The effects of dexmedetomidine on attenuation of stress response to endotracheal intubation in patients undergoing elective off-pump coronary artery bypass grafting

Effect of Dexmedetomidine on Cardiac Surgery Patients

ABSTRACT

Dexmedetomidine, an alpha-2 adrenoreceptor agonist that is widely used as a sedative medication, is becoming more and more attractive in clinical application on cardiac surgery patients. In this review, we aim to summarize and discuss both retrospective studies and clinical trials regarding the effect of dexmedetomidine on patients who underwent cardiac surgery (including coronary artery bypass grafting, valve surgery, aortic surgery, percutaneous coronary intervention, and so on), which illustrates that the clinical effects of dexmedetomidine could effectively reduce mortality, major complications, and the intensive care unit and hospital length of stay without comprising safety. In addition, inconsistent results from both retrospective studies and clinical trials have also been demonstrated. Although the effectiveness and safety of dexmedetomidine on cardiac surgery patients is suggested, high-quality clinical trials are needed for further verification.

Loss of α7nAChR enhances endothelial-to-mesenchymal transition after myocardial infarction via NF-κB activation

The myocardial fibrosis in response to myocardial infarction (MI) is closely related to the dysbalance of endothelial-to-mesenchymal transition (EndMT). Although numerous reports indicate that α7 nicotinic acetylcholine receptor (α7nAChR) activates the cholinergic anti-inflammatory pathway (CAP) to regulate the magnitude of inflammatory responses, the role of α7nAChR in myocardial fibrosis, as well as the underlying mechanisms, have not been elucidated. In this study, we evaluated cardiac function, fibrosis, and EndMT signaling using a mouse model of MI and interleukin (IL)-1β-induced human cardiac microvascular endothelial cells (HCMECs). In vivo, α7nAChR deletion increased cardiac dysfunction, exacerbated the cardiac inflammatory response, and NF-κB activation, and enhanced EndMT, as shown by higher expression levels of fibroblast markers (FSP-1, α-SMA, collagen I, Snail) and decreased levels of the FGFR1, glucocorticoid receptor (GR) and endothelial marker (CD31) compared to wild-type mice. In vitro, the pharmacological activation of α7nAChR with PNU282987 significantly inhibited IL-1β-induced EndMT, as shown by a reduced transition to the fibroblast-like phenotype and the expression of fibrotic markers. Moreover, the IL-1β-mediated activation of NF-κB pathway was suppressed by PNU282987. This anti-EndMT effect of α7nAChR was associated with regulation of Snail. Furthermore, Western blot analysis further revealed that the GR antagonist RU38486 could partially counteract the effect of PNU282987 on NF-κB expression. In conclusion, our results show that α7nAChR is involved in cardiac fibrosis by inhibiting EndMT, providing a novel approach to the treatment of MI.

Effect of dexmedetomidine on postoperative systemic inflammation and recovery in patients undergoing digest tract cancer surgery: A meta-analysis of randomized controlled trials

Perioperative immune function, postoperative cognitive function and prognosis are momentous issues for patients undergoing digestive tract cancer surgery. Studies have investigated the efficacy of dexmedetomidine (DEX) administration on these issues, but the results are inconsistent. Therefore, this meta-analysis aimed to summarize all the existing evidence and draw a conclusion more accurately on these associations. Trials were located through electronic searches of the PubMed, Embase, the Cochrane Library and Web of Science databases sources (from the establishment date of databases to April 2022). Bibliographies of the retrieved articles were checked. A total of 17 RCTs involving 1619 patients were included. The results showed that DEX decreased the level of C-reactive protein (SMD = -4.26, 95%CI: -6.16, -2.36), TNF-α (SMD = -4.22, 95%CI: -5.91, -2.54) and IL-6 (SMD = -2.71, 95%CI: -4.46, -0.97), and increased the level of IL-10 (SMD = 1.74, 95%CI: 0.25, 3.24). DEX also increased CD4+ T cells (SMD = 0.55, 95%CI: 0.29, 0.82) and CD4+/CD8+ ratio (SMD = 0.62, 95%CI: 0.24, 1.01). Thus, DEX was associated with alleviation of postoperative systemic inflammatory response and immune dysfunction. Furthermore, DEX increased mini-mental state examination scores at 12h (SMD = 1.10, 95%CI: 0.74,1.45), 24h (SMD = 0.85, 95%CI: 0.59, 1.11), 48h (SMD = 0.89, 95%CI: 0.50, 1.28) and 72h (SMD = 0.75, 95%CI: 0.38, 1.11) after surgery. DEX decreased the occurrence of postoperative cognitive dysfunction (POCD) at 24h (OR = 0.22, 95%CI: 0.11, 0.46) and 72h (OR = 0.39, 95%CI: 0.22, 0.68) after surgery. DEX decreased first flatus time (SMD = -1.55, 95%CI: -2.82, -0.27) and hospital stay (SMD = -1.23, 95%CI: -1.88, -0.59). Therefore, based on perioperative immune dysfunction alleviation, DEX attenuated POCD and potential neuroinflammation, improved postoperative recovery and clinical prognosis of patients undergoing digest tract cancer surgery. Further studies are necessary to elucidate the clinical application of DEX from an immunological perspective.

Anesthetic Management of a Patient With Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmogenic disorder induced by adrenergic stress. Electrophysiologically, it is characterized by emotional stress- or exercise-induced bidirectional ventricular tachycardia that may result in cardiac arrest. Minimizing perioperative stress is critical as it can reduce fatal arrhythmias in patients with CPVT. Dexmedetomidine (DEX), a centrally acting sympatholytic anesthetic agent, was used in the successful intravenous (IV) moderate sedation of a 27-year-old female patient with CPVT, a history of cardiac events, and significant dental fear and anxiety scheduled to undergo mandibular left third molar extraction. Oral surgery was successfully performed under DEX-based IV sedation to reduce stress, and no arrhythmias were observed. IV sedation with DEX provided a sympatholytic effect with respiratory and cardiovascular stability in this patient with CPVT who underwent oral surgery.

A clinical comparative study of dexmedetomidine as an adjuvant to 2% plain lignocaine and 2% lignocaine with 1:200,000 adrenaline as local anesthetic agents for surgical removal of impacted mandibular third molars

Introduction

Dexmedetomidine is a selective alpha-2 adrenoceptor agonist. It is conventionally used as a sedative in the intensive care unit. However, recently, the application of dexmedetomidine as an adjuvant to a local anesthetic agent has been studied. The present study intends to evaluate the effectiveness of dexmedetomidine as an adjuvant to 2% plain lignocaine for surgical removal of impacted mandibular third molar and to compare the efficacy of dexmedetomidine with 2% plain lignocaine with 2% lignocaine and 1:200000 adrenaline.

Materials and Methods

A total of 80 patients who required surgical removal of impacted mandibular third molar extraction were included in the study. Patients were randomly divided into two groups using a computer-generated table. Patients in the study group received 2% plain lignocaine with 1 mcg/ml dexmedetomidine. Patients in the control group received 2% lignocaine with 1:200000 adrenaline. The parameters evaluated were onset and duration of action, pulse rate, blood pressure, oxygen saturation, and blood loss.

Results

Onset of action was faster and the duration of action was longer when dexmedetomidine was used with lignocaine as a local anesthetic agent. The vital parameters in both the groups were stable. Bleeding at the surgical site was less in the dexmedetomidine group.

Conclusion

The study concluded that the combination of dexmedetomidine with lignocaine enhances the local anesthetic potency of lignocaine when injected for nerve blocks.

Premedication with dexmedetomidine for prevention of hyperdynamic response after electroconvulsive therapy: a cross-over, randomized controlled trial

BACKGROUND

Electroconvulsive therapy (ECT) is an effective therapy for psychiatric disorders, but is associated with acute hyperdynamic responses including transient hypertension and tachycardia. This study aimed to assess the effectiveness of premedication with dexmedetomidine for hemodynamic attenuation after ECT and to evaluate its effects on seizure duration, postictal asystole duration, post ECT agitation and recovery time.

METHODS

Twenty-four psychiatric patients who underwent a total of 72 ECT sessions (three sessions per patient) were randomly allocated to receive either dexmedetomidine 0.5 mcg/kg intravenous, dexmedetomidine 1 mcg/kg intravenous, or saline (control group) 15 min before the first ECT session. The patients subsequently received the other two premedication options for their next two ECT sessions. Blood pressure and heart rate were recorded at 5, 10, and 15 min after drug infusion and at 2.5, 5, 7.5, 10, 15, 20, 25, and 30 min after ECT. Asystole duration, seizure duration, post ECT agitation and recovery times were also recorded.

RESULTS

The baseline characteristics were similar between the groups. Systolic blood pressure in both dexmedetomidine groups was significantly lower than that in the control group after ECT (p = 0.002). Diastolic blood pressure and heart rate were significantly lower in the dexmedetomidine 1 mcg/kg group (p = 0.002 and p = 0.013, respectively) compared with the control group. Asystole duration, seizure durations, post ECT agitation and recovery times were similar between the groups.

CONCLUSIONS

Dexmedetomidine 1 mcg/kg administered 15 min before ECT attenuated the hemodynamic response, including suppressing the systolic, diastolic and heart rate increases, during ECT without affecting recovery time. It also did not prolong the post-stimulus asystole duration.

TRIAL REGISTRATION

TCTR20170715003 , registered at Thai Clinical Trials Registry (TCTR), principal investigator: Pattika Subsoontorn, date of registration: 15/07/2017.

Comparison between dexmedetomidine and fentanyl bolus in attenuating the stress response to laryngoscopy and tracheal intubation: a randomized double-blind trial

Background and objectives

Laryngoscopy and tracheal intubation lead to a sympathoadrenal response. We compared the efficacy of dexmedetomidine with fentanyl bolus to attenuate this response.

Methods

One hundred patients admitted for routine surgical procedures under general anesthesia were enrolled in this double blind, randomized, controlled study. Patients were randomly assigned to two groups: Group F received injection of fentanyl 2 μg.kg^-1 and Group D received injection of dexmedetomidine 0.5 μg.kg^-1 diluted up to 5 mL by adding normal saline intravenously over 60 seconds. Five minutes thereafter, following induction with propofol and vecuronium, tracheal intubation was performed after 3 minutes of mask ventilation. Hemodynamic parameters were observed at an interval of 2 minutes before tracheal intubation and at an interval of 1 minute for 5 minutes after tracheal tube cuff inflation. Continuous variables are presented as mean with 95% confidence interval, and t-test was applied for comparing the difference of means between two groups after checking the normality condition. Chi-square test was applied to test the independence of attributes of categorical variables. Repeated measures two-way ANOVA was performed to compare the outcome variables between the two groups.

Results

The difference in heart rate and mean arterial pressure of patients in two groups after laryngoscopy and intubation was not statistically significant at any point of time. The hemodynamic changes did not require any intervention in the form of administration of rescue medication.

Conclusions

Dexmedetomidine 0.5 μg.kg^-1 is as effective as fentanyl 2 μg.kg^-1 in attenuating the hemodynamic response accompanying laryngoscopy and tracheal intubation.

Clinical trial number & registry URL

CTRI/2017/09/009857 [ctri.nic.in]

Effect of dexmedetomidine on hemodynamic responses to tracheal intubation: A meta-analysis with meta-regression and trial sequential analysis

STUDY OBJECTIVE

An uncontrolled adrenergic response during tracheal intubation may lead to life-threatening complications. Dexmedetomidine binds to α2-receptors and may attenuate this response. The primary aim of our meta-analysis is to investigate dexmedetomidine efficacy in attenuating sympathetic response to tracheal intubation, compared with placebo or no dexmedetomidine, in terms of heart rate and blood pressure at intubation.

DESIGN

Meta-analysis with meta-regression and trial sequential analysis.

SETTING

Systematic search from inception until December 1, 2020 in the following databases: Pubmed, Scopus, the Cochrane Central Register of Controlled Trials, EMBASE and Google Scholar.

INTERVENTIONS

All randomized controlled trials investigating intravenous dexmedetomidine as premedication in adult patients undergoing tracheal intubation were included in our study. Studies were included without any language or publication date restriction. A trial sequential analysis and a post-hoc meta-regression were performed on the main outcomes.

MEASUREMENTS

Hemodynamic parameters and heart rate at tracheal intubation, dose of anesthetic needed for induction of anesthesia, total anesthetic requirement throughout the operative procedure, postoperative pain and percentage of patients requiring analgesics at 24 postoperative hours, postoperative nausea and vomiting, intraoperative and postoperative bradycardia, hypotension, dizziness, shivering and/or respiratory depression.

MAIN RESULTS

Ninety-nine included studies randomized 6833 patients. During laryngoscopy, all hemodynamic parameters were significantly greater in the no dexmedetomidine group. In particular, in the dexmedetomidine group, systolic blood pressure differed by -21.8 mm Hg (95% CI -26.6 to -17.1, p-value < 0.001, I² 97%), mean arterial pressure by -12.8 mm Hg (95% CI -15.6 to -10.0, p-value < 0.001, I² 98%), and heart rate by -16.9 bpm (95% CI -19.8 to -13.9, p-value < 0.001, I² 98%).

CONCLUSIONS

Patients receiving premedication with dexmedetomidine for tracheal intubation, compared with no dexmedetomidine, have a lower blood pressure and heart rate, however, the risk of bradycardia and hypotension is relevant and its use during daily practice should be cautiously evaluated for each patient.

Intranasal dexmedetomidine for attenuation of hemodynamic response to laryngoscopy and intubation in adults

Background : To evaluate effectiveness of intranasal dexmedetomidine for attenuation of hemo-dynamic response to laryngoscopy and intubation in adults. Design and setting : This prospective randomized study included 90 American Society of Anesthesiologists (ASA) status I, adult patients of either sex, aged between 18-60 years, and undergoing elective surgery under general anesthesia requiring endotracheal intubation. Methods : Patients were randomly assigned to one of three groups of 30 each, to receive either intranasal saline (Group C), intranasal dexmedetomidine 1µg/kg (Group D 1 ) or intranasal dexmedetomidine 2µg/kg (Group D 2) , administered 30 minutes before the induction of anesthesia. Anesthesia technique was standardized for all patients taking part in the study. Main outcome measures : Primary outcome studied was attenuation of hemodynamic response to laryngoscopy and intubation. Secondary parameters studied were sedation score and dose of propofol required at induction. Results : There was a statistically significant rise in heart rate and systolic, diastolic and mean arterial pressures at 1, 3, and 5 minutes of intubation in group C as compared to groups D 1 and D 2 . Sedation score was significantly higher in groups D 1 and D 2 (p<0.0001). Propofol requirement was significantly lower in groups D 1 and D 2 (p<0.0001). Intranasal dexmedetomidine 2µg/kg was associated with higher a incidence of bradycardia. Conclusion : Intranasal dexmedetomidine (1µg/kg and 2µg/kg) effectively diminishes hemodynamic changes associated with laryngoscopy and intubation in adult patients undergoing elective surgery. Intranasal dex-medetomidine 2µg/kg is associated with significant bradycardia. Intranasal dexmedetomidine also provides effective preoperative sedation and decreases the dose of propofol required for induction of anesthesia.

Effect of dexmedetomidine on attenuation of hemodynamic response to intubation, skin incision, and sternotomy in coronary artery bypass graft patients: A double-blind randomized control trial

Background and Aims:

Coronary artery bypass grafting (CABG) surgery involves various noxious stimuli resulting in stress response, which in turn increases the risk of perioperative myocardial ischemia. The present study was conducted to evaluate the effect of dexmedetomidine on the attenuation of hemodynamic response to intubation, skin incision, and sternotomy in CABG surgery.

Material and Methods:

Sixty patients were randomized into two groups of 30 each. Group D patients received dexmedetomidine 1 μg/kg as loading dose over 10 min, followed by continuous infusion of 0.5 μg/kg/h. In group P, normal saline was infused as loading and maintenance dose at similar rate. Hemodynamic parameters, total induction dose of thiopentone, and adverse effects were recorded. Statistical analysis was performed using SPSS version 20.0. Chi-square test and ANNOVA test were used and P < 0.05 was considered significant.

Results:

The percentage increase in heart rate was significantly lesser in group D than group P after intubation (7.04% v/s 15.08%), skin incision (5.91% v/s 10.11%), and sternotomy (5.33% v/s 11.65%). Similarly increase in systolic, diastolic, and mean blood pressure were significantly lesser in group D than group P after intubation, skin incision, and sternotomy. There was a significant reduction of mean total of thiopentone in group D in comparison to group P. (1.16 mg/kg v/s 2.44 mg/kg) (P<0.001).

Conclusion:

Dexmedetomidine resulted in significant attenuation of hemodynamic response to intubation, skin incision, and sternotomy in CABG surgery without significant adverse effects. It also significantly reduced the dose of thiopentone required for induction.

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine

Dexmedetomidine (DEX) is a highly selective α2 adrenergic receptor (α2AR) agonist currently used in clinical settings. Because DEX has dose-dependent advantages of sedation, analgesia, antianxiety, inhibition of sympathetic nervous system activity, cardiovascular stabilization, and significant reduction of postoperative delirium and agitation, but does not produce respiratory depression and agitation, it is widely used in clinical anesthesia and ICU departments. In recent years, much clinical study and basic research has confirmed that DEX has a protective effect on a variety of organs, including the nervous system, heart, lungs, kidneys, liver, and small intestine. It acts by reducing the inflammatory response in these organs, activating antiapoptotic signaling pathways which protect cells from damage. Therefore, based on wide clinical application and safety, DEX may become a promising clinical multiorgan protection drug in the future. In this article, we review the physiological effects related to organ protection in α2AR agonists along with the organ-protective effects and mechanisms of DEX to understand their combined application value.

Comparison of the efficacy of two doses of dexmedetomidine in attenuating the hemodynamic response to intubation in patients undergoing elective cardiac surgery: A randomized double-blinded study

Background and Aims:

Transient tachycardia and hypertension associated with laryngoscopy and intubation may be hazardous to patients presenting for cardiac surgery. The α 2 agonist dexmedetomidine may blunt this stress response, but the optimal dose which will accomplish this without causing hypotension and bradycardia is not well established. The primary objective of this study was to compare the efficacy of two doses of dexmedetomidine (0.5 and 1 μg/kg) as a 15 min infusion in attenuating the hemodynamic stress response to laryngoscopy and endotracheal intubation in elective cardiac surgery.

Material and Methods:

Seventy six patients scheduled for elective cardiac surgery received a single preoperative dose of dexmedetomidine of either 0.5 μg/kg (low dose) or 1 μg/kg (high dose) as a 15-min infusion prior to induction. The hemodynamic response to laryngoscopy and endotracheal intubation (heart rate, systolic blood pressure, mean arterial pressure, and diastolic blood pressure) were recorded at different times. Independent sample t-test, Chi-square test of association, and repeated measures analysis of variance were used to analyze the collected data.

Results:

The incidence of hypertension following intubation was significantly more in the low-dose group. Administration of 1 μg/kg dexmedetomidine was not accompanied by hypotension or bradycardia.

Conclusion:

Dexmedetomidine in a dose of 1 μg/kg is more effective than 0.5 μg/kg for attenuation of hemodynamic stress response to intubation in cardiac surgery. A more graded increase in the dose of dexmedetomidine may lead to an optimum dose in attenuating the hemodynamic response to intubation.

Effects of dexmedetomidine versus remifentanil on mothers and neonates during cesarean section under general anesthesia

BACKGROUND AND AIMS

Dexmedetomidine and remifentanil use in obstetric general anesthesia is controversial. This study aimed to compare the effects of remifentanil and dexmedetomidine on mothers and neonates during cesarean section under general anesthesia.

METHODS

A total of 120 patients scheduled for elective cesarean section under general anesthesia were randomly allocated to dexmedetomidine (D), remifentanil (R), and control (C) groups. Anesthesia was induced with propofol and muscle relaxants in all groups. Anesthesia in groups D and R was induced with dexmedetomidine (induction, 0.5 µg/kg; maintenance, 0.5 µg/kg.h) and remifentanil (induction, 0.5 µg/kg; maintenance, 2 µg/kg.h), respectively, until birth. Group C received equivalent volumes of normal saline. Mean arterial blood pressure (MAP), heart rate (HR), plasma catecholamine, visual analog pain score (VAS), and total tramadol consumption at 1, 2, and 3 hours after extubation were recorded. Neonatal effects were assessed by Apgar scores and umbilical blood gas analysis.

RESULTS

Post induction, MAP was significantly higher in group D compared to groups C and R, and significantly lower in group R than in group C. At intubation/skin incision and delivery, MAP, HR, and plasma epinephrine and norepinephrine concentrations were significantly lower in groups D and R than in group C. Compared to group R, MAP was significantly higher, and HR, plasma epinephrine, and norepinephrine concentrations were significantly lower in group D. Compared with groups C and D, the percentage of neonates with Apgar score < 7 was higher in group R at 1 min after delivery. Compared with groups C and R, the VAS was significantly lower in group D at 1 and 2 h postoperatively. Total tramadol consumption was significantly lower in group D at 3 hours postoperatively.

CONCLUSION

During general anesthesia for cesarean section, remifentanil demonstrated better control of hemodynamic stability, while dexmedetomidine demonstrated better neonatal Apgar scores, postoperative analgesia, and decreased catecholamine release.

TRIAL REGISTRATION

Chinese Clinical Trial Register (ChiCTR) - ChiCTR1800017125.

Attenuation of haemodynamic responses to laryngoscopy and endotracheal intubation with dexmedetomidine: A comparison between intravenous and intranasal route

Background and Aims:

Haemodynamic changes during endotracheal intubation are major concerns in general anaesthesia This study compared the efficacy of intranasal and intravenous dexmedetomidine (DEX) to attenuate the stress response of laryngoscopy and endotracheal intubation.

Methods:

In this prospective, randomised, double-blinded study, 70 adults were divided into two groups [Group D_IV(n=35) and Group D_IN(n=35)]. D_IV group received intravenous dexmedetomidine (DEX) infusion (0.5 μg/kg) over 40 min and D_IN group received intranasal dexmedetomidine (1 μg/kg) 40 min before induction. The primary objective was the comparison the mean arterial pressure (MAP) between two groups from 40 min before induction at every 10 min intervals till induction of anaesthesia, at the time of intubation, thereafter every 1 min interval till 5 min, at 7 min and 10 min after intubation. The secondary outcomes were comparison of heart rate, systolic and diastolic blood pressure along with sedation and other adverse effects. Statistical analysis was with Statistica 6.0 and Graph Pad prism version 5.

Results:

In both the groups, all the haemodynamic parameters were maintained within (20% of baseline values) throughout the study period. There was no statistically significant difference in MAP between two groups (P>0.05). Preoperative sedation score was significantly higher in the D_IV group than the D_IN group (P = 0.014).

Conclusion:

Like IV DEX, intranasal DEX can also attenuate the haemodynamic stress responses of laryngoscopy and endotracheal intubation without significant differences in MAP between two groups.

The comparison of dexmedetomidine, esmolol, and combination of dexmedetomidine with esmolol for attenuation of sympathomimetic response to laryngoscopy and intubation in patients undergoing coronary artery bypass grafting

Background:

The aim of this study was to compare the effects of dexmedetomidine, esmolol, and combination of both on control of sympathetic response to laryngoscopy and tracheal intubation in coronary artery disease patients.

Material and Methods:

A prospective, randomized, double-blinded clinical study included 90 patients scheduled for elective coronary artery bypass surgery. Patients were randomly allocated into three groups of 30 each: dexmedetomidine group (Group D) 1 μg/kg, esmolol group (Group E) 2 mg/kg, and group dexmedetomidine with esmolol (Group DE) 0.5 μg/kg of dexmedetomidine with 1 mg/kg of esmolol. Each drug was diluted with 0.9% normal saline to 20 ml volume and infused in 10 min before induction of anesthesia. Hemodynamic changes (heart rate [HR], arterial blood pressure, and pulmonary artery pressure) were compared at various time intervals as follows-baseline, after study drug, after induction, and 1, 3, and 5 min after intubation. Statistical analysis included analysis of variance, Chi-square, and Fisher's exact test.

Results:

In Group DE, there was no significant increase in HR at all-time intervals, and the HR was stable compared to Group D and Group E. Blood pressure values were comparable in all groups except in Group E at 5 min. The pulmonary arterial pressures were statistically less in DE group except at 3 and 5 min.

Conclusions:

The combination of dexmedetomidine and esmolol group has beneficial effect on HR and pulmonary arterial pressures but has no additional advantage with respect to arterial blood pressure when compared with dexmedetomidine and esmolol groups in patients undergoing elective coronary artery bypass grafting.

Comparison of Intravenous Dexmedetomidine versus Esmolol for Attenuation of Hemodynamic Response to Tracheal Intubation after Rapid Sequence Induction: A Systematic Review and Meta-Analysis

The present study aims to investigate whether intravenous dexmedetomidine shows superiority to esmolol for hemodynamic response to tracheal intubation after rapid sequence induction. In the present meta-analysis, PubMed, EMBASE, and the Cochrane Library were searched for trials comparing dexmedetomidine with esmolol for the attenuation of the hemodynamic response to intubation. Ten trials were selected in the present meta-analysis. Compared to esmolol, the use of dexmedetomidine maintains stable heart rates (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) at 1 min, 3 min, and 5 min after tracheal intubation. Dexmedetomidine causes less hemodynamic response to tracheal intubation after rapid sequence induction compared with esmolol.

Efficacy of dexmedetomidine in reducing post-operative pain and improving the quality of recovery in patients with burn wounds undergoing tangential excision skin grafting

Burn-induced acute post-operative pain and the associated stress response may result in prolonged convalescence. The present study investigated the effects of dexmedetomidine (DEX) administration on post-operative pain and the quality of recovery following surgical treatment of moderate-to-severe burn injuries. A total of 60 adult patients undergoing tangential excision skin grafting were randomized into two groups. The DEX group (Group D) received an intravenous (i.v.) single-dose bolus injection of DEX 0.5 µg/kg >10 min prior to induction of anesthesia. Patient-controlled intravenous analgesia (PCIA) was provided to the patients from the end of the surgery, which consisted of 100 µg sufentanil plus 200 µg DEX. The control group (Group C) received an equal volume of normal saline as a pre-operative bolus and post-operative PCIA of 100 µg sufentanil infusion. The Visual Analogue Scale (VAS) score at rest and during movement, the cumulative dose of sufentanil and the 40-item quality of recovery questionnaire (QoR-40) score were assessed at various time-points after the surgery. During the first 24 h post-surgery, patients in Group D exhibited a lower VAS score at rest and during movement, a lower number of PCIA pump presses (29.17±1.91 vs. 34.13±2.73) and lower sufentanil consumption (62.58±0.96 vs. 65.27±1.26) compared with those in Group C (P<0.05). Furthermore, the QoR-40 recovery score of patients in Group D at 24 h post-surgery was higher compared with that in Group C (P<0.01). In conclusion, the present study indicated that a pre-operative bolus of DEX (0.5 µg/kg) followed by DEX plus sufentanil by PCIA subsequent to surgery improved the quality of analgesia and promoted the quality of recovery at 24 h following tangential excision skin grafting treatment of patients with moderate-to-severe burn injuries compared to PCIA of 100 µg sufentanil only. The present study was retrospectively registered with the trial registration no. ChiCTR1800016646 (date of registration, 14/06/2018).

The Security Rating on Local Ablation and Interventional Therapy for Hepatocellular Carcinoma (HCC) and the Comparison among Multiple Anesthesia Methods

Recently, the interventional therapies are used more often in clinical practice for hepatocellular carcinoma. The most commonly used methodologies include radiofrequency ablation, microwave ablation, laser ablation, and cryotherapy. Most of the interventional operations need local anesthesia combined with intravenous sedation. Also, some interventional therapy centers apply general anesthesia. However, different anesthesia methods can cause diverse effects on patients' pain management, recovery time, and hospitalization time. For the better understanding of the current anesthesia application status, we summarize and analyze multiple anesthesia methods while being applied in interventional therapy for hepatocellular carcinoma; in addition, their characters are also compared in this paper.

Efficacy of Adding Dexmedetomidine to Intra-articular Levobupivacaine on Postoperative Pain after Knee Arthroscopy

Background and Aims:

Intrarticular ingection of local anesthetics in the knee joint decreases postoperative pain after knee arthrosopy. Dexmedetomidine an α₂ agonist has sedative and analgesic effects and decreases postoperative pain after knee arthroscopy when injected intraarticulary. Levobubivacaine is a long acting local anesthetic with less toxicity than bubivacaine. We compared the analgesic effects of dexmedetomidine when added to intraarticular levobupivacaine in patients posted for knee arthroscopy.

Methods:

Data were first tested for normality by Kolmogorov–Smirnov test. Study was done on 90 patients. Patients were divided into 3 groups 30 patients each. Group (C) received 50 ml saline only as a control group. Group (L) received 50 ml 0.25% levobupivacaine. Group (L/D) received 50 ml 0.25% levobupivacaine and dexmedetomidine 1μg.kg-1. (VAS) score was used to assess postoperative pain. Time of first pethidine demand and total dose of pethidine in the first 24 h were recorded, also postoperative complications such as pruritis, nausea and vomiting. SPSS version 16 was used for data analysis. P < 0.05 was considered significant.

Results:

Postoperative VAS sore at different intervals was less in Group LD than Group L than Group C, time to the first pethedine injection in (min) was longer (39 ± 6, 31 ± 7, 21 ± 6), and total pethedine dose given (mg) was lower (36 ± 9.8, 64 ± 19, 102 ± 24) in Group LD than Group L than Group C respectively.

Conclusion:

Adding dexmedetomidine to intraarticular levobupivacaine in patients undergoing knee arthroscopy provides more analgesic effect with lower pain scores than levobupivacaine alone with less use of postoperative analgesics during the first 24 h.

Comparative Evaluation of the Effects of Pregabalin, Dexmedetomidine, and Their Combination on the Hemodynamic Response and Anesthetic Requirements in Patients undergoing Laparoscopic Cholecystectomy: A Randomized Double-Blind Prospective Study

Background

In this study, we evaluated the efficacy of premedication with dexmedetomidine, pregabalin, and dexmedetomidine-pregabalin combination for attenuating the haemodynamic stress response to laryngoscopy and intubation and pneumoperitoneum (primary outcome), and for reducing anaesthetic requirement (secondary outcome) in patients undergoing laparoscopic cholecystectomy.

Methods

Ninety ASA physical status classes I-II patients, between 18 to 65 years of age, of either sex, scheduled to undergo laparoscopic cholecystectomy were included in this randomised double blind study. Morbidly obese patients and those with history of hypertension, cardiac, renal, hepatic, endocrine or pulmonary dysfunction were excluded. Patients were randomized to three groups - Group P- received oral pregabalin (150 mg) one hour before induction and 100 mL of i.v normal saline (0.9%) over 10 minutes, 10 minutes before induction; Group D- received i.v dexmedetomidine (1 μg.kg^-1) prepared in 100 mL of 0.9% normal saline and given over 10 minutes, 10 minutes before induction, and an oral placebo tablet one hour before induction; and Group C-received a combination of oral pregabalin 75 mg one hour before induction, and IV dexmedetomidine (0.5 μg.kg^-1) prepared in 100 mL of 0.9% normal saline over 10 minutes, 10 minutes before induction.

Results

Dexmedetomidine significantly attenuated the stress response to laryngoscopy and intubation and pneumoperitoneum and reduced anaesthetic requirement as compared to the other two groups. Dexmedetomidine was associated with significantly lower mean arterial pressures and higher sedation score in the preoperative and postoperative period and significantly lower heart rate and arterial pressures and reduced anaesthetic requirement in the intraoperative period as compared to the other groups.

Conclusion

Dexmedetomidine is a valuable adjunct to the technique of balanced anaesthesia for maintaining haemodynamic stability.

The efficacy and safety of dexmedetomidine in cardiac surgery patients: A systematic review and meta-analysis

This study aimed to evaluate the efficacy and safety of dexmedetomidine versus any other treatment without dexmedetomidine in patients who have undergone cardiac surgery. Electronic databases including PubMed, Embase, and Cochrane Library were systematically searched without limitations of language and publication time. Randomized controlled trials (RCTs) aiming to evaluate the efficacy and safety of dexmedetomidine versus any other treatment without dexmedetomidine in patients that have undergone cardiac surgery were selected. Endpoints such as hemodynamic indexes and adverse events in eligible studies were extracted by two researchers, independently. The data was analyzed using RevMan 5.3 and Stata 11.0 software. A total of 18 RCTs met the inclusion criteria, involving 1730 patients. Compared to control (any treatment without dexmedetomidine), dexmedetomidine showed a pooled mean difference (MD) of -14.46 [95% confidence interval(CI): -24.69, -4.23; p<0.01] for systolic arterial pressure, a standardized mean difference (SMD) of -1.74 for mean arterial blood pressure (95% CI: -2.80, -0.68; P < 0.01), -2.12 (95%CI: -3.23, -1.00; p<0.01) for heart rate, and combined odds ratio (OR) of 0.22 (95%CI: 0.11, 0.44; p<0.01) for tachycardia, 3.44 (95%CI: 1.95, 5.96; p<0.01) for bradycardia, 0.74 (95%CI: 0.49, 1.12; p>0.05) for atrial fibrillation, and 0.99 (95%CI: 0.51, 1.90; p>0.05) for hypotension. In addition, dexmedetomidine could reduce time of surgery and stay in intensive care units, improve delirium with good safety. Our study shows clinical application of dexmedetomidine in cardiac surgery patients can reduce risks of abnormal hemodynamics with good safety.

Clinical Pharmacokinetics and Pharmacodynamics of Dexmedetomidine

Dexmedetomidine is an α₂-adrenoceptor agonist with sedative, anxiolytic, sympatholytic, and analgesic-sparing effects, and minimal depression of respiratory function. It is potent and highly selective for α₂-receptors with an α₂:α₁ ratio of 1620:1. Hemodynamic effects, which include transient hypertension, bradycardia, and hypotension, result from the drug’s peripheral vasoconstrictive and sympatholytic properties. Dexmedetomidine exerts its hypnotic action through activation of central pre- and postsynaptic α₂-receptors in the locus coeruleus, thereby inducting a state of unconsciousness similar to natural sleep, with the unique aspect that patients remain easily rousable and cooperative. Dexmedetomidine is rapidly distributed and is mainly hepatically metabolized into inactive metabolites by glucuronidation and hydroxylation. A high inter-individual variability in dexmedetomidine pharmacokinetics has been described, especially in the intensive care unit population. In recent years, multiple pharmacokinetic non-compartmental analyses as well as population pharmacokinetic studies have been performed. Body size, hepatic impairment, and presumably plasma albumin and cardiac output have a significant impact on dexmedetomidine pharmacokinetics. Results regarding other covariates remain inconclusive and warrant further research. Although initially approved for intravenous use for up to 24 h in the adult intensive care unit population only, applications of dexmedetomidine in clinical practice have been widened over the past few years. Procedural sedation with dexmedetomidine was additionally approved by the US Food and Drug Administration in 2003 and dexmedetomidine has appeared useful in multiple off-label applications such as pediatric sedation, intranasal or buccal administration, and use as an adjuvant to local analgesia techniques.

Feasibility of dexmedetomidine as sole analgesic agent during robotic urological surgery: A pilot study

BACKGROUND AND AIMS

Opioid-free anesthesia decreases postoperative nausea and vomiting, emergence agitation, prolonged sedation, ileus, and urinary retention. The feasibility of the use of dexmedetomidine as sole analgesic agent has been shown in patients undergoing bariatric and gynecological laparoscopic surgery. We explored its use for robotic urological surgery.

MATERIAL AND METHODS

Thirty patients were randomized to receive either dexmedetomidine (Group D) or fentanyl (Group F) along with total intravenous anesthesia with propofol. The hemodynamic parameters and number of doses of rescue analgesics used intraoperatively and postoperatively were noted. Recovery parameters at the end of surgery were also recorded.

RESULTS

The dose of intraoperative rescue fentanyl was not significantly different between groups (P = 0.13). The hemodynamic profile of patients in the two groups was comparable except the heart rate was significantly more in Group D after intubation and at 60 min. The mean arterial pressure was significantly lower after the initial loading dose of study drug in Group D. The recovery profiles were not significantly different between groups.

CONCLUSION

The study reveals that dexmedetomidine has equal analgesic efficacy as fentanyl for intraoperative use and can be used as the sole analgesic agent in patients undergoing robotic urological surgery.

Myocardial protective effects of dexmedetomidine in patients undergoing cardiac surgery: A meta-analysis and systematic review

Arrhythmias are the common complications following cardiac surgery and contribute to hemodynamic instability, cognitive impairment, thromboembolic events, and congestive heart failure. Prevention of atrial fibrillation following cardiac surgery reduces morbidity and among the many available preventive approaches dexmedetomidine shows many positive effects on cardiovascular stability. Even though many studies indicated the beneficial effects of dexmedetomidine, the power of the analysis and conclusion of these studies is rather weak due to relatively smaller number of patients in these studies. In the present meta-analysis, we included a large number of patients, both children and adults, undergoing cardiac surgery, to address the efficacy of dexmedetomidine. Several databases were searched to identify clinical studies comparing the efficacy of dexmedetomidine in myocardial protection in patients undergoing cardiac surgery. Cardiac function related parameters including heart rate, blood pressure, tachycardia, arrhthmias, and bradycardia were measured. In accordance with the selection criteria, a total of 18 studies published between 2003 and 2016, with a total of 19,225 patients were included in the present meta-analysis. Dosage of dexmedetomidine was in the range of 0.5-1 µg/kg body weight loading followed by continuous infusion at a rate of 0.2-0.7 µg/kg/h. Dexmedetomidine treatment was found to lower heart rate, systolic blood pressure, incidence of tachycardia and arrhythmias in both adult and pediatric patients, but elevated the risk of bradycardia. In conclusion, results of this meta-analysis indicate that dexmedetomidine is an efficacious cardioprotective drug in adults and children undergoing cardiac surgery.

Efficacy of intravenous dexmedetomidine on patient's satisfaction, comfort and sedation during awake fibre-optic intubation in patients with cervical spondylotic myelopathy posted for elective cervical fixation

Background and Aims:

Various anaesthetic drugs, in addition to airway block, are used for producing favourable intubation conditions during awake fibre-optic intubation (AFOI), but most of them cause respiratory depression and hypoxaemia. The aim of this study was to evaluate the efficacy of intravenous (IV) dexmedetomidine (DEX) on sedation, patient comfort and cardiovascular responses during AFOI in patients with cervical spondylotic myelopathy (CSM).

Methods:

This randomised, placebo-controlled, double-blinded, prospective study was conducted on 56 adult patients with cervical spondylotic myelopathy (CSM) undergoing elective cervical fixation, who were randomly allocated into two groups - Group D and Group C. Group D patients received DEX infusion at a rate of 1 μg/kg for the first 10 min followed by 0.5 μg/kg/h and Group C received 0.9% normal saline infusion in the same manner. Airway blocks with lignocaine were given to all patients before undergoing AFOI. Patient's alertness, sedation and cardiorespiratory changes during the procedure were assessed by the Observer Assessment Awareness and Sedation (OAA/S) scale. On the 1^st post-operative day, patient's' comfort during AFOI was assessed by visual analogue scale (VAS).

Results:

Patients of Group D had an acceptable level of sedation (OAA/S score: 20 to 17 with greater comfort and satisfaction (VAS: 40–60), compared to control group (VAS: 50–90, P < 0.001.). Moreover, haemodynamic parameters were less significantly altered in the DEX group during AFOI.

Conclusions:

IV DEX infusion during AFOI improves patient's tolerances with an acceptable level of sedation without significant haemodynamic instability and respiratory depression.

Attenuation of haemodynamic responses to laryngoscopy and endotracheal intubation with intravenous dexmedetomidine: A comparison between two doses

Background and Aims:

Laryngoscopic manipulation and endotracheal intubation are noxious stimuli capable of producing tachycardia, arrhythmias and hypertension. The aim of this study was to arrive at an optimal dose of dexmedetomidine by comparing two doses with placebo to attenuate stress response during laryngoscopy and endotracheal intubation.

Methods:

It was a randomised, prospective, double-blind placebo-controlled study. After Institutional Ethical Committee clearance, ninety patients of American Society of Anesthesiologists Physical Status 1 were enrolled in the study and divided into three equal groups. Group A received normal saline, Group B received injection dexmedetomidine 0.5 μg/kg and Group C received injection dexmedetomidine 0.75 μg/kg as infusion over 10 min. The general anaesthesia technique was standardised for all three groups. The primary outcome measures were haemodynamic response at 1, 3 and 5 min after intubation. The secondary outcome measures were to note down any adverse effects associated with drugs. The statistical package used was SPSS version 15.

Results:

Groups were well matched for their demographic data. There was a statistically significant difference (P < 0.05) between dexmedetomidine and normal saline in heart rate, systolic, diastolic and mean arterial pressures at all time points after tracheal intubation with dexmedetomidine 0.75 μg/kg being most effective. Sedation scores were more with dexmedetomidine. None of the patients had any adverse effects such as hypotension, bradycardia, respiratory depression and fall in oxygen saturation.

Conclusion:

Dexmedetomidine in a dose of 0.75 μg/kg intravenous is the optimal dose to attenuate stress response to laryngoscopy and endotracheal intubation.

Dexmedetomidine in Attenuation of Haemodynamic Response and Dose Sparing Effect on Opioid and Anaesthetic Agents in Patients undergoing Laparoscopic Cholecystectomy- A Randomized Study

INTRODUCTION

Perioperative procedures are stressful and lead to haemodynamic instability with potentially devastating consequences. Dexmedetomidine is found to have many of the desired characteristics that are required in perioperative period.

AIM

To evaluate the ability of pre and intraoperative dexmedetomidine to attenuate stress induced haemodynamic responses, quantifying the anaesthetic agents sparing as well as its cost-effectiveness in patients undergoing laparoscopic cholecystectomy.

MATERIALS AND METHODS

The present single blind randomized study was conducted with 120 ASA I and II consented patients who underwent laparoscopic cholecystectomy. Patients were randomly divided into 2 groups (i.e., group D and group N). Prior to induction, group D received 1 μg/kg of Dexmedetomidine and group N received Normal saline infusion over 20 minutes. Group D also received maintenance Dexmedetomidine intraoperatively. Bispectral index and minimum alveolar concentration monitoring was done in both the groups. Haemodynamic parameters were noted till 100 minutes post laryngoscopy. Opioid and anaesthetic agent consumptions were also noted and cost analysis was done. Medcalc-Version 12.5.0.0 software was used for statistics and p <0.05 was considered significant.

RESULTS

Dexmedetomidine attenuated the stress induced haemodynamics responses and produced stable, relatively non fluctuating haemodynamics throughout. The Minimum Alveolar Concentration (MAC) requirement and the consumptions of Fentanyl and Isoflurane were significantly less in the Dexmedetomidine group (p<0.0001). However, despite anaesthetic dose sparing effect the anaesthetic technique was not cost-effective.

CONCLUSION

Dexmedetomidine is effective in attenuating haemodynamic responses in laparoscopic surgery and having dose sparing effect on Fentanyl, Propofol and Isoflurane. However, overall this technique is not cost-effective.

Comparison of the efficacy of lornoxicam and fentanyl in attenuating the hemodynamic response to laryngoscopy and intubation

BACKGROUND AND OBJECTIVES

Laryngoscopy and intubation elicits huge spectrum of stress response which is hazardous in high-risk patients. Many drugs and techniques have been used to attenuate the stress response. Lornoxicam 16 mg is a potent nonsteroidal anti-inflammatory drug agent with analgesic potency equivalent to morphine 10 mg, fentanyl 100 μg and tramadol 100 mg. Lornoxicam has been found to attenuate stress response in some studies. We compared the lornoxicam with fentanyl in attenuating stress response.

MATERIALS AND METHODS

A double blind randomized controlled study was conducted on 60 adult patients of American Society of Anesthesiologist physical status 1 and 2. Group L (n = 30) receives injection lornoxicam 16 mg intravenous 30 min before induction, Group F (n = 30) receives injection fentanyl 2 μg/kg during induction. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) were recorded baseline (BL), before induction, every minute up to 5 min and at 10 min after intubation.

RESULTS

After intubation, there is a gradual decrease in SBP and DBP in both groups. The MAP was also comparable between the two groups except at 5 min and 10 min during which MAP recovered toward BL in Group L where as it remained low in Group F which was statistically significant (P < 0.05). Both the drugs have successfully attenuated the HR response.

CONCLUSION

Lornoxicam successfully attenuated the hemodynamic response to laryngoscopy and endotracheal intubation and is equally efficacious as fentanyl.

Intraoperative effect of dexmedetomidine infusion during living donor liver transplantation: A randomized control trial

BACKGROUND

Dexmedetomidine hydrochloride (Dex) is a useful adjuvant for general anesthesia. The aim was to evaluate the effects of Dex infusion during living donors liver transplantation (LDLT) on the general anesthetic requirements, hemodynamics, oxygen consumption (VO2), and CO2 production (VCO2).

MATERIALS AND METHODS

Forty LDLT recipients were allocated randomly to receive either Dex (0.2-0.7 μg/kg/h) or placebo (control [C]). Patient state index (PSI), SEDLine monitored anesthesia depth (25-50) with desflurane (Des) % and fentanyl altered accordingly. Transesophageal Doppler (TED), invasive mean arterial blood pressure (MAP) and heart rate (HR) were monitoring any Dex side effects and altering infusion rate accordingly; TED was used for fluid optimization. Metabolic gas monitoring (VO2, VCO2) and Des consumption were recorded.

RESULTS

Dex reduced Des and fentanyl consumption versus C (120.0 ± 30.2 vs. 248.0 ± 38.8) ml, (440.0 ± 195.74 vs. 1300.0 ± 32) μg, respectively (P < 0.01). Dex was delivered for 11.35 ± 2.45 h with comparable HR, MAP, and TED variables versus C and with similar mean noradrenaline support (5.63 ± 2.44 vs. 5.83 ± 2.57 mg, P = 0.81). VO2 was reduced with Dex vs. C during anhepatic, 30 min postreperfusion and end of surgery (193.2 ± 26.78 vs. 239 ± 14.93) (172.1 ± 28.14 vs. 202.7 ± 18.03) and (199.7 ± 26.63 vs. 283.8 ± 14.83) ml/min/m(2) respectively (P < 0.01). VCO2 was also reduced with Dex versus C during the same periods (195.2 ± 46.41 vs. 216.7 ± 29.90, P = 0.09), (210.6 ± 60.71 vs. 253.9 ± 32.51, P = 0.01), and (158.7 ± 49.96 vs. 209.7 ± 16.78, P < 0.01), ml/min/m(2) respectively.

CONCLUSION

TED and PSI guided Dex infusion helped to reduce Des and fentanyl consumption as well as VO2 and VCO2 at a lower cost with no adverse effects on hemodynamics.

Nitroglycerine, esmolol and dexmedetomidine for induced hypotension during functional endoscopic sinus surgery: A comparative evaluation

Background and Aim:

Induced hypotension limits intra-operative blood loss to provide better visibility of the surgical field and diminishes the incidence of major complications during functional endoscopic sinus surgery (FESS). We aimed at comparing nitroglycerine, esmolol and dexmedetomidine for inducing controlled hypotension in patients undergoing FESS.

Material and Methods:

One hundred and fifty American Society of Anesthesiologists physical status I or II adult patients undergoing FESS under general anesthesia were randomly allocated to three groups of 50 patients each. Group E received esmolol in a loading and maintenance dose of 1 mg/kg over 1 min and 0.5-1.0 mg/kg/h, respectively. Group D received a loading dose of dexmedetomidine 1 μg/kg over 10 min followed by an infusion 0.5-1.0 μg/kg/h, and group N received nitroglycerine infusion at a dose of 0.5-2 μg/kg/min so as to maintain mean arterial pressure (MAP) between 60 and 70 mmHg in all the groups. The visibility of the surgical field was assessed by surgeon using Fromme and Boezaart scoring system. Hemodynamic variables, total intra-operative fentanyl consumption, emergence time and time to first analgesic request were recorded. Any side-effects were noted. The postoperative sedation was assessed using Ramsay Sedation Score.

Result:

The desired MAP (60-70 mmHg) could be achieved in all the three study groups albeit with titration of study drugs during intra-operative period. No significant intergroup difference was observed in Fromme's score during the intra-operative period. The mean total dose of fentanyl (μg/kg) used was found to be significantly lower in group D compared to groups E and N (1.2 ± 0.75 vs. 3.6 ± 1.3 and 2.9 ± 1.1 respectively). The mean heart rate was significantly lower in group D compared to groups E and N at all times of measurement (P < 0.05). The MAP was found to be significantly lower in group D compared to groups E and N after infusion of study drugs, after induction, just after intubation and 5 min after intubation (P < 0.05). The Ramsay Sedation Scores were significantly higher in group D (score 3 in 46%) when compared to group E (score 2 in 50%) and group N (score 2 in 54%) (P < 0.001). The emergence time was significantly lower in group E and group N compared to group D. Time to first analgesic request was significantly longer in group D.

Conclusion:

Dexmedetomidine and esmolol provided better hemodynamic stability and operative field visibility compared to nitroglycerin during FESS. Dexmedetomidine provides an additional benefit of reducing the analgesic requirements and providing postoperative sedation.

Oral clonidine and gabapentin suppress pressor response: A prospective, randomized, double blind study

Background:

Pressor response is a part of stress response caused by reflex sympathetic discharge due to direct laryngoscopy and tracheal intubation resulting in tachycardia, hypertension and arrhythmias. Both clonidine, and gabapentin administered orally can effectively blunt this detrimental hemodynamic response.

Aim:

To study the effect of oral clonidine to blunt the pressor response to direct laryngoscopy and to compare it with oral gabapentin. To observe for postoperative sedation and side effects if any.

Settings and Design:

Sixty patients of American Society of Anaesthesiologist Grade I and II scheduled for surgery under general anesthesia were considered in this prospective randomized double-blind study. They were randomly allocated into two groups of 30 each using computerized randomization.

Materials and Methods:

Group A was given oral clonidine 5 μg/kg and Group B was given oral gabapentin 800 mg. Both the drugs were given 90 min prior to surgery. Heart rate (HR) and blood pressure were monitored at baseline, 0, 1, 3, 5, 10, 15, and 30^th min of laryngoscopy. Sedation was monitored by Ramsay Sedation Scale score and side effects were noted.

Results:

HR decreased in both groups at 0 and 1 min, increased at 3^rd min and gradually decreased by 30^th min. Statistically, significant difference was found between two groups at 1, 3, 5, 10, and 15^th min (P < 0.05). Though there was no significant difference in systolic blood pressure, diastolic blood pressure and mean arterial pressure between the two groups, there was no rise in these parameters. Gabapentin produced more sedation than clonidine postoperatively, and few side effects were noted.

Conclusion:

Both oral clonidine and gabapentin are effective in obtunding pressor response to direct laryngoscopy, clonidine being better in terms of controlling HR. Gabapentin produces more postoperative sedation than clonidine.

Clinical evaluation of the effect of intravenous dexmedetomidine on the hemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing thyroid surgeries

Background:

The procedures in anesthesia such as laryngoscopy and endotracheal intubation are the most important skills to be mastered by an anesthesiologist. However, they produce marked cardiovascular responses such as hypertension and tachycardia. Various drugs have been used to suppress this response. One of those is a novel centrally acting α₂ agonist - dexmedetomidine. It has numerous uses in anesthesia as it is having sedative, analgesic, hypnotic, and opioid sparing effects. It is also known to suppress the hemodynamic response to laryngoscopy and intubation.

Aims:

This study is aimed to know the effect of intravenous dexmedetomidine 0.6 μg/kg body weight on hemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing thyroid surgeries.

Setting and Design:

Sixty patients of American Society of Anaesthesiologist health status class I and II scheduled for thyroid surgery under general anesthesia were considered in this prospective randomized controlled double-blind study. The study population was randomly divided into two groups with 30 patients in each group using sealed envelopes containing the name of the group and patient is asked to pick up the envelope.

Materials and Methods:

Sixty euthyroid patients, scheduled for thyroid surgeries was randomly divided into two groups with 30 patients in each group. Group A (n = 30) received injection dexmedetomidine 0.6 μg/kg body weight and Group B (n = 30) received 10 ml of normal saline. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded at regular intervals after intubation.

Results:

Statistically significant decrease in HR, SBP, DBP, and MAP were observed in Group A after intubation when compared to Group B.

Conclusion:

We conclude that dexmedetomidine 0.6 μg/kg body weight obtunds the hemodynamic responses to laryngoscopy and tracheal intubation in patients undergoing thyroid surgeries.

The effects of dexmedetomidine on attenuation of hemodynamic changes and there effects as adjuvant in anesthesia during laparoscopic surgeries

Background:

As an anesthetic adjuvant dexmedetomidine has been shown to provide good perioperative hemodynamic stability with minimum alveolar concentration sparing effect on inhalational anesthetic agents during laparoscopic surgeries performed under general anesthesia.

Aim:

The study was planned to investigate the effects of dexmedetomidine on attenuation of hemodynamic changes and requirements of intra-operative analgesic and inhalational anesthetic during laparoscopic surgeries and its postoperative side effects.

Materials and Methods:

A total of 70 patients scheduled for elective laparoscopic surgeries were randomized to receive bolus infusion of dexmedetomidine (group D) or saline (group S) 1 mcg/kg/h, followed by continuous infusion of the same, at the rate of 0.5 mcg/kg/h. Anesthesia was maintained with nitrous oxide in oxygen, muscle relaxant and isoflurane. Supplementation with end-tidal isoflurane was considered when heart rate (HR) and mean arterial blood pressure (BP) exceeded 20% of the baseline value. Hemodynamics, end-tidal isoflurane concentration and adverse events were recorded.

Results:

Intra-operative mean HR and mean BP in group D were lower than group S (P < 0.05) throughout the laparoscopy surgery. Requirement of intra-operative fentanyl, end-tidal isoflurane and postoperative tramadol were significantly more in group S compared to group D (P < 0.05) Statistically significant nausea and vomiting were noted in group S. Undue sedation and other adverse effects are comparable in both the groups.

Conclusion:

Dexmedetomidine as an adjuvant in general anesthesia for laparoscopic surgeries provided a stable hemodynamic profile in the perioperative period and effectively blunted pressor response to intubation and extubation, leading to minimal requirements for additional analgesics and potent inhalational agents. There were less adverse events.

Efficacy of alpha2 agonists in obtunding rise in intraocular pressure after succinylcholine and that following laryngoscopy and intubation

Context:

Elevation of intraocular pressure (IOP) is an inherent and inadvertent association with the use of succinylcholine and alpha₂ agonists can be used to obtund this effect.

Aims:

The study was aimed to assess the efficacy of intravenous dexmedetomidine and clonidine premedication in attenuating rise in IOP during laryngoscopy and intubation following administration of succinylcholine.

Settings and Design:

This prospective, observational study was conducted in 40 patients aged 20–60 years undergoing non ophthalmic surgical procedures.

Subjects and Methods:

For patients in Group D, dexmedetomidine 0.4 mcg/kg and in Group C clonidine 1 μg/kg over 10 min was administered before induction. All patients were induced with propofol. Laryngoscopy and intubation were performed 1 min after administration of succinylcholine 2 mg/kg.

Statistical Analysis Used:

Mann–Whitney, Chi-square and Wilcoxon tests.

Results:

Mean baseline IOP of both groups were comparable (15.4 ± 2.6 vs. 14.7 ± 2.3). Following premedication and induction, IOP decreased in both groups and the reduction was significantly more in Group D. Following administration of succinylcholine and 1 min after intubation IOP raised and exceeded the baseline value in Group C (16.0 ± 1.6 and 18.6 ± 2.2). Though there was an increase in IOP in Group D (12.0 ± 1.9 and 14.0 ± 2.1), it did not reach up to baseline values. Then there was a gradual reduction in IOP in both groups at 3, 5, and 10 min and Group D continued to have a significantly low IOP than Group C up to 10 min.

Conclusions:

Dexmedetomidine 0.4 μg/kg resulted in a reduction of IOP and blunted the increase in IOP, which followed administration of succinylcholine, laryngoscopy, and intubation. Though clonidine 1 μg/kg reduced IOP, it did not prevent rise in IOP following succinylcholine, laryngoscopy, and intubation.

Comparative Evaluation of Bolus Administration of Dexmedetomidine and Fentanyl for Stress Attenuation During Laryngoscopy and Endotracheal Intubation

BACKGROUND

Laryngoscopy and endotracheal intubation can cause hypertension and tachycardia which can result in myocardial ischemia or stroke in vulnerable people. The objective of our study was to compare the efficacy of bolus dose of dexmedetomidine and fentanyl in attenuating haemodynamic stress responses following laryngoscopy and intubation.

MATERIALS AND METHODS

Sixty patients who were fixed to undergo elective surgeries under general anaesthesia were randomly divided into 2 groups. Group 1 received 1 mcg/kg of dexmedetomidine over 10 minutes and group 2 received fentanyl 2mcg/kg before induction. Anaesthesia was standardized in both the groups and vital parameters were recorded for up to 10 minutes after intubation.

RESULTS

Dexmedetomidine in a dose of 1mcg/kg prevented an increase in heart rate following laryngoscopy when compared to fentanyl group. This effect lasted for 10 minutes after intubation is performed. Though dexmedetomidine prevented an increase in blood pressure, this effect was statistically significant only for 2 minutes after intubation when compared to fentanyl group.

CONCLUSION

Attenuation of rise in heart rate and blood pressure following laryngoscopy and endotracheal intubation was better with 1mcg/kg of dexmedetomidine when compared to fentanyl.

Comparison between dexmedetomidine and fentanyl on intubation conditions during awake fiberoptic bronchoscopy: A randomized double-blind prospective study

Background and Aims:

Various drugs are used for providing favorable intubation conditions during awake fiberoptic intubation (AFOI). However, most of them cause respiratory depression and airway obstruction leading to hypoxemia. The aim of this study was to compare intubation conditions, and incidence of desaturation between dexmedetomidine and fentanyl group during AFOI.

Material and Methods:

This randomized double-blind prospective study was conducted on a total of 60 patients scheduled for elective laparotomies who were randomly allocated into two groups: Group A received dexmedetomidine 1 mcg/kg and Group B received fentanyl 2 mcg/kg over 10 min. Patients in both groups received glycopyrrolate 0.2 mg intravenous, nebulization with 2% lidocaine 4 ml over 20 min and 10% lidocaine spray before undergoing AFOI. Adequacy of intubation condition was evaluated by cough score and post-intubation score. Incidence of desaturation, hemodynamic changes and sedation using Ramsay sedation scale (RSS) were noted and compared between two groups.

Results:

Cough Score (1-4), post-intubation Score (1-3) and RSS (1-6) were significantly favorable (P < 0.0001) along with minimum hemodynamic responses to intubation (P < 0.05) and less oxygen desaturation (P < 0.0001) in Group A than Group B.

Conclusion:

Dexmedetomidine is more effective than fentanyl in producing better intubation conditions, sedation along with hemodynamic stability and less desaturation during AFOI.

Safe Sedation and Hypnosis using Dexmedetomidine for Minimally Invasive Spine Surgery in a Prone Position

Dexmedetomidine, an imidazoline compound, is a highly selective α2-adrenoceptor agonist with sympatholytic, sedative, amnestic, and analgesic properties. In order to minimize the patients' pain and anxiety during minimally invasive spine surgery (MISS) when compared to conventional surgery under general anesthesia, an adequate conscious sedation (CS) or monitored anesthetic care (MAC) should be provided. Commonly used intravenous sedatives and hypnotics, such as midazolam and propofol, are not suitable for operations in a prone position due to undesired respiratory depression. Dexmedetomidine converges on an endogenous non-rapid eye movement (NREM) sleep-promoting pathway to exert its sedative effects. The great merit of dexmedetomidine for CS or MAC is the ability of the operator to recognize nerve damage during percutaneous endoscopic lumbar discectomy, a representative MISS. However, there are 2 shortcomings for dexmedetomidine in MISS: hypotension/bradycardia and delayed emergence. Its hypotension/bradycardiac effects can be prevented by ketamine intraoperatively. Using atipamezole (an α2-adrenoceptor antagonist) might allow doctors to control the rate of recovery from procedural sedation in the future. MAC, with other analgesics such as ketorolac and opioids, creates ideal conditions for MISS. In conclusion, dexmedetomidine provides a favorable surgical condition in patients receiving MISS in a prone position due to its unique properties of conscious sedation followed by unconscious hypnosis with analgesia. However, no respiratory depression occurs based on the dexmedetomidine-related endogenous sleep pathways involves the inhibition of the locus coeruleus in the pons, which facilitates VLPO firing in the anterior hypothalamus.

Comparison of the efficacy of dexmedetomidine with that of esmolol in attenuating laryngoscopic and intubation response after rapid sequence induction

CONTEXT

Laryngoscopy and tracheal intubation produce sympathetic overdrive by catecholamine release resulting in hypertension and tachycardia. Various agents are being tried to combat the intubation response over years.

AIMS

This study is aimed at comparing dexmedetomidine which is a highly selective alpha-2 agonist with an ultra-short acting beta blocker, esmolol to see which among the two is better in attenuating the hemodynamic response to laryngoscopy and tracheal intubation.

SETTINGS AND DESIGN

This was a prospective randomized double-blind control study.

SUBJECTS AND METHODS

Sixty patients scheduled for general anesthesia were divided into two groups, D and E with 30 patients in each group. Group-D patients received dexmedetomidine 0.5 mcg/kg and Group-E patients received esmolol 0.5 mg/kg as intravenous premedication over 5 min before a rapid sequence induction and tracheal intubation. Systolic, diastolic and mean arterial pressures along with heart rate were measured using invasive arterial line at various time points. The percentage change of hemodynamic parameters at those time points from the baseline was compared between the groups.

STATISTICAL ANALYSIS USED

Descriptive and inferential statistical methods were used to analyze the data.

RESULTS

The percentage change of all hemodynamic parameters from base line were less in the dexmedetomidine group than in esmolol group at all-time points of measurement. However, a statistically significant difference was observed often at the time points within 1 min after tracheal intubation.

CONCLUSIONS

Dexmedetomidine is superior to esmolol in attenuating the hemodynamic response to laryngoscopy and tracheal intubation.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Inflammatory Response in Patients under Coronary Artery Bypass Grafting Surgery and Clinical Implications: A Review of the Relevance of Dexmedetomidine Use

Despite the fact that coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB) prolongs life and reduces symptoms in patients with severe coronary artery diseases, these benefits are accompanied by increased risks. Morbidity associated with cardiopulmonary bypass can be attributed to the generalized inflammatory response induced by blood-xenosurfaces interactions during extracorporeal circulation and the ischemia/reperfusion implications, including exacerbated inflammatory response resembling the systemic inflammatory response syndrome (SIRS). The use of specific anesthetic agents with anti-inflammatory activity can modulate the deleterious inflammatory response. Consequently, anti-inflammatory anesthetics may accelerate postoperative recovery and better outcomes than classical anesthetics. It is known that the stress response to surgery can be attenuated by sympatholytic effects caused by activation of central (α-)2-adrenergic receptor, leading to reductions in blood pressure and heart rate, and more recently, that they can have anti-inflammatory properties. This paper discusses the clinical significance of the dexmedetomidine use, a selective (α-)2-adrenergic agonist, as a coadjuvant in general anesthesia. Actually, dexmedetomidine use is not in anesthetic routine, but this drug can be considered a particularly promising agent in perioperative multiple organ protection.