Use of high-frequency ultrasound to detect heel pressure injury in elders

To examine the usefulness of high-frequency ultrasound (HFU) to detect heel pressure injury in geriatric medical patients, to compare the prevalence rates of visualized pressure ulcers with the prevalence of hidden injury, and to determine whether HFU could assist in predicting the development of heel pressure injury.

The sample comprised 100 medical patients who were aged 65 years or older, had a Braden Scale score of 10 to 17, and remained hospitalized 28 days or less. Participants had at least 1 heel free of visible pressure injury. The study setting was a 528-bed urban hospital in the northeastern United States.

The study used a prospective, descriptive, observational design for data collection. At the initial visit, chart review and physical examination were used to obtain data about pressure ulcer risk factors, and heels were assessed visually and with HFU. Subsequent visits included visual and scan evaluations for pressure injury. Patients in the study were seen at least twice; 82 were assessed 3 times and 43 were assessed 4 times.

The prevalence rate of visible heel pressure ulcers was 7.3% for 520 patients who met inclusion criteria. Slightly more than one-tenth (10.1%) of subjects without heel ulcers had 2 normal heels scans upon entry into the study. Age, Braden Scale score, foot temperature, edema, and turgor were not statistically significant predictors of abnormal heel scans. However, there was a statistically significant relationship between low friction/shear scores and abnormal heel scans, particularly in relation to the right foot.

High-frequency ultrasound detected occult injury more than visual assessment, but scans are not easy to interpret in heels due to calluses and other skin changes. It appears that patients have a greater tendency for pressure injury on the right heel than on the left heel and risk may be predicted by low friction/shear scores.