Burn wound depth assessment--is laser Doppler imaging the best measurement tool available?

Evaluation of hyperspectral imaging as a modern aid in clinical assessment of burn wounds of the upper extremity

The most common burn wound assessment continues to be the clinical inspection and the tactile examination, which are subjective and remain challenging even for experienced burn surgeons. Recently, hyperspectral imaging camera systems have been increasingly used to support the evaluation of burn wounds. The aim of our study was to determine if hyperspectral imaging analysis differentiates and objectifies the assessment of burn wounds in burns of the upper extremities. We included 97 superficial partial, deep partial dermal burns, and full thickness burns. Hyperspectral imaging analysis was performed for all burns using proprietary software. The software recorded parameters for tissue oxygenation (StO2), tissue hemoglobin index, and near-infrared perfusion. These values were compared with the recordings for healthy, non-burned skin. We found that hyperspectral imaging analysis effectively differentiates burn wounds and shows the ability to distinguish even superficial partial burns from deep partial burns in the near-infrared perfusion analysis feature. Although, it was not possible to differentiate burn wounds in all features. Currently, it is important to optimize the respective reference values of the individual burn degrees for an objectified assessment.

Evidence Based Burn Depth Assessment Using Laser-Based Technologies: Where Do We Stand?

Early clinical assessment of burn depth and associated healing potential (HP) remains extremely challenging, even for experienced surgeons. Inaccurate diagnosis often leads to prolonged healing times and unnecessary surgical procedures, resulting in incremental costs, and unfavorable outcomes. Laser Doppler imaging (LDI) is currently the most objective and accurate diagnostic tool to measure blood flow and its associated HP, the main predictor for a patient's long-term functional and aesthetic outcome. A systematic review was performed on non-invasive, laser-based methods for burn depth assessment using skin microcirculation measurements to determine time to healing: Laser Doppler flowmetry (LDF), LDI and laser speckle contrast imaging (LSCI). Important drawbacks of single point LDF measurements are direct contact with numerous small points on the wound bed and the need to carry out serial measurements over several days. LDI is a fast, "non-contact," single measurement tool allowing to scan large burned areas with a 96% accuracy. LDI reduces the number of surgeries, improves the functional and aesthetic outcome and is cost-effective. There is only limited evidence for the use of LSCI in burn depth assessment. LSCI still needs technical improvements and scientific validation, before it can be approved for reliable burn assessment. LDI has proven to be invaluable in determining the optimal treatment of a burn patient. For unclear reasons, LDI is still not routinely used in burn centers worldwide. Additional research is required to identify potential "barriers" for universal implementation of this evidence-based burn depth assessment tool.

Outcome Measurements in Wound Healing Are Not Inclusive: A Way Forward

Standardized outcome measurement in wound healing has been an elusive goal. Whilst research into wound healing science and technology continues to progress rapidly, the lack of a uniform outcome assessment is making comparative analysis of results difficult. This paper seeks to outline the reported clinical, physiological, and histological outcomes that have been utilized in the literature. A minimal data set base for wound outcome evaluation is also established to be validated by future multivariate analysis of patient data.

ICG angiography predicts burn scarring within 48 h of injury in a porcine vertical progression burn model

The current standard of care in determining the need to excise and graft a burn remains with the burn surgeon, whose clinical judgment is often variable. Prior work suggests that minimally invasive perfusion technologies are useful in burn prognostication. Here we test the predictive capabilities of Laser Doppler Imaging (LDI) and indocyanine green dye (ICG) angiography in the prediction of burn scarring 28 days after injury using a previously validated porcine burn model that shows vertical progression injury. Twelve female Yorkshire swine were burned using a 2.5 × 2.5 cm metal bar at variable temperature and application times to create distinct burn depths. Six animals (48 injuries total) each were analyzed with LDI or ICG angiography at 1, 24, 48, and 72 h following injury. A linear regression was then performed correlating perfusion measurements against wound contraction at 28 days after injury. ICG angiography showed a peak linear correlate (r(2)) of .63 (95% CI .34 to .92) at 48 h after burn. This was significantly different from the LDI linear regression (p < .05), which was measured at r(2) of .20 (95% CI .02 to .39). ICG angiography linear regression was superior to LDI at all timepoints. Findings suggest that ICG angiography may have significant potential in the prediction of long-term burn outcomes.

The critical evaluation of laser Doppler imaging in determining burn depth

This review article discusses the use of laser Doppler imaging as a clinimetric tool to determine burn depth in patients presenting to hospital. Laser Doppler imaging is a very sensitive and specific tool to measure burn depth, easy to use, reliable and acceptable to the patient due to its quick and non-invasive nature. Improvements in validity, cost and reproducibility would improve its use in clinical practice however it is difficult to satisfy the entire evaluation criterion all the time. It remains a widely accepted tool to assess burn depth, with an ever-increasing body of evidence to support its use, as discussed in this review. Close collaboration between clinicians, statisticians, epidemiologists and psychologists is necessary in order to develop the evidence base for the use of laser Doppler imaging as standard in burn depth assessment and therefore act as an influencing factor in management decisions.