Prevention of Pressure Injuries During Aeromedical Evacuation: A Randomized Control Trial


Name: Elizabeth Bridges

Rank: Col (ret)

Organization: University of Washington

Performance Site: University of Washington

Year Published: 2018

Abstract Status:


Between 2001 and 2014, 137,433 patients were moved on 210,863 flights in the USAF Aeromedical Evacuation (AE) system. On average, 19% of these patients were immobile on a litter, placing them at high risk for a skin pressure injury. A very high-risk group of patients are casualties who require spinal immobilization using the vacuum spine board. A military unique aspect of nursing care for these critically ill/injured patients is pressure injury prevention during the 8 to 16- hour transports from the battlefield to Germany and the US. Pressure injuries are localized damage to the skin and underlying soft tissue due to intense or prolonged pressure or shear on bony prominences (e.g., heels, sacrum/buttocks), along with changes in skin temperature, moisture, and perfusion. During AE, patients are transported on a 23 x 72-inch mesh litter, with or without a 30° removable backrest. A 2.5-inch mattress is placed on the litter, if possible. The only en route care recommendations for pressure injury prevention are to use the AE mattress and to reposition the patient and elevate their heels, and to log roll patients in the VSB. However, these interventions are only partially effective in preventing pressure injuries. Between 2009-2012, 141 (4.9%) of critically injured patients transported from the combat zone developed a pressure injury, and in casualties transported on the VSB, the incidence was 10%. In addition to directly impacting their treatment and recovery, extrapolating from civilian literature, a conservative cost estimate for these 141 pressure injuries is $1.1 million dollars. In high risk, intensive care, civilian populations recent studies document a decrease in pressure injuries related to the use of a sacral dressing (Mepilex, Mölnlycke Healthcare). The use of the Mepilex dressing offers an intervention that is potentially relevant and feasible for use during AE. Existing studies have not addressed the effects of this dressing on factors associated with tissue injury, or how the dressing performs under AE conditions. This military unique proposal seeks to identify a feasible strategy to augment pressure injury prevention during AE.We propose a randomized control trial to assess the effects of Mepilex sacral dressing with 48 subjects on two different transport surfaces (litter plus AE mattress and VSB). Subjects will undergo positioning consistent with current AE care recommendations. A unique aspect of this proposal is that we use measures of not only skin interface pressure, but of skin perfusion, skin microclimate (skin moisture and temperature) and cellular injury.Specific Aims: Under conditions simulating aeromedical transport:Aim 1. Compare the effects of the presence/absence of Mepilex sacral dressing on skin cellular injury (skin interleukin-1α), skin perfusion (transcutaneous tissue oxygen saturation -TcPO2), and skin microclimate (moisture and temperature) on two transport surfaces (Litter + AE mattress + 30° backrest and Vacuum Spine Board).Aim 2. Compare the effects between two transport surfaces (Litter + AE mattress + 30° backrest and Vacuum Spine Board), and the interactions of the platform with presence/absence of Mepilex, on skin cellular injury, skin perfusion, and skin microclimateThe application of Mepilex may be a solution that is low cost and logistically feasible and addresses the challenge that any intervention not interfere with vertebral stabilization provided by the VSB. Before we can consider its use as standard of care for our wounded warriors, it is essential to evaluate it under AE specific conditions. The design of this study addresses research gaps identified in a recent scoping study conducted for the DoD Committee on En Route Care: 1) Extend evaluations of mitigating strategies to 2 hours (maximum time for supine position) under AE conditions and 2) include microclimate (skin temperature/moisture) in evaluation of any device (e.g., VSB) to identify strategies to mitigate pressure injuries. This study, will also address a third gap, and inform the development of en route care specific care recommendations for pressure injury prevention, which will result in the dissemination of an evidence-based solution to meet our challenge of the highest quality of care for our most critically ill/injured patients.