title: Quantification of patient migration in bed: catalyst to improve hospital bed design to reduce shear and friction forces and nurses' injuries.
abstract: OBJECTIVE
  The study objective was to quantify the movement of hospital bed occupants relative to the bed in typical bed articulations.
  
  
  BACKGROUND
  Movement of a patient in bed results in two common adverse events: (a) increase in shear and friction forces between the patient and bed, which are extrinsic pressure ulcer risk factors, and (b) musculoskeletal injuries to nurses, resulting from repositioning patients who have migrated down in bed.
  
  
  METHODS
  The study involved 12 participants who lay supine in three hospital beds, which were articulated to common positions. Body movement relative to the bed was quantified with the use of motion capture. Cumulative movement, net displacement, and torso compression (shoulder to trochanter distance) were calculated for different bed types and bed movements.
  
  
  RESULTS
  Bed design and bed movement had a significant effect on most of the dependent variables. Bed design (e.g., type) influenced cumulative movement by up to 115%, net displacement by up to 70%, and torso compression by about 20%. Bed movement (e.g., knee elevation) reduced cumulative migration by up to 35%.
  
  
  CONCLUSIONS
  The quantification of patient migration provides a metric for evaluating the interaction between body and bed surfaces. Overall, the measures were sensitive to design changes in bed frames, bed articulations, and mattress inflation.
  
  
  CONCLUSIONS
  Documentation of the cumulative movement, net displacement, and torso compression provides hospital bed designers quantifiable measures for reducing migration and potentially shear and friction forces when designing bed frames, bed articulations, and mattresses. Optimization of these metrics may ultimately have an impact on patient and caregiver health.
authors.affiliation: University of Cincinnati, College of Allied Health Sciences, Department of Rehabilitation Sciences, 3202 Eden Avenue, Cincinnati, OH 45267-0394, USA. susan.kotowski@uc.edu
authors.forename: Susan E
authors.initials: SE
authors.lastname: Kotowski
authors.forename: Kermit G
authors.initials: KG
authors.lastname: Davis
authors.forename: Neal
authors.initials: N
authors.lastname: Wiggermann
authors.forename: Rachel
authors.initials: R
authors.lastname: Williamson
mesh_terms: D000328:Adult; D001513:Beds / Q000009:adverse effects* / Q000592:standards; D004867:Equipment Design / Q000592:standards; D005260:Female; D017276:Friction / Q000502:physiology; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D055805:Moving and Lifting Patients / Q000009:adverse effects / Q000451:nursing*; D009140:Musculoskeletal Diseases / Q000209:etiology* / Q000517:prevention & control; D060051:Occupational Injuries / Q000209:etiology / Q000517:prevention & control; D003668:Pressure Ulcer / Q000209:etiology* / Q000517:prevention & control; D012867:Skin / Q000293:injuries*