Dynamics of heart rate variability in patients with type 2 diabetes mellitus during spinal anesthesia using...

Objective The aim of this study was to investigate the heart rate variability (HRV) in patients with Type 2 diabetes mellitus (T2DM) who underwent spinal anesthesia using dexmedetomidine for lower limb surgery.

T2DM patients were divided into two groups, namely the controlled group (HbA1c < 7%) and the uncontrolled group (HbA1c > 7%) according to the glycosylated hemoglobin (HbA1c) level, and patients with non-T2DM as the normal group, 30 cases in each group. The HRV, including low-frequency (LF) power, high-frequency (HF) power, total power (TP) and LF/HF ratio, was measured 10 min before spinal anesthesia (T0) and 10 min (T1), 20 min (T2) and 30 min (T3) after spinal anesthesia with dexmedetomidine.

We observed that TP, LF, and HF power in the uncontrolled group were remarkably lower than that in the other two groups at T0 (P < 0.05). In the controlled group, the LF power dropped markedly at T1-2 than the normal group. The LF power in the uncontrolled group did not show significant change at all time points, but was significantly lower than the level in the controlled group at T1-3. The HF power in the three groups did not alter markedly at different time points, but the HF power in the uncontrolled group was markedly lower than that in the normal group and the controlled group. In all three groups, the LF/HF ratio dropped markedly at T1-3 with no markedly difference between the groups. The heart rhythms in the three groups showed a decrease trend after spinal anesthesia with no markedly difference between the groups. The SBP and DBP at T1-3 in the three groups were markedly lower than that at T0, and the systolic blood pressure (SBP) and diastolic blood pressure (DBP) at T1-3 in the uncontrolled group were markedly higher than those in the normal group and the controlled group.

Spinal anesthesia with dexmedetomidine affects autonomic nerve function in patients whose glycemic control is better during the lower limb surgery in T2DM patients, but has no significant effect on patients who fail to do so. For such patients, spinal anesthesia can result in a markedly increase in SBP and DBP.