Pressure Injury Prevention in AE and PFC

This study evaluates the effect of a multilayer skin dressing (Mepilex) placed on the sacrum or a fluid filled pad (LiquiCell) on risk factors for pressure injuries under conditions consistent with military long-distance transport or prolonged field care. Participants will be assigned to one of six groups - air transport, air transport on a spinal immobilization surface with or without Mepilex or on a field stretcher with or without LiquiCell.

Combat casualties undergoing long distance aeromedical evacuation (AE), particularly casualties who are immobilized because of possible spine injuries, and casualties who required prolonged field care are at increased risk for pressure injuries. The risk factors pressure and shear are potentially modifiable via solutions appropriate for these austere conditions. Two interventions (Mepilex and LiquiCell) will be evaluated under conditions simulating military medical transport on a standard stretcher or with spinal immobilization in a vacuum spine board (VSB) or on a military stretcher used under field conditions. Mepilex is a multi-layer dressing that can be placed on the skin (sacrum/buttocks) and LiquiCell is a pad filled with pockets of fluid that is placed under the back and buttocks. The effect of these interventions compared to not using them will be studied under the three conditions with or without the intervention (Mepilex or LiquiCell) using measures obtained on the lower back/sacrum including skin interface pressure, oxygen, moisture, and temperature and a cytokine indicating possible tissue damage.

Stratified randomized control trial with subjects assigned to either the simulated aeromedical evacuation (standard mattress or vacuum spine board) or Prolonged Field Care arms with or without the intervention. Stratification will be based on body fat percentage. Study does not involve FDA-regulated drug.

Mepilex Border Sacrum dressing is a multi-layered soft silicone dressing that is a recommended strategy to augment standard nursing interventions (i.e., repositioning, offloading) to prevent pressure injuries. The dressing will be placed on the sacrum.

LiquiCell is a thin layer of low-viscosity fluid contained in a series of bursa-like pouches. Baffles within each pouch channel the liquid to disperse pressure and the volume of liquid in the pouch is so small that there is no pressure-build up. LiquiCell is available commercially as a 36 X 18-inch mattress overlay (LiquiCell Shear Reducing Mattress Overlay) with a soft pliable top and a non-slip bottom. The overlay is positioned from the shoulders to below the hips to minimize shear.

Skin cytokine (IL-1) and total protein will be obtained using a small strip of specialized tape placed on the sacrum/buttocks. After 1-minute application the tape is removed and analyzed for quantity of interleukin-1 (indicator of skin irritation)

Tissue oxygen is measured continuously on the sacrum using a noninvasive sensor and on the midsternum (midchest) as a control

Measured continuously during the baseline (sidelying), supine (120 minutes) and post-sidelying (15 minutes) periods

Two components of skin moisture will be measured on the sacrum using the Delfin MoistureMeter. The epidermal moisture, which reflects perspiration and subepidermal moisture , which reflects water content of the tissues. The values range from 1-80, with higher numbers reflecting increased moisture.

Measured continuously during the baseline (sidelying), supine (120 minutes) and post-sidelying (15 minutes) periods

The pressure between the support surface and the skin will be measured continuously during the supine position using the X Sensor system. This system measures force/unit area (e.g., pressure). The peak and average pressure on the sacrum/buttocks will be measured.

This scale asks the participant to describe in verbal terms the pressure intensity or discomfort associated with the stimulus (i.e., sacral/buttocks pressure or discomfort). The participant can then fine tune their assessment using a numeric score. The final score is an analog. The score ranges from 0-52, with higher scores indicating higher pressure or more severe discomfort. The investigator will ask the participant to limit their evaluation to the pressure/discomfort sensed on the sacrum/buttocks, but the investigator will also ask the participants to identify on their body where they are experiencing the most pressure/discomfort.

The score will be obtained at baseline and every 30 minutes in the supine position (total 5 measurements).

Inclusion Criteria: Men and women Age 18 to 55 Meet the physical standards for military personnel Weigh less than 250 pounds Be able to remain in the study position for the duration of the study. Exclusion Criteria Previous injuries to sacrum/buttocks with scarring History of pressure injuries Cardiovascular disease Neurological disease that would affect vascular response Diabetes History of malignancy Current skin condition (e.g., eczema or psoriasis) Current neck/back pain or history of chronic neck/back pain Known vertebral/spinal cord disease/injury (scoliosis, kyphosis, or lordosis) Self-reported pregnancy Concern about ability to remain in the vacuum spine board for 120 minutes

Bridges E, Whitney JD, Burr R, Tolentino E. Reducing the Risk for Pressure Injury During Combat Evacuation. Crit Care Nurse. 2018 Apr;38(2):38-45. doi: 10.4037/ccn2018223.