BACKGROUND: In pressure ulcers (PUs), significant tissue damage often develops beneath the skin before any visual or tactile symptoms manifest. The breakthrough technology of the SEM Scanner identifies localized micro-edema that forms at tissue depths of several millimeters up to 4 cm. This empowers critical care nurses to implement proactive preventive measures. PURPOSE: To compare the effectiveness of the SEM scanner and Modified Cubbin and Jackson (MCJ) Scale risk assessment tool in predicting PU among immobile patients in Intensive Care Unit (ICU). METHODS: A descriptive comparative, longitudinal study was carried out in ICU of Government Hospitals in Bahrain. Two independent raters blindly evaluated risk of PU against MCJ Scale, and a trained critical care nurse used SEM scanner. RESULTS: SEM scanner demonstrated a true positive rate of 51.6 % in predicting PU development (Δ ≥ 0.6), significantly higher than the 29.7 % prediction rate of MCJ Scale (p <
0.001(. Furthermore, 28.1 % of patients developed PUs that were not predicted by MCJ (false negatives), compared to only 6.2 % with SEM scanner. The sensitivity of SEM scanner was 89.2 %, compared to 48.6 % of MCJ. The area under the curve was 0.880 for the SEM scanner versus 0.739 for MCJ. SEM scanner identified PU risk earlier than MCJ in 188 readings (35.1 %), with an average of 3.07 ± 2.93 days. CONCLUSIONS: The SEM scanner was effective in detecting PUs three days earlier than MCJ. The SEM canner also reported more true positives of PU and more sensitivity than MCJ scale. IMPLICATIONS FOR CLINICAL PRACTICE: Investing in advanced technology by integrating a reliable, evidence-based tool such as the SEM scanner into routine ICU care protocols, along with staff training, is crucial to guide clinical decision-making, reduce the variability in skin assessment, which ultimately reduces the incidence and severity of Hospital-Acquired PUs, and enhance patient outcomes.