Transcutaneous electrical acupoint stimulation for prevention of postoperative delirium in geriatric patients with silent lacunar infarction: a preliminary study

Abstract

Purpose: This study aims to investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on postoperative delirium (POD) in elderly patients with silent lacunar infarct and preliminarily to determine the relationship among TEAS, blood-brain barrier (BBB), neuroinflammation, and POD.

Patients and methods: Sixty-four-old patients with silent lacunar infarct were randomly divided into two groups: group TEAS and control group (group C). Patients in the group TEAS received TEAS (disperse-dense waves; frequency, 2/100 Hz) on acupoints Hegu and Neiguan of both sides starting from 30 minutes before induction of anesthesia until the end of surgery, and the intensity was the maximum current that could be tolerated. In group C, electrodes were placed on the same acupoints before anesthesia induction, but no current was given. At 0 minute before the treatment of TEAS, 30 minutes after skin incision, and after completion of surgery (T_1-3), blood samples were extracted to detect the concentration of serum tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), and S100β. We assessed patients for delirium and coma twice daily in the first 3 postoperative days using the Confusion Assessment Method for the intensive care unit and the Richmond Agitation-Sedation Scale.

Results: This study preliminarily suggests that TEAS can reduce the development of POD in elderly patients with silent lacunar infarction (6.3% vs 25.0%; P=0.039). Compared with the baseline value at T₁, the serum concentrations of IL-6, TNF-α, MMP-9, and S100β were significantly increased at T_2-3 in both the groups (P<0.05). Compared with group TEAS, serum levels of TNF-α and IL-6 were higher at T_2-3 and serum levels of MMP-9 and S100β were higher at T₃ in group C (P<0.05). The intraoperative anesthetic consumptions were less in group TEAS than group C.

Conclusion: TEAS can alleviate POD in older patients with silent lacunar infarction and may be related to reduce the neuroinflammation by lowering the permeability of BBB.

Keywords: blood–brain barrier; delirium; geriatric; lacunar infarction; neuroinflammation; transcutaneous electrical acupoint stimulation.

Figure 1

Experimental flow of this study. Abbreviations: C, control; LI4, Hegu acupoint; PC6, Neiguan acupoint; TEAS, transcutaneous electrical acupoint stimulation.

Figure 2

The location of the electrodes used for transcutaneous electrical acupoint stimulation. Notes: (A) PC6, located in the palmar of the forearm, 2 inches in the wrists. (B) LI4, located at the back of the hand, between the first and second metacarpal bones, at the midpoint of the second metacarpal radius. Abbreviations: LI4, Hegu acupoint; PC6, Neiguan acupoint.