Optical Fibre Sensor for Capillary Refill Time and Contact Pressure Measurements under the Foot.

Capillary refill time (CRT) refers to the time taken for body tissue to regain its colour after an applied blanching pressure is released. Usually, pressure is manually applied and not measured. Upon release of pressure, simple mental counting is typically used to estimate how long it takes for the skin to regain its colour. However, this method is subjective and can provide inaccurate readings due to human error. CRT is often used to assess shock and hydration but also has the potential to assess peripheral arterial disease which can result in tissue breakdown, foot ulcers and ultimately amputation, especially in people with diabetes. The aim of this study was to design an optical fibre sensor to simultaneously detect blood volume changes and the contact pressure applied to the foot. The CRT probe combines two sensors: a plastic optical fibre (POF) based on photoplethysmography (PPG) to measure blood volume changes and a fibre Bragg grating to measure skin contact pressure. The results from 10 healthy volunteers demonstrate that the blanching pressure on the subject's first metatarsal head of the foot was 100.8 ± 4.8 kPa (mean and standard deviation), the average CRT was 1.37 ± 0.46 s and the time to achieve a stable blood volume was 4.77 ± 1.57 s. For individual volunteers, the fastest CRT measured was 0.82 ± 0.11 and the slowest 1.94 ± 0.49 s. The combined sensor and curve fitting process has the potential to provide increased reliability and accuracy for CRT measurement of the foot in diabetic foot ulcer clinics and in the community.

Using patient and public involvement to identify priorities for research in long-term conditions management.

BACKGROUND: Patient and public involvement (PPI) is increasingly important in healthcare research. Although this is accepted at the level of individual research studies, it has been less well used in scoping fundamental research priorities. It has been suggested that patients with long-term conditions (LTCs) are well placed to influence research priorities in this area due to their accumulated experience of illness over time. AIMS: To obtain PPI in research-priority setting for a group with a special interest in LTC research. DISCUSSION: PPI representatives provided views on issues they thought required further research. The facilitators were able to move from the specifics of these ideas to identify cross-cutting research priorities. CONCLUSION: It was possible to determine broad research themes despite PPI representatives initially articulating identified issues in very specific terms. Facilitating a better understanding of the research process for PPI representatives would allow their contribution to be more effective. Implications for practice PPI should be considered at the beginning of the process when broad research priorities are considered and before the study design. This is particularly so for broad, non-specialty-focused research themes such as LTCs. More work is required to ensure the views of harder-to-reach groups are included in this type of PPI.

Examining diabetic heel ulcers through an ecological lens: microbial community dynamics associated with healing and infection.

PURPOSE: While some micro-organisms, such as Staphylococcus aureus, are clearly implicated in causing tissue damage in diabetic foot ulcers (DFUs), our knowledge of the contribution of the entire microbiome to clinical outcomes is limited. We profiled the microbiome of a longitudinal sample series of 28 people with diabetes and DFUs of the heel in an attempt to better characterize the relationship between healing, infection and the microbiome. METHODOLOGY: In total, 237 samples were analysed from 28 DFUs, collected at fortnightly intervals for 6 months or until healing. Microbiome profiles were generated by 16S rRNA gene sequence analysis, supplemented by targeted nanopore sequencing.Result/Key findings. DFUs which failed to heal during the study period (20/28, 71.4 %) were more likely to be persistently colonized with a heterogeneous community of micro-organisms including anaerobes and Enterobacteriaceae (log-likelihood ratio 9.56, P=0.008). During clinically apparent infection, a reduction in the diversity of micro-organisms in a DFU was often observed due to expansion of one or two taxa, with recovery in diversity at resolution. Modelling of the predicted species interactions in a single DFU with high diversity indicated that networks of metabolic interactions may exist that contribute to the formation of stable communities. CONCLUSION: Longitudinal profiling is an essential tool for improving our understanding of the microbiology of chronic wounds, as community dynamics associated with clinical events can only be identified by examining changes over multiple time points. The development of complex communities, particularly involving Enterobacteriaceae and strict anaerobes, may be contributing to poor outcomes in DFUs and requires further investigation.

Using image J to document healing in ulcers of the foot in diabetes.

The aim of the study was to assess the reliability of measuring the cross-sectional area of diabetic foot ulcers using Image J software. The inter- and intra-rater reliability of ulcer area measures were assessed using digital images of acetate tracings of ulcers of the foot affecting 31 participants in an off-loading randomised trial. Observations were made independently by five specialist podiatrists, one of whom was experienced in the use of Image J software and educated the other four in a single session. The mean (±SD) of the mean cross-sectional areas of the 31 ulcers determined independently by the five observers was 1386·7 (±22·7) mm2 . The correlation between all pairs of observers was >0·99 (P < 0·001). There was no significant difference overall between the five observers (ANOVA F1.538; P = 0·165) and no difference between any two (paired samples test t = -0·787-1·396; P ≥ 0·088). The correlation between the areas determined by two observers on two occasions separated by not less than 1 week was very high (0·997 and 0·999; P < 0·001 and <0·001, respectively). The inter- and intra-reliability of the Image J software is very high, with no evidence of a difference either between or within observers. This technique should be considered for both research and clinical use in order to document changes in ulcer area.

Evaluation of the effectiveness and cost-effectiveness of lightweight fibreglass heel casts in the management of ulcers of the heel in diabetes: a randomised controlled trial.

BACKGROUND: Ulcers of the foot in people with diabetes mellitus are slow to heal and result in considerable cost and patient suffering. The prognosis is worst for ulcers of the heel. OBJECTIVE: To assess both the clinical effectiveness and the cost-effectiveness of lightweight fibreglass casts in the management of heel ulcers. DESIGN: A pragmatic, multicentre, parallel, observer-blinded randomised controlled trial. A central randomisation centre used a computer-generated random number sequence to allocate participants to groups. SETTING: Thirty-five specialist diabetic foot secondary care centres in the UK. Those recruited were aged ≥ 18 years and had diabetes mellitus complicated by ulcers of the heel of grades 2-4 on the National Pressure Ulcer Advisory Panel and European Pressure Ulcer Advisory Panel scale. PARTICIPANTS: In total, 509 participants [68% male, 15% with type 1 diabetes mellitus, mean age 67.5 years (standard deviation 12.4 years)] were randomised 1 : 1 to the intervention (n = 256) or the control (n = 253) arm. The primary outcome data were available for 425 participants (212 from the intervention arm and 213 from the control arm) and exceeded the total required; attrition was 16.5%. The median ulcer area at baseline was 275 mm2 [interquartile range (IQR) 104-683 mm2] in the intervention group and 206 mm2 (IQR 77-649 mm2) in the control group. There were no differences between the two groups at baseline in any parameter, neither in relation to the participant nor in relation to their ulcer. INTERVENTIONS: The intervention group received usual care supplemented by the addition of an individually moulded, lightweight, fibreglass heel cast. The control group received usual care alone. The intervention phase continued either until the participant's ulcer had healed (maintained for 28 days) or for 24 weeks, whichever occurred first. During this intervention phase, the participants were reviewed every 2 weeks, and the fibreglass casts were replaced when they were no longer usable. MAIN OUTCOME MEASURES: The primary outcome measure was ulcer healing (confirmed by a blinded observer and maintained for 4 weeks) within 24 weeks. Other outcome measures included the time taken for the ulcer to heal, the percentage reduction in the cross-sectional area, the reduction in local pain, amputation, survival and health economic analysis. The study was powered to define a difference in healing of 15% (55% intervention vs. 40% control). RESULTS: Forty-four per cent (n = 94) of the intervention group healed within 24 weeks, compared with 37% (n = 80) of the control participants (odds ratio 1.42, 95% confidence interval 0.95 to 2.14; p = 0.088), using an intention-to-treat analysis. No differences were observed between the two groups for any secondary outcome. LIMITATIONS: Although the component items of care were standardised, because this was a pragmatic trial, usual care was not uniform. There was some evidence of a small excess of adverse events in the intervention group; however, non-blinded observers documented these events. There was no excess of adverse device effects. CONCLUSIONS: There may be a small increase in healing with the use of a heel cast, but the estimate was not sufficiently precise to provide strong evidence of an effect. There was no evidence of any subgroup in which the intervention appeared to be particularly effective. A health economic analysis suggested that it is unlikely that the intervention represents good value for money. The provision of a lightweight heel cast may be of benefit to some individuals, but we have found no evidence to justify the routine adoption of this in clinical practice. FUTURE WORK: It is unlikely that further study of this intervention will have an impact on usual clinical care, and so future efforts should be directed towards other interventions designed to improve the healing of ulcers in this population. TRIAL REGISTRATION: Current Controlled Trials ISRCTN62524796. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 34. See the NIHR Journals Library website for further project information.