Application of high-frequency ultrasound in the early detection of pressure injury and evaluation of decompression treatment.

Abstract

Background: Pressure injury (PI) is an ischemic necrosis caused by long-term pressure on the local skin, which is common in the sacrococcygeal region of long-term bedridden patients. The main treatment for PI is decompression. The Braden scale is the primary clinical evaluation tool for PI, but it cannot quantitatively evaluate PI. High-frequency ultrasound (HFUS) can be used for the real-time quantitative evaluation of PI. This study used HFUS to qualitatively and quantitatively assess the soft tissues of the sacrococcygeal region in different risk PI groups to investigate any differences in HFUS manifestations and evaluate the efficacy of decompression treatment in stage 1 PI patients.

Methods: A total of 70 patients were recruited from the Intensive Care Unit at West China Hospital, Sichuan University, of whom, 28 were allocated to the case group (a moderate or higher risk for PI, and a Braden score of 15-17) and 42 were allocated to the control group (a very mild risk for PI, and a Braden score ≥18). HFUS was used to measure tissue thickness and ultrasonographic characteristics, as well as blood flow signals at 10 target sites along the transverse plane from the sacral protrusion to the top. Differences between groups were compared, and diagnostic efficacy was evaluated by a receiver operating characteristic (ROC) curve analysis, and the area under the curve (AUC) was calculated. A subgroup of 12 extremely high-risk patients receiving decompression treatment was also examined. The HFUS parameters were compared before and after treatment to evaluate efficacy.

Results: In the case group, ultrasonographic uneven echo, unclear boundaries between adipose/muscular layers and dermis/adipose layers, and discontinuous deep/superficial fascia were more common closer to sacral protrusions (P<0.05). The case group had thinner median and paraspinal fat layers at all 10 sites than the control group (P<0.05). Certain sites (3, 5-7, and 9-10) in the case group had thicker epidermis (P<0.05), while the muscle layer was thinner at sites 5-10 of the case group (P<0.01). The ROC curve analysis indicated that the median and paraspinal fat layers could be used to effectively classify medium-high-risk patients with optimal performance at sites 3-5. The blood flow signal characteristics and composition ratios differed significantly between the case and control groups at each analyzed site (P<0.05). No significant changes in the Braden scores were found following decompression therapy, but the thickness of the paraspinal fat layer at sites 3 and 4 and the thickness of the median spinal fat layer at site 4 increased significantly (P<0.05). Further, the paraspinal fat layer thickness differed significantly between the initial and sixth ultrasound assessments (P<0.05). Most participants experienced reduced blood flow at the targeted site after decompression treatment.

Conclusions: HFUS enables the quantitative and qualitative assessment of soft tissues in the sacrococcygeal region and could be a valuable tool for predicting PI risks and evaluating treatment effectiveness.