Beneficial effects of intravenous dexmedetomidine on cognitive function and cerebral injury following a carotid endarterectomy

Abstract

The present study aimed to investigate the effects of dexmedetomidine (DEX) on cognition following a carotid endarterectomy (CEA). In addition, the neuroprotective effects of DEX against ischemia-reperfusion injury during CEA were analyzed. Patients due to undergo elective CEA under general anesthesia were randomly assigned to either the DEX-treated group (group D; n=25) or the control group (group C; n=25). Patients in group D were treated with 0.3 µg/kg DEX pre-CEA, followed by 0.3 µg/kg/h DEX intraoperatively up to 30 min prior to the completion of surgery, and the patients in group C received an equal volume of normal saline. Cognitive function was assessed prior to CEA (T0), and at 24, 48, and 72 h, 7 days and 1 month post-surgery (T1-5, respectively), using the Mini-Mental State Examination (MMSE). Blood samples were drawn from the ipsilateral jugular bulb of all patients at 20 min prior to anesthesia (t0), and at 10 min following tracheal intubation, 15 min following clamping and unclamping of the carotid artery, and at 6 and 24 h postoperatively (t1-5, respectively). The protein expression levels of markers of cerebral ischemia and injury, namely S100 calcium-binding protein B (S100B) and neuron-specific enolase (NSE), and the concentration of the oxidative stress marker malondialdehyde (MDA), were analyzed. Patients in group D exhibited elevated MMSE scores at T2 and T3 post-CEA, as compared with group C. Furthermore, the protein expression level of S100B and the concentration of MDA in the jugular bulb of group D patients were markedly decreased compared with those in group C at t3-5 and t3, respectively. The results of the present study suggested that DEX was able to enhance the recovery of cognition following CEA, and this was associated with decreased cerebral damage and antioxidative effects.

Keywords: Mini-Mental State Examination; S100 calcium-binding protein B; carotid endarterectomy; cognitive function; dexmedetomidine; malondialdehyde.

Figures

Figure 1.

MAP recordings at various time points: 20 min prior to anesthesia (0); immediately following tracheal intubation (1); 10 min following tracheal intubation (2); 5, 10 and 15 min following clamping of the carotid artery (–5); and 5 and 10 min following unclamping of the carotid artery (6,7). *P#P<0.05 vs. the baseline in group C, ΔP<0.05 vs. group D at the same time point in. MAP, mean arterial pressure.

Figure 2.

MMSE scores of the two groups on 1 day prior to surgery (T0), and at 24, 48 and 72 h, and 7 days and 1 month post-carotid endarterectomy (T1–5, respectively). *P#P<0.05 vs. T0. MMSE, Mini-Mental State Examination score.

Figure 3.

Protein expression levels of (A) S100B and (B) NSE and (C) concentration of MDA in the jugular bulb of group C and group D patients at 20 min prior to anesthesia (t0), 10 min following tracheal intubation (t1), 15 min following clamping of the carotid artery (t2), 15 min following unclamping of the carotid artery (t3), and 6 and 24 h (t4 and t5) post-carotid endarterectomy. *P#P<0.05 vs t0. S100B, S100 calcium-binding protein B; NSE, neuron-specific enolase; MDA, malondialdehyde.