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

Effect of ultrasound-guided stellate ganglion block on cerebral oxygen metabolism and S100B protein during carotid endarterectomy

OBJECTIVE

To investigate the effect of ultrasound-guided stellate ganglion block (SGB) on cerebral oxygen metabolism and serum S100B during carotid endarterectomy (CEA).

METHODS

Patients who were prospectively enrolled to receive CEA under elective general anesthesia were randomized into an SGB group and a control group (ChiCTR2000033385). Before anesthesia, the SGB group underwent ipsilateral SGB under ultrasound guidance, while the control group did not. Ultrasound-guided right subclavian internal jugular vein catheterization was performed under general anesthesia. Mean arterial pressure (MAP) and heart rate (HR) were monitored at various time points (T0-T4). Arterial and internal jugular venous bulb blood were collected for blood gas analysis, determining jugular venous oxygen saturation (SjvO2), arteriovenous oxygen difference (AVDO2), cerebral oxygen extraction ratio (COER), lactate production rate (LPR), and lactate-oxygen index (LOI). The serum concentration of S100B in the internal jugular venous bulb at each time point was measured.

RESULTS

The results revealed significantly lower HR during anesthesia induction and surgery in the SGB group, with more stable MAP and HR during endotracheal intubation and surgery compared to the control group (P<0.05). The control group exhibited decreases at T3 and a slight increase at T4. SjvO2 was significantly higher in the SGB group, while AVDO2 and COER gradually decreased over time, but they were significantly higher in the control group (P<0.05). LPR and LOI in both groups peaked at T3 and were significantly different between T4 and T2 (P<0.05). Serum S100B levels in both groups rose and then decreased at each time point, but they were consistently lower in the SGB group (P<0.05).

CONCLUSION

SGB before CEA effectively suppresses the stress response, maintains intraoperative hemodynamic stability, improves brain tissue oxygen supply, and demonstrates a neuroprotective effect.

Outcomes of Dexmedetomidine with Local Regional Anesthesia in Carotid Endarterectomy

BACKGROUND

Adequate sedation to complement regional techniques in carotid endarterectomy (CEA) can be challenging. Dexmedetomidine has both analgesic and amnesic properties and is reported to be a safe and acceptable alternative to conventional general endotracheal anesthesia (GETA). Outcomes observing dexmedetomidine in conjunction with regional anesthesia in CEA are not well described or known.

OBJECTIVE

Compare the immediate (during hospitalization) and short-term (within 30 days of hospitalization) postoperative outcomes in patients who underwent CEA using GETA versus local regional anesthesia (LRA) alone versus dexmedetomidine with LRA at a single institution to determine whether dexmedetomidine is a safe adjunct and if there are anesthesia advantages over LRA alone.

METHODS

A retrospective cohort study from January 2015 to December 2019 at Saint Joseph Mercy Ann Arbor. Patients were stratified into three groups based on anesthesia type: GETA, LRA, and dexmedetomidine (D) + LRA. Primary outcomes included stroke, myocardial infarction (MI), and death. Patient demographics were characterized and adjusted using propensity score weighting.

RESULTS

Three hundred seventy nine patients met inclusion criteria; 182 patients in the GETA group, 66 in the D + LRA, and 131 in LRA. There were no significant differences across anesthesia groups in primary outcomes of stroke, MI, and death during the admission. The GETA group had significantly longer length of stay (LOS) compared to the D + LRA group (LOS = 1.51 days versus 0.85 days; P = 0.011) and the LRA group (LOS = 1.08 days; P = 0.003). However, there was no significant difference in hospital LOS between the D + LRA group and LRA only groups (P = 0.952). There was no significant difference between stroke (LRA 0.87%, GETA 0.85%, and LRA + Dex 3.52%), MI (LRA 0%, GETA 0.49%, LRA + Dex 0%), or death (LRA 5.24%, GETA 1.16%, LRA + Dex 0%), within 30 days between all three of the anesthesia groups. There was no significant difference in postoperative pain scores when comparing the GETA group (mean 1.3, standard deviation [SD] 2.5) to LRA (mean 1.2, SD 2.1) and between LRA and D + LRA (mean 0.9, SD 2.1). Procedure time (time of skin incision to closure) and total room time were comparable among all three anesthesia groups (LRA 2.2 hr, SD 2.2; GETA 2.1 hr, SD 0.5; LRA + Dex 2.1 hr, SD 0.5).

CONCLUSIONS

The use of dexmedetomidine in addition to LRA is a safe and acceptable alternative to conventional GETA or LRA alone in CEA with shorter length of hospital stay when compared with GETA, improved patient tolerance based on physician observation, and similar rates of immediate and short-term complications and postoperative pain scores.

What Is the Role of Dexmedetomidine in Modern Anesthesia and Critical Care?

Dexmedetomidine's unique sedative properties have led to its widespread use. Dexmedetomidine has a beneficial pharmacologic profile including analgesic sparing effects, anxiolysis, sympatholysis, organ-protective effects against ischemic and hypoxic injury, and sedation which parallels natural sleep. An understanding of predictable side effects, effects of age-related physiologic changes, and pharmacokinetic and pharmacodynamic effects of dexmedetomidine is crucial to maximize its safe administration in adults and children. This review focuses on the growing body of literature examining advances in applications of dexmedetomidine in children and adults.

Effect of dexmedetomidine for sedation and cognitive function in patients with preoperative anxiety undergoing carotid artery stenting

Objective

This study was performed to examine the effect of dexmedetomidine for intraoperative sedation and postoperative cognitive function in patients with preoperative anxiety undergoing carotid artery stenting.

Methods

Eighty patients were randomly divided into two groups: the dexmedetomidine group and the control group. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Anxiety was evaluated using the Amsterdam Preoperative Anxiety and Information Scale. Routine monitoring indices were recorded during surgery, and cognitive function indices were recorded before drug infusion (T₀), 10 minutes after drug infusion (T₁), at the end of surgery (T₂), and 6 hours after surgery (T₃).

Results

The anxiety scores were not significantly different between the two groups at T0, but they became significantly different at T_1–3. The MMSE scores in both groups increased at 1 and 7 days postoperatively; although the increase in the dexmedetomidine group was sharper, there was no significant difference. In both groups, the MMSE scores at 1 and 7 days after surgery were not significantly different from those at 1 day before surgery.

Conclusion

Dexmedetomidine can improve patients’ anxiety and achieve a sufficient sedation effect without causing postoperative cognitive dysfunction.

Association of biomarker S100B and cerebral oximetry with neurological changes during carotid endarterectomy performed in awake patients

Background: This study attempted to correlate neurological symptoms in awake patients undergoing carotid endarterectomy (CEA) under local anaesthesia (LA) with serum concentration of S100B protein and measurement of cerebral oximetry with near-infrared spectroscopy (NIRS). Patients and methods: A total of 64 consecutive CEAs in 60 patients operated under LA during an 18-month period were prospectively evaluated. A cerebral oximeter was used to measure cerebral oxygen saturation (rSO₂) before and after cross-clamping along with serum concentration of the S100B protein. Selective shunting was performed when neurological changes occurred, regardless of NIRS. Neurological deterioration occurred (neurological symptoms group) in 7 (10.9 %) operations. In 57 (89.1 %) operations, the patients were neurologically stable (no neurological symptoms group). Results: The neurological symptoms that occurred after clamping correlated with an increase in the serum level of S100B (P = .040). The cut-off of 22.5 % of S100B increase was determined to be optimal for identifying patients with neurological symptoms. There was no correlation between rSO₂ decline and neurological symptoms (P = .675). Two (3.1 %) perioperative strokes occurred. Conclusions: We found a correlation between neurological symptoms and serum S100B protein increase. However, because of the long evaluation time of serum S100B, this monitoring technique cannot be performed during CEA.

Use of Dexmedetomidine in Cardiothoracic and Vascular Anesthesia

Dexmedetomidine is a highly selective α₂-adrenergic agonist with analgesic and sedative properties. In the United States, the Food and Drug Administration approved the use of the drug for short-lasting sedation (24 h) in intensive care units (ICUs) in patients undergoing mechanical ventilation and endotracheal intubation. In October 2008, the Food and Drug Administration extended use of the drug for the sedation of nonintubated patients before and during surgical and nonsurgical procedures. In the European Union, the European Medicine Agency approved the use of dexmedetomidine in September 2011 with a single recognized indication: ICU adult patients requiring mild sedation and awakening in response to verbal stimulus. At present, the use of dexmedetomidine for sedation outside the ICU remains an off-label indication. The benefits of dexmedetomidine in critically ill patients and in cardiac, electrophysiology-related, vascular, and thoracic procedures are discussed.

Post-Operative Cognitive Dysfunction: An exploration of the inflammatory hypothesis and novel therapies

Post-Operative Cognitive Dysfunction (POCD) is a highly prevalent condition with significant clinical, social and financial impacts for patients and their communities. The underlying pathophysiology is becoming increasingly understood, with the role of neuroinflammation and oxidative stress secondary to surgery and anaesthesia strongly implicated. This review aims to describe the putative mechanisms by which surgery-induced inflammation produces cognitive sequelae, with a focus on identifying potential novel therapies based upon their ability to modify these pathways.