Backrest elevation and tissue interface pressure by anatomical location during mechanical ventilation

Mary Jo Grap, Cindy L. Munro, Paul A. Wetzel, Christine M. Schubert, Anathea Pepperl, Ruth S. Burk, Valentina Lucas

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Background Backrest elevations less than 30° are recommended to reduce pressure ulcers, but positions greater than 30° are recommended during mechanical ventilation to reduce risk for ventilator-associated pneumonia. Interface pressure may vary with level of backrest elevation and anatomical location (eg, sacrum, heels). Objective To describe backrest elevation and anatomical location and intensity of skin pressure across the body in patients receiving mechanical ventilation. Methods In a longitudinal study, patients from 3 adult intensive care units in a single institution receiving mechanical ventilation were enrolled within 24 hours of intubation from February 2010 through May 2012. Backrest elevation (by inclinometer) and pressure (by a pressure-mapping system) were measured continuously for 72 hours. Mean tissue interface pressure was determined for 7 anatomical areas: left and right scapula, left and right trochanter, sacrum, and left and right heel. Results Data on 133 patients were analyzed. For each 1° increase in backrest elevation, mean interface pressure decreased 0.09 to 0.42 mm Hg. For each unit increase in body mass index, mean trochanter pressure increased 0.22 to 0.24 mm Hg. Knee angle (lower extremity bent at the knee) and mobility were time-varying covariates in models of the relationship between backrest elevation and tissue interface pressure. Conclusions Individual factors such as patient movement and body mass index may be important elements related to risk for pressure ulcers and ventilator-associated pneumonia, and a more nuanced approach in which positioning decisions are tailored to optimize outcomes for individual patients appears warranted. (American Journal of Critical Care. 2016;25:e56-e63).

Original languageEnglish (US)
Pages (from-to)e56-e63
JournalAmerican Journal of Critical Care
Issue number3
StatePublished - May 1 2016
Externally publishedYes

ASJC Scopus subject areas

  • Critical Care


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