A persistent—if less glamorous—challenge in hospitals lies in the day-to-day work of moving and lifting patients with impaired mobility. This is a challenge intensified by our burgeoning aging population, the obesity epidemic, and our aging healthcare workforce. Given the critical shortage of direct care hospital personnel, particularly nursing staff, as well as the potential for injury to staff during patient transfer and repositioning, this is a challenge that merits further scrutiny and investment in technological innovation.
Hospitals face growing pressure to attract and retain their nursing staff. At the same time a mounting body of evidence points to short staffing as a leading cause of medical errors, injuries, and avoidable deaths among patients and disabling musculoskeletal disorders (MSD) among nursing staff. High patient-to-nurse ratios, fatigue on long shifts, mandatory overtime, lack of experienced staff, and inadequate time to monitor patients have been associated with such poor health outcomes as falls, fractures, skin breakdown, and death among patients, and with back and shoulder injuries among nursing staff. Indeed, the rate at which healthcare workers experience musculoskeletal disorders exceeds the rates observed among workers in construction, mining, and manufacturing.
A mobile robotic nurse assistant is highly desired to enhance the efficacy and quality of care that nurses and their paraprofessional staff can provide. Such an assistant could improve a nurse’s working conditions by off-loading some of his or her most physically demanding duties, thereby reducing the potential for self-injury or injury to the patient. It is anticipated that robotic maneuvering assistants would increase a nurse’s work satisfaction, decrease lifting-related injuries, and extend the years of effective service nurses could render in hospitals. These effects would reduce hospitals costs and ameliorate the problem posed by the shortage of nursing staff.
A patient lifting technology has been developed by Hstar Technologies. Commonly recognized as RoNA, the system is designed in an effort to assist nurses and other health care workers (HCWs) in lifting immobile patients into and out of their beds and wheelchairs.
The RoNA system will strengthen and transform the nurse’s leading role as protector and driver of quality patient care. Doing so will free clinical staff to devote more time to higher level, patient critical functions, while performing those lower level tasks reliably and more cost effectively.
The commercial version of RoNA system is designed to reposition and lift patients weighing up to 500 pounds under the control from nurse. The RoNA system has a whole body lifting feature which includes a mobile base platform, a vertical lift column, two lifting arms, an upper body, a HRI, and a display head.
Each arm has endless conveyor belts to minimize shearing forces to the patient’s skin and support the entire back to eliminate pressure points, and never move patients over open space.
The RoNA forearm is the primary contact surface when lifting a patient. As such, it must be safe and ergonomically designed. The flipper requires increased force-fidelity and physical compliance to allow RoNA to safely guide its arms underneath a prone patient. Interaction between the patient and RoNA must be convenient, painless, and above all, safe.
When RoNA’s arms are placed in contact with the back of the patient for lifting, rather than moving forward and potentially pushing or poking the patient, the high friction, high torque, wedge-shaped belt engages and slowly drives itself under the patient’s body. By coordinating the speed of the forward motion of the arm with the speed of the rotation of the conveyor belt, there is no relative motion and thus no uncomfortable rubbing friction against the patient’s skin.
In addition, the RoNA also has a lifting column which can provide a high power torque output for heavy patient lifting. Non- backdrivable lead-screws were installed to RoNA lifting column for safety reason while lifting a patient.
The entire RoNA system is carried by a holonomic mobile platform with two crab-drives and caster wheels that has full maneuverability and can move to any direction at any position. A holonomic mobile platform is suitable to work in the tight and constrained workspace like the patient’s room. A motorized leg pivoting mechanism has been implemented in the mobile base to ensure that the RoNA system will not tip over during the lifting.
Illustration of RoNA system; (Left) Approaching to the patient and (Right) Transferring the Patient.
RoNA system features
Human-Robot Interface (HRI) includes mainly three sub-components; 1) cap light indicating system status, 2) patient monitoring and touch screen to control a camera position, and 3) control panel.
The figures below show RoNA’s system design and actual system built, respectively. Due to RoNA’s maneuverability, it doesn’t require any infrastructure redesign which can be an expensive barrier to adopting currently available sling-style lifting devices. RoNA also reduces the need for specialized lifting teams, which are already in short supply. By reducing the reliance on lifting teams, patient’s wait time can be reduced, thus providing better service. RoNA directly assists the nurse with lifting and maneuvering patients and towing a gurney, and delivers patient assistive mobility, helping patients to and from bed and walking beyond the hospital room.
RoNA Beta system design
RoNA Beta system built