Effect of ephedrine on gastric conduit perfusion measured by laser speckle contrast imaging after esophagectomy: a prospective in vivo cohort study

Abstract

Compromised perfusion due to ligation of arteries and veins in esophagectomy with gastric tube reconstruction often (5-20%) results in necrosis and anastomotic leakage, which relate to high morbidity and mortality (3-4%). Ephedrine is used widely in anesthesia to treat intraoperative hypotension and may improve perfusion by the increase of cardiac output and mean arterial pressure (MAP). This study tests the effect of ephedrine on perfusion of the future anastomotic site of the gastric conduit, measured by laser speckle contrast imaging (LSCI). This prospective, observational, in vivo pilot study includes 26 patients undergoing esophagectomy with gastric tube reconstruction from October 2015 to June 2016 in the Academic Medical Center (Amsterdam). Perfusion of the gastric conduit was measured with LSCI directly after reconstruction and after an increase of MAP by ephedrine 5 mg. Perfusion was quantified in flux (laser speckle perfusion units, LSPU) in four perfusion locations, from good perfusion (base of the gastric tube) toward decreased perfusion (fundus). Intrapatient differences before and after ephedrine in terms flux were statistically tested for significance with a paired t-test. LSCI was feasible to image gastric microcirculation in all patients. Flux (LSPU) was significantly higher in the base of the gastric tube (791 ± 442) compared to the fundus (328 ± 187) (P < 0.001). After administration of ephedrine, flux increased significantly in the fundus (P < 0.05) measured intrapatients. Three patients developed anastomotic leakage. In these patients, the difference between measured flux in the fundus compared to the base of the gastric tube was high. This study presents the effect of ephedrine on perfusion of the gastric tissue measured with LSCI in terms of flux (LSPU) after esophagectomy with gastric tube reconstruction. We show a small but significant difference between flux measured before and after administration of ephedrine in the future anastomotic tissue (313 ± 178 vs. 397 ± 290). We also show a significant decrease of flux toward the fundus.