Lower temperature at the wound edge detected by thermography predicts undermining development in pressure ulcers: a pilot study

Beyond visual inspection: The value of infrared thermography in skin diseases, a scoping review

Although warmth is a key sign of inflammatory skin lesions, an objective assessment and follow-up of the temperature changes are rarely done in dermatology. The recent availability of accurate, sensitive and cost-effective thermography devices has made the implementation of thermography in clinical settings feasible. The aim of this scoping review is to summarize the evidence around the value and pitfalls of infrared thermography (IRT) when used in the dermatology clinic. A systematic literature search was done for original articles using IRT in skin disorders. The results concerning the potential of IRT for diagnosis, severity staging and monitoring of skin diseases were collected. The data on the sensitivity and specificity of IRT were extracted. Numerous studies have investigated IRT in various skin diseases, revealing its significant value in wound management, skin infections (e.g. cellulitis), vascular abnormalities and deep skin inflammation (e.g. hidradenitis suppurativa). For other dermatological applications such as the interpretation of intradermal and patch allergy testing, hyper-/anhidrosis, erythromelalgia, cold urticaria and lymph node metastases more complex calculations, provocation tests or active cooling procedures are required. Dermatologists should be aware of a learning curve of IRT and recognize factors contributing to false positive and false negative results. Nonetheless, enough evidence is available to recommend IRT as a supplement to the clinical evaluation for the diagnosis, severity and follow-up of several skin diseases.

A pressure-resistant zwitterionic skin sensor for domestic real-time monitoring and pro-healing of pressure injury

Pressure injury (PI) is a hard-to-heal wound to patients with the limited mobility, especially paralyzed or elderly persons. These patients also commonly suffer from sensation loss or dementia that is unable to indicate symptoms in time, resulting in missing the "golden period" for treatment. Therefore, it is highly required to domestic continously real-time monitoring as well as promoting wound healing of PI. However, no existing device has realized these functions for PI. Herein, we prepare a zwitterionic skin sensor that enables pro-healing as well as domestic real-time monitoring the multi-indicators of PI. To apply for a PI dressing that requires to tolerate patient body weight, organosilicon nanoparticles (OSNPs) are designed as crosslinks in the zwitterionic conductive hydrogel (CH-OSNP), which exhibits pressure-resistant properties (99.81% compression to recovery) as well as anti-bacterial adhesion. Moreover, the CH-OSNP-based skin sensor is developed, and the resultant sensor can be sensitive to stress stimuli even under a long-term constant heavy load, which stimulates the pressure of a PI person lying down. In vivo results show that this sensor can not only promote PI healing, but also continuously monitor and distinguish multiple information, such as exudate, swelling, and infection, to prevent PI from being worsen. This work provides a domestic feasible device to cure and monitor the PI of patients.

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.

Pressure Injury Link to Entropy of Abdominal Temperature

This study examined the association between pressure injuries and complexity of abdominal temperature measured in residents of a nursing facility. The temperature served as a proxy measure for skin thermoregulation. Refined multiscale sample entropy and bubble entropy were used to measure the irregularity of the temperature time series measured over two days at 1-min intervals. Robust summary measures were derived for the multiscale entropies and used in predictive models for pressure injuries that were built with adaptive lasso regression and neural networks. Both types of entropies were lower in the group of participants with pressure injuries (n=11) relative to the group of non-injured participants (n=15). This was generally true at the longer temporal scales, with the effect peaking at scale τ=22 min for sample entropy and τ=23 min for bubble entropy. Predictive models for pressure injury on the basis of refined multiscale sample entropy and bubble entropy yielded 96% accuracy, outperforming predictions based on any single measure of entropy. Combining entropy measures with a widely used risk assessment score led to the best prediction accuracy. Complexity of the abdominal temperature series could therefore serve as an indicator of risk of pressure injury.

Tissue Oxygenation Measurements to Aid Scalpel Debridement Removal in Patients With Diabetes

BACKGROUND

Callus formation in the diabetic foot increases the risk of ulcer onset. It is standard procedure to remove these dead tissue layers to reduce rising pressures. In a surgical procedure known as scalpel debridement, or chiropody the callus tissue is removed up to the epidermal layer. Factors may influence the outcome of this surgical process such as clinician inexperience. In an effort to standardize the debridement process, tissue oxygenation (TO) measurements are obtained before and after to study the effect of debridement on callus tissue.

METHODS

Fifteen debridement cases were analyzed using near infrared (NIR) imaging to study changes in TO. The NIR-based device used in this study estimates effective changes in TO in terms of oxy-, deoxy-, total hemoglobin, and oxygen saturation. Weber contrasts between callus tissue and the surrounding normal tissue were compared following debridement for all TO parameters. In a secondary analysis, callus tissue was segmented into quadrants and a percent of significance (in terms of total TO change) was calculated using a t-test.

RESULTS

Results show majority of cases displayed greater than 80% as the significant change in TO following debridement, except in cases with the presence of blood clot (a common precursor for ulceration). In cases where incomplete debridement was suspected, a significant change in TO was still observed.

CONCLUSIONS

With extensive systematic studies in the future, NIR imaging technique to measure changes in TO may be implemented as a low-cost hand-held imaging device useful for objectively assessing the effectiveness of the scalpel debridement process.

Increased temperature at the healed area detected by thermography predicts recurrent pressure ulcers

Preventing recurrent pressure ulcers is an important challenge in healthcare. One of the reasons for the high rate of recurrent pressure ulcers is the lack of assessment methods for their early detection. Therefore, this study aimed to determine the thermographic characteristics of the healed area and to consider the predictive validity of thermographic images for recurrent pressure ulcers within a 2-week period. This observational study was conducted at a long-term care facility in Japan between July 2017 and February 2019 among patients whose pressure ulcers had healed. Thermographic images of the healed area were recorded once a week until recurrence or until the end of the study. We enrolled 30 participants, among whom 8 developed recurrent pressure ulcers. The generalised estimation equation revealed that the thermographic finding of increased temperature at the healed area compared to that of the surrounding skin was significantly associated with recurrent pressure ulcers (odds ratio: 101.13, 95% confidence interval: 3.60-2840.77, p = .007); the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for recurrent pressure ulcers within 2 weeks were 0.80, 0.94, 0.62, 0.97, 12.9 and 0.2, respectively. Our thermographic findings revealed that the temperature of the healed area was higher than that of the surrounding skin; this could be a useful predictor of pressure ulcer recurrence within 2 weeks, even in the absence of macroscopic changes.

Quantifying skin sensitivity caused by mechanical insults: A review

BACKGROUND

Skin sensitivity (SS) is a commonly occurring response to a range of stimuli, including environmental conditions (e.g., sun exposure), chemical irritants (e.g., soaps and cosmetics), and mechanical forces (e.g., while shaving). From both industry and academia, many efforts have been taken to quantify the characteristics of SS in a standardised manner, but the study is hindered by the lack of an objective definition.

METHODS

A review of the scientific literature regarding different parameters attributed to the loss of skin integrity and linked with exhibition of SS was conducted. Articles included were screened for mechanical stimulation of the skin, with objective quantification of tissue responses using biophysical or imaging techniques. Additionally, studies where cohorts of SS and non-SS individuals were reported have been critiqued.

RESULTS

The findings identified that the structure and function of the stratum corneum and its effective barrier properties are closely associated with SS. Thus, an array of skin tissue responses has been selected for characterization of SS due to mechanical stimuli, including: transepidermal water loss, hydration, redness, temperature, and sebum index. Additionally, certain imaging tools allow quantification of the superficial skin layers, providing structural characteristics underlying SS.

CONCLUSION

This review proposes a multimodal approach for identification of SS, providing a means to characterise skin tissue responses objectively. Optical coherence tomography (OCT) has been suggested as a suitable tool for dermatological research with clinical applications. Such an approach would enhance the knowledge underlying the multifactorial nature of SS and aid the development of personalised solutions in medical and consumer devices.

Skin surface infrared thermography in pressure ulcer outcome prognosis

OBJECTIVE

To assess the usefulness of skin surface infrared thermography (SSIT) as a prognostic tool in the treatment of stages III and IV pressure ulcers (PU), with hydrocolloid/hydrogel dressings plus 20 exposures to low-level laser therapy (LLLT), compared with hydrocolloid dressings alone, in a group of long-term bedbound care patients.

METHOD

In this comparative study, participants were randomly assigned to group I: PUs treated with specialist wound dressings and laser therapy, or to group II: PUs treated with specialist wound dressings without laser therapy. Thermal imaging sessions were carried out at the beginning of the study, and after two and four weeks of treatment. Thermal imaging processing was applied to compare percentage differences in the temperature distribution between the groups within selected regions of interest (ROIs). The correlation between the temperature distribution and PU healing was evaluated.

RESULTS

A total of 43 patients took part. In the study, three variants of PU healing were observed: pure healing (H) with minimal granulation; healing with hypergranulation (H+G); and non-healing (NH). Analyses of SSIT-related thermographic patterns revealed their dependence on the course of healing. The percentage of successful PU healing reached 79.2% in group I compared with 73.7% in group II (p<0.05) The dominant variant of healing in Group I was H, while in group II the variants H and H+G were present with equal frequency.

CONCLUSION

Thermal imaging processing allowed comparison of differences in the temperature distribution between the groups within ROIs. Application of LLLT significantly improved the healing process (p<0.05). The clinical significance of this finding should be confirmed with larger studies; however, SSIT may be useful as a prognostic tool during the treatment of PUs, with the ability to predict the course of healing initially, that is independent of LLLT treatment.

Higher Periwound Temperature Associated with Wound Healing of Pressure Ulcers Detected by Infrared Thermography

Visual and empirical assessments do not enable the early detection of wound deterioration or necroses. No suitable objective indicator for predicting poor wound-healing is currently available. We used infrared thermography to determine the association between wound temperature and pressure-wound healing. We examined patients with grades 2–4 pressure ulcers from a medical center in southern Taiwan and recorded the temperatures of the wound bed, periwound, and normal skin using infrared thermographic cameras. A total of 50 pressure ulcers and 248 infrared-thermography temperature records were analyzed. Normal skin temperature was not related to pressure ulcer wound healing. In a multivariate analysis, higher malnutrition universal-screening-tool scores were associated with poor wound-healing (p = 0.020), and higher periwound-temperature values were associated with better wound-healing (p = 0.028). In patients who had higher periwound-skin temperature than that of the wound bed, that result was also associated with better wound-healing (p = 0.002). Wound-bed and periwound temperatures differed significantly with the grade of the pressure ulcer, and a high periwound temperature was positively correlated with wound healing. Infrared thermography can objectively serve as indicators for assessing pressure-ulcer healing.

A model for predicting 7-day pressure injury outcomes in paediatric patients: A machine learning approach

AIMS

We sought to explore factors associated with early pressure injury progression and build a model for predicting these outcomes using a machine learning approach.

DESIGN

A retrospective cohort study.

METHODS

In this study, we recruited paediatric patients, with hospital-acquired stage I pressure injury or suspected deep tissue injury, who met the inclusion criteria between 1 January 2015-31 October 2018. We divided patients into two groups, namely healing or delayed healing, then followed them up for 7 days. We analysed patient pressure injury characteristics, demographics, treatment, clinical situation, vital signs, and blood test results, then build prediction models using the Random Forest and eXtreme Gradient Boosting approaches.

RESULTS

The best prediction model, trained and tested using Random Forest with 10 variables, achieved an accuracy, sensitivity, specificity, and area under the curve of 0.82 (SD 0.06), 0.80 (SD 0.08), 0.84 (SD 0.08), and 0.89 (SD 0.06), respectively. The most contributing variables, in order of importance, included serum creatinine, red blood cell, and haematocrit.

CONCLUSION

An awareness of specific conditions and areas that could lead to delayed healing pressure injury in paediatric patients is needed.

IMPACT

This evidence-based prediction model, coupled with the aforementioned clinical indicators, is expected to enhance early prediction of outcomes in paediatric patients thereby improve the quality of care and the outcome of children with PIs.

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

AIMS AND OBJECTIVES

To verify the ability of infrared thermography in objectively identifying pressure injury and its application value in the early warning of pressure injury.

BACKGROUND

There is subjectivity in assessing the risk of pressure injury as well as diagnosis in clinical settings, which makes early detection and prevention difficult.

DESIGN

Prospective, cohort study.

METHOD

Four hundred and fifteen patients admitted to the adult intensive care units were enrolled by a convenience sampling method, and they received a follow-up monitoring for 10 days. The risk of pressure injury was assessed via Braden scale, and thermal images of sacral area were obtained by infrared thermal imager once a day. The predictive effects of infrared thermography and Braden scale on pressure injury were compared by the receiver operating characteristic curve from which the optimal cut-off value of skin temperature for predicting pressure injury was determined. The effect of skin temperature on pressure injury was described and compared, using Kaplan-Meier curve and Cox proportional hazard regression model, respectively. We followed STROBE checklist for reporting the study.

RESULTS

The relative temperature of sacral area was negatively correlated with the risk of pressure injury. The efficiency of infrared thermography for diagnosing pressure injury was better than that of Braden scale. Based on the relative temperature optimal cut-off value (-0.1°C), Kaplan-Meier curve and Cox proportional hazard regression model analysis showed the incidence of pressure injury with relative temperature below -0.1°C was higher than the group with relative temperature above -0.1°C.

CONCLUSIONS

Infrared thermography can objectively and accurately identify local hypothermia warnings of pressure injury before visual recognition. The application of infrared thermography into routine pressure injury risk assessment provides a timely and reliable method for nursing practitioners.

RELEVANCE TO CLINICAL PRACTICE

Infrared thermography has great value of clinical application in daily pressure injury assessment. It is of great significance to make a faster and more objective clinical judgement for patients at risk of pressure injury.

Skin temperature and vascular attributes as early warning signs of pressure injury

OBJECTIVES

This study aimed to validate the skin temperature on sacral region and vascular attributes as early warning signs of pressure injury.

METHODS

Totally 415 patients admitted to the adult intensive care unit from August 2018 to April 2019 were prospectively screened. Daily blood pressure and blood glucose affecting vascular attributes and the relative skin temperature of sacral region were measured for 10 consecutive days. Collect the changes of these indicators during the occurrence of pressure injury. The optimal cut-off values of indicators were determined by X-tile analysis. The risk ratios of indicators associated with pressure injury were compared using the Cox proportional hazards regression model.

RESULTS

There were no obvious interactions among blood pressure, blood glucose and relative skin temperature (P > 0.05). The optimal cutoff value for above indicators was 63.5 mmHg, 9.9 mmol/L and -0.1 °C, respectively. The incidence of pressure injury peaked on the 4th and 5th day after hospitalization when categorizing the patients into low- and high-risk groups according to the cutoff values (P < 0.05). Based on relative skin temperature, patients in the high-risk group were more likely to develop pressure injury (hazard ratio = 6.36, 95% confidence interval = 3.91, 10.36), when compared to the other two indicators of blood pressure and blood glucose.

CONCLUSION

Stringent skin temperature and vascular attributes measurements were necessary for preventing pressure injury. Nursing measures should be taken according to warning sings to reduce the incidence of pressure injury.

Ultrasound assessment of deep tissue on the wound bed and periwound skin: A classification system using ultrasound images

AIMS

Given the utility of ultrasonography in assessing pressure injury, some ultrasonographic findings have already been used as indicators of deep tissue pressure injury. Despite reports showing that a cloud-like ultrasonographic pattern reflected the presence of deep tissue necrosis, identifying cloud-like patterns was difficult given the presence of similar findings, such as a cobblestone-like pattern. This case series reports patients with pressure injuries who presented with a cloud-like (five cases) and cobblestone-like (four cases) pattern during ultrasonography.

METHODS

This study was conducted at a Japanese university hospital. Participants included patients who underwent routine examination by an interdisciplinary pressure injury team. Pressure injury severity was assessed using the DESIGN-R® scoring system and the wound size were measured using ImageJ software based on the wound photograph.

RESULTS

Among the five cases showing a cloud-like pattern upon ultrasonography, all exhibited an increase in the total DESIGN-R® score, while three exhibited an increase in wound size. On the other hand, all four cases showing a cobblestone-like pattern displayed no increase in the total DESIGN-R® score and a decrease in wound size.

CONCLUSION

This study suggested that distinguishing between cloud-like and cobblestone-like ultrasonography patterns is necessary for determining the presence or absence of deep tissue pressure injury. In order to comprehensively assess pressure injuries with ultrasonography, future studies should be conducted in a large number of participants.

Thermographic Characterization of Cutaneous Ulcers of Different Etiologies

The characterization of the temperature of skin ulcers may provide preliminary diagnostic evidence. The aim of this study was to characterize cutaneous ulcers of different etiologies by infrared thermography. 122 cutaneous ulcers of 87 patients (age 60.1 ± 15.7 years) were evaluated, allocated into five groups: venous ulcers (VU) n = 26, arterial ulcers (AU) n = 20, mixed ulcers (MU) n = 25, pressure ulcers (PU) n = 29, and neuropathic ulcers (NU) n = 22. The cutaneous temperature was recorded by infrared thermography (FLIR-450™); we also evaluated the ulcer area, the ankle brachial index (ABI), the range of motion (ROM) of the ankle, and pain. For the different variables, the statistical analysis was performed using the Kruskal Wallis test, ANOVA, the chi-squared test, and the Spearman test (SPSS™ software version 20, p < 0.05). A significant difference was found between the temperatures of PU and NU. The ABI was significantly lower in the MU and AU groups, and pain was also higher in these groups. The ROM was decreased in all groups, and the MU and VU groups had the lowest ROM. There was no correlation between temperature and the clinical findings (ABI, ROM, and pain). There was a moderate correlation in the analysis between the temperature and the area of the ulcer in the PU group, as larger ulcers had lower temperatures. It is possible to characterize cutaneous ulcers by infrared thermography, and there are temperature differences among ulcers with different etiologies.

Infrared thermography to prognose the venous leg ulcer healing process-preliminary results of a 12-week, prospective observational study

Venous leg ulcers are complex, and their multifactorial etiology make successful treatment a difficult and long process. Nonhealing ulcers are the greatest challenge because they are resistant to standard therapies. In this study, we analyzed whether monitoring the temperature of the ulcered limb wound area could benefit the diagnosis of the wound's tendency to heal (estimating the presence of a healing or nonhealing wound) in patients with two-sided venous leg ulcers. This prospective, 12-week observational study included 57 adult individuals with chronic venous leg ulcers. The dynamics of wound healing was assessed by planimetry and infrared thermography every two weeks. We analyzed temperatures measured at three marked areas-the wound, the periwound skin, and the reference area. An initial wound area larger than 1 cm² was associated with a temperature increase of 0.027 °C in the periwound skin. A 1-cm² decrease in the wound area was associated with a 0.04 °C decrease in the temperature difference between the periwound skin and wound. A strong positive relationship was identified for both the bacteriology variables (the presence of bacteria: temperature increase in the periwound skin of 0.4 °C, p < 0.001; the number of bacterial species in a wound, temperature increase of 0.95 °C, p < 0.001). The temperature in the reference area was significantly correlated with the failure of the superficial and perforating veins (temperature increase of 0.69 °C, p = 0.04). This study reports that the assessment of the temperature a limb may be beneficial in predicting whether an ulcer is a healing or a nonhealing ulcer. The decrease in the temperature differences between the areas referred to as healing wounds was the only beneficial prognostic marker. Other temperature differences in the periwound skin were caused by disorders, such as multibacterial wound infections and superficial venous inflammation.

Pressure injury identification, measurement, coding, and reporting: Key challenges and opportunities

Pressure injury (PI) rates are a commonly used indicator of performance of health care facilities, both in acute and subacute settings. However, measuring PI rates in an accurate and reproducible fashion has been challenging. The consequences of poor measurement may include failure to identify poorly performing institutions or incorrect accusations of poor quality care. In this article, we describe the main challenges in identification, coding, and reporting of PIs. Issues include inconsistent identification of PIs at the time of admission, variations in the intensity of PI detection, and differing approaches to coding and the adjustment for differing risks amongst different patient population. These are compounded by differences in the epidemiological approach because rates will differ according to whether patients are surveyed cross-sectionally (eg, on a set day per month) or if the survey is undertaken at discharge. In some cases, financial incentives may also influence PI reporting. We also discuss potential strategies for improving data collection and benchmarking as an aid to reducing PI prevalence.

Continuous thermographic observation may predict extravasation in chemotherapy-treated patients

PURPOSE

Extravasation, or leakage of vesicant drugs into subcutaneous tissues, causes serious complications such as induration and necrosis in chemotherapy-treated patients. As macroscopic observation may overlook symptoms during infusion, we focused on skin temperature changes at puncture sites and studied thermographic patterns related to induration or necrosis caused by extravasation.

METHODS

Outpatients undergoing chemotherapy using peripheral intravenous catheters were enrolled in this prospective observational study. We filmed and classified infrared thermography movies of puncture sites during infusion; ultrasonography was also utilized at puncture sites to observe the subcutaneous condition. Multiple logistic regression analysis was performed to examine the association of thermographic patterns with induration or necrosis observed on the next chemotherapy day. Differences in patient characteristics, puncture sites, and infusions were analyzed by Mann-Whitney's U test and Fisher's exact test according to thermographic patterns.

RESULTS

Eight patients developed induration among 74 observations in 62 patients. Among six thermographic patterns, a fan-shaped lower temperature area gradually spreading from the puncture site (fan at puncture site) was significantly associated with induration. Ultrasonography revealed that catheters of patients with fan at puncture site remained in the vein at the end of infusion, indicating that the infusion probably leaked from the puncture site. Patients with fan at puncture site had no significant differences in characteristics and infusion conditions compared with those with the other five thermographic patterns.

CONCLUSION

We determined that fan at puncture site was related to induration caused by extravasation. Continuous thermographic observation may enable us to predict adverse events of chemotherapy.