NATO Litter: Fluid Immersion System (FIS) Versus Traditional Mattress for Pressure Dispersion

The purpose of this study is to measure peak skin interface pressures and the total area of
the body exposed to skin interface pressure above 30 mm Hg at different areas of the body in
the supine position on two different support surfaces applied to a standard North Atlantic
Treaty Organization (NATO) litter (NSN: 6530-01-380-7309) and a Raven 90C Litter
(NSN6530-01-432-5114). The Raven 90C is the official litter for the U.S. Navy. It is approved
for flight on USAF aircraft. It can be easily folded for storage and transport to remote
settings. The support surfaces are the Warrior Evacuation Litter Pad (WELP) and the Dolphin
Fluid Immersion Simulation Stretcher System (FIS). In theory, mattresses that reduce and/or
minimize pressure on the capillary bed's perfusion can help reduce pressure related injury
such as pressure or decubitus ulcer development. Skin interface pressure measurements using a
pressure mapping system along with laser doppler flow and transcutaneous oxygenation readings
will allow us to determine these differences between support surfaces. A better understanding
of skin interface pressure associated with the litter support surfaces is vital for military
nurses to develop and implement preventative interventions to reduce pressure ulcer
development in our patients. In addition, this study will provide information to help
determine the usefulness and feasibility of incorporating the fluid immersion system (FIS) as
a litter support surface.

This research protocol has one major aim:

To determine the difference in the pressure redistribution qualities between the WELP and the
Dolphin FIS

There are also two secondary aims:

1. To determine the difference in the pressure redistribution qualities of the WELP when
used as the mattress on the NATO litter and Raven litter.

2. To determine the difference in the pressure redistribution qualities of the Dolphin FIS
when used as the mattress on the NATO litter and Raven litter.

Inclusion Criteria:

- Adults over the age of 18 years with lawful access to Travis AFB

Exclusion Criteria:

- Orthopedic or neurological conditions that prevent a subject from lying flat (supine)
without any pillows for head, neck, or lumbar support

- Medical conditions (such as an uncontrollable tremor or twitch) that prevent a subject
from staying still for the required periods of time (20 minute increments).

- Pregnancy

- Inability to ambulate unassisted, unstable gate (presenting increased fall risk)

- Extremity prosthetics (hand/arm or foot/leg)

- Height greater than 72 inches (6 feet) - exceeds length of the litter & mattress
surfaces

- Body weight greater than 300 lbs

- Subjects who find it difficult, uncomfortable or impossible to remain still for the
necessary study time durations (20 minute increments) on the relatively narrow litter
surfaces will be removed from the study.

- Subject does not speak or understand the English language