One of the growing problems facing the nursing career is a thinning staff, and with it the need to care for overweight patients with very little help. This effort has led to musculoskeletal disorders (MSDs) including back injuries, the most costly MSD injury. Until recently, moving a patient was performed manually or with minimal automation. Allowing a single nurse to safely and comfortably transfer a patient without risk of injury required a fully automated device. Astir Technologies (Concord, MA) took this on as a goal to use the latest technologies available to provide patient transfer in a manner that decreases hospital costs and reduces injuries to healthcare professionals, while minimizing the discomfort to the patient. With this in mind, the company designed and manufactured the PowerNurse for that purpose. All of the mechanisms are packaged in a low-profile (74×28×3-inch) assembly that rides over a standard hospital stretcher. With the PowerNurse, patients can be moved between hospital beds, stretchers, imaging equipment, operating room tables, and exam tables. Originally, the PowerNurse traveled at only one speed (1 inch per second). Although this speed was fine for patient pick-up and delivery, it was too slow for the lateral transfer process. So, Chris incorporated a two-speed option into his beta model, where the device operated at 1 or 2 inches per second. Paring the Maxon DEC 50/5 motor control with either the EC45 or ECmax 40 motor smoothed the design as well as the overall operation of the device. The PowerNurse incorporates four ECmax 40 motors; four GP 42C, three-stage 43:1 gearboxes; and four DEC50/5 servo-amplifiers along with a 400W, 48 VDC power supply. An all push-button driven device requiring no software interface, the PowerNurse operates in three distinct modes: burrow, pad align, and transfer. During the burrow mode, belts are used to pull the patient onto the top of the device while belts on the bottom move the device under the patient. Done simultaneously, the result is the patient feels a much smoother transfer than with any other device.
In pad-align mode, only the top conveyor belts are energized. This aligns the patient and incontinence pad if necessary. Transfer mode energizes only the bottom belts, which transfers the PowerNurse, with the patient riding on top of the device, to an adjacent surface. Rotation and translation are available in any mode and the result is a tank-like translation or rotation. Four Maxon motors are required to achieve all of the device’s operational modes. Astir Technologies is now investigating the addition of a yaw gyro for the system to enhance the machine-human interface and bring the motor controls to a new level of performance. This is expected to make the PowerNurse even easier to use.