool.
[0070] Figures 13 through 15 show close-up views of the belt
3, the breakable link
89 and the liner socks
182 and
183 surrounding the portions
3R and
3L of the belt that contact the patient and also shows the breakable link
89. (The peg
34, eyelet
33, spline
66 and various sections of the belt
16,17, 18, 19, 20 and
21 are shown for reference. The compression pad and cover plate are not shown in order
to more clearly show the belt liner.) The loosely fitted liner socks protect the patient
from friction. The belt generates friction along the surface of the patient as the
belt repetitively compresses the patient's chest. Without some means for reducing
the friction, the belt would likely cause injury during compressions, such as abrasions,
contusions or other compression-related injuries. In addition, friction increases
the energy required to operate the compression device and thereby reduces battery
life. The liner socks protect the patient and increase energy efficiency by allowing
the belt to easily slide along the liner, with the liner only moving slightly against
the patient's chest. (Some bunching of the liner socks may occur during compressions.)
[0071] The liner socks are tubes of Tyvek™ (high-density, spun bonded polyethylene) that
are attached to the belt cartridge to form socks around the right
73 and left
3L portions of the belt. (The liner socks may comprise other materials that are water
resistant and have a similar coefficient of friction to Tyvek™, Teflon™ or like substances.
The liner socks may also have multiple layers of material; that is, socks within socks.)
The left sock
182 is attached to the left belt guard
68 at one end and to the left load distribution section
17 of the belt at the other end. A hole in the left sock allows the peg
34 to be inserted into the eyelet
33. The left sock is attached to the belt at any point near the free end of the load
distribution section. The right sock
183 is attached to the right belt guard
67 at one end and to the right load distribution section
16 of the belt at the other end. The right sock is attached to the belt at any point
near the free end of the right load distribution section. The right sock wraps around
the compression pad
65 and surrounds the breakable link.
[0072] The breakable link
89 is a cylinder made of aluminum or other suitable material. The central portion
190 of the cylinder has a smaller diameter than the end portions
191 and
192 of the cylinder. Since the link will break at the thinnest portion of the cylinder,
the amount of force required to break the link is precisely controlled by setting
the radius of the central portion
190 of the cylinder. If the link
89 breaks under tension then the two remaining ends of the link remain within the sock.
The liner sock thus reduces the chance that a broken link will lash out and cause
injury to the patient or bystanders. In addition, a separate bag or sleeve
184 may be attached to the belt near either end of the link. The bag surrounds the breakable
link and contains the link in the event that the link breaks.
[0073] The link or links attached to the belt may be provided with additional features.
For example, a link may be additionally designed to serve as a swivel joint. The swivel
joint link connects the pull straps to the belt transition sections of the belt. The
swivel joint link allows the load distribution sections to twist relative to the pull
straps, about the longitudinal axis of the belt, without twisting the pull straps
themselves. (The pull straps are sufficiently stiff that they do not twist during
use.) The swivel joint link helps prevent the device from malfunctioning as a result
of the pull straps becoming twisted and helps prevent the link from breaking due to
shear forces or twisting forces. In other devices, separate swivel joints are provided
and attached to the belt as described above. For these devices the swivel joint and
the link may be connected to each other, but may also be disposed at separate locations
on the belt.
[0074] In addition, a link or swivel link may be designed to be re-engaged (or to be re-attached
to the belt) if one or more links do separate. For example, the link or swivel link
may be attached to the belt with a clip that fails at a pre-determined force, but
that can be re-attached to the belt. Similarly, the swivel link may be provided in
two pieces joined by a joint that separates at a pre-determined force, but that can
be re-attached to each other. (Other re-attachable links or swivel link designs may
also be used.) Thus, in the event of a link failure during chest compressions, the
entire belt cartridge need not be replaced. Instead, the problem that caused the failure
can be addressed, the failed link or links quickly re-engaged or re-attached and chest
compressions then resumed. The re-attached link will fail at the same force as the
force required to cause the link to originally fail.
[0075] The detachable link may comprise a detachable device operably connected to a force
sensor, pressure sensor or strain gauge. The detachable device is highly resistant
to breaking under force, but the detachable device will separate when the force sensor,
pressure sensor or strain gauge measures an excessive force. Such a detachable device
may be designed so that a user may reattach the link to itself or to the belt, thereby
allowing the user to restart compressions quickly.
[0076] Figure 14 shows the belt
3 attached to the breakable link
89. The breakable link is located on the belt in a place where the belt tension most
closely corresponds to the actual load on the patient. Thus, the breakable link
89 is located between the pull straps and the transition-section of the belt. The breakable
link may be located elsewhere on the belt, though the link would have to be adjusted
to break at a different amount of belt tension since the tension and sheer forces
on the link would be different, Multiple links may be provided on either side of the
belt. Preferably, one link is provided on each side of the belt relative to the patient.
[0077] The link is designed to break in the presence of excessive tension (over about 200
pounds to about 500 pounds on one side of the patient, and preferably at about 300
pounds). The breakable link breaks cleanly under excessive tension and experiences
little plastic deformation before breaking. Thus, if the belt experiences excessive
tension, the link will break, the belt will separate and the patient will be protected
from excessive forces.
[0078] To attach the link to the belt, the belt is separated into two sections and corresponding
flaps
185 and
186 near opposing ends of each section are folded over themselves to form pockets in
each belt section. The pockets are held in place by stitches
187. A pin
188 is disposed within each pocket and held in place by the stitches. The pins are exposed
in the area of holes
189 that are provided in a corresponding end of each pocket. The holes provide space
to receive the ends of the link and allow the pins to be threaded through apertures
provided in the link. (The unexposed portions of the pins are shown in phantom to
indicate their position inside the pockets and inside the link.) Thus, a pin connects
a section of the belt to the link and the belt sections are thereby connected to each
other via the link. The link is designed so that the center of the link will break,
thereby separating the belt, before the pins or any other part of the link will break.
[0079] Figure 15 shows another cross-section of the breakable link. The breakable link
89 is an aluminum cylinder. The central portion
190 of the cylinder has a smaller diameter than the end portions
191 and
192 of the cylinder. Since the link will break at the thinnest portion of the cylinder,
the amount of force required to break the link is precisely controlled by setting
the cross-sectional area of the smallest part of the central portion
190 of the cylinder. The material used to make the link also controls the force required
to break the link. Different materials will break at different levels of force depending
on a number of factors, including the cross sectional area of the link, the type of
alloy used, whether the link is heat treated, the type of surface finish provided
and the like.
[0080] Each end portion of the cylinder is provided with a hole
193 to accommodate the pins. The holes are drilled from either side of the cylinder with
a conical drill. The conical drill creates opposing ridges
194 in the center of each hole. A pin contacts the link in the area of the ridges so
that the pin is loaded at a point. This orientation prevents excessive forces from
developing in directions other than in the direction the link is intended to break.
The combination of the conical holes and the pins permit the link to bend or break
only in the direction the link is intended to break. To further reduce bending or
shear forces, the pins and/or the link are coated with Teflon™ (polytetrafluoroethylene)
so that the pins may wobble with minimal friction within the link holes.
[0081] The breakable link has a length of 0.942 inches, has a radius of 0.310 inches at
the end portions and a radius of 0.088 inches at the thinnest central portion. The
end portions of the link are 0.310 inches long each and the central portion of the
link is 0.322 inches long. The thinnest central portion of the link is 0.042 inches
long (and is part of the overall 0.322 inch length of the central section). An aluminum
link of these dimensions will break when about 300 pounds of force is applied along
the long axis 195 of the link. The dimensions of the link may be varied to vary the
force required to break the link, preferably about 300 pounds for the detachable device
and belt cartridge shown in Figures 3 through 5. In addition to aluminum, the link
may be made of a variety of materials, including other metals (such as steel or magnesium),
polymers, composites or fibers. However, the link must predictably break when exposed
to a given force applied in a given direction.
[0082] Other devices and methods may also be used to increase the safety of using a belt
to perform chest compressions. For example, other forms of reducing the coefficient
of friction of the belt may be used. The liner, belt or patient may be provided with
a layer of friction-reducing material. For example, a layer of Teflon™ may be placed
between the belt and the liner sock, between the belt and the compression pad or between
the belt and the patient. (The layer of friction-reducing material decreases the chance
that the patient will be injured during chest compressions and increases the energy
efficiency of chest compressions.) Thus, one or more liner sheets can replace or be
used in addition to the liner socks to prevent injury to the patient. The coefficient
of friction of the belt may also be reduced by super-cooling the belt. A lubricating
substance, such as talc powder or a liquid may placed between the patient and the
belt, but means for preventing the lubricant from entering the belt drive platform
should also be provided.
[0083] Additionally, the belt and belt cartridge may be provided in different sizes to accommodate
differently sized patients. The belt and belt cartridge described herein is sized
to accommodate about 95% of the population. Thus, if one smaller belt size and one
larger belt size are available, then the three belt sizes will accommodate the vast
majority of all patient sizes (though a range of belt sizes is possible). Another
design scheme uses one size of belt and cartridge and provides detachable belt extensions
to increase the size of the belt. A belt extension is a length of belt having similar
properties to the belt on the cartridge. A suitable fastener, such as a hook and loop
fastener or a detachable link, connects the belt extension to the belt on the cartridge.
[0084] When multiple belt sizes are available the belt may be provided with markings that
allow the rescuer to measure the length of the belt with respect to the patient. The
user then manually enters the size of the belt into the belt drive platform through
a user interface in the belt drive platform. To accommodate the new belt size the
device's software alters how the device performs chest compressions. Thus, the device
will perform chest compressions consistent with medical guidelines, regardless of
the size of the belt or the size of the patient (to the design limits of the device).
[0085] In other devices, the belt cartridge is provided with an identifying code, pinout
or other identifier that automatically inputs the size of the belt into the belt drive
platform. The device changes how it performs chest compressions (in terms of how much
belt slack is taken up by the means for tightening) based on the size of the belt.
In the case of belt extensions, the new belt length is manually entered into the processor,
though the belt extension may be provided with a switch or other identifying mechanism
that automatically inputs the new overall belt length into the processor. Again, the
belt drive platform's software accordingly alters how the device performs chest compressions.
[0086] In addition, other means for tightening the belt may be used to drive the belt, such
as multiple motors and drive spools, pistons, scissors mechanisms or other mechanical
actuators. Moreover, the belt drive platforms or housings containing such means may
have a variety of shapes and sizes, so long as the belt and belt cartridge are designed
to attach to a particular belt drive platform and to means for tightening the belt.
[0087] While the preferred embodiments of the devices and methods have been described in
reference to the environment in which they were developed, they are merely illustrative
of the principles of the inventions. Other embodiments and configurations may be devised
without departing from the spirit of the inventions and the scope of the appended
claims.
[0088] Preferably, a system for performing chest compressions on a patient, said system
can comprise a compression belt and a belt drive platform, wherein the belt drive
platform can comprise a housing, a motor disposed within the housing and a drive spool
operatively connected to the motor, wherein: said belt has a width corresponding to
the superior-inferior height of the patient when the belt is disposed around the patient,
said belt also having a length corresponding to the medial-lateral circumference of
the patient when the belt is disposed around the patient; said belt has pull straps,
a first load distribution section attached to a first end of the pull straps, and
a second load distribution section attached to a second end of the pull straps; wherein
the first load distribution section and the second load distribution are wider than
the pull straps; and the compression belt is operably connected to a compression belt
cartridge which is releasably attachable to the belt drive platform; and the compression
belt is further provides with means for releasably attaching the compression belt
to the drive spool.
[0089] Preferably, a system wherein the belt can further comprise a first transition section
attached to the first load distribution section and to the pull straps, and a second
transition section attached to the second load distribution section and to the pull
straps, wherein the second transition section is opposite the first transition section.
[0090] Preferably, a system wherein the first and second transition sections have a trapezoidal
shape.
[0091] Preferably, a system wherein the belt cartridge can further comprise a first reinforcing
plate attached to the first transition section and a second reinforcing plate attached
to the second transition section.
[0092] Preferably, a system wherein the belt cartridge can further comprise an eyelet attached
to the first load distribution section and a peg attached to the second load distribution
section, wherein the eyelet is sized and dimensioned to receive the peg and wherein
the peg may be inserted into the eyelet when the first and second load distribution
sections are secured over the chest of the patient.
[0093] Preferably, a system which can further comprise a means for determining if the peg
is inserted into the eyelet.
[0094] Preferably, a system wherein the belt can comprise at least one layer of unidirectional
fibers held together with a resin.
[0095] Preferably, a system wherein: the belt can comprise a plurality of layers and each
layer can comprise a plurality of fibers held together by a resin; wherein all of
the fibers which can compose any given layer are oriented along one direction; and
the orientation of the fibers of one layer is different from the orientation of the
fibers of a second layer.
[0096] Preferably, a method of performing chest compressions on a patient, said method can
comprise the steps of: providing a system for performing chest compressions which
can comprise a compression belt and a belt drive platform, wherein the belt drive
platform can comprise a housing, a motor disposed within the housing and a drive spool
operatively connected to the motor said system can further comprise: a compression
belt cartridge which can comprise: a belt, said belt having a width corresponding
to the superior-inferior height of the patient when the belt is disposed around the
patient, said belt also having a length corresponding to the medial-lateral circumference
of the patient when the belt is disposed around the patient; said belt having pull
straps, a first load distribution section attached to a first end of the pull straps,
and a second load distribution section attached to a second end of the pull straps;
wherein the first load distribution section and the second load distribution are wider
than the pull straps; and means for releasably attaching the compression belt catridge
to the belt drive platform; means for releasable attaching the belt to the drive spool.
releasably attaching the compression belt to the drive spool; releasably attaching
the compression belt cartridge to the blet drive platform; placing the compression
belt about ht e chest of the patient; attaching the load distribution sections of
the belt to each other and placing the load distribution sections over the chest of
the patient; and tightening the belt to compress the chest of the patient.
[0097] Preferably, a system for performing chest compressions on a patient, said system
which can comprise: a belt drive platform which can comprise: a housing; a drive spool
operably attached to the housing; and a means for rotating the drive spool, said means
for rotating disposed within the housing and operably attached to the drive spool;
a compression belt cartridge which can comprise: a belt suitable for compressing the
chest of the patient; and a spline attached to the belt; wherein the spline is removably
attachable to the drive spool; wherein rotation of the drive spool tightens the belt
to compress the chest.
[0098] Preferably, a system which can further comprise a slot disposed in the drive spool,
said slot having a particular shape, wherein the spline has a particular shape conforming
to the shape of the slot and wherein the spline fits into the slot.
[0099] Preferably, a system which can further comprise a means for identifying whether the
spline is inserted into the slot, said means for identifying operably connected to
the slot.
[0100] Preferably, a system which can further comprise a guide plate operably attached to
the housing and to the drive spool, said guide plate having a slot disposed within
the guide plate, said slot sized and dimensioned to permit passage of a portion of
the spline into the drive spool slot.
[0101] Preferably, a system which can further comprise a guide plate operably attached to
the housing and to the drive spool, said guide plate having a slot disposed within
the guide plate, said slot sized and dimensioned to permit passage of a portion of
the spline into the drive spool slot.
[0102] Preferably, a system wherein the drive spool is rotatable by the user and wherein
spline may be inserted into the drive spool slot when the guide plate slot and the
drive spool slot are aligned.
[0103] Preferably, a system wherein the guide plate is rotatable by the user and wherein
the spline may be inserted into the drive spool slot when the guide plate slot and
the drive spool slot are aligned.
[0104] Preferably, a system which can further comprise: a guide plate operably attached
to the housing, wherein the guide plate is disposed in relation to the drive spool
such that the spline may not be inserted into and removed from the drive spool slot
unless the guide plate is moved; a means for providing a biasing force to the guide
plate such that the guide plate is biased to be disposed in relation to the drive
spool to prevent the spline from being inserted into and removed from the drive spool
slot; wherein a user may manually move the guide plate sufficiently to insert the
spline into and remove the spline from the slot.
[0105] Preferably, a system for performing chest compressions on a patient, said system
can comprise: a housing; a drive spool operably attached to the housing; a means for
rotating the drive spool, said means for rotating disposed within the housing and
operably attached to the drive spool; a compression belt which can comprise: a belt
suitable for compressing the chest of the patient; and a liner sock loosely fitted
over the belt; wherein the belt is adapted for attachment to the drive spool and is
operable to slide within the sock liner.
[0106] Preferably, a system for performing chest compressions on a patient, said system
can comprise: a housing; a drive spool operably attached to the housing; a means for
rotating the drive spool, said means for rotating disposed within the housing and
operably attached to the drive spool; a compression belt cartridge which can comprise:
a belt suitable for compressing the chest of the patient; and a breakable link attached
to the belt, said breakable link sized and dimensioned to break when a particular
amount of force is applied to the link, and wherein the breakable link is attached
to the belt such that if the breakable link breaks, the belt will separate; wherein
the belt is adapted for attachment to the drive spool.
[0107] Preferably, a system for performing chest compressions on a patient, said system
can comprise: a housing; a drive spool operably attached to the housing; a means for
rotating the drive spool, said means for rotating disposed within the housing and
operably attached to the drive spool; a first spindle rotatably attached to the housing;
a second spindle rotatably attached to the housing; a compression belt cartridge comprising:
a belt suitable for compressing the chest of the patient; a first belt guard operably
attached to the belt such that the belt may slide through the first belt guard; and
a second belt guard operably attached to the belt such that the belt may slide through
the second belt guard; wherein the belt is removably attachable to the drive spool,
the first belt guard is removably attachable to the first spindle and the second belt
guard is emovably attachable to the second spindle.
[0108] Preferably, a system for performing chest compressions on a patient, said system
can comprise: a housing; a drive spool operably attached to the housing; a means for
rotating the drive spool, said means for rotating disposed within the housing and
operably attached to the drive spool; a first spindle rotatably attached to the housing;
a second spindle rotatably attached to the housing; a compression belt cartridge comprising:
a belt suitable for compressing the chest of the patient, said belt having a first
portion and a second portion; a cover plate removably attachable to the housing; a
first belt guard operably attached to the cover plate, said first belt guard operably
attached to the belt such that the belt may slide through the first belt guard; a
second belt guard operably attached to the cover plate opposite the first belt guard,
said second belt guard operably attached to the belt such that the belt may slide
through the second belt guard; a first liner sock loosely fitted over the first portion
of the belt, said first liner sock attached to the first portion of the belt and attached
to the first belt guard; a second liner sock loosely fitted over the second portion
of the belt, said second liner sock attached to the second portion of the belt and
attached to the second belt guard; a compression pad attached to the first portion
of the belt and disposed within the first liner sock; and a breakable link attached
to the belt, said breakable link sized and dimensioned to break when a particular
amount of force is applied to the link, and wherein the breakable link is attached
to the belt such that if the breakable link breaks, the belt will separate; wherein
the belt is removably attachable to the drive spool, the first belt guard is removably
attachable to the first spindle and the second belt guard is removably attachable
to the second spindle.