Laser doppler imaging - the role of poor burn perfusion in predicting healing time and guiding operative management

AIM

To identify if the proportion of poor blood flow (blue) within an LDI (Laser doppler Imaging) image of a burn independently correlates with healing time.

METHODS

Patient age, gender, burn type, and burn surface area were collected from the IBID (International Burn Injury Database). All LDI images were copied from the MoorLDI2-BI- Laser Doppler (MLDI) Scanner, onto Adobe Photoshop® version 2020 for pixel counting analysis and calculation of % TBSA (Total Body Surface Area) blue. Multiple linear regression analysis determined whether a proportional relationship was present for each parameter (age, gender, % TBSA Blue and comorbidities) with healing time.

RESULTS

110 patients with 197 burns were scanned with MLDI. Median age was 5 years (IQR 1-6). Median burn surface area was 1.5% (IQR 1-2.4). 56.4% of patients were male and patients were scanned an average of 2.68 days (SD±1.37) following burn injury. Number of physical comorbidities and age were found to have a statistically significant relationship with healing time (p = 0.03, p = 0.002). Gender and %TBSA blue did not have a statistically significant relationship with healing time (p = 0.07 and p = 0.058 respectively). We found a statistically significant difference in the mean healing time between burns with and without blue (3.43 weeks vs. 2.80 weeks, p = 0.0001). % TBSA Blue was more than four times higher in the operated group (0.48% vs. 0.11%) and was shown to have a statistically significant relationship with decision to operate (p = 0.027). Positive predictive value for the presence of blue on operative rate was 71.6%. Age, gender and number of comorbidities did not have a statistically significant influence on operative rate (p = 0.07, p = 0.50 and p = 0.49).

CONCLUSION

% TBSA blue was not found to be a reliable independent indicator of burn healing time, but the presence of blue within an LDI image, advanced patient age and increased number of comorbidities did have a statistically significant relationship with healing time. This suggests their standardised inclusion into management decisions regarding intermediate depth burns is warranted.

Effectiveness of a hydrogel dressing as an analgesic adjunct to first aid for the treatment of acute paediatric burn injuries: a prospective randomised controlled trial

OBJECTIVE

To compare the effectiveness of two acute burn dressings, Burnaid hydrogel dressing and plasticised polyvinylchloride film, on reducing acute pain scores in paediatric burn patients following appropriate first aid.

DESIGN

Single-centre, superiority, two-arm, parallel-group, prospective randomised controlled trial.

PARTICIPANTS AND SETTING

Paediatric patients (aged ≤16) presenting to the Emergency Department at the Queensland Children's Hospital, Brisbane, Australia, with an acute thermal burn were approached for participation in the trial from September 2017-September 2018.

INTERVENTIONS

Patients were randomised to receive either (1) Burnaid hydrogel dressing (intervention) or (2) plasticised polyvinylchloride film (Control) as an acute burn dressing.

PRIMARY AND SECONDARY OUTCOMES

Observational pain scores from nursing staff assessed 5 min post application of the randomised dressing, measured using the Face Legs Activity Cry and Consolability Scale was the primary outcome. Repeated measures of pain, stress and re-epithelialisation were also collected at follow-up dressing changes until 95% wound re-epithelialisation occurred.

RESULTS

Seventy-two children were recruited and randomised (n=37 intervention; n=35 control). No significant between-group differences in nursing (mean difference: -0.1, 95% CI -0.7 to 0.5, p=0.72) or caregiver (MD: 1, 95% CI -8 to 11, p=0.78) observational pain scores were identified. Moreover, no significant differences in child self-report pain (MD: 0.3, 95% CI -1.7 to 2.2, p=0.78), heart rate (MD: -3, 95% CI -11 to 5, p=0.41), temperature (MD: 0.6, 95% CI -0.13 to 0.24, p=0.53), stress (geometric mean ratio: 1.53, 95% CI 0.93 to 2.53, p=0.10), or re-epithelialisation rates (MD: -1, 95% CI -3 to 1, p=0.26) were identified between the two groups.

CONCLUSIONS

A clear benefit of Burnaid hydrogel dressing as an analgesic adjunct to first aid for the treatment of acute paediatric burns was not identified in this investigation.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12617001274369).

Diagnostic Accuracy of Laser Doppler Imaging for the Assessment of Burn Depth: A Meta-analysis and Systematic Review

An overall assessment of the diagnostic value of laser Doppler imaging (LDI) to assess burn depth in patients is presented based on relevant studies. Both eligible research and relevant articles were identified through specific index searches of Embase, Cochrane, and PubMed databases. The latest study included was published in March 2019 and all eligible publications reported on cohort or cross-sectional research. All articles were tested for heterogeneity by using a suitable effect model to calculate amalgamative values of sensitivity, specificity, and the diagnostic odds ratio (DOR). Analyses of summary receiver operating characteristic (SROC) are given for burn depth values. After rigorous screening, 14 studies with a total cohort of 1,818 patients were chosen for the meta-analysis to explore the validity of LDI diagnosis to assess the depth of burns. The burn depth overall sensitivity for LDI was 91% (95% CI: 86–95%) and global specificity was 96% (95% CI: 92–98%). The overall positive likelihood ratio of LDI was 20.35 (95% CI: 10.71–38.69) and the overall negative likelihood ratio was 0.09 (95% CI: 0.05–0.15). The overall DOR was 152.93 (95% CI: 69.44–336.81) of LDI. The acreage under the SROC was not low for LDI (AUC = 0.98; 95% CI: 0.96–0.99). In conclusion, the present analysis reviewed the literature and meta-analysis of studies to validate LDI for the diagnosis of burn depth. The results indicated that LDI has a high accuracy for this diagnostic function.

Diagnostic and Prognostic Utility of Non-Invasive Multimodal Imaging in Chronic Wound Monitoring: a Systematic Review

Monitoring chronic wound [CW] healing is a challenging issue for clinicians across the world. Moreover, the health and cost burden of CW are escalating at a disturbing rate due to a global rise in population of elderly and diabetic cases. The conventional approach includes visual contour, sketches, or more rarely tracings. However, such conventional techniques bring forth infection, pain, allergies. Furthermore, these methods are subjective as well as time-consuming. As such, nowadays, non-touching and non-invasive CW monitoring system based on imaging techniques are gaining importance. They not only reduce patients' discomfort but also provide rapid wound diagnosis and prognosis. This review provides a survey of different types of CW characteristics, their healing mechanism and the multimodal non-invasive imaging methods that have been used for their diagnosis and prognosis. Current clinical practices as well as personal health systems [m-health and e-health] for CW monitoring have been discussed.

Development of a Consistent and Reproducible Porcine Scald Burn Model

There are very few porcine burn models that replicate scald injuries similar to those encountered by children. We have developed a robust porcine burn model capable of creating reproducible scald burns for a wide range of burn conditions. The study was conducted with juvenile Large White pigs, creating replicates of burn combinations; 50°C for 1, 2, 5 and 10 minutes and 60°C, 70°C, 80°C and 90°C for 5 seconds. Visual wound examination, biopsies and Laser Doppler Imaging were performed at 1, 24 hours and at 3 and 7 days post-burn. A consistent water temperature was maintained within the scald device for long durations (49.8 ± 0.1°C when set at 50°C). The macroscopic and histologic appearance was consistent between replicates of burn conditions. For 50°C water, 10 minute duration burns showed significantly deeper tissue injury than all shorter durations at 24 hours post-burn (p ≤ 0.0001), with damage seen to increase until day 3 post-burn. For 5 second duration burns, by day 7 post-burn the 80°C and 90°C scalds had damage detected significantly deeper in the tissue than the 70°C scalds (p ≤ 0.001). A reliable and safe model of porcine scald burn injury has been successfully developed. The novel apparatus with continually refreshed water improves consistency of scald creation for long exposure times. This model allows the pathophysiology of scald burn wound creation and progression to be examined.

Long-term scar quality in burns with three distinct healing potentials: A multicenter prospective cohort study

The laser Doppler imager is used in cases of indeterminate burn depth to accurately predict wound healing time at an early stage. The laser Doppler imager classifies burns into three estimated healing potentials as follows: high, <14 days; intermediate, 14-21 days; and low, >21 days. At this time, the relationship between these healing potentials and long-term scar quality is unknown. The objective of this study was to determine the long-term scar quality of burns with three distinct healing potentials. The secondary objectives were to compare treatment strategies in intermediate wounds, to study the effect of the timing of surgery on low healing potential wounds and to identify predictors of reduced scar quality. Hence, in a prospective cohort study, scar quality was determined in patients whose burns were assessed with laser Doppler imaging. Scar Quality was assessed with objective and subjective measurement tools, including overall scar quality (Patient and Observer Scar Assessment Scale) as a primary outcome and color and elasticity parameters. A total of 141 patients (>19 months postburn) with 216 scars were included. Wounds with high and intermediate healing potential did not significantly differ regarding scar quality. Wounds with a low healing potential had a significantly lower scar quality. Analysis of 76 surgically treated low healing potential wounds showed no significant differences in the primary outcome regarding the timing of surgery (≤14 days vs. >14). Predictors of reduced long-term scar quality were darker skin type and multiple surgeries. In conclusion, scar quality was strongly related to the healing potential category. Scar quality was very similar in high and intermediate healing potential wounds. No positive effects were found on scar quality or on healing time in surgically treated wounds with intermediate healing potential, advocating a conservative approach. Further studies should focus on the optimal timing of surgery in low healing potential wounds.

Microvascular blood flow in scalds in children and its relation to duration of wound healing: A study using laser speckle contrast imaging

BACKGROUND

Microvascular perfusion changes in scalds in children during the first weeks after injury is related to the outcome of healing, and measurements of perfusion, based on laser Doppler imaging, have been used successfully to predict the need for excision and grafting. However, the day-to-day changes in perfusion during the first weeks after injury have not to our knowledge been studied in detail. The aim of this study, based on a conservative treatment model where excision and grafting decisions were delayed to day 14 after injury, was to measure changes in perfusion in scalds using laser speckle contrast imaging (LSCI) during the first three weeks after injury.

METHODS

We measured perfusion with LSCI in 34 patients at regular intervals between 6h after injury until complete reepithelialization or surgery. Duration of healing was defined as the time to complete reepithelialization.

RESULTS

Less perfusion, between 6 and 96h after injury, was associated with longer duration of healing with the strongest association occurring between 72 and 96h. Burns that healed within 14 days had relatively high initial perfusion, followed by a peak and subsequent slow decrease. Both the maximum perfusion and the time-to-peak were dependent on the severity of the burn. Burns that needed excision and grafting had less initial perfusion and a gradual reduction over time.

CONCLUSION

The perfusion in scalds in children shows characteristic patterns during the first weeks after injury depending on the duration of wound healing, the greatest difference between wounds of different severity being on the 4th day. Perfusion should therefore preferably be measured on the fourth day if it is to be used in the assessment of burn depth.