Application of infrared thermography in the early warning of pressure injury: A prospective observational study

Biomarkers of local inflammation at the skin's surface may predict both pressure and diabetic foot ulcers

This commentary considers the similarities which exist between pressure ulcers (PUs) and diabetic foot ulcers (DFUs). It aims to describe what is known to be shared-both in theory and practice-by these wound types. It goes on to detail the literature surrounding the role of inflammation in both wound types. PUs occur following prolonged exposure to pressure or pressure in conjunction with shear, either due to impaired mobility or medical devices. As a result, inflammation occurs, causing cell damage. While DFUs are not associated with immobility, they are associated with altered mobility occurring as a result of complications of diabetes. The incidence and prevalence of both types of lesions are increased in the presence of multimorbidity. The prediction of either type of ulceration is challenging. Current risk assessment practices are reported to be ineffective at predicting when ulceration will occur. While systemic inflammation is easily measured, the presence of local or subclinical inflammation is harder to discern. In patients at risk of either DFUs or PUs, clinical signs and symptoms of inflammation may be masked, and systemic biomarkers of inflammation may not be elevated sufficiently to predict imminent damage until ulceration appears. The current literature suggests that the use of local biomarkers of inflammation at the skin's surface, namely oedema and temperature, may identify early tissue damage.

Exploring Thermal Dynamics in Wound Healing: The Impact of Temperature and Microenvironment

Exploring the critical role of thermal dynamics in wound healing, this manuscript navigates through the complex biological responses initiated upon wound infliction and how temperature variations influence the healing trajectory. Integrating biothermal physics, clinical medicine, and biomedical engineering, it highlights the significance of thermal management in wound care, emphasizing the wound microenvironment's division into internal and external domains and their collaborative impact on tissue repair. Innovations in real-time wound temperature monitoring, especially through intelligent wireless sensor dressings, are spotlighted as transformative, enabling precise wound condition management. The text underscores the necessity for further research to elucidate thermal regulation's molecular and cellular mechanisms on healing processes. It advocates for standardized protocols for localized heating treatments, integrating them into personalized wound care strategies to enhance therapeutic outcomes, improve patient well-being, and achieve cost-effective healthcare practices. This work presents a forward-looking perspective on refining wound management through sophisticated, evidence-based interventions, emphasizing the interplay between thermal dynamics and wound healing.

A novel deep-learning based weighted feature fusion architecture for precise classification of pressure injury

Introduction: Precise classification has an important role in treatment of pressure injury (PI), while current machine-learning or deeplearning based methods of PI classification remain low accuracy. Methods: In this study, we developed a deeplearning based weighted feature fusion architecture for fine-grained classification, which combines a top-down and bottom-up pathway to fuse high-level semantic information and low-level detail representation. We validated it in our established database that consist of 1,519 images from multi-center clinical cohorts. ResNeXt was set as the backbone network. Results: We increased the accuracy of stage 3 PI from 60.3% to 76.2% by adding weighted feature pyramid network (wFPN). The accuracy for stage 1, 2, 4 PI were 0.870, 0.788, and 0.845 respectively. We found the overall accuracy, precision, recall, and F1-score of our network were 0.815, 0.808, 0.816, and 0.811 respectively. The area under the receiver operating characteristic curve was 0.940. Conclusions: Compared with current reported study, our network significantly increased the overall accuracy from 75% to 81.5% and showed great performance in predicting each stage. Upon further validation, our study will pave the path to the clinical application of our network in PI management.

Use of Infrared Thermography in Medical Diagnosis, Screening, and Disease Monitoring: A Scoping Review

Thermography provides non-invasive, radiation-free diagnostic imaging. Despite the extensive literature on medical thermography, a comprehensive overview of current applications is lacking. Hence, the aim of this scoping review is to identify the medical applications of passive infrared thermography and to catalogue the technical and environmental modalities. The diagnostic performance of thermography and the existence of specific reference data are evaluated, and research gaps and future tasks identified. The entire review process followed the Joanna Briggs Institute (JBI) approach and the results are reported according to PRISMA-ScR guidelines. The scoping review protocol is registered at the Open Science Framework (OSF). PubMed, CENTRAL, Embase, Web of Science, OpenGrey, OSF, and PROSPERO were searched using pretested search strategies based on the Population, Concept, Context (PCC) approach. According to the eligibility criteria, references were screened by two researchers independently. Seventy-two research articles were identified describing screening, diagnostic, or monitoring studies investigating the potential of thermography in a total of 17,314 participants within 38 different health conditions across 13 therapeutic areas. The use of several camera models from various manufacturers is described. These and other facts and figures are compiled and presented in a detailed, descriptive tabular and visual format. Thermography offers promising diagnostic capabilities, alone or in addition to conventional methods.

The correlation between transcutaneous oxygen pressure (TcPO2 ) and forward-looking infrared (FLIR) thermography in the evaluation of lower extremity perfusion according to angiosome

The increased peripheral arterial disease (PAD) incidence associated with aging and increased incidence of cardiovascular conditions underscores the significance of assessing lower limb perfusion. This study aims to report on the correlation and utility of two novel non-invasive instruments: transcutaneous oxygen pressure (TcPO2 ) and forward-looking infrared (FLIR) thermography. A total of 68 patients diagnosed with diabetic foot ulcer and PAD who underwent vascular studies at a single institution between March 2022 and March 2023 were included. Cases with revascularization indications were treated by a cardiologist. Following the procedure, ambient TcPO2 and FLIR thermography were recorded on postoperative days 1, 7, 14, 21 and 28. In impaired limbs, TcPO2 was 12.3 ± 2 mmHg and FLIR thermography was 28.7 ± 0.9°C. TcPO2 (p = 0.002), FLIR thermography (p = 0.015) and ankle-brachial index (p = 0.047) values significantly reduced with greater vascular obstruction severity. Revascularization (n = 39) significantly improved TcPO2 (12.5 ± 1.7 to 19.1 ± 2.2 mmHg, p = 0.011) and FLIR (28.8 ± 1.8 to 32.6 ± 1.6°C; p = 0.018), especially in severe impaired angiosomes. TcPO2 significantly increased immediately post-procedure, then gradually, whereas the FLIR thermography values plateaued from day 1 to 28 post-procedure. In conclusion, FLIR thermography is a viable non-invasive tool for evaluating lower limb perfusion based on angiosomes, comparable with TcPO2 .

Advance in topical biomaterials and mechanisms for the intervention of pressure injury

Pressure injuries (PIs) are localized tissue damage resulting from prolonged compression or shear forces on the skin or underlying tissue, or both. Different stages of PIs share common features include intense oxidative stress, abnormal inflammatory response, cell death, and subdued tissue remodeling. Despite various clinical interventions, stage 1 or stage 2 PIs are hard to monitor for the changes of skin or identify from other disease, whereas stage 3 or stage 4 PIs are challenging to heal, painful, expensive to manage, and have a negative impact on quality of life. Here, we review the underlying pathogenesis and the current advances of biochemicals in PIs. We first discuss the crucial events involved in the pathogenesis of PIs and key biochemical pathways lead to wound delay. Then, we examine the recent progress of biomaterials-assisted wound prevention and healing and their prospects.

Nutritional status as a predictor of the incidence of pressure injury in adults: A systematic review and meta-analysis

AIM

Pressure injuries are a significant health care problem worldwide, and many factors influence their occurrence and development. The purpose of this systematic review and meta-analysis was to investigate the role of nutritional status in the development rate of pressure injuries as a potentially modifiable risk factor.

METHODS

Study designs included cohort (prospective and retrospective), case-control, and RCTs if the association between nutrition status and pressure injuries was reported. Databases searched included: PubMed, CINAHL, Embase, Scopus, Web of Science, and Cochrane Library on April 20th, 2022. The data were analyzed using OR and random effect model in Revman5.3 and STATA 15 Software. Report this systematic review and meta-analysis according to the PRISMA 2020 statement.

RESULTS

A total of 22 separate studies were retained in this systematic review. Of these, 16 articles were included in the meta-analysis. Three studies were assessed as low risk and sixteen as a moderate risk of bias. All RCTs were B quality. The odds ratio of the incidence of pressure injuries in malnourished and non-malnourished patients was 3.66(95% CI: 2.77-4.83). In the three RCTs studies(n = 870), the odds ratio of the incidence of pressure ulcers in patients with standard nutrition to those with specific nutritional interventions was 1.35(95%CI:1.02-1.78).

CONCLUSIONS

This systematic review and meta-analysis showed that nutritional status is significantly associated with pressure injuries. Malnutrition can increase the incidence of pressure injuries, and specific nutritional interventions can reduce the incidence of pressure injuries compared to standard nutrition.

Accuracy of Thermographic Imaging in the Early Detection of Pressure Injury: A Systematic Review

OBJECTIVE

To verify the accuracy of thermographic images in the early detection of pressure injury (PI) in adult patients.

DATA SOURCES

Between March 2021 and May 2022, researchers searched 18 databases for relevant articles using nine keywords. In total, 755 studies were evaluated.

STUDY SELECTION

Eight studies were included in the review. Studies were included if they evaluated individuals older than 18 years who were admitted to any healthcare setting; were published in English, Spanish, or Portuguese; examined the accuracy of thermal imaging in the early detection of PI, including suspected stage 1 PI or deep tissue injury; and they compared the region of interest to another area or control group, or to the Braden Scale or Norton Scale. Animal studies and reviews, studies with contact infrared thermography, and those including stages 2, 3, 4, and unstageable PIs were excluded.

DATA EXTRACTION

Researchers examined sample characteristics and assessment measures related to image capture, including environmental, individual, and technical factors.

DATA SYNTHESIS

Across the included studies, sample sizes ranged from 67 to 349 participants, and patients were followed up for periods ranging from a single assessment up to 14 days, or until the appearance of a PI, discharge, or death. Evaluation with the infrared thermography identified temperature differentials between regions of interest and/or in comparison with risk assessment scales.

CONCLUSIONS

Evidence on the accuracy of thermographic imaging in the early detection of PI is limited.

Racial Disparities and Pressure Injuries Among Hospitalized Patients

OBJECTIVE

To describe the demographic factors, hospitalization-related factors, comorbid states, and social determinants of health among racial groups in a sample of patients with a primary or secondary diagnosis of pressure injury (PI) admitted to New Jersey hospitals during the year 2018.

METHODS

Researchers conducted a retrospective analysis of the Health Care Utilization Project's 2018 New Jersey State Inpatient Database. Patients with a primary or secondary diagnosis of PI (sacrum, buttocks, or heels; N = 17,781) were included in the analytic sample. Analysis compared patients who identified as Black (n = 3,515) with all other racial groups combined (n = 14,266).

RESULTS

A higher proportion of Black patients were admitted for a PI (P < .001) and had higher proportions of stage 4 PIs (P < .001) but a lower proportion of stage 1 PIs (P < .001). Higher proportions of Black patients were younger, resided in lower income communities, and identified Medicaid as their primary payor source.

CONCLUSIONS

Results highlight the racial disparities that exist among patients with PIs in this diverse state and may represent a much larger problem. Clinical research examining the impact of skin tone rather than by racial group is needed. The impact of racial disparities on social determinants of health with regard to PIs remains largely unknown, but its importance cannot be underestimated.

Application of an infrared thermography-based model to detect pressure injuries: a prospective cohort study

BACKGROUND

It is challenging to detect pressure injuries at an early stage of their development.

OBJECTIVES

To assess the ability of an infrared thermography (IRT)-based model, constructed using a convolution neural network, to reliably detect pressure injuries.

METHODS

A prospective cohort study compared validity in patients with pressure injury (n = 58) and without pressure injury (n = 205) using different methods. Each patient was followed up for 10 days.

RESULTS

The optimal cut-off values of the IRT-based model were 0·53 for identifying tissue damage 1 day before visual detection of pressure injury and 0·88 for pressure injury detection on the day visual detection is possible. Kaplan-Meier curves and Cox proportional hazard regression model analysis showed that the risk of pressure injury increased 13-fold 1 day before visual detection with a cut-off value higher than 0·53 [hazard ratio (HR) 13·04, 95% confidence interval (CI) 6·32-26·91; P < 0·001]. The ability of the IRT-based model to detect pressure injuries [area under the receiver operating characteristic curve (AUC)_{lag 0 days} , 0·98, 95% CI 0·95-1·00] was better than that of other methods.

CONCLUSIONS

The IRT-based model is a useful and reliable method for clinical dermatologists and nurses to detect pressure injuries. It can objectively and accurately detect pressure injuries 1 day before visual detection and is therefore able to guide prevention earlier than would otherwise be possible. What is already known about this topic? Detection of pressure injuries at an early stage is challenging. Infrared thermography can be used for the physiological and anatomical evaluation of subcutaneous tissue abnormalities. A convolutional neural network is increasingly used in medical imaging analysis. What does this study add? The optimal cut-off values of the IRT-based model were 0·53 for identifying tissue damage 1 day before visual detection of pressure injury and 0·88 for pressure injury detection on the day visual detection is possible. Infrared thermography-based models can be used by clinical dermatologists and nurses to detect pressure injuries at an early stage objectively and accurately.

Can technology change the status quo for pressure injury prevention?

Linked Article:  Jiang et al. Br J Dermatol 2022; 187:571–579.

Infrared Thermography in Wound Care, Surgery, and Sports Medicine: A Review

For many years, the role of thermometry was limited to systemic (core body temperature) measurements (e.g., pulmonary catheter) or its approximation using skin/mucosa (e.g., axillary, oral, or rectal) temperature measurements. With recent advances in material science and technology, thermal measurements went beyond core body temperature measurements and found their way in many medical specialties. The article consists of two primary parts. In the first part we overviewed current clinical thermal measurement technologies across two dimensions: (a) direct vs. indirect and (b) single-point vs. multiple-point temperature measurements. In the second part, we focus primarily on clinical applications in wound care, surgery, and sports medicine. The primary focus here is the thermographic imaging modality. However, other thermal modalities are included where relevant for these clinical applications. The literature review identified two primary use scenarios for thermographic imaging: inflammation-based and perfusion-based. These scenarios rely on local (topical) temperature measurements, which are different from systemic (core body temperature) measurements. Quantifying these types of diseases benefits from thermographic imaging of an area in contrast to single-point measurements. The wide adoption of the technology would be accelerated by larger studies supporting the clinical utility of thermography.

Early Identification of Deep-Tissue Pressure Injury Using Long-Wave Infrared Thermography: A Blinded Prospective Cohort Study

BACKGROUND

The current clinical standard for diagnosing deep-tissue pressure injury (DTPI) is visual inspection. This method is subjective and only presents to the observer the external "picture;" deeper tissues are disguised from the observer. In contrast, long-wave infrared thermography (LWIT) can capture an image of the area of concern and detect tissue temperature relative to the level of tissue perfusion.

OBJECTIVE

To determine the efficacy of a handheld LWIT device and software solution as an adjunct to the current clinical standard of visual skin assessment to detect nonvisual pathophysiologic changes of DTPI.

METHODS

Investigators performed a blinded, prospective cohort study scanning participants' sacral area and bilateral heels with the LWIT device. Follow-up imaging took place throughout patient stays (on admission and 3, 7, 14, and 25 days thereafter). Clinicians were blinded to the LWIT images, and all participants received standard care for the prevention and treatment of wounds.

RESULTS

Among the 70 participants enrolled in this study, there were 131 anatomical areas with intact skin at the time of admission. Four areas with initially intact skin progressed to visually identifiable DTPI. On all four of these areas, the LWIT device identified a previsual temperature anomaly before there existed a visually identifiable DTPI.

CONCLUSIONS

The outcomes of this study suggest objective and quantitative documentation of temperature change using the LWIT device can serve as an indication of DTPI formation before visual identification is possible. Accordingly, it may allow for earlier detection of DTPI, decreasing the risk of associated complications to the patient and allowing for earlier, targeted intervention.