Nursing homes patients handling has been rated as the top most dangerous job in the USA, based on lost work time to back injuries. Many studies supported the “zero lifting” approach focusing on disk compression forces. Therefore the floor-based (FB) devices have largely been introduced into clinical practice and soon the operators reported share forces related complains. Recently 70-100 Kg disk share forces limits were proposed, while 350 Kg disk compressing forces limit still remains. Ceiling-based (CB) patient transfer devices seem the proper solution but only a few studies investigated share forces estimate.
Methods
A laboratory and on-the-field study was conducted on the comparison between FB and CB patient transfer devices. Pushing and pulling forces were measured by means of a computer assisted dynamometer linked to the devices. Electromiographic (EMG) signals were collected by means of 8 wireless electrodes (Aurion) instrumented on upper arms, trunk and abdominal muscles. Maximum voluntary contraction (MCV) was assessed for comparison purposes. Standardized patient transfers were setup as following: from bed to a wheelchair close to the room door and back to bed with 180° sharp turn. The patients weight was 70 kg. Demographics, anthropometric, pain history and device specific satisfaction questionnaires were self-administered. Data were analysed using SPSS.
Results
FB devices showed pushing and pulling forces from 2 to 3 times higher than CB ones. Results are consistent for both sexes, initial and sustained forces, handle height, actions/minutes and different operations. CB paths are smoother without continuous accelerations and decelerations due to floor friction. EMG data related to upper arms and trunk muscles showed stable lower loads for CB. Particularly upper arms remains below 30% MCV.
Discussion
The study supports the evidence that CB patient transfer devices reduce share and compressive forces on the back, showing they are the best tools for decreasing patient handling biomechanical overload.