Validation of scanning laser Doppler flowmetry against single point laser Doppler flowmetry in the measurement of human gastric serosal/muscularis perfusion.

BACKGROUND

Single point laser Doppler (LDF) has been employed intra-operatively to measure gastro-intestinal tissue perfusion, but despite reports that it may have a role in predicting post-operative complications consequent upon hypo-perfusion, methodological drawbacks have prevented its routine clinical application. Scanning laser Doppler flowmetry (SLDF) may address these drawbacks, but this new development has not been previously validated in human gastro-intestinal tissue.

AIMS

This study assessed the ability of Scanning laser Doppler flowmetry to measure human gastric perfusion.

METHODS

10 patients undergoing oesophageal resection were studied. In each 6 measurements of gastric corporal serosal/muscularis were made over 30 seconds using the previously validated single point LDF technique. A single 1 cm2 SLDF scan was made of the same area prior to any vascular division. These measurements were repeated after partial gastric devascularisation and the two techniques' measurements then compared.

RESULTS

Correlation between the 2 methods was good (coefficient of correlation was 0.955 (p<0.01). The mean bias (scan - single point PUs) was -3 PUs (95% CIs 16.3 to 45 PUs) and the limits of agreement were -64 to 58 PUs. The coefficients of variation for the 6 sets of single point measurements made in each patient ranged between 3.0% and 30.4% (mean = 12.5%).

CONCLUSION

These results validate SLDF as a method of measuring gastric tissue perfusion intra-operatively.