The relationship between intestinal and oral mucosa microcirculation in anaesthetized horses

Objective: To compare alteration in intestinal blood flow in anaesthetized horses with changes in oral mucosa blood flow.

Study design: Prospective, randomized clinical study.

Animals: Eight warmblood horses.

Methods: After induction with guaifenesin and ketamine, anaesthesia was maintained with isoflurane at 1.5 vol% in oxygen. The tissue blood flow was measured using laser Doppler flowmetry at the jejunum, colon, rectal mucosa, oesophageal mucosa and the oral mucosa. After three baseline measurements, blood flow was first increased by dobutamine infusion and thereafter decreased by increasing isoflurane concentration and all measurements repeated twice. anova was used for comparing the measured parameters to baseline and correlation between the different measurement localizations was examined using Pearson correlation (p < 0.05).

Results: Microperfusion at all measurement sites increased significantly during dobutamine infusion and decreased significantly during high isoflurane concentration. There was a significant correlation between flow at the oral mucosa and flow at the jejunum (r² = 0.77, p = 0.002), colon (r² = 0.76, p < 0.001), rectal mucosa (r² = 0.88, p < 0.001) and oesophageal mucosa (r² = 0.83, p <0.001).

Conclusions and clinical relevance: Oral mucosa blood flow can be used in isoflurane anaesthetized horses to reflect changes of intestinal microcirculation.