Dexmedetomidine for awake carotid endarterectomy: efficacy, hemodynamic profile, and side effects

Comparison of Opioid-Based Versus Opioid-Sparing Anesthesia in Patients Undergoing Glioma Surgery

Background In the neurosurgical population, opioids may cause respiratory depression, leading to hypercapnia, increased cerebral blood flow (CBF), and ultimately increased intracranial pressure (ICP), which can mask early signs of intracranial complications and delayed emergence. This study was designed to compare perioperative hemodynamic stability, analgesia, and recovery parameters in opioid-based (fentanyl) general anesthesia versus opioid-sparing (dexmedetomidine) general anesthesia in patients undergoing glioma surgeries. Methodology This prospective observational comparative study compared 52 patients in two groups. Twenty-six (50%) patients in group F received Inj. fentanyl IV (intravenous; bolus 2 mcg/kg 10 minutes before induction and then infusion 1 mcg/kg/hour till 30 minutes before skin closure), whereas 26 (50%) patients in group D received Inj. dexmedetomidine IV (0.5 mcg/kg infusion 10 minutes before induction and then maintenance with a 0.5 mcg/kg/hour infusion till 30 minutes before skin closure). Perioperative heart rate (HR), mean arterial pressure (MAP), Numerical Rating Scale for Pain (NRS) assessment and postoperative emergence time, modified Aldrete score, patient satisfaction, and surgeon satisfaction score were estimated and compared in both groups. Results The mean HR was less in group D compared to group F at following time points - 10 minutes after infusion (P = 0.006), laryngoscopy and intubation (P = 0.003), pinning of the skull (P < 0.001), one hour after dura opening (P = 0.007), two hours after dura opening (P = 0.006), five minutes after extubation (P < 0.001), and 30 minutes after extubation (P = 0.011). MAP was lower in group D compared to group F at the following time intervals: 10 minutes after infusion (P = 0.008), five minutes after extubation (P = 0.007), 30 minutes after extubation (P < 0.001), and one hour after extubation (P = 0.023). A significant decrease in emergence time in group D compared to group F (P < 0.001) was noted. NRS was lower in group D at eight hours (P = 0.005) and 12 hours (P < 0.001) post-extubation. Conclusions Dexmedetomidine can be used as an alternative to fentanyl in terms of perioperative hemodynamic stability, perioperative analgesia, smooth early recovery from anesthesia, patient satisfaction, and surgeon satisfaction.

Dexmedetomidine for sedation during epicardial ablation for ventricular tachycardia: a single-center experience

BACKGROUND

Epicardial approach to ventricular tachycardia (VT) ablation is mainly performed under general anesthesia (GA). Although catheter manipulation and ablation in the epicardial space could be painful, GA lowers blood pressure and may interfere with arrhythmia induction and mapping, and the use of muscle relaxants precludes identification of the phrenic nerve (PN). Moreover, an anesthesiologist's presence is required during GA for the whole procedure, which may not always be possible. Therefore, we evaluated the feasibility and safety of epicardial VT ablations performed under conscious sedation using dexmedetomidine in our center.

METHODS

Between January 2018 and January 2022, all patients who underwent epicardial VT ablation under continuous dexmedetomidine infusion were prospectively included in the study. All patients received premedication 30 min before the epicardial puncture with paracetamol (acetaminophen 10 mg/ml) 1000 mg and ketorolac 30 mg. Sedation protocol included an intravenous bolus of midazolam hydrochloride (0.03-0.05 mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an intravenous fentanyl citrate bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose repeated after 30 to 45 min. Sedation-related complications were defined in case of respiratory failure, severe hypotension, and bradycardia requiring treatment.

RESULTS

Sixty-nine patients underwent epicardial or endo-epi VT ablation under conscious sedation and were included in the analysis. The mean age was 65.4 ± 12.1 years; forty-six patients were males (66.6%). All patients had drug-refractory recurrent VT. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy (NICM), 13 patients (18.9%) had ischemic-cardiomyopathy (ICM), and 9 patients (13%) had myocarditis. Standard percutaneous sub-xiphoid access was attempted in all patients. Non-inducibility of any VT was achieved in 82.6% (9/9 myocarditis, 10/13 ICM, 38/47 NICM, n = 57/69 patients), inducibility of non-clinical VT in 13% (3/13 ICM, 6/38 NICM, n = 9/69 patients), and failure in 4.3% (3/38 NICM, n = 3/69 patients). Although we observed procedural-related complications in five patients (7.2%), one transient PN palsy, two pericarditis, and two vascular complications, those were not related to the conscious sedation protocol. No respiratory failure, severe hypotension, or bradycardia requiring treatment has been observed among the patients.

CONCLUSIONS

Prompt availability of anesthesiology support remains crucial for complex procedures such as epicardial VT ablation. Continuous infusion of dexmedetomidine and administration of midazolam and fentanyl seem to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Efficacy of different dose of dexmedetomidine combined with remifentanil in colonoscopy: a randomized controlled trial

Background

Dexmedetomidine has advantages during colonoscopy as it allows the patient to cooperate during the procedure. Few studies examined the dexmedetomidine-remifentanil combination. This study was to evaluate the effects of different doses of the dexmedetomidine-remifentanil combination in colonoscopy.

Methods

This was a prospective trial carried out at the Fourth Hospital of Hebei Medical University between 02/2018 and 10/2018. The patients were randomized: group I (dexmedetomidine 0.2 μg·kg^− 1), group II (dexmedetomidine 0.3 μg·kg^− 1), and group III (dexmedetomidine 0.4 μg·kg^− 1), all combined with remifentanil. The primary outcomes were the patient’s body movements during the procedure and adverse events.

Results

Compared with at admission (T₀), the SBP, HR, and RR at immediately after giving DEX (T₁), at the beginning of the examination (T₂), 5 min after the beginning of the examination (T₃), 10 min after the beginning of the examination (T₄), and at the end of the examination (T₅) in the three groups were all reduced (all P < 0.05), but all were within the clinically normal range. SpO₂ remained > 98% in all patients during the examination. Compared with T₀, the BIS values of the three groups were decreased at T₁ and T₂ (all P < 0.05). There were no significant differences in BIS among the three groups (all P > 0.05). The minimum BIS value in group III was lower than in groups I and II (P < 0.05). The degree of satisfaction with the anesthesia effect was higher in groups II and III that in group I (P < 0.05). No hypotension occurred, seven patients had bradycardia, and four patients had nausea/vomiting.

Conclusions

Dexmedetomidine 0.3 μg·kg^− 1 combined with remifentanil was effective for colonoscopy and had few adverse reactions.

Chinese Clinical Trial Registry: ChiCTR2000029105, Registered 13 January 2020 - Retrospectively registered.

Dexmedetomidine Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Dexmedetomidine (DEX) is a highly selective α2-adrenergic agonist with sedative and analgesic properties, with minimal respiratory effects. It is used as a sedative in the intensive care unit and the operating room. The opioid-sparing effect and the absence of respiratory effects make dexmedetomidine an attractive adjuvant drug for anesthesia in obese patients who are at an increased risk for postoperative respiratory complications. The pharmacodynamic effects on the cardiovascular system are known; however the mechanisms that induce cardioprotection are still under study. Regarding the pharmacokinetics properties, this drug is extensively metabolized in the liver by the uridine diphosphate glucuronosyltransferases. It has a relatively high hepatic extraction ratio, and therefore, its metabolism is dependent on liver blood flow. This review shows, from a basic clinical approach, the evidence supporting the use of dexmedetomidine in different settings, from its use in animal models of ischemia-reperfusion, and cardioprotective signaling pathways. In addition, pharmacokinetics and pharmacodynamics studies in obese subjects and the management of patients subjected to mechanical ventilation are described. Moreover, the clinical efficacy of delirium incidence in patients with indication of non-invasive ventilation is shown. Finally, the available evidence from DEX is described by a group of Chilean pharmacologists and clinicians who have worked for more than 10 years on DEX.

Outcomes of Carotid Endarterectomy according to the Anesthetic Method: General versus Regional Anesthesia

Background

The surgical strategies for carotid endarterectomy (CEA) vary in terms of the anesthesia method, neurological monitoring, shunt usage, and closure technique, and no gold-standard procedure has been established yet. We aimed to analyze the feasibility and benefits of CEA under regional anesthesia (RA) and CEA under general anesthesia (GA).

Methods

Between June 2012 and December 2017, 65 patients who had undergone CEA were enrolled, and their medical records were prospectively collected and retrospectively reviewed. A total of 35 patients underwent CEA under RA with cervical plexus block, whereas 30 patients underwent CEA under GA. In the RA group, a carotid shunt was selectively used for patients who exhibited negative results on the awake test. In contrast, such a shunt was used for all patients in the GA group.

Results

There were no cases of postoperative stroke, cardiovascular events, or mortality. Nerve injuries were noted in 4 patients (3 in the RA group and 1 in the GA group), but they fully recovered prior to discharge. Operative time and clamp time were shorter in the RA group than in the GA group (119.29±27.71 min vs. 161.43±20.79 min, p<0.001; 30.57±6.80 min vs. 51.77±13.38 min, p<0.001, respectively). The hospital stay was shorter in the RA group than in the GA group (14.6±5.05 days vs. 18.97±8.92 days, p=0.022). None of the patients experienced a stroke or restenosis during the 27.23±20.3-month follow-up period.

Conclusion

RA with a reliable awake test reduces shunt use and decreases the clamp and operative times of CEA, eventually resulting in a reduced length of hospital stay.

Dexmedetomidine reduces inflammation in traumatic brain injury by regulating the inflammatory responses of macrophages and splenocytes

Traumatic brain injury (TBI) affects people in all demographics, since it is associated with a variety of chronic degenerative diseases, such as Alzheimer's and Parkinson's disease. In TBI, the central nervous system elicits an immune response involving various immune cells that is necessary for healing and defending the body against pathogens, but can also cause secondary damage to the brain if the response is prolonged. In our clinical practice, it has been identified that administration of dexmedetomidine was associated with reduced production of inflammatory cytokines in patients with TBI, which led to the hypothesis that dexmedetomidine may regulate certain inflammatory responses. To test this hypothesis, the roles of dexmedetomidine in the immune system of mice were investigated. Different biological assays were used to assess the influence of dexmedetomidine on the production of inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 and IL-1β. To understand how dexmedetomidine affects different types of immune cells, the influence of dexmedetomidine on splenocytes was also investigated. Finally, the effects of dexmedetomidine on macrophage activation and inflammatory functions were studied. In the present study, clinical observations and in vivo results using a mouse model of TBI revealed the regulatory functions of dexmedetomidine in TBI-associated immune response.

Evaluation and Comparison of Fentanyl versus Nalbuphine for Attenuation of Hemodynamic Response to Laryngoscopy and Endotracheal Intubation in General Anesthesia

Background:

General anesthesia administration involves laryngoscopy and endotracheal intubation which are associated with the pressor response and can lead to tachycardia, hypertension, and arrhythmias, which can be deleterious in compromised patients and hence, this response needs to be suppressed.

Aims:

The aim of the study is to compare the effectiveness of intravenous (i.v) fentanyl and nalbuphine on the suppression of hemodynamic response in patients undergoing surgery under general anesthesia.

Setting and Design:

This prospective comparative study was conducted in the department of anesthesiology of a tertiary care center, and patients posted for elective surgery under general anesthesia were included.

Methods:

A total of 100 patients of either sex in the age group of 20–50 years, belonging to the American Society of Anesthesiologists physical status classes I and II undergoing surgery under general anesthesia, were divided into two groups: Group N (n = 50) – who received injection nalbuphine 0.2 mg/kg diluted in 10 mL normal saline i.v and Group F (n = 50) – who received injection fentanyl 2 μg/kg diluted in 10 mL of normal saline i.v over 1 min, 5 min prior to intubation. Technique of anesthesia was standardized for all the patients in the study. Heart rate (HR), blood pressure (systolic, diastolic, and mean arterial pressure [SBP, DBP, and MAP]), and oxygen saturation were recorded at baseline, induction, and at 1, 3, 5, and 10 min after intubation.

Statistical Analysis:

Descriptive statistics were done using mean with standard deviation for quantitative variables, and categorical variables were presented in frequencies along with respective percentages. The statistical comparisons for quantitative variables were done using Student's t-test and for categorical variables, Chi-square was used according to the data. All statistical analyses were performed using SPSS software (Version 22, SPSS Inc., Chicago, IL, USA). All analyses were two tailed, and results were discussed on 5% level of significance, i.e., P < 0.05 was considered statistically significant.

Results:

The demographic characteristics were comparable in both groups. HR was statistically insignificant between the two groups at all intervals. Comparing SBP, DBP, and MAP between the two groups, there was a significant increase in nalbuphine group than fentanyl group postintubation and was statistically significant at all intervals of time. Maximum rise in SBP, DBP, and MAP was 5.49%, 6.03%, and 5.80% for fentanyl group and 12.88%, 9.37%, and 10.86% for nalbuphine group, respectively. Comparison of oxygen saturation in two groups was statistically insignificant.

Conclusion:

Fentanyl is better than nalbuphine in blunting the pressor response of laryngoscopy and endotracheal intubation.

Ultrasound-guided superficial cervical plexus block under dexmedetomidine sedation versus general anesthesia for carotid endarterectomy: a retrospective pilot study

Background

Carotid endarterectomy (CEA) has been performed under regional and general anesthesia (GA). The general anesthesia versus local anesthesia for carotid surgery study compared the two techniques and concluded that there was no difference in perioperative outcomes. However, since this trial, new sedative agents have been introduced and devices that improve the delivery of regional anesthesia (RA) have been developed. The primary purpose of this pilot study was to compare intraoperative hemodynamic stability and postoperative outcomes between GA and ultrasound-guided superficial cervical plexus block (UGSCPB) under dexmedetomidine sedation for CEA.

Methods

Medical records from 43 adult patients who underwent CEA were retrospectively reviewed, including 16 in the GA group and 27 in the RA group. GA was induced with propofol and maintained with sevoflurane. The UGSCPB was performed with ropivacaine under dexmedetomidine sedation. We compared the intraoperative requirement for vasoactive drugs, postoperative complications, pain scores using the numerical rating scale, and the duration of hospital stay.

Results

There was no difference between groups in the use of intraoperative antihypertensive drugs. However, intraoperative inotropic and vasopressor agents were more frequently required in the GA group (p<0.0001). In the GA group, pain scores were significantly higher during the first 24 h after surgery (p<0.0001 between 0-6 h, p<0.004 between 6-12 h, and p<0.001 between 12-24 h). The duration of hospital stay was significantly more in the GA group (13.3±4.6 days in the GA group vs. 8.5±2.4 days in the RA group, p<0.001).

Conclusion

In this pilot study, intraoperative hemodynamic stability and postoperative outcomes were better in the RA compared to the GA group.

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.

Use of Dexmedetomidine for Prophylactic Analgesia and Sedation in Patients With Delayed Extubation After Craniotomy: A Randomized Controlled Trial

Background:

We conducted a randomized trial to evaluate the efficacy and safety of dexmedetomidine for prophylactic analgesia and sedation in patients with delayed extubation after craniotomy.

Methods:

From June 2012 to July 2014, 150 patients with delayed extubation after craniotomy were randomized 1:1 and were assigned to the dexmedetomidine group that received a continuous infusion of 0.6 μg/kg/h (10 μg/mL) or the control group that received a maintenance infusion of 0.9% sodium chloride for injection. The mean percentage of time under optimal sedation (SAS3-4), the percentage of patients who required rescue with propofol/fentanyl, and the total dose of propofol/fentanyl required throughout the course of drug infusion, as well as VAS, HR, MAP, and SpO₂ were recorded.

Results:

The percentage of time under optimal sedation was significantly higher in the dexmedetomidine group than in the control group (98.4%±6.7% vs. 93.0%±16.2%, P=0.008). The VAS was significantly lower in the dexmedetomidine group than in the control group (1.0 vs. 4.0, P=0.000). The HR and mean BP were significantly lower in the dexmedetomidine group than in the control group at all 3 time points (before endotracheal suctioning, immediately after extubation, and 30 min after extubation). No significant difference in SpO₂ was observed between the 2 groups. For hemodynamic adverse events, patients in the dexmedetomidine group were more likely to develop bradycardia (5.3% vs. 0%, P=0.043) but had a lower likelihood of tachycardia (2.7% vs. 18.7%, P=0.002).

Conclusions:

Dexmedetomidine may be an effective prophylactic agent to induce sedation and analgesia in patients with delayed extubation after craniotomy. The use of dexmedetomidine (0.6 μg/kg/h) infusion does not produce respiratory depression, but may increase the incidence of bradycardia.

The myocardial protective effect of dexmedetomidine in high-risk patients undergoing aortic vascular surgery

Objective:

The aim of the study was to assess the effect of dexmedetomidine in high-risk patients undergoing aortic vascular surgery.

Design:

A randomized prospective study.

Setting:

Cairo University, Egypt.

Materials and Methods:

The study included 150 patients undergoing aortic vascular surgery.

Intervention:

The patients were classified into two groups (n = 75). Group D: The patients received a loading dose of 1 μg/kg dexmedetomidine over 15 min before induction and maintained as an infusion of 0.3 μg/kg/h to the end of the procedure. Group C: The patients received an equal volume of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly.

Measurements:

The monitors included the heart rate, mean arterial blood pressure, central venous pressure, electrocardiogram (ECG), serum troponin I level, end-tidal sevoflurane, and total dose of morphine in addition transthoracic echocardiography to the postoperative in cases with elevated serum troponin I level.

Main Results:

The dexmedetomidine decreased heart rate and minimized the changes in blood pressure compared to control group (P < 0.05). Furthermore, it decreased the incidence of myocardial ischemia reflected by troponin I level, ECG changes, and the development of new regional wall motion abnormalities (P < 0.05). Dexmedetomidine decreased the requirement for nitroglycerin and norepinephrine compared to control group (P < 0.05). The incidence of hypotension and bradycardia was significantly higher with dexmedetomidine (P < 0.05).

Conclusion:

The dexmedetomidine is safe and effective in patients undergoing aortic vascular surgery. It decreases the changes in heart rate and blood pressure during the procedures. It provides cardiac protection in high-risk patients reflected by decreasing the incidence of myocardial ischemia and serum level of troponin. The main side effects of dexmedetomidine were hypotension and bradycardia.

Regional Anesthesia with Dexmedetomidine Infusion: A Feasible Method for the Awake Test during Carotid Endarterectomy

Background: Carotid endarterectomy (CEA) is the standard treatment modality for the prevention of stroke in patients with carotid stenosis. This study reports our experiences during CEA with routine awake tests under regional anesthesia (RA) combined with light sedation by dexmedetomidine infusion. Materials and Methods: We retrospectively reviewed 23 patients who had undergone CEA between April 2013 and June 2015. All patients underwent the awake test during CEA with cervical plexus block and light sedation by continuous dexmedetomidine infusion. Results: Mean operation and clamp times were 108.5 ± 20.1 min and 30.1 ± 6.9 min, respectively. Selective shunt placement was performed in three patients (13.0%). There were no cases of perioperative stroke, myocardial infarction, or death. There were no occurrences of residual stenosis, thrombosis, or dissection. One patient had a hypoglossal nerve injury but fully recovered before discharge. Mean (± standard deviation) hospital stay was 7.5 ± 2.6 days. There were no incidences of death, stroke, or restenosis during a mean follow-up period of 9.2 ± 8.8 months. Conclusions: RA with dexmedetomidine infusion appears to be a safe and feasible option. A lower shunt placement rate and favorable patient outcomes were observed following the awake test during CEA.

Comparison of Dexmedetomidine Versus Midazolam-Fentanyl Combination for Monitored Anesthesia Care During Burr-Hole Surgery for Chronic Subdural Hematoma

BACKGROUND

Intraoperative movements are marker of inadequate level of sedation and are undesirable during burr-hole surgery under monitored anesthesia care (MAC). It distracts surgeon, hinders surgical procedure, and may lead to iatrogenic complication. Dexmedetomidine has shown to provide excellent analgesia, cooperative sedation with fewer fluctuations in sedation level during MAC. We compared the effect of dexmedetomidine on intraoperative patient movement, postoperative recovery time, and the surgeon and patient satisfaction scores with commonly used midazolam-fentanyl combination.

METHODS

Fifty-two patients undergoing burr-hole surgery for chronic subdural hematoma under MAC were randomly assigned to receive either IV dexmedetomidine 1 μg/kg over 10 minutes followed by continuous infusion 0.03 to 0.07 μg/kg/h (group D) or IV fentanyl 0.5 μg/kg and midazolam 0.03 mg/kg over 10 minutes followed by continuous infusion of 0.5 to 1.16 μg/kg/h fentanyl and 0.03 to 0.07 mg/kg/h midazolam (group M/F) titrated to maintain Ramsay sedation scale 3. Total number of intraoperative patient movements, postoperative recovery time, and patient and surgeon satisfaction scores were recorded.

RESULTS

Demographic and baseline characteristics were comparable between the 2 groups. Intraoperative patient movements were significantly less in group D than group M/F (median interquartile range, 1.00 [0.00 to 2.00] vs. 3.00 [1.00 to 3.25], P=0.007). Group D patients showed faster postoperative recovery (mean ± SD, 7.00 ± 6.96 vs. 13.69 ± 6.18 min, P=0.000). Surgeon satisfaction scores were better in group D compared with group M/F (median interquartile range, 1.00 [1.00 to 1.25] vs. 2.00 [1.00 to 2.00], P=0.014). However, patient satisfaction score and hemodynamic parameters were comparable (P>0.05) between both the groups.

CONCLUSIONS

Use of dexmedetomidine for MAC is associated with lesser number of intraoperative patient movements, faster postoperative recovery, better surgeon satisfaction score, and comparable patient's satisfaction compared with midazolam-fentanyl combination.

The Safety and Efficacy of Dexmedetomidine vs. Sufentanil in Monitored Anesthesia Care during Burr-Hole Surgery for Chronic Subdural Hematoma: A Retrospective Clinical Trial

Background: Chronic subdural hematoma (CSDH) is a very common clinical emergency encountered in neurosurgery. While both general anesthesia (GA) and monitored anesthesia care (MAC) can be used during CSDH surgery, MAC is the preferred choice among surgeons. Further, while dexmedetomidine (DEX) is reportedly a safe and effective agent for many diagnostic and therapeutic procedures, there have been no trials to evaluate the safety and efficacy of DEX vs. sufentanil in CSDH surgery.

Objective: To evaluate the safety and efficacy of DEX vs. sufentanil in MAC during burr-hole surgery for CSDH.

Methods: In all, 215 fifteen patients underwent burr-hole surgery for CSDH with MAC and were divided into three groups: Group D1 (n = 67, DEX infusion at 0.5 μg·kg⁻¹ for 10 min), Group D2 (n = 75, DEX infusion at 1 μg·kg⁻¹ for 10 min), and Group S (n = 73, sufentanil infusion 0.3 μg·kg⁻¹ for 10 min). Ramsay sedation scale (RSS) of all three groups was maintained at 3. Anesthesia onset time, total number of intraoperative patient movements, hemodynamics, total cumulative dose of DEX, time to first dose and amount of rescue midazolam or fentanyl, percentage of patients converted to alternative sedative or anesthetic therapy, postoperative recovery time, adverse events, and patient and surgeon satisfaction scores were recorded.

Results: The anesthesia onset time was significantly less in group D2 (17.36 ± 4.23 vs. 13.42 ± 2.12 vs. 15.98 ± 4.58 min, respectively, for D1, D2, S; P < 0.001). More patients in groups D1 and S required rescue midazolam to achieve RSS = 3 (74.63 vs. 42.67 vs. 71.23%, respectively, for D1, D2, S; P < 0.001). However, the total dose of rescue midazolam was significantly higher in group D1 (2.8 ± 0.3 vs. 1.9 ± 0.3 vs. 2.0 ± 0.4 mg, respectively, for D1, D2, S; P < 0.001). The time to first dose of rescue midazolam was significantly longer in group D2 (17.32 ± 4.47 vs. 23.56 ± 5.36 vs. 16.55 ± 4.91 min, respectively, for D1, D2, S; P < 0.001). Significantly fewer patients in groups S and D2 required rescue fentanyl to relieve pain (62.69 vs. 21.33 vs. 27.40%, respectively, for D1, D2, S; P < 0.001). Additionally, total dose of rescue fentanyl in group D1 group was significantly higher (212.5 ± 43.6 vs. 107.2 ± 35.9 vs. 98.6 ± 32.2 μg, respectively, for D1, D2, S; P < 0.001). Total number of patient movements during the burr-hole surgery was higher in groups D1 and S (47.76 vs. 20.00 vs. 47.95%, respectively, for D1, D2, S; P < 0.001). Four patients in D1 and five in S converted to propofol. The time to recovery for discharge from the PACU was significantly shorter in group D2 (16.24 ± 4.15 vs. 12.48 ± 3.29 vs. 15.91 ± 3.66 min, respectively, for D1, D2, S; P < 0.001). Results from the patient and surgeon satisfaction scores showed significant differences favoring group D2 (P < 0.05). More patients in groups D1 and S showed higher levels of the overall incidence of tachycardia and hypertension, and required higher doses of urapidil and esmolol (P < 0.05). Six patients experienced respiratory depression in group S.

Conclusion: Compared with sufentanil, DEX infusion at 1 μg·kg⁻¹ was associated with fewer intraoperative patient movements, fewer rescue interventions, faster postoperative recovery, and better patient and surgeon satisfaction scores and could be safely and effectively used for MAC during burr-hole surgery for CSDH.

The protective and hemodynamic effects of dexmedetomidine on hypertensive cerebral hemorrhage patients in the perioperative period

The aim of the present study was to analyze the protective and hemodynamic effects of dexmedetomidine in hypertensive cerebral hemorrhage (HCH) patients during perioperative period. In total, 50 HCH patients were selected and randomly divided into two groups, one group was administered with dexmedetomidine and the other groups with midazolam. The mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO₂) were monitored in the two groups of patients before and during the operation. The MAP, HR, SpO₂ and P_ETCO₂ recorded 5 min after admission into the operation room was considered T₁, the same parameters recorded 10 min after drug administration were considered T₂, just after starting the operation were considered T₃ and 30 min after start of operation were considered T₄. The preoperative sedation and analgesia were evaluated by the Ramsay scoring method and the neuron-specific enolase (NSE) and S100 protein (S100β) were estimated using ELISA. The patients of the midazolam group experienced mild respiratory depression during the period of sedation. Levels of, MAP, HR and P_ETCO₂ were significantly increased whereas SPO₂ was decreased (P<0.05). The MAP, HR, SPO₂ and P_ETCO₂ were stable during the period of sedation (P>0.05). The plasma concentrations of epinephrine and norepinephrine at T₁ were similar in the two groups (P>0.05), but decreased after drug administration. This decrease was more prominent in the dexmedetomidine group patients (P<0.05) than midazolam group patients. The epinephrine and norepinephrine concentrations just after starting operation (T₃) were higher than the basal level (T₁) in the midazolam group, but close to the basal level in the dexmedetomidine group (P<0.05). The serum concentration of NSE and S100β in the two groups showed no difference (P>0.05) at the end of operation (T₅), but after 24 h of operation (T₇) NSE and S100β in the dexmedetomidine group were significantly lower compared to the midazolam group (P<0.05). In conclusion, the administration of dexmedetomidine for patients with HCH during perioperative period is safe and serves as an effective sedative, without causing respiratory depression and does not influence stable haemodynamics with certain brain protective effect.

Effect of perioperative dexmedetomidine on the endocrine modulators of stress response: a meta-analysis

This study examined the effects of perioperative dexmedetomidine treatment on physiological modulators of surgical stress response. The quality of the included studies was assessed prior to performing meta-analyses of the weighted mean differences in the changes from baseline of stress hormones and interpreted in the light of statistical heterogeneity between the studies. Nineteen studies (844 surgical subjects) data were used for this meta-analysis. Dexmedetomidine administration significantly decreased blood cortisol levels (μg/dL) postoperatively (mean difference with 95% confidence interval (CI) from controls: -18.78 (-28.45, -9.10); P < 0.05). In the subgroup analysis, the mean difference between dexmedetomidine-treated and saline-treated subjects in the changes from baseline of the cortisol levels was -20.10 (-30.96, -9.25; P < 0.05) but, between dexmedetomidine- and comparator-treated subjects, it was not statistically significantly different (-15.13 (-49.78, 19.52); P < 0.05). Compared with controls, dexmedetomidine treatment also decreased adrenaline and noradrenaline levels significantly (mean difference in the percent changes from baseline: -90.41 (-145.79, -35.03)%; P < 0.05 and -62.82 (-85.47, -0.40.17)%; P < 0.05, respectively). Dexmedetomidine also decreased prolactin levels with a mean difference of -19.42 (-39.37, 0.52) μg/L (P = 0.06). In conclusion, perioperative use of dexmedetomidine reduces serum catecholamine and cortisol levels but the decrease in cortisol levels was not statistically different from the comparator anaesthetics. More data will be required to assess the effects of dexmedetomidine on corticotropin, prolactin, and growth hormone.

Current role of dexmedetomidine in clinical anesthesia and intensive care

Dexmedetomidine is a new generation highly selective α2-adrenergic receptor (α2-AR) agonist that is associated with sedative and analgesic sparing effects, reduced delirium and agitation, perioperative sympatholysis, cardiovascular stabilizing effects, and preservation of respiratory function. The aim of this review is to present the most recent topics regarding the advantages in using dexmedetomidine in clinical anesthesia and intensive care, while discussing the controversial issues of its harmful effects.

Premedication with dexmedetomidine in pediatric patients: a systematic review and meta-analysis

Premedication is important in pediatric anesthesia. This meta-analysis aimed to investigate the role of dexmedetomidine as a premedicant for pediatric patients. A systematic literature search was conducted to identify randomized controlled trials comparing dexmedetomidine premedication with midazolam or ketamine premedication or placebo in children. Two reviewers independently performed the study selection, quality assessment and data extraction. The original data were pooled for the meta-analysis with Review Manager 5. The main parameters investigated included satisfactory separation from parents, satisfactory mask induction, postoperative rescue analgesia, emergence agitation and postoperative nausea and vomiting. Thirteen randomized controlled trials involving 1190 patients were included. When compared with midazolam, premedication with dexmedetomidine resulted in an increase in satisfactory separation from parents (RD = 0.18, 95% CI: 0.06 to 0.30, p = 0.003) and a decrease in the use of postoperative rescue analgesia (RD = -0.19, 95% CI: -0.29 to -0.09, p = 0.0003). Children treated with dexmedetomidine had a lower heart rate before induction. The incidence of satisfactory mask induction, emergence agitation and PONV did not differ between the groups. Dexmedetomidine was superior in providing satisfactory intravenous cannulation compared to placebo. This meta-analysis suggests that dexmedetomidine is superior to midazolam premedication because it resulted in enhanced preoperative sedation and decreased postoperative pain. Additional studies are needed to evaluate the dosing schemes and long-term outcomes of dexmedetomidine premedication in pediatric anesthesia.

Dexmedetomidine in current anaesthesia practice- a review

Dexmedetomidine is an alpha 2 adrenergic receptor agonist, even ten times more selective than clonidine. It is a very versatile drug in anaesthesia practice, finding place in increasing number of clinical scenarios and is no more limited to intensive care unit (ICU) sedation. It is analgesic, has anaesthetic sparing effect, sympatholytic property, useful in other procedural sedation and also has cardiovascular stabilizing property. It reduces delirium and preserves respiratory function which adds benefits to its uses. The aim of this review is to make awareness of its role in present anaesthesia and discuss its limitations at the same time.

Regional anaesthesia for carotid endarterectomy

Summary Regional anaesthesia is a popular choice for patients undergoing carotid endarterectomy (CEA). Neurological function is easily assessed during carotid cross-clamping; haemodynamic control is predictable; and hospital stay is consistently shorter compared with general anaesthesia (GA). Despite these purported benefits, mortality and stroke rates associated with CEA remain around 5% for both regional anaesthesia and GA. Regional anaesthetic techniques for CEA have improved with improved methods of location of peripheral nerves including nerve stimulators and ultrasound together with a modification in the classification of cervical plexus blocks. There have also been improvements in local anaesthetic, sedative, and arterial pressure-controlling drugs in patients undergoing CEA, together with advances in the management of patients who develop neurological deficit after carotid cross-clamping. In the UK, published national guidelines now require the time between the patient's presenting neurological event and definitive treatment to 1 week or less. This has implications for the ability of vascular centres to provide specialized vascular anaesthetists familiar with regional anaesthetic techniques for CEA. Providing effective regional anaesthesia for CEA is an important component in the armamentarium of techniques for the vascular anaesthetist in 2014.

Benefits of using dexmedetomidine during carotid endarterectomy: A review

As per current recommendation, patients with acute ischemic stroke should be offered carotid endarterectomy (CEA) within 24-72 hours. The same applies to patients with recurrent transient ischemic attacks (TIA). This time is usually less for hemodynamic optimization of patients who’ve suffered acute ischemic stroke. Hence’ they are hemodynamically labile and can have accelerated hypertension on induction/extubation. This can have disastrous outcomes. It is a common practice among anesthesiologists to avoid angiotensin converting enzyme(ACE) inhibitors or angiotensin receptor blockers on the day of surgery. This also adds to hypertensive issues perioperatively. Dexmedetomidine is a wonderful drug which can be used during CEA. Due to its centrally mediated sympatholytic effect, it confers good hemodynamic control during induction, intraoperatively, and during extubation. We did a search on PubMed and Google for carotid endarterectomies done under general and locoregional anesthesia during which dexmedetomidine was used. The keywords used by us during the search were as follows: anesthesia, carotid endarterectomy, anesthesia. We also searched for use of dexmedetomidine infusion to attenuate hypertensive response to intubation and for providing stability in major surgeries like CABG, craniotomies, bariatric surgeries, and valve replacements.

Dexmedetomidine: an adjuvant making large inroads into clinical practice

The introduction of newer more selective α(-2) adrenergic agonist, dexmedetomidine has made a revolution in the field of anesthesia owing to its varied application. The aim of the current review is to highlight the various clinical and pharmacological aspects of dexmedetomidine in daily routine practice of anesthesiology and intensive care besides its potential role in other clinical specialties. This review of dexmedetomidine was carried out after searching the medical literature in Pubmed, Science direct, Scopus, Google scholar and various text books and journal articles using keywords anesthesia, dexmedetomidine, neurosurgery, pediatric surgery, regional dexmedetomidine, anesthesia, regional, neurosurgery, and pediatric surgery. Dexmedetomidine has made its application from a novel sedating agent in the intensive care unit to its use as an adjuvant in various regional anesthetic techniques because of its "cooperative sedation" without any respiratory depression. It has a favorable pharmacokinetic profile suitable to be used in the perioperative period to reduce the requirements of opioids and anesthetic drugs. There are few side-effects of dexmedetomidine, which should always be kept in mind before choosing the patients for its use. The various side-effects associated with dexmedetomidine include, but are not limited to hypotension, bradycardia, worsening of heart block, dry mouth, and nausea. However, large scale randomized controlled trials are still needed to establish various effects of dexmedetomidine and to clearly define its safety profile.

Use of dexmedetomidine for prophylactic analgesia and sedation in delayed extubation patients after craniotomy: a study protocol and statistical analysis plan for a randomized controlled trial

BACKGROUND

Pain and agitation are common in patients after craniotomy. They can result in tachycardia, hypertension, immunosuppression, increased catecholamine production and increased oxygen consumption. Dexmedetomidine, an alpha-2 agonist, provides adequate sedation without respiratory depression, while facilitating frequent neurological evaluation.

METHODS/DESIGN

The study is a prospective, randomized, double-blind, controlled, parallel-group design. Consecutive patients are randomly assigned to one of the two treatment study groups, labeled 'Dex group' or 'Saline group.' Dexmedetomidine group patients receive a continuous infusion of 0.6 μg/kg/h (10 ug/ml). Placebo group patients receive a maintenance infusion of 0.9% sodium chloride for injection at a volume and rate equal to that of dexmedetomidine. The mean percentages of time in optimal sedation, vital signs, various and adverse events, the percentage of patients requiring propofol for rescue to achieve/maintain targeted sedation (Sedation-Agitation Scale, SAS 3 to 4) and total dose of propofol required throughout the study drug infusion are collected. The percentage of patients requiring fentanyl for additional rescue to analgesia and total dose of fentanyl required are recorded. The effects of dexmedetomidine on hemodynamic and recovery responses during extubation are measured. Intensive care unit and hospital length of stay also are collected. Plasma levels of epinephrine, norepinephrine, dopamine, cortisol, neuron-specific enolase and S100-B are measured before infusion (T1), at two hours (T2), four hours (T3) and eight hours (T4) after infusion and at the end of infusion (T5) in 20 patients in each group.

DISCUSSION

The study has been initiated as planned in July 2012. One interim analysis advised continuation of the trial. The study will be completed in July 2013.

TRIAL REGISTRATION

ClinicalTrials (NCT): ChiCTR-PRC-12002903.

Attenuation of pressor response and dose sparing of opioids and anaesthetics with pre-operative dexmedetomidine

Background and Aims:

Alpha-2 agonists are being increasingly used as adjuncts in general anaesthesia, and the present study was carried out to investigate the ability of intravenous dexmedetomidine in decreasing the dose of opioids and anaesthetics for attenuation of haemodynamic responses during laryngoscopy and tracheal intubation.

Methods:

One hundred patients scheduled for elective general surgery were randomized into two groups: D and F (n=50 in each group). Group D were administered 1 μg/kg each of dexmedetomidine and fentanyl while group F received 2 μg/kg of fentanyl pre-operatively. Thiopental was given until eyelash reflex disappeared. Anaesthesia was maintained with 33:66 oxygen: nitrous oxide. Isoflurane concentration was adjusted to maintain systolic blood pressure within 20% of the pre-operative values. Haemodynamic parameters were recorded at regular intervals during induction, intubation, surgery and extubation. Statistical analysis was carried out using analysis of variance, chi-square test, Student's t test and Mann–Whitney U test.

Results:

The demographic profile was comparable. The pressor response to laryngoscopy, intubation, surgery and extubation were effectively decreased by dexmedetomidine, and were highly significant on comparison (P<0.001). The mean dose of fentanyl and isoflurane were also decreased significantly (>50%) by the administration of dexmedetomidine. The mean recovery time was also shorter in group D as compared with group F (P=0.014).

Conclusions:

Dexmedetomidine is an excellent drug as it not only decreased the magnitude of haemodynamic response to intubation, surgery and extubation but also decreased the dose of opioids and isoflurane in achieving adequate analgesia and anaesthesia, respectively.

Dexmedetomidine: current role in anesthesia and intensive care

BACKGROUND AND OBJECTIVES

To update and review the application of dexmedetomidine in anesthesia and intensive care. This study is a comprehensive review of clinical uses, pharmacology, pharmacokinetics, mechanism of action and adverse effects of dexmedetomidine.

CONTENT

The effective use of sedative-hypnotic agents and analgesics is an integral part of comfort and safety of patients. Dexmedetomidine is a potent and highly selective α-2 adrenoceptor agonist with sympatholytic, sedative, amnestic, and analgesic properties, which has been described as a useful and safe adjunct in many clinical applications. It provides a unique "conscious sedation", analgesia, without respiratory depression. The current reviewed uses include sedation at Intensive Care Unit-ICU (both adult and pediatric), emergency department, regional and general anesthesia, neurosurgery, sedation for pediatric procedures, awake fiber-optic intubation, cardiac surgery and bariatric surgery.

CONCLUSIONS

Dexmedetomidine offers a unique ability of providing both sedation and analgesia without respiratory depression. It is a new agent with a wide safety margin, excellent sedative capacity and moderate analgesic properties. Although its wide use is currently in patients of surgical and non-surgical intensive care units, dexmedetomidine seems to have promising future applications in neuroprotection, cardioprotection and renoprotection. More detailed studies are required to define its role as sedative in critical, neurosurgical and pediatric patients, as anesthesia adjunct and sedative during procedures.

Hemodynamic characteristics of midazolam, propofol, and dexmedetomidine in healthy volunteers

STUDY OBJECTIVE

To study the effect of intravenous (IV) sedation on blood pressure (BP), heart rate (HR), and respiratory rates (RR) to determine if IV sedatives differ with respect to their effect on BP, HR, and RR.

DESIGN

Prospective, randomized, single-blinded, placebo-controlled study.

SETTING

Monitored patient care room at a clinical research center.

SUBJECTS

60 healthy ASA physical status 1 volunteers.

INTERVENTIONS

Subjects were randomized to receive, in increasing doses, one of three IV sedatives: propofol, midazolam, or dexmedetomidine; or saline control.

MEASUREMENTS

Blood pressure (systolic, diastolic), HR, and RR were recorded.

MAIN RESULTS

A significant dose-dependent BP reduction occurred with dexmedetomidine and, to a lesser degree, with propofol; and there was good agreement of predicted versus measured drug concentrations for all sedatives. Blood pressure and HR of participants who received midazolam did not change.

CONCLUSIONS

When administered in sedative doses, dexmedetomidine and, to a lesser extent, midazolam, reduces BP in a dose-dependent fashion. Dexmedetomidine also reduces HR. Midazolam does not affect BP or HR.

A Prospective, Randomized, Placebo-Controlled Study Evaluating the Efficacy of Dexmedetomidine for Sedation During Vascular Procedures

Objective: To examine the efficacy of dexmedetomidine (DEX) as a primary sedative during vascular procedures performed under monitored anesthesia care (MAC). A total of 55 patients were randomized in a 2:2:1 ratio to receive either DEX 1.0 μg/kg load or DEX 0.5 μg/kg load versus midazolam (MDZ) boluses, the current standard of care. This was followed by a maintenance infusion of DEX versus a normal saline infusion for the control group. Midazolam was given in 0.5 mg increments to maintain an equivalent target level of sedation among the 3 study groups. Fentanyl was given in 25 μg increments to treat pain as needed. The percentage of DEX patients not requiring MDZ and the total dose of MDZ and fentanyl were compared to the control. Dexmedetomidine was efficacious as a sole sedative for 50% of patients. The total dose of MDZ and fentanyl was significantly less during the DEX infusions. Patient satisfaction was superior with DEX.

Safety and efficacy of dexmedetomidine in neurosurgical patients

PRIMARY OBJECTIVE

Very little information regarding effects on ICP, CPP and the safety of dexmedetomidine in neurosurgical patients has been published. The objective of this study is to gather information on the dosage, sedative effects and adverse effects of dexmedetomidine in neurosurgical patients.

RESEARCH DESIGN

The study design was retrospective and descriptive.

METHODS AND PROCEDURES

Computerized data were collected from the records of 39 neurosurgical patients in the ICU who received dexmedetomidine between October 2001 and December 2004. MAP, SBP, DBP, HR, ICP and CPP were recorded. The parameter means and standard deviations were obtained and plotted against time.

EXPERIMENTAL INTERVENTIONS

Dexmedetomidine, an alpha-2 agonist, provides adequate sedation without altering respiratory drive, while facilitating frequent neurological examinations. The FDA approved a dosage range for a loading infusion of 0.1 mcg kg-1 infused over 10 minutes followed by 0.2-0.7 mcg kg-1 h-1 continuous infusion for 24 hours.

MAIN OUTCOMES AND RESULTS

A total of 39 patients were enrolled in the study; 26 men and 13 women. The mean age was 34 years. Of the patients enrolled in the study, 15 were successfully extubated with no adverse reactions while maintaining adequate sedation. Agitation was the predominant adverse reaction. Hypotension occurred in 10 patients. The mean CPP increased and the mean ICP decreased. The standard deviation for the means of the ICP and CPP were small and did not fluctuate as widely as the haemodynamic parameters.

CONCLUSIONS

Dexmedetomidine can be a safe and effective sedative agent for neurosurgical patients. A loading infusion should be avoided and higher maintenance doses may be required to ensure adequate sedation. Further studies are necessary to establish an optimal dosage regimen.

Dexmedetomidine sedation for laryngeal framework surgery

OBJECTIVES

Sedation for laryngeal framework surgery has lacked easy modulation between appropriate pain control, airway protection, and the alertness appropriate for vocal testing. Our objective was to determine whether dexmedetomidine hydrochloride could safely and effectively be used as the sole intravenous anesthetic agent in conjunction with local anesthesia for laryngeal framework procedures.

METHODS

We undertook a prospective review of 14 patients who underwent laryngeal framework surgery with dexmedetomidine anesthesia in 2004 and 2005. All dexmedetomidine doses, sedation levels, and vital signs, including blood pressure, heart rate, respiratory rate, and oxygen saturation level, were recorded every 15 minutes by the anesthesiologist throughout the duration of the procedures. Operative conditions were noted by the surgeon, focusing special attention on airway protection, patient arousability, and patient comfort.

RESULTS

Dexmedetomidine sedation produced hemodynamic and respiratory values that were maintained near preoperative values, and overall pharyngeal-laryngeal integrity provided superior operating conditions for the patient and the operating surgeon.

CONCLUSIONS

We believe that dexmedetomidine provides excellent sedative and operative conditions for awake laryngeal framework procedures. Coupled with local anesthesia, dexmedetomidine produced virtually no undesirable hemodynamic or respiratory effects, while allowing for adequate sedation the majority of the time. The operative conditions were markedly improved over those of previous standard monitored anesthesia regimens.