Observational study of the effects of age, diabetes mellitus, cirrhosis and chronic kidney disease on sublingual microvascular flow

Introduction

Sidestream dark-field (SDF) imaging is an important new technology that has been used to demonstrate microcirculatory abnormalities in a variety of critical illnesses [1]. The microcirculation is also affected by age and chronic comorbidities. However, the effect of these conditions on SDF microcirculatory parameters has not been well described.

Methods

Sublingual SDF images were obtained from five groups of 20 participants: healthy volunteers under 25 years, healthy volunteers over 55 years, and stable patients over 55 years with one of diabetes mellitus (DM), cirrhosis and stage 5 chronic kidney disease (CKD). Microcirculatory parameters [1] between the groups were then compared for significance using ANOVA for parametric data and the Kruskal-Wallis test for nonparametric data. This was approved by the local ethics committee.

Results

All DM patients were type 2, with mean glycated haemoglobin (HbA1c) of 8.8% (SD 1.7%). Seventeen cirrhotic patients were Child- Pugh-Turcotte score A and one was score B. For CKD, the mean estimated glomerular filtration rate was 11.5 ml/minute (SD 2.9). Median microvascular flow index (MFI) was 2.85 (IQR 2.75 to 3.0) for participants aged <25, 2.81 (2.66 to 2.97) for those aged >55, 2.88 (2.75 to 3.0) for those with DM, 3.0 (2.83 to 3.0) for those with cirrhosis and 3.0 (2.78 to 3.0) for those with CKD (P for difference = 0.14). There were no significant differences in the proportion of perfused vessels and perfused vessel density between the groups. See Figure 1

Figure 1

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Conclusion

Older age, diabetes, and chronic kidney and liver disease need not be considered confounding factors for comparison of SDF microcirculatory parameters in the critically ill.