High frequency ultrasound sacral images in the critically ill: Tissue characteristics versus visual evaluation.
Mary Jo Grap, Christine M Schubert, Ruth S Burk and 4 others
PMID 28274684WHAT IT FOUND
Ultrasound tissue measurements did not match visual evaluation of the ultrasound image in 113 critically ill adults over up to seven days.
The one-day worsening density difference did not hold after adjustment, so the scan did not show added early change detection.
Key findings
01For one-day sacral ultrasound comparisons, dermal thickness did not differ by injury type, and the higher dermal median intensity seen with worsening injury was not significant after adjustment.
02For two-day comparisons and for three-day, four-day, five-day and six-day comparisons, neither dermal thickness nor dermal median intensity differed significantly by injury type.
03BMI, APACHE score, age, race and gender did not significantly affect dermal thickness or dermal median intensity in any day comparison model.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
This was a secondary analysis, not the original parent study. Many data points were missing because patients were unavailable, off the unit, in critical condition or had poor images: 136 subjects had 786 of 1088 possible study subject days available, and only 113 subjects contributed one-day comparisons. Images were obtained side-lying at 60 to 90 degrees rather than the manufacturer's recommended prone position. Most comparisons showed normal images or no change, so the study had little opportunity to detect day-to-day tissue change. Observed changes were within the variability seen in normal volunteers, including dermal thickness changes less than 0.526 and dermal density changes less than 8.22. The units had recently implemented a sacral adhesive pad protocol, which may have reduced shear and pressure ulcer risk. Common standard high-frequency ultrasound measures of tissue injury are not available, and the study used only dermal thickness and median intensity.
Declared interests
No conflicts of interest were reported.
The easy way to misread this
Do not read this as evidence that high-frequency ultrasound detects pressure ulcers early. The main day-to-day comparisons were null, and the one-day dermal median intensity p value of 0.0669 did not remain significant after adjustment.