Development of modified laser Doppler flowmetry device for real-time monitoring of esophageal mucosal blood flow: a preclinical assessment with an animal model

This study aimed to modify a laser Doppler flowmeter designed and assembled at our institute. After measuring sensitivity evaluation in ex vivo experiments, we confirmed the efficacy of this new device for monitoring real-time esophageal mucosal blood flow changes after thoracic stent graft implantation by simulating various clinical situations in an animal model. Thoracic stent graft implantation was performed in a swine model (n = 8). Esophageal mucosal blood flow decreased significantly from baseline (34.1 ± 18.8 ml/min/100 g vs. 16.7 ± 6.6 ml/min/100 g, P < 0.05) in the lower esophagus (Th6-Th8) where the stent graft covered the aorta. In the hemorrhagic shock model (shock index ≥ 1.0), esophageal mucosal blood flow showed a remarkable change from baseline in the upper esophagus (Th1-Th3), where the stent graft did not cover the aorta (20.8 ± 9.8 ml/min/100 g vs. 12.9 ± 8.6 ml/min/100 g, P < 0.01); however, it returned to the baseline value within a 30-min period. Mucosal blood flow remained stable in the esophagus, where the stent graft did not cover the aorta. After elevating the mean blood pressure to > 70 mmHg with continuous intravenous noradrenaline infusion, esophageal mucosal blood flow increased significantly in both regions; however, the reaction was different between the two regions. Our newly developed laser Doppler flowmeter could measure real-time esophageal mucosal blood flow changes in various clinical situations during thoracic stent graft implantation in a swine model. Hence, this device can be applied in many medical fields by downsizing it.