Quantification of the Pressure Threshold Related to Tissue Injury in Bedriden Paraplegics

The aim of this study is to correlate the intensity and the duration of a mechanical strain, applied over the skin of a bedridden paraplegics, with the microvascularization parameters (oxygen saturation, blood flow and blood volume) and the early inflammatory mechanism. We want to detect the early stage of irreversible damage for each patient. To achieve this goal, we measure some specifics data over a group of 48 paraplegics admitted in the hospital for a pressure ulcer surgical treatment. The patients are randomly distributed in 4 groups. First the interface pressure between the patient body and the air mattress is recorded continuously for 3 hours (= the repositioning patient frequency): we have the pressure over each point of the patient body in contact with the mattress on this time lap. Then, we will measure the microvascularization parameters, using an O2C medical device over a trochanter on a specific anatomical area which will be thereafter biopsied. Finally, depending on the group in which they were randomly distributed, the patient will undergo a muscle biopsy on his or her trochanter at 0h, 1h, 2h or 3h after they lie down on the air mattress. This way, we will be able to determine the effect of the mechanical strain duration on the physiologic parameters. The following day, the patient is undergoing his or her surgery for removing the necrotic area of the bedsore. At the same time, we will recover some of the sample near the bedsore which would serve as a maximum inflammatory response. Then a second muscle biopsy will be performed on an innervated area to be able to determine a basal concentration of biomarkers.

The inclusion period for this study will be 3 years. All the patients are followed for 24 hours then they will be followed by medical staff in their bedsore resection setting.

The data gained for this study will hopefully help the scientific world to achieve a better understanding of the pressure ulcer aetiology. They will also be helpful to achieve a mobilization of the patient specific of his or her inherent characteristics with a high sensitivity level. This way we will have a more efficient bedsore prevention.