Dexmedetomidine versus esmolol to attenuate the hemodynamic response to laryngoscopy and tracheal intubation: A randomized double-blind clinical study

Superior Laryngeal Nerve Block for Microlaryngoscopic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

To assess the safety and efficacy of superior laryngeal nerve block (SLNB) for microlaryngoscopic surgery (MLS).

DATA SOURCES

PubMed, Embase, Web of Science, Ovid Medline, Cochrane Library, CNKI database, VIP database, Wanfang database, and trial registry databases.

METHODS

PICOS principles were performed: adults undergoing MLS receiving SLNB compared with no-SLNB in randomized controlled trials were included. Primary outcome included the incidence of severe postoperative sore throat (POST). Secondary outcomes included perioperative mean arterial pressure (MAP) and heart rate (HR), incidence of severe postoperative cough, and anesthesia recovery time.

RESULTS

Eleven articles with 728 patients were included. Results indicated that SLNB provides lower incidence of severe POST in post-extubation 30 min (relative ratio [RR] = 0.13; 95% confidence intervals [CIs]: 0.05 ~ 0.34), 2 h (RR = 0.09; 95% CI: 0.02 ~ 0.36), 4-6 h (RR = 0.11; 95% CI: 0.03 ~ 0.41), and 24 h (RR = 0.15; 95% CI: 0.03 ~ 0.83); lower MAP (tracheal intubation: standardized mean difference [SMD] = -1.59; 95% CI: -1.69 to -0.42); suspension laryngoscope insertion: (SMD = -0.98; 95% CI: -1.49 to -0.46); tracheal extubation: (SMD = -0.78; 95% CI:-1.24 to -0.31); post-extubation 5 min: (SMD = -0.95; 95% CI: -1.41 to -0.49); lower HR (tracheal intubation: mean difference [MD] = -9.71; 95% CI: -17.16 to -2.27); suspension laryngoscope insertion: (MD = -8.64; 95% CI: -16.79 to -0.49); tracheal extubation: (MD = -10.13; 95% CI: -17.86 to -2.39); post-extubation 5 min: (MD = -13.44; 95% CI: -22.53 to -4.35); lower incidence of severe postoperative cough in post-extubation 30 min (RR = 0.18; 95% CI: 0.06 ~ 0.57) and 2 h (RR = 0.13; 95% CI: 0.02 ~ 0.69); and shorter anesthesia recovery time (MD = -5.34; 95% CI: -8.81 to -1.86) compared to controls.

CONCLUSIONS

SLNB could provide lower incidence of severe POST, more stable perioperative MAP and HR, lower incidence of severe postoperative cough, and shorter anesthesia recovery time for MLS.

LEVEL OF EVIDENCE

I Laryngoscope, 134:3437-3446, 2024.

Association of intraoperative dexmedetomidine use with postoperative hypotension in unilateral hip and knee arthroplasties: a historical cohort study

PURPOSE

Dexmedetomidine is frequently used as a sedative agent for orthopedic surgery patients undergoing total hip or knee arthroplasty. Although the benefits of dexmedetomidine are well described in the literature, there is also potential for harm, especially regarding the hemodynamic effects of dexmedetomidine in the postoperative setting.

METHODS

This historical cohort study included all primary unilateral total hip or knee arthroplasties conducted from April 2017 to February 2020 in a single, university-affiliated, tertiary care centre (Jewish General Hospital, Montreal, QC, Canada). We used multivariable logistic regression to analyze the predictors for postoperative hypotension, defined as a systolic blood pressure < 90 mm Hg or any systolic blood pressure while on a vasopressor infusion in the postanesthesia care unit. Models were validated using calibration and discrimination with bootstrapping technique.

RESULTS

One thousand five hundred and eighty-eight patients were included in this study. Postoperative hypotension occurred in 413 (26%) patients. Statistically significant predictors for postoperative hypotension included female sex (adjusted odds ratio [aOR], 3.24; 95% confidence interval [CI], 2.29 to 4.58), a history of transient ischemic attack or cerebrovascular accident (aOR, 1.97; 95% CI, 1.04 to 3.72), and intraoperative dexmedetomidine use (aOR, 2.61; 95% CI, 1.99 to 3.42). Moreover, the risk of postoperative hypotension was approximately two times higher than baseline, with a total intraoperative dexmedetomidine dose above 50 μg (relative risk, 1.99; 95% CI, 1.63 to 2.44; P < 0.001). A higher preoperative systolic blood pressure (aOR, 0.98; 95% CI, 0.97 to 0.99) was a protective factor for postoperative hypotension.

CONCLUSION

In this historical cohort study, dexmedetomidine was a strong risk factor for postoperative hypotension in total hip or knee arthroplasty patients. Dexmedetomidine, and particularly at high cumulative doses above 50 μg, should be administered judiciously in high-risk surgical patients to minimize the risk of postoperative hypotension.

Evaluation of Nebulised Dexmedetomidine Given Pre-operatively to Attenuate Hemodynamic Response to Laryngoscopy and Endotracheal Intubation: A Randomised Control Trial

Background and aim

A variety of medications have been studied to reduce the hemodynamic response to laryngoscopy and intubation. Dexmedetomidine has been used intravenously in many studies to reduce the hemodynamic response to laryngoscopy and intubation. In high-risk patients, this pressor response can increase morbidity and mortality. As dexmedetomidine has a good bioavailability via the nebulisation route, we formulated this study to evaluate the effect of nebulised dexmedetomidine on the hemodynamic response to laryngoscopy and endotracheal intubation.

Methods

This is a prospective, randomised controlled trial conducted on 100 patients with the American Society of Anesthesiologists grade I and II. The primary objective of the study was to see if nebulised dexmedetomidine at a dose of 1 microgram/kg could reduce the stress reaction to laryngoscopy and intubation. The secondary objective was to study the dose sparing effect of nebulised dexmedetomidine on the amount of propofol used during induction of general anaesthesia. The study population was randomly divided into two groups: group A (n = 50) included patients nebulised with dexmedetomidine 1 microgram/kg and group B (n = 50) included patients nebulised with 5 ml saline 30 minutes before induction of anaesthesia in a sitting position.

Results

The demographics were similar in both groups. Following laryngoscopy and intubation, the systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate showed a significant increase in the control group B as compared to the treatment group A. In group A, there was attenuation in SBP (one minute = 113.2 ± 14.503, P < 0.001; five minutes = 109.86 ± 8.342, P < 0.001; 10 minutes = 114.24 ± 7.797, P = 0.010), DBP (one minute = 73.72 ± 10.986, P = 0.011; five minutes = 71.62 ± 9.934, P = 0.005; 10 minutes = 76.1 ± 8.006, P = 0.009), MAP (one minute = 86.80 ± 11.86, P = 0.001; five minutes = 84.44 ± 8.97, P = 0.006; 10 minutes = 88.72 ± 7.44, P = 0.018), and heart rate (one minute = 83.34 ± 12.325, P = 0.001; five minutes = 81.56 ± 13.33, P = 0.003; 10 minutes = 80.16 ± 14.086, P = 0.013) following laryngoscopy and intubation. Induction dose of propofol was significantly lower in the dexmedetomidine group (73 ± 19.509, P < 0.001).

Conclusion

Nebulised dexmedetomidine effectively blunts the hemodynamic response to laryngoscopy and intubation and also has a dose sparing effect on the induction dose of propofol.

A comparative study of intravenous low doses of dexmedetomidine, fentanyl, and magnesium sulfate for attenuation of hemodynamic response to endotracheal intubation

BACKGROUND

Endotracheal intubation is an integral part of general anesthesia. The hemodynamic stress responses associated with it, though transient, are unpredictable and variable. In comparison with healthy individuals, those with comorbid health issues can have life-threatening complications with this sympathetic response. Hence, in this study, we compared the efficacy of intravenous low doses of dexmedetomidine, fentanyl, and magnesium sulfate (MgSO₄) in reduction of the hemodynamic response to endotracheal intubation.

MATERIALS AND METHODS

This prospective randomized study compared three groups of dexmedetomidine (0.6 μg/kg) (Group D), fentanyl (2 μg/kg) (Group F), and MgSO₄ 30 mg/kg (Group M). A total of 105 American Society of Anesthesiologist's 1 and 2 patients were selected with 35 in each group. The hemodynamic variables recorded at baseline, during induction and intubation up to ten minutes were pulse rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure. The assessment of quantitative and qualitative data was done with the one-way ANOVAs, Student's t-test, and Chi-square test. Analysis of variance was done by post hoc tests.

RESULTS

There were statistically significant differences that were observed with dexmedetomidine and fentanyl groups in respect to heart rate and blood pressure responses to laryngoscopy and intubation when compared to MgSO₄. A significant attenuation of response from baseline values was also noted with dexmedetomidine and fentanyl groups.

CONCLUSION

Efficacy of low doses of both dexmedetomidine and fentanyl was equipotent in attenuating response in comparison with MgSO₄, and we conclude that dexmedetomidine can serve as an alternative to fentanyl.

Comparison of the hemodynamic response of dexmedetomidine versus additional intravenous lidocaine with propofol during tracheal intubation: a randomized controlled study

Background

Laryngoscopy and tracheal intubation are strong stimuli that cause a reflex increase in blood pressure (BP), heart rate (HR), and serum catecholamine level. These can lead to myocardial infarction or cerebrovascular accidents. The purpose of this study is to compare the efficacy of dexmedetomidine and lidocaine combined with propofol in attenuating the hemodynamic response following laryngoscopy and endotracheal intubation.

Methods

This study was a randomized controlled study and adhered to the CONSORT guidelines. One-hundred and six patients undergoing elective general anesthesia with endotracheal intubation were divided randomly into two groups. Group D received dexmedetomidine (1 μg kg^− 1) before induction. Group LP received lidocaine (1.5 mg kg^− 1) before induction with additional propofol (0.5 mg kg^− 1) before laryngoscopy. The primary endpoint was hemodynamic including systolic (S) BP, diastolic (D) BP, mean arterial blood pressure (MAP) and HR measured before and after induction and ≤ 10 min after intubation. Secondary outcome was complications/adverse effects.

Results

After induction, the mean SBP, DBP, MAP and HR decreased significantly from baseline in both groups except for mean HR in group LP at 1 min. Differences in mean values of SBP, DBP, and MAP were significantly lower in group D after intubation at 4–10 min (P <  0.05). Group LP had a non-inferior effect in blunting BP at all time points except 1 and 2 min after induction, and 2 min after intubation. The mean difference in HR in group D was significantly lower than that in group LP at all time points (P <  0.001). Group D had significantly more episodes of bradycardia (18.87% vs. 0%, P = 0.001) and hypotension (52.83% vs. 15.09%, P < 0.001) than did group LP.

Conclusion

Lidocaine (1.5 mg kg^− 1) with additional propofol (0.5 mg kg^− 1) had a non-inferior effect compared with dexmedetomidine (1 μg kg^− 1) in attenuating the hemodynamic response following laryngoscopy and endotracheal intubation, and had fewer adverse effects.

Trial registration

Thai Clinical Trial Registry, (TRTC20190206002). Retrospectively registered 4 February 2019.

Comparison of Esmolol and Dexmedetomidine Infusion in Attenuating Haemodynamic and Blood Glucose Response to Laryngoscopy and Intubation: A Single Blinded Study

Background

This study aims to compare the effect of infusions of two agents, dexmedetomidine and esmolol, with the control group in attenuating the haemodynamic stress response and neuroendocrine modulation surrogated by capillary blood glucose (BG) during the procedures.

Methods

Sixty patients aged 18–70 years old who underwent elective surgeries involving endotracheal intubation were randomised into three groups of equal size: i) control; ii) dexmedetomidine and iii) esmolol. Heart rate (HR) was measured at baseline (T0), after drug administration (T1), after induction of anaesthesia (T2), immediately after intubation (T3), and 3 min, 5 min and 10 min after intubation (T4, T5 and T6). BG was measured pre-operatively and 30 min post-intubation.

Results

Two-way repeated-measures analysis of variance showed significant time [within-group changes, F(3.2, 182.5) = 30.39, P < 0.001], treatment [between-group differences regardless of time, F(2, 57) = 50.24, P < 0.001] and interaction [between-group differences based on time, F(6.4, 182.5) = 37.65, P < 0.001] effects on HR. A significantly higher HR was observed in the control group compared to the dexmedetomidine and esmolol groups from T2 to T6. BG exhibited a significant time effect [F(1, 57) = 41.97, P < 0.001] with no significant treatment and interaction effects. All three groups showed a significant increase in BG from baseline.

Conclusion

Both dexmedetomidine and esmolol are equally effective in attenuating haemodynamic responses to laryngoscopy and intubation. However, both do not significantly modulate neuroendocrine stress.

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.

Comparison of Dexmedetomidine, Lidocaine, and Fentanyl in Attenuation Hemodynamic Response of Laryngoscopy and Intubation in Patients Undergoing Cardiac Surgery

Materials and Methods

This clinical trial was conducted on 90 patients, aged 30–70 years, who had heart surgery. The participants were categorized into three groups. Group D received 1 µg/kg intravenous dexmedetomidine in 10 minutes, group L received 1.5 mg/kg lidocaine (1%) 90 seconds before intubation, and group F received 2 µg/kg fentanyl. The vital signs (HR, SBP, DBP, and MAP) were measured before intubation and 1st, 3rd, 5th, and 10th minutes after intubation. Data were analyzed with SPSS 19 software (chi-square, one-way ANOVA, or Kruskal–Wallis).

Results

The age (P=0.389) and gender distributions of patients were similar in all three groups. Dexmedetomidine significantly attenuated HR in the 3^rd (P=0.001), 5^th (P=0.001), and 10^th (P=0.003) minutes after intervention. It also reduced the systolic blood pressure in the 5^th (P=0.024) and 10^th (P=0.006) minutes. This reduction was significantly higher in the dexmedetomidine group than that in the two other groups. In addition, dexmedetomidine caused a greater reduction in MAP in the 1^st (P=0.048), 5^th (P=0.0001), and 10^th (P=0.0001) minutes. Discussion. All three medications were effective in controlling HR; however, dexmedetomidine caused bradycardia in the 3^rd, 5^th, and 10^th minutes. Lidocaine resulted in an increase in MAP in the 1^st minute after intubation; whereas, dexmedetomidine reduced MAP at the 5^th and 10^th minutes after intubation. Changes in blood pressure and mean arterial pressure in the fentanyl group was lower than the two other groups.

Conclusion

As a result, dexmedetomidine was not suitable for hemodynamic control and led to hypotension and bradycardia; on the other hand, fentanyl was more effective than two other medications in patients undergoing cardiac surgery. This trial is registered with IRCT2017013132320N1.

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).

Comparison of Esmolol and Dexmedetomidine for Suppression of Hemodynamic Response to Laryngoscopy and Endotracheal Intubation in Adult Patients Undergoing Elective General Surgery: A Prospective, Randomized Controlled Double-blinded Study

Context:

Laryngoscopy and endotracheal intubation lead to strong sympathetic response which may precipitate arrhythmias, myocardial ischemia and cerebrovascular accidents in patients with preexisting cardiovascular disease.

Aims:

This study was aimed to compare the effect of dexmedetomidine and esmolol on hemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing elective surgery under general anesthesia.

Settings and Design:

This was a prospective, randomized controlled double-blinded study.

Materials and Methods:

A total of ninety patients were selected and randomized into three groups of thirty patients each: Group C received infusion of 20 mL 0.9% normal saline (NS) over 10 min, Group D received infusion of dexmedetomidine 1 μg/kg diluted in 20 mL NS over 10 min, and Group E received infusion of esmolol 1.5 mg/kg diluted in 20 mL NS over 10 min. Three minutes after the completion of infusion, patients were induced with general anesthesia. Baseline parameters such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and rate pressure product (RPP) were recorded before administration of study drugs and at 1, 3, 5, 7, and 10 min after intubation.

Statistical Analysis Used:

One-way ANOVA was used for comparison among the groups and unpaired t-test was used for comparison within the groups along with Tukey's test for post test analysis.

Results:

Mean HR, SBP, DBP, MAP, and RPP values remained significantly lower in Group D than that of Group C and Group E at all time intervals up to 10 min after intubation.

Conclusions:

Both dexmedetomidine and esmolol suppressed the hemodynamic response to intubation when compared to control group, but dexmedetomidine is more effective than esmolol in maintaining hemodynamic stability following laryngoscopy and intubation.

Prospective randomized study to compare between intravenous dexmedetomidine and esmolol for attenuation of hemodynamic response to endotracheal intubation

Background:

Esmolol has an established role in attenuation of hemodynamic response to laryngoscopy and endotracheal intubation. We studied the effect of dexmedetomidine compared to that of esmolol in this study.

Aim:

To study the role of dexmedetomidine in attenuation of hemodynamic response to laryngoscopy and oral endotracheal intubation compared to that of esmolol hydrochloride in patients posted for elective surgery under general anesthesia.

Study Design:

Prospective randomized study double-dummy blinding method.

Materials and Methods:

A total of 60 American Society of Anesthesiologists I patients, aged 18–60 years randomly divided into two groups; Group A patients received dexmedetomidine 1 mcg/kg diluted in 50 ml with normal saline and infused over 10 min before induction and also 20 ml of normal saline intravenous (IV) 2 min before endotracheal intubation. Group B patients received 50 ml IV infusion of normal saline over 10 min before induction and IV bolus of esmolol 0.5 mg/kg diluted in 20 ml with normal saline given 2 min before intubation. Standard induction technique followed. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded just before induction and after intubation at 1 min, 3 min, and 5 min after intubation.

Statistical Analysis:

Independent samples t-test and repeated measures of analysis of variance.

Results:

Dexmedetomidine group showed statistically significant reduction in all the study parameters at all study time intervals following intubation. While esmolol group showed significant attenuation of HR, SBP, and MAP following intubation but failed to produce significant reduction in DBP.

Conclusion:

Dexmedetomidine is more effective in attenuating the hemodynamic response to oral endotracheal intubation compared to that of esmolol hydrochloride.

Different doses of intravenous Magnesium sulfate on cardiovascular changes following the laryngoscopy and tracheal intubation: A double-blind randomized controlled trial

OBJECTIVE

Laryngoscopy and intratracheal intubation may cause acute hemodynamic instabilities due to catecholamine release. Magnesium sulfate (MgSO4) prevents catecholamine release and results in bradycardia and vasodilatation, so can be used to diminish complications of laryngoscopy and intubation in doses > 50 mg/kg. The aim of this study was to compare the different doses of MgSO4 used to improve cardiovascular instabilities due to laryngoscopy and intratracheal intubation.

METHODS

In this double-blind randomized controlled trial, 120 patients undergoing elective surgery were divided equally into four groups (n = 30) and received different doses of MgSO4 as case groups (Group I: 30 mg/kg, Group II: 40 mg/kg, Group III: 50 mg/kg) or the equal volume of normal saline as a control group. The patients' hemodynamic status was recorded at baseline, before laryngoscopy and in 1, 3, 5, and 10 minutes after laryngoscopy. Bradycardia, tachycardia, hypertension, hypotension, ST-T changes, arrhythmias, and duration of extubation and laryngoscopy were also recorded.

FINDINGS

There was no significant difference in heart rate between four groups (Pbaseline = 0.46, Ppreoperation = 0.55, P1 min = 0.86, P3 min = 0.30, P5 min = 0.63, P10 min = 0.74). Systolic, diastolic and mean arterial pressures were statistically significant less at 1, 3, and 5 minutes after intubation in comparison with other times of following-up in the three groups received MgSO4 than the control group.

CONCLUSION

The use of MgSO4 in doses less than 50 mg/kg can be effective to reduce cardiovascular instability related to laryngoscopy and tracheal intubation.

A randomized controlled trial of the effect of preoperative dexmedetomidine on the half maximal effective concentration of propofol for successful i-gel insertion without muscle relaxants

BACKGROUND

Dexmedetomidine is a useful anesthetic adjuvant for general anesthesia. We determined whether preoperative dexmedetomidine administration could reduce the half maximal effective concentration (EC50) of propofol for successful i-gel insertion without muscle relaxants.

METHODS

Thirty-seven patients were randomly allocated to one of two groups. In the dexmedetomidine group (n = 19), dexmedetomidine (1 µg/kg) was loaded for 10 min preoperatively. In the control group (n = 20), the same volume of 0.9% normal saline was administered in the same manner. The EC50 of propofol for successful i-gel insertion was determined using Dixon's up-and-down method. The EC50 of propofol was calculated as the midpoint concentration after at least six crossover points had been obtained. For successful i-gel insertion, all of the following four factors were required—(1) no major movement of the body within 1 min of insertion, (2) no significant resistance to mouth opening, (3) cough ≤2, and (4) visible square wave capnogram without air leakage at a peak airway pressure of <10 cmH2O. Mean blood pressure (MBP) and heart rate (HR) were monitored during the peri-insertion period of i-gel.

RESULTS

The EC50 of propofol for successful i-gel insertion was 3.18 μg/mL in the dexmedetomidine group and 6.75 μg/mL in the control group (p < 0.001). The incidence of hypotension (MBP <80% of the baseline) during the peri-insertion period of i-gel was higher in the control group (p = 0.001), whereas the incidence of bradycardia (HR <80% of the baseline) was higher in the dexmedetomidine group (p = 0.001).

CONCLUSIONS

Preoperative dexmedetomidine reduced the EC50 of propofol for successful i-gel insertion without muscle relaxants.