Early Detection of Pressure Injury Using a Forensic Alternate Light Source

Heather Hettrick, PT, PhD, CWS, CLT-LANA, CLWT; Cheryl Hill, PT, PhD, DPT; Patrick Hardigan, PhD


Wounds. 2017;29(8):222-228. 

In This Article

Materials and Methods

Institutional Review Board approval was obtained at Nova Southeastern University (Fort Lauderdale, FL). A prospective, single-institution, repeated-measures design was employed to collect participant data. The study was conducted at a long-term care facility (MorseLife, West Palm Beach, FL). Potential participants were referred by the Director of Nursing to the Primary Investigator (PI). Study participation was limited to residents who were medically stable with at least 1 intact lower extremity, given that the body region under investigation involved the heels.

Study equipment included SPEX Forensics Mini-CrimeScope (Edison, NJ); single-lens reflex (SLR) camera; tripod; yellow, orange, and red camera lenses; yellow, orange, and red goggles; blackout goggles (for participants and research assistants); 2 black sheets; 2 foam rolls; white board with dry erase marker; and a photographic grid. The study protocol involved positioning the participants in bed, side-lying on their preferential side. Prior to data collection, the ALS equipment was plugged in to a wall socket and turned on to warm up for maximum luminosity. The camera, tripod, lenses, and goggles were arranged for easy access during data collection.

Various colored goggles were worn by the PI taking the photographs and Research Assistant 1 operating the light source to view the ALS findings. The violet spectrum was viewed using 415-nm and 445-nm wavelengths with a yellow camera lens and yellow goggles. The blue spectrum was viewed using 455-nm, 475-nm, 495-nm, and 515-nm wavelengths with an orange camera lens and orange goggles. The 455-nm and 475-nm wavelength were also viewed under the yellow lens and goggles, as these combinations effectively showed absorption. The green spectrum was viewed using 535-nm, 555-nm, and 575-nm wavelengths with a red camera lens and red goggles. The colored lenses were used on the SLR camera to photograph the findings viewed with the ALS equipment. The investigators' goggles and the SLR camera lenses were changed as described above for each of the 3 wavelengths. The participants' heels were first exposed to the violet, then blue, then green wavelengths through the ALS equipment. When illuminated with each wavelength, the PI took the photograph using the appropriate colored lens to capture photographic evidence of any absorption if present.

The camera aperture was set as low as possible to allow the proper light and ranged from F2.8 to F8. The exposure time was set at 1/100 seconds, and the camera distance from the photographed area was set at 24 in. Data were collected in the evening to allow for minimal natural light and for participant convenience.

A black sheet was placed under the participant's legs, and the lower extremities were supported with foam rolls to position and provide comfort during data collection. One roll was placed beneath the lower leg to elevate above the bed surface, and the other was placed between the medial malleoli to separate the feet and heels to maximize viewing area. The second black sheet was used to provide a backdrop and to maximize contrast for the photographs. A white board and photographic grid was placed next to the participant's feet containing the following information included in for each photograph: position indicated by L or R (left side-lying or right side-lying), participant number, date, and wavelength (nm).

The participant's heels were photographed first in ambient light. Next, a series of photographs were taken using the ALS equipment and SLR camera under the various wavelengths as described above. Window shades were drawn and room lights were turned off for the ALS data collection. A minimum of 12 photos were taken per participant per week. If absorption was noted, it was documented on the data collection sheet by the respective wavelength.

The roles and responsibilities of the research team were as follows: the PI took photographs and managed the camera; the co-PI recorded findings on data collection sheets; Research Assistant 1 handled the ALS equipment, which provided the light source for data collection; Research Assistants 2 and 3 draped the second black sheet to provide contrast and supported/guarded the participant during data collection. The PI and Research Assistant 1 verified whether absorption was present. It took about 30 minutes to complete data collection per visit per participant. In addition, the PI had full access to all study data and took responsibility for the integrity of the data and the accuracy of the data analysis.