There is an impending crisis in the health care field due to rapid growth of the elderly population relative to the number of care providers available to assist them. In 1950. the ratio of working adults to elderly persons was 8:1. This projected ratio will decline to 5:1 by 2020, and by 2050, it will drop to only three working adults per elderly person. It is thus critical to develop technologies that maximize patient independence and caregiver efficiency. It is also important to minimize stress placed upon caregivers in both domestic and institutional settings.
The primary physical stress imposed on a caregiver (in residential, institutional and emergency settings) occurs when the caregiver is required to lift and transfer patients (e.g., from a wheel chair to a toilet or bed). Risk of injury increases when the patient is relatively large, or the caregivers themselves have a predisposition to injury. One out of three nurses is injured from the physical exertion of transferring patients, costing their employers an estimated $35,000 to $50,000 per injury.
In 2005, the National Institutes of Standards and Technology (NIST) Intelligent Systems Division began conducting research in the area of health care mobility. The NIST Healthcare Mobility Project identified the staggering need for technology to assist with lifting and mobility. In 2004-2006, NIST researchers conducted a survey of available lift and mobility devices summarized in a report submitted by Roger Bostelman and James Albus, Survey of Patient Mobility and Lift Technologies Toward Advancements and Standards, NISTIR #7384, 2006.
Further research was presented by Roger Bostelman and James Albus at the 3rd International Workshop on Advances in Service Robotics (ASER06), in Vienna, Austria on Jul. 7, 2006 in a seminal report entitled “HLPR Chair: A Service Robot for the Healthcare Industry” ( hereinafter referred to as the “2006 report”).
The 2006 report identified standard ranges of motion that would be necessary in a device to assist caregivers in safely conducting patient lift and transfer activities: rotation of an outer frame, rotation of a patient seat within the outer frame, motion along an x-axis (forward and backward axis) and motion along a z-axis (vertical lift). The researchers proposed the design of an apparatus to safely accommodate these ranges of motion using a single device for patients who might be very frail, large in size, or have a wide range of disabilities and physical limitations.
To illustrate how existing technology might be incorporated, the 2006 report discussed a prototype “service robot” utilizing an “off-the-shelf sturdy forklift,” which would be “powered similar to typically powered chairs on the market” and a standard “joystick” type steering mechanism. The research paper taught a lift mechanism using “a steel chain fix-mounted at one end to the HLPR chair frame and to the lift plate at the other end.” Rollers were mounted to “the lift plate [and] roll inside the HLPR chair.” The roller configuration later proved unfeasible, and numerous safety issues were identified.
The 2006 report explained that the prototype would operate as follows in transferring a patient from the chair to a toilet:                To place a HLPR Chair user on another seat, they can drive to for example: a toilet, seat, or bed. Once there, the HLPR Chair rotates the footrest up and beneath the seat and the patient's feet are placed on the floor personally or by a caregiver. The HLPR Chair inner L-frame can then be rotated manually with respect to the chair frame allowing the patient to be above the toilet. Padded torso lifts then lift the patient from beneath his/her arm joints similar to crutches. The seat, with the footrest beneath, then rotates from horizontal to vertical behind the patients back clearing the area beneath the patient to be placed on the toilet, seat, bed, etc.        Once the person is in place on the toilet, the HLPR Chair can remain in the same position to continue supporting them from potential side, back or front fall.        
Thus, in addition to identifying the movement axis that would be required for an HLPR chair, the 2006 report taught a footrest mechanism that would move out of the way and also a mechanical “torso lift” component to lift the patient out of the chair.
While these concepts were intriguing to the health care community, there was consensus that the prototype did not enable or teach the design of a safe, commercially viable apparatus. Further research would be needed. For example, the “padded torso lifts” deployed by a “torso lift actuator” which would pull patient up by their arm joints and suspend them in this manner above a surface, such as a toilet, were an unsafe way of suspending a patient—particularly a large or frail one. The torso lifts would place considerable stress on the patient, while their lower body would be dangerously unsupported. Thus, it was a challenge to develop a device that would lift and suspend a patient without injuring them.
Additionally, the 2006 report proposed the concept of a chair seat that could actually rotate from beneath a patient “from horizontal to vertical.” There was consensus in the medical community that this would indeed be a desirable feature. However, a seat that would fit within a fork-lift type frame would need to be compact and custom-made to rotate and clear the outer frame of the device. The seat would also have to efficiently reposition itself from a vertical to horizontal position, or there would be great risk to the patient. The seat would also have to accommodate the weight and width of larger patients, and be of sufficient length to prevent patients with poor motor control from simply falling off the front edge.
Just as importantly, to be commercially viable, an HLPR seat would need to accommodate the heights of structures (e.g., chairs, toilets and beds) without requiring exact and complex adjustments. The seat would need to retract completely, allowing for height variances and contouring in the structure that could interfere with the full range of necessary motion in the seat.
Finally, a commercially viable HLPR device would need to resist destabilizing torque forces caused by the motion of both the seat and the patient, yet be light enough to be moved and manipulated by caregivers and transported for commercial and residential use. The welded aluminum frame of the initial prototype was unwieldy, costly to produce, and heavy to transport and manipulate. Yet the 2006 report still expressed the concern that “[h]eavier patients would require additional counterweight” to provide stability and counter torque forces during rotation, if the patient leaned forward or if the HLPR was moving forward or down a slope.
Despite these formidable design obstacles, the 2006 report contemplated that a safe device could be manufactured for approximately $10,000. and could be sold to medical equipment rental companies for less than $30,000. If rented for $100 per day, each device could pay for itself in less than a year.
Moreover, the 2006 report contemplated that an HLPR apparatus should not be limited to use by patients in a sitting position, and that it would be desirable to design a versatile device that would enable a wider range of support and lift functions, including rehabilitative functions to assist semi-mobile and ambulatory patients.
The 2006 report led to additional research to develop an affordable apparatus to perform lift, transfer and rehabilitative activities. This research has also been directed at facilitating patient transfer and lift in emergency, institutional and rehabilitative settings.
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