Reducing Pressure, Shear and Discomfort on a Lateral Transfer Chair: A Comparison of Three Innovative Seating Surface Designs

Introduction: The ability to mobilize patients out of bed is influenced by overall debility, patient size, weight-bearing limitations, and diminished core muscle strength. One mechanism to assist with these complex transfers is the use of a lateral transfer chair to move the patient from bed and into a seated position.  The limited mobility of this patient population puts them at higher risk for pressure ulcer development.

Purpose: The purpose of this study was to compare the pressure and shear reducing properties of the standard Lateral Transfer Chair (LTC) pad with three innovative pad designs, in three positions.  A secondary aim of the study was to examine the degree of discomfort on each surface and in each position.

Methodology: This study used an experimental, repeated measures design.  Forty healthy adult volunteers were enrolled and instructed not to reposition themselves when randomly seated in the LTC surfaces.  A pressure mapping system was used to non-invasively measure tissue interface pressure (TIP) at the sacrum and ischial tuberosities.   The amount of forward motion of the external hip trochanters with head of chair elevation to 60 and 90 degrees was measured and used as an indirect measure of shear force.  Pressure readings and subjective discomfort scores were recorded after 5 minutes in each position.

Statistics: Differences in pressure, shear, and discomfort noted on the four surfaces and at three different positions were tested using Analysis of Variance.

Results: Mean TIP and the amount of forward motion were significantly less (p<.001) on the 3 innovative seating surfaces than on the standard LTC pad.  The degree of discomfort was rated significantly greater on the standard pad at zero (p<.001) and 60 degrees (p0.004) but not at 90 degrees (p0.102).

Conclusion: A new surface that reduces pressure and shear is needed for the LTC.