Changes in the sublingual microcirculation during major abdominal surgery and post-operative morbidity.

BACKGROUND: Little is known about perioperative microcirculatory changes during major abdominal surgery, and the main objectives of this study were to evaluate perioperative microcirculatory alterations in this setting, and if changes in microcirculatory parameters are associated with post-operative morbidity and/or with changes in parameters reflecting oxygen delivery.
METHODS: Patients scheduled for major abdominal surgery with an estimated Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) score of > 30 and operation time > 3 h were eligible for inclusion. Perioperative microcirculatory alterations were evaluated in the sublingual mucosa using Sidestream Dark Field (SDF) imaging. Perfused vessel density (PVD), vessel perfusion [microvascular flow index (MFI)], and flow heterogeneity [heterogeneity index (HI)] were analysed. Central venous oxygen saturation (ScvO2) and lactate were measured simultaneously. During a 30-day follow-up period, post-operative complications were registered according to predefined criteria.
RESULTS: Forty-two patients with a median P-POSSUM of 33 were included in the study. MFI was higher during anaesthesia than pre- and post-anaesthesia. PVD and HI did not change during the observation period. Lactate and ScvO2 increased during surgery. Perioperative lactate and ScvO2 values were not correlated with microcirculatory parameters. Complications occurred in 16 patients. No differences in microcirculatory parameters were detected between patients with and without complications.
CONCLUSIONS: Perioperative changes in the sublingual microcirculatory parameters measured with the SDF-imaging technique appear to be minor, and no association with outcome after major abdominal surgery could be demonstrated. Changes in ScvO2 and serum lactate do not reflect sublingual microcirculatory alterations in this setting.