This patent application is directed to a system for rotating, transferring, positioning, or lifting a patient for purposes of performing a medical procedure where a patient is rotated from a supine position to a prone position, and vice versa. The apparatus may be used for transferring a patient to and from an operating table.
Generally, surgeries and procedures performed to the posterior of a patient require the patient to be positioned in a prone position to provide access to a surgical site. Prior to performing the surgery, protocol typically requires that the patient be anesthetized and intubated while lying on their back. For the vast majority of back surgeries performed in the United States today, most patients are still anesthetized on a gurney, and then manually lifted, inverted and deposited on an operating table.
There are many challenges associated with the transfer of the patient to the operating table from the gurney, and vice versa. The manual process of transfer is physically demanding and non-physiologic for the staff, and is potentially unsafe for the anesthetized patient. For instance, an anesthetized patient who is in an unconscious state has absolutely no control over their appendages and head, which all have a tendency to flop-down from gravity. If any appendages are not properly supported, it is possible to break, dislocate, or otherwise injure the patient's neck, shoulder area, and/or appendages while manually lifting and inverting the patient. Additionally, the patient may have a preexisting disease or injury to the spine, which if moved or twisted improperly could cause damage or paralysis to the patient. Thus, the staff must remain vigilant to properly support the appendages and body of the patient each time the patient is lifted and inverted. There is also a potential to accidentally lose control of or drop a patient incurring injury to the patient and/or staff.
Additionally, an anesthetized patient assumes “dead weight” which makes that person feel heavier. The weight of the patient exposes staff members, such as nurses, assistants, and doctors, to injuries when lifting the patient. Often times a staff member must lean across a gurney or operating room table exposing themselves to lifting injuries. Sometimes, the weight of the patient is not evenly distributed potentially risking injury to a staff member or patient. Accordingly, liability issues arise when patients are dropped or injured while being oriented on the operating table while sedated. Doctors and hospitals are also exposed to liability when operating staff are injured lifting and positioning sedated patients.
A further potential problem associated with turning the patient from his/her stomach or back involves the potential for patient motion or staff interference with life-support and life-monitoring systems that may be attached to the patient, such as an intravenous line, a catheter, electrode monitoring lines for monitoring the patient's vital signs, and an endotracheal tube for the purposes of administering oxygen and/or anesthesia to the patient. If any one of these life-support or life-monitoring systems is pulled out, crimped, or twisted, it can injure the patient and/or the operating staff.
Still another complication associated with manually lifting and inverting a patient onto an operating table for back surgery involves positioning the patient in proper alignment on the table. Some patients are placed on a “Wilson Frame” to properly align the back properly thereby and enhancing proper ventilation. The Wilson Frame allows the abdomen to hang pendulous and free. It is often difficult to manually manipulate the patient once placed onto the operating table to ensure proper alignment with the Wilson Frame underneath the patient.
Other ancillary problems involve positioning of the head, chest, and legs with proper support and access for devices such as the endotracheal tube. Anthropometric considerations, such as patient size, including weight and width, cause the operating staff to ensure that proper padding and elevations are used to support the head, chest, and legs. It is not uncommon to find operating staff stuffing pillows or bedding underneath a patient to adjust for different anthropometric features of a patient.
Attempts have been made to solve the transfer problems described above including systems which can turn rotate a patient. Unfortunately, many such systems for turning a patient have an axis of rotation and a center of gravity that are different. In such systems the separation of the rotation axis and the center of gravity make the system “top-heavy”, or unbalanced, and therefore it is difficult to manually turn a patient. Furthermore, the unbalanced load creates greater stresses on the mechanical equipment and presents greater risk of mechanical failure to the patient.
Described herein is a patient-safety-transfer system for rotating, transferring, positioning, or lifting a patient for purposes of performing a medical procedure where a patient is rotated from a supine position to a prone position, and vice versa. The system may be used for lifting, positioning, rotating and/or transferring an anesthetized patient for purposes of performing posterior surgery, and related medical procedures.
In one embodiment, the system includes first and second center-of-gravity (COG) assemblies. Opposing patient-support platens—an anterior platen (for abutting the front portions of the patient) and a posterior platen (for abutting back portions of the patient)—are coupled to a corresponding end of the first and second COG assemblies. The first and second COG assemblies are each coupled to a corresponding one of a pair of floating-spindle heads. Each one of the floating-spindle heads is disposed on a corresponding lift column. The COG assemblies provide for an axis of rotation that is outside the plane of platens upon which the patient is disposed. Specifically, the system provides a rotation axis outside the plane of either subjacent or superjacent patient-support platform, and more closely aligned with the center-of-gravity.
In other embodiments, the COG assemblies adjust a separation distance between the axis of rotation and the center-of-gravity defined by a combination of the patient and the supporting platens.
Achieving controlled patient pad compression is a pre-condition to safely clamp, secure, pick up, and rotate a patient 180 degrees from prone to supine position, or supine to prone position. To achieve optimal compression, in another embodiment, a lost-motion-over-travel system prevents the platens from continuing to travel toward the patient when lowering a platen toward to the patient, once optimal compression forces exerted on the patient via a platen (and/or the platen's constituent-support padding) is obtained.
In yet another embodiment, registration plates, coupled to the system, conveniently align the attachment mechanisms of each COG assembly with distal ends of one or more platens. For instance, when the anterior platen is placed on the surface of an operating table and is detached from the system, the distal ends of the anterior platen may telescopically extend beyond the ends of the table. When retrieving a patient from the operating table, the registration plates allow for medical staff to align the system so that it straddles the operating table with the attachment mechanisms of the COG assembly in alignment with platen tubes (or other complimentary attachment mechanisms) located at the distal ends of the anterior platen.
The system eliminates the need for operating room staff to manually lift and place an anesthetized patient in prone or supine positions. The system also provides safety for the patient and for medical staff charged with turning the patient. The system includes powered-lift columns that lift and lower platens between which a patient is disposed. The powered-lift columns, in embodiments described herein, are typically electrically powered, but it is appreciated by those skilled in the art having the benefit this disclosure, that these powered-lift columns are not so limited and may be powered by any suitable means including but not limited to hydraulics and pneumatics.
Various embodiments described herein provide a solution to achieve an optimum center-of-gravity (i.e., a balanced load) between platens, having a patient sandwiched therein, to the rotation axis of two rotation spindles. With an optimized center-of-gravity relative to the spindle axis, personnel are provided with the optimal-balanced load for manually rotating the patient 180 degrees. This provides a safe condition for both patient and staff while the patient is rotated from the supine to prone position, or from the prone to supine position.
Various embodiments of the present invention include several mechanical elements, assemblies and subsystems, such as, but not limited to, dual-rack-and-pinion subsystems, lost motion devices, gas shock absorbers, and ratchet and pawl subsystems. These mechanical elements, assemblies, and subsystems are combined in a unique manner to provide a patient safety transfer system operable to safely rotate a patient from a supine to prone position, and from a prone to supine position.
Regarding the exemplary dual-rack-and-pinions, each of these allow a top set of racks to extend simultaneously with the lower set of racks. This is used in the COG assembly (described in greater below) and provides a self-centering function. With respect to lost-motion devices, in most applications the driven load stops moving when it contacts a fixed stop and the powered device continues to lower in a free state.
Gas-shock absorbers are used to counter-act large weights in many mechanisms such as a rear hatch door in a vehicle. The gas-shock absorbers are sized to each application in order to reduce free energy caused by gravity as well as provide an ergonomic, realistic amount of energy for human beings to safely perform a given manual function, such as, in the embodiments, rotating a patient from supine to prone and vice versa.
Ratchet-and-pawl systems provide mechanisms with the ability to back-drive in one direction and catch in the opposite direction of rotation as is used in the adjustable frame system.
The various embodiments are part of an illustrative patient-safety-transfer system that includes a lift-column assembly that is mounted to a portable-caster-base assembly. Each caster-base assembly is tied to the other with a drawbar that has an operating position (as shown
One posterior platen is used for the posterior side of patients and has two telescoping shafts to provide a safety distance (approximately 6.0 inches in one embodiment, but other suitable distances may be implemented) between the COG-platen latches and the patient, while the patient is lying on the platen. Platen-tube extensions can be collapsed so as to be flush with an operating table when a transfer or rotation is complete in order to provide patient access during an operating room procedure.
One anterior platen is used for the anterior side of patients and also has two telescoping devices to provide patients a safe distance away from the COG assembly during the hook-up phase of the transfer. A safety-belt system (one or more safety belts) is used to engage the posterior platen and the anterior platens together for the rotate, or patient turning, phase. Padding may be coupled to the safety-belt system to help ensure appendages of the patient are secured while rotated.
Pre-stage conditions for an illustrative embodiment describe specifics of the lowering function, latching of COG assembly to posterior and anterior platens, COG self centering features, COG assembly-self-centering-ratchet-and pawl-functions, and finally the spindle-lost motion functions. More particularly, the pre-stage conditions are: (1) the posterior platen is manually pre-staged onto the operating room (OR) table and each telescopic end of the platen is advanced into a locked position; (2) a patient is positioned on top of the posterior platen for rotation into the prone position; (3) the upper and lower dual-rack-and-pinion shafts of each COG assembly are extended and locked into their fully extended positions; (4) the anterior platen assembly is already locked onto its respective COG latches and is rotated in a ready-to-receive position over the top of the patient lying on the posterior platen and operating table; (5) the floor frame system has already been located to the lower platen with a caster-base-mounted registration plate; (6) all casters are locked in-position; and (7) the linear actuator drive is powered-on.
In practice, a staff member of the hospital or similar facility controls a pendant button in order to lift or lower platens onto or off from the operating table. When the pendant button (or other suitable control mechanism) for lowering is actuated, both linear actuator devices lower simultaneously with respect to each other. The pendant button is depressed and two lift columns lower the COG assemblies. The anterior-frame latch mechanism mounted on each of the COG assemblies fully nest over the platen tubes during this downward motion. Once contact with the platen tubes has occurred, the dual rack and pinion system of the COG assemblies begins to close and the COG-assembly-release-mechanism ratchet-and-pawl device begins to back-drive and the platens adjust themselves to the size of patient (vertical thickness). During this downward self-adjusting motion, the anterior platen foam pads eventually make contact with the patient and a controlled patient pad compression is reached. The anterior platen, the two COG assemblies, and the two spindle assemblies stop lowering while the linear motion columns are free to continue traveling until a limit switch is made (approximately two inches of travel). This provides a safe and reliable system for patients, and provides staff members with peace of mind that this system can safely perform its function.
The posterior platen is latched onto the dual-rack-and-pinion shafts of the COG assembly. The pad compression system is checked and adjusted by manually pulling the anterior platen down until a safe amount of pad compression is achieved. Next, safety belts are attached to the mushroom head pins and belts are cinched to secure the patient. Finally the lift and rotate functions are achieved.
Further details and advantages of a patient transfer system will become apparent with reference to the accompanying drawings and the following detailed description.
The detailed description is presented with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. It is emphasized that the various features in the figures are not drawn to scale, and dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
Reference herein to “one embodiment”, “an embodiment”, or similar formulations, means that a particular feature, structure, operation, or characteristic described in connection with the embodiment, is included in at least one embodiment. Thus, the appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.
The expression “center-of-gravity” refers to the point at which the resultant gravitational force acts upon an object. The center of gravity is not necessarily inside the object. For example, the center of gravity of a ring is at the center of symmetry. If the geometry of the object does not change with time, the center of gravity will remain unchanged in relation to the object. In embodiments described herein, the center-of-gravity changes as patients placed in and removed from the system.
As used herein the expression “operating table” refers to general operating room tables, medical procedural tables, x-ray tables, and potentially other surfaces for performing a medical procedure usually under sedation and/or general anesthesia. The term “gurney” and “gurney-like,” refers to a mobile platform used in a facility, such as a hospital, to move a patient that is lying down.
The term “over travel”, as used herein refers to the distance over which the moving member(s) travel after a platen has come to rest on a support structure.
The term “platen”, as used herein refers to an assembly having a framework and a patient support area disposed within an area defined by the framework. The term “anterior platen” generally refers to the platen which is configured to support the anterior side of a patient. The term “posterior platen” generally refers to the platen which is configured to support the posterior side of the patient. While specific examples may refer to one or the other, it should be appreciated by those skilled in the art, that either platen is interchangeable with the other, and such terminology is not necessarily intended to limit the scope of the claims.
The term “prone” refers to a patient lying face downward.
The term “supine” refers to a patient lying face upward.
The expression “ratchet-and-pawl system” refers to a mechanism having the ability to back-drive in one direction and catch in the opposite direction of rotation.
Described herein is a patient-safety-transfer system configured to lift, rotate, and transfer a patient to/from an operating table. An embodiment of the patient-safety-transfer system 100 is depicted in
Chassis 101 serves as a framework for apparatus 100, which is configured to straddle an OR table. Chassis 101 includes two portable-caster-base assemblies 110(1), 110(2). Portable-caster-base assemblies 110 are coupled to each other by drawbar 112. Drawbar 112 includes an operating position, and a second collapsible-storage position. In the collapsible-storage position, drawbar 112 slidably folds together, which enables storage or transportation of system 100.
Powered-lift columns 102(1), 102(2), in embodiments described herein, are typically electrically powered, but it is appreciated by those skilled in the art having the benefit this disclosure, that these powered-lift columns are not so limited and may be powered by any suitable means including but not limited to hydraulics and pneumatics. 102(1), 102(2) are located at distal ends of drawbar 112. Powered-lift columns 102(1), 102(2) vertically extend and retract allowing for adjustability in height of platens 114 and 122. In one embodiment, the height of both powered-lift columns 102(1), 102(2) move in unison. Powered-lift columns 102 may incorporate actuators (not shown) that telescopically expand and contract each column to control their height.
Attached to the powered-lift columns 102 are a pair of rotation systems including COG assemblies 106(1), 106(2) each coupled to respective spindle assemblies 108(1), 108(2) (which are obstructed in
Referring to
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Anterior platen 122 includes a removable head-support assembly (not shown), a torso support 174, and leg pads 176 and 178 which support the patient while laying in a prone position, and provide friction support to secure the patient disposed between the platens 114/122, when rotated 180 degrees. Torso support 174 and leg pads 176, 178 are attached to rails 180(1), 180(2), and can slide longitudinally along rails 180 via brackets 182 that fit around rails 180.
A groove 184 located on each side of platens 114, 122 permits a safety-belt system (one or more safety belts 186) to be slidably attached to grooves 184 of both platens 114, 122.
Torso support 174 consists two pads in the general shape of Wilson-styled chest frame which supports the outer portions of the side of patient. These pads extend from the upper thighs to the shoulders of a patient. The height of the center portion of the torso support is adjustable by a manual or powered crank system.
Generally, system 100 eliminates the need for operating room staff to manually lift and place patient on and off an operating table.
Various embodiments disclosed herein include several mechanical elements, assemblies and subsystems, such as, but not limited to, dual-rack-and-pinion subsystems, lost-motion devices, gas-shock absorbers, and ratchet-and-pawl subsystems. These mechanical elements, assemblies, and subsystems are combined in a unique manner to provide a patient-safety-transfer system 100 operable to safely rotate a patient from a supine to prone position, and from a prone to supine position.
Regarding the dual-rack-and-pinions in embodiments to be described, each of these allow a top set of racks to extend simultaneously with a lower set of racks comprising the dual-rack-and-pinions. This is used in each COG assembly (described in greater detail below) and provides a self centering function. With respect to lost motion devices, in most application the driven load stops moving when it contacts a fixed stop and the powered device (i.e., columns 102) continue to lower in a free state.
Gas-shock absorbers (described in greater detail below) are used to counter-act large weights in many mechanisms such as a rear hatch door in a vehicle. The gas-shock absorbers are sized to each application in order to reduce free energy caused by gravity as well as provide an ergonomic, realistic amount of energy for human beings to safely perform a given manual function, such as, rotating a patient from supine to prone and vice versa.
Ratchet-and-pawl systems provide mechanisms with the ability to back-drive in one direction and catch in the opposite direction of rotation as is used in COG assemblies 106.
Pre-stage conditions for an illustrative embodiment of the present invention are set as listed below in order to facilitate detailed descriptions of the specifics of the lowering function, latching of COG to posterior and anterior platens, COG self centering features, COG assembly self-centering-ratchet-and-pawl functions, and finally the spindle lost motion functions. More particularly, the pre-stage conditions are: (1) posterior platen 114 is manually pre-staged onto the OR table and each telescopic end 202 (
In practice, a staff member of the hospital or similar facility controls a pendant-control panel (not shown) in order to lift or lower platens onto or off from the operating table. When the pendant button for lowering is actuated, both columns 102 lift and lower simultaneously with respect to each other. The pendant button is depressed and the two lift columns lower the COG assemblies 106. Latch mechanisms 160 mounted on each of the COG assemblies fully nest over the platen tubes 204 (
Posterior platen 114 is manually latched onto dual rack and pinion shafts 301, 302 (
Spindle assembly 108 mounts on a top portion of lift column 102. In a first case, when lift columns 102 are raised, spindle assemblies 108 stay in contact with the top portion of lift column 102, and therefore COG assemblies (each coupled to the inboard spindle 210 (
In a second case, when powered-lift columns 102 are lowered, spindle assemblies 108 stay in contact with the top portion of their respective lift columns 102, and therefore the COG assemblies 106 and platens 114/122 are lowered.
In a third case, when the powered-lift columns 102 are lowered, (i) the platen-latch assemblies 160 are nested on the platen-tube extensions 204, (ii) each COG assembly 106 begins to collapse on itself, (iii) patient-pad contact is made and (iv) platens 114/122, COG assemblies 106, and spindle assemblies 108 stop lowering when columns 102 lower and stop based on contacting an internal limit switch (not shown).
An adjustable COG assembly 106 is mounted to the inboard side of each spindle assembly 108 with a spindle 210 allowing for rotation of COG assembly 106.
Referring to
COG assembly 106 adjusts open and shut with a dual-rack-and-pinion device to open both or close both posterior and anterior shafts simultaneously. As noted above, platen latch assemblies 315, 316 are mounted to each end respectively of the COG to manually lock onto the platen frames. There is one latch assembly for the posterior platen and one latch assembly for the anterior platen.
Gas-shock absorber 310 performs two functions. The first function is to expand the COG assembly 106 to pre-stage for a pick-up condition. The second function is to provide a metered support force onto a platen (usually the upper platen) when columns 102 are lowering and platen pads make contact with the patient. These shock absorbers 310 will support the majority of the weight of spindle assemblies 108, COG assemblies 106, and a portion of the anterior or posterior platens 114/122.
Each end of COG assembly 106 has a platen-latch assembly (anterior platen latch 315 and posterior platen latch 316 respectively). After each column 103 is completely lowered and located onto the tube 204 of the posterior platen and the lost-motion limit switch is made, staff members, or operators, manually turn either one of knobs 502 (
In one illustrative embodiment, a system for turning a patient from a supine to prone position and from a prone to supine position, includes a first-lifting column having top end and a bottom end; a second-lifting column having a top end and a bottom end; a first-spindle assembly disposed over the top end of the first-lifting column; a second spindle-assembly disposed over the top end of the second-lifting column; a first-COG assembly coupled to the first-spindle assembly; a second-COG assembly coupled to the second-spindle assembly; a posterior platen having a first-frame assembly, the first-frame assembly coupled to a posterior-platen latch assembly of the first-COG assembly, and further coupled to a posterior-platen-latch assembly of the second-COG assembly; an anterior platen having a second frame assembly, the second-frame assembly coupled to an anterior-platen latch assembly of the first-COG assembly, and further coupled to an anterior-platen latch assembly of the second-COG assembly; and a safety-belt system coupled between the anterior-platen and the posterior platen.
Some embodiments also include a first-caster base coupled to the bottom end of the first-lifting column; and a second-caster base coupled to the bottom end of the second lifting column.
Still other embodiments include a drawbar coupled between the first-caster base and the second-caster base, wherein the drawbar is operable to maintain the coupling of the first and the second-lifting columns while changing the distance between the first and the second-lifting columns by telescoping.
In some of these embodiments, each COG assembly includes a housing; am upper pair of racks, each disposed at least partially within the housing, each coupled to one of a corresponding first pair of pinions, and each of the upper pair of racks spaced apart from each other by a first distance; a lower pair of racks, each disposed at least partially within the housing, each coupled to one of a corresponding second pair of pinions, and each of the lower pair of racks spaced apart from each other by a second distance; wherein the first distance is greater than the second distance.
In another illustrative embodiment, an apparatus suitable for forming part of a patient turning system, includes a COG assembly coupled to a spindle, thereby allowing the COG assembly to rotate about an axis defined by the spindle; a spindle assembly upon which the spindle is attached; a lifting column having a first end and a second end, with the spindle assembly disposed upon the first end; and a caster base to which the second end of the lifting column is attached.
In some embodiments, the caster base includes an attachment point for a drawbar. The lifting column is operable to move the spindle assembly thereby changing the vertical position of the spindle assembly. The COG assembly includes a housing; an upper pair of rack shafts, each disposed at least partially within the housing, each coupled to one of a pair of pinion gears, and each of the upper pair of racks spaced apart from each other by a first distance; a lower pair of rack shafts, each disposed at least partially within the housing, each coupled to one of the pair of pinion gears, and each of the lower pair of racks spaced apart from each other by a second distance; and a gas shock absorber, disposed in the housing and mechanically connected to the anterior-platen-latch assembly; wherein the first distance is greater than the second distance; and wherein a first one of the upper pair of rack shafts and a first one of the lower pair of rack shafts are each coupled to a first-pinion gear of the pair of pinion gears in a first-dual-rack-and-pinion arrangement, and a second one of the upper pair of rack shafts and a second one of the lower pair of rack shafts are each coupled to a second pinion gear of the pair of pinion gears in a second-dual-rack-and-pinion arrangement. It is noted that the ends of the first-dual-rack-and-pinion arrangement and the ends of the second dual rack and pinion arrangement all expand and collapse simultaneously with each other.
The exemplary methods and apparatus illustrated and described herein find application in at least the field of patient safety transport systems.
It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the subjoined Claims and their equivalents.
The present patent application claims benefit of U.S. Provisional Application Ser. No. 61/165,897 filed on 1 Apr. 2009 entitled Patient-Transfer System with Horizontal-Center-of-Gravity (COG) Rotational Assembly, incorporated herein by reference.
Number | Date | Country | |
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61165897 | Apr 2009 | US |