Regional tissue oxygen saturation measured by near-infrared spectroscopy to assess the depth of burn injuries.

The burn severity depends on the wound depth and area affected. Hitherto burn depth has been judged mainly by visual observation, although concerns have been raised about its validity. The regional tissue blood flow (rTBF) measured by laser Doppler imaging (LDI) in damaged tissue correlates with the depth. However, very few reports are available on the significance of the regional tissue oxygen saturation (rSO2) as an indicator of burn depth. We investigated whether rSO2 by Near-infrared spectroscopy (NIRS) in burn injuries correlates with rTBF by LDI, which would facilitate quantification of the severity of the tissue damage. Methods: We measured rTBF and rSO2 in 50 lesions from 14 patients of burn injury within 24 hours after injury. The correlation between rTBF and rSO2 was evaluated by Spearman rank correlation analysis. Results: The rSO2 (%; range, 52-82) by NIRS and the rTBF (perfusion unit; range, 61-704) by LDI in burn lesions were positively correlated (r=0.755, p<0.001). This statistically positive correlation still remained significant (r=0.678, p<0.001) after the rSO2 values were standardized. Conclusion: This study suggests that NIRS determination of rSO2 in burn injuries shows promise as a reliable and quick method to estimate the depth of burn lesion.