RATIONALE: Pressure ulcers are a major economic and clinical problem in hospitals and intensive care units. Current methods to detect and grade pressure ulcers use subjective measures, and, presently, there are few ways to detect...
moreRATIONALE: Pressure ulcers are a major economic and clinical problem in hospitals and intensive care units. Current methods to detect and grade pressure ulcers use subjective measures, and, presently, there are few ways to detect developing pressure ulcers which are not clinically evident. Here we aimed to employ a model to identify if volatile organic compounds (VOCs) released from skin could Leporidae be used to biochemically separate intact skin from skin with experimentally-induced ulcers. METHODS: Four New Zealand female white rabbits underwent experimental ulcer formation on their right ear while their left ear was used as a control. Ulcers were created using 7/16 x 1/16-inch neodymium magnets (KJ Magnetic Inc, Pipersvile, PA) for 60 minutes. The goal was to achieve an erythematous ring without causing skin breakage or necrosis (i.e., an early-stage ulcer). Following ulcer formation, 5-mm diameter circular polydimethylsiloxane sorbent patches (PDMS; 0.6-mm thick, Goodfellow, Coraopolis, PA) were placed in close proximity to the ulcer on the experimental ears and in a similar location on the control ears. These were covered with polytetrafluoroethylene patches and affixed with Tegaderm® dressings. Skin VOCs were sampled with the PDMS for 30 minutes, and patches were removed, placed into sterile, nitrogen-purged borosolicate vials, capped, and routed for gas chromatography-mass spectrometry (GC/MS) analysis. For analysis, the sampled chemicals were desorbed off the patch at 200C, and 500 µL of headspace was aspirated from the vials and injected into a GC/MS instrument. Two rabbits underwent necropsy for ear histology. Data from each group was compared using Student's test for each VOC. t RESULTS: A significant number of emitted VOCs that were clearly different for the background were detected for each category of samples (ulcer vs non-ulcer). We identified two compounds which were unique to the ulcer group, one of which we tentatively identified as benzyl alcohol. A number of compounds were found to differ in abundance between ulcer and non-ulcer samples. Histologic analysis of two rabbits showed 1-1.5 cm erythematous lesions with acute heterophilic dermatitis, edema, and micro-hemorrhage on the ulcerated ears with normal findings on the control ears. CONCLUSIONS: In this small animal model study, we showed that VOCs are released from rabbit skin, VOCs change as a result of induced experimental ulcers, and VOCs likely correlate with histologic evidence of early-stage ulcers. VOCs may be useful for future, non-invasive monitoring of pressure ulcers in humans.
