Graduation Year


Document Type




Degree Granting Department

Biomedical Engineering

Major Professor

William Lee, Ph.D.

Co-Major Professor

John Lloyd, Ph.D.

Committee Member

Andrea Baptiste, MA

Committee Member

Gail Powell-Cope, Ph.D.


height, floor mats, bedrails, elderly, acceleration


The incidence of falls in the elderly population is a growing concern in the healthcare industry as associated morbidity is high, particularly morbidity associated with falls from bed. Bedrails were implemented as a device intended to reduce the incidence of falls from bed; however, recent evidence may indicate that bedrails contribute to adverse events including entrapment and entanglement. As such, efforts have been made to reduce the use of bedrails and implement alternatives including height adjustable beds and floor mats. An instrumented anthropomorphic test dummy was used in the current study to measure the deceleration profiles of the head, thorax, and pelvis upon impact onto a tile surface or floor mat. The height of the fall was varied by using a height adjustable bed, and the impact site was varied by head or feet first falls. The deceleration profiles were used to determine mean maximum values across repeated trials and to calculate injury criteria at the head (HIC), thorax (TIC), and pelvis (PIC). The mean maximum values were further used to estimate the effect of adding bedrails. Injury severity was then predicted from the injury criteria calculated for the head.

From this study, the mean maximum values were found to significantly increase with an increase in height regardless of fall direction. As such, the addition of bedrails consequently increased these values. Furthermore, the use of a floor mat significantly reduced the mean maximum values at the head and pelvis during head first falls and at the head and thorax during feet first falls. Injury criteria were also calculated for each body region and found to be significantly increased with an increase in height and decreased with the use of the floor mat. The HIC values were used to predict injury severity and resulted in nearly a 40 percent chance of sustaining a serious brain injury under any condition tested during this study. Based on these results, the recommendation was made to position hospital beds to the lowest available position, place floor mats by the bedside, and remove bedrails to decrease the risk of injury as a result of falling from bed.