title: Effects of bed height on the biomechanics of hospital bed entry and egress.
abstract: BACKGROUND
  Although a significant proportion of patient falls in hospitals occur in the vicinity of the hospital bed, little is known about the contribution of bed height to fall risk.
  
  
  OBJECTIVE
  To compare lower extremity joint torques and angles during hospital bed entry and egress at two bed heights.
  
  
  METHODS
  Twelve adults (age > 55) were purposively selected and had variety of strength and mobility limitations. Biomechanical data for this pilot study were collected with three digital video cameras and processed to obtain estimates for joint torques and included angles.
  
  
  RESULTS
  At the low bed height, hip torque for bed entry was significantly higher, and hip, knee, and ankle flexion angles were significantly smaller. The absence of significant differences in knee and ankle torques were the result of a compensation strategy that shifts the center of mass forward by flexing the torso during low bed ingress. Torque data from the egress motion were similar, however 50% of participants were unable to rise from the low bed without assistance.
  
  
  CONCLUSIONS
  Healthcare providers should be aware that low bed heights pose safety risks to the population for which they were designed-elderly persons at high risk for falling.
authors.affiliation: Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Merryweather
authors.affiliation: College of Nursing, University of Utah, Salt Lake City, UT, USA.
authors.forename: Janice M
authors.initials: JM
authors.lastname: Morse
authors.affiliation: College of Nursing, University of Utah, Salt Lake City, UT, USA.
authors.forename: Alexa K
authors.initials: AK
authors.lastname: Doig
authors.affiliation: Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Godfrey
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gervais
authors.affiliation: Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Bloswick
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000502:physiology; D001513:Beds; D001696:Biomechanical Phenomena; D005260:Female; D006621:Hip Joint / Q000502:physiology; D006761:Hospitals; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D019415:Torque; D060726:Torso / Q000502:physiology
keywords: Patient safety; accidental falls; caregiver; equipment safety; healthcare provider