Preoperative Dexmedetomidine Research Articles

Dexmedetomidine Nasal Spray on Emergence Agitation After Ear, Nose, and Throat Surgery: Protocol for a Randomized, Double-Blind, Controlled Trial.

Emergence agitation (EA) is a state of psychomotor hyperactivity following general anesthesia and is associated with postoperative complications. Patients undergoing ear, nose, and throat (ENT) surgery are at a high risk for EA. We aim to assess whether preoperative dexmedetomidine nasal spray reduces the occurrence of EA for patients undergoing ENT surgery. This is a protocol for a randomized, double-blind, controlled trial that will include 160 adults scheduled for ENT surgery. Patients will be randomly assigned, in a 1:1 ratio, to receive dexmedetomidine nasal spray (100μg) or a same volume of normal saline approximately 30min before general anesthesia induction. The primary endpoint is the incidence of EA, defined as a Riker sedation agitation scale (RSAS) score ≥5 from discontinuation of sevoflurane until 5min after tracheal extubation. Secondary endpoints include (1) the maximal RSAS score during emergence; (2) the incidence of agitation in the postoperative care unit (PACU); (3) pain at rest and while coughing in the PACU and at 24h postoperatively; (4) postoperative sleep disturbance on the first night after surgery; (5) anxiety within 24h postoperatively; and (6) postoperative delirium during the first 24h after surgery. All analyses will be performed on a modified intention-to-treat basis. For the primary endpoint, subgroup analysis will be conducted on sex, age, and type of surgery. We expect that preoperative dexmedetomidine nasal spray would reduce the incidence of EA after ENT surgery. Our results offer clinical evidence for improving anesthetic care for patients undergoing ENT surgery. Chinese Clinical Trial Registry (Identifier: ChiCTR2400086731).

Effects of short-term preoperative intranasal dexmedetomidine plus conventional treatment on delirium following cardiac surgery in patients with sleep disorders

Study objectivesTo assess whether preoperative dexmedetomidine (DEX) nasal drips combined with conventional treatment could mitigate the occurrence of postoperative delirium (POD).DesignA prospective randomised controlled study.SettingThe cardiac surgery intensive care unit (CSICU) and patient hospitalisation ward at a university hospital.ParticipantsA total of 100 patients (aged ≥60 years) undergoing cardiac surgery at a university hospital between 7 January 2022, and 30 November 2022 met the eligibility criteria and were included in the study.InterventionsPatients with sleep disorders (Pittsburgh Sleep Quality Index ≥8) were divided into two groups: Group A (the placebo group, n=50), receiving a short-term preoperative placebo combined with conventional treatment and Group B (the DEX group, n=50), receiving short-term preoperative DEX combined with conventional treatment.Measurements and resultsThe Confusion Assessment Method for the ICU (CAM-ICU) was used for POD assessment in the CSICU, while the CAM was employed to assess delirium in the patient ward. Group B demonstrated a reduced incidence of POD compared to Group A (12% vs. 30%, odds ratio: 0.318, 95% confidence interval: 0.112–0.905, p=0.027).ConclusionThe combined treatment involving DEX demonstrated a decreased incidence of POD in elderly individuals with sleep disorders undergoing cardiac surgery compared to the placebo combination treatment.Trial registrationURL: www.chictr.org.cn with registration number ChiCTR 2100043968, registered on 06/03/2021.

A randomized double blind study to evaluate the effect of nebulized dexmedetomidine on the haemodynamic response to laryngoscopy – Intubation and intubation conditions

: A cardiovascular stress response is frequently brought on by direct laryngoscopy and intubation. It is widely known that the sympathetic adrenal stimulation elicited by mechanical stimulation to the upper respiratory tract is what causes the haemodynamic response during laryngoscopy and intubation. The study's goal was to assess the impact of preoperative dexmedetomidine nebulization on the patient's hemodynamic response to laryngoscopy- intubation and the intubation conditions.: The American Society of Anaesthesiologists (ASA) I & II adult patients, of either gender, undergoing elective surgeries requiring tracheal intubation were randomized to receive nebulized dexmedetomidine (Group D) or 0.9% saline (Group P), 30 minutes prior to the induction of anesthesia. This study was conducted in the department of anesthesia and critical care at the Christian Medical College in Ludhiana. Following laryngoscopy, the patient's heart rate and non-invasive systolic and diastolic blood pressure will be monitored for 10 minutes. The intubation conditions were noted during laryngoscopy.Total 100 patients with 50 in each group were included. At the time of laryngoscopy and after the intubation 1 min, 3 min,5 min, 7min and 10 min there were significantly lower trend in increasing HR, SBP, DBP and RPP in dexmedetomidine group versus saline. The intubation score representing conditions for intubation was significantly better in the dexmedetomidine group (P=0.013) than the saline group. There was no significant side effect noted (p=1.000). There was significant reduction in intraoperative analgesic and sedative requirement observed in dexmedetomidine groupOur study concluded that the nebulized dexmedetomidine attenuated haemodynamic response to laryngoscopy- intubation and provided better intubation conditions without significant side effects. We advise using nebulized dexmedetomidine pre-operatively for a surgical procedure requiring general anesthesia in order to reduce the haemodynamic response to intubation and to facilitate intubation conditions without experiencing any severe adverse effects.

The Beneficial Effect of Preoperative Dexmedetomidine in Controlling Postoperative Pain, Nausea, and Vomiting After Orthognathic Surgery: A Triple-blind Randomized Clinical Trial

Controlling postoperative pain and nausea (PONV) following orthognathic surgery can be challenging. The aim of the study was to assess the efficacy of dexmedetomidine (DEX) in reducing pain and preventing nausea and vomiting in subjects undergoing orthognathic surgery. The authors implemented a triple-blinded, randomized clinical trial. Healthy adults with class III jaw deformity scheduled for bimaxillary orthognathic surgery were included. Subjects were randomized to the DEX or placebo groups. The DEX group received premedication with DEX 1μg/kg IV over 10minutes followed by a maintenance dose (0.2μg/kg/hour) while the placebo group received normal saline. The primary outcome variables were postoperative pain, postoperative nausea, and postoperative vomiting . Pain was assessed using a visual analog scale at 1, 3, 6, 12, 18, and 24hours, postoperatively). Nausea and vomiting were recorded throughout the postoperative period. Statistical analysis was performed using χ2, t test, and repeated measures ANOVA with a P value<.05 considered significant. A total of 60 consecutive subjects with a mean age of 24.6±3.5years completed the study. There were 38 females (63.33%) and 22 males (36.66%). The mean visual analog scale was significantly lower in the DEX group at all time-points (P<.05). There was a significantly greater demand for rescue analgesics in the placebo group compared to the DEX group (P=.01). Fourteen subjects (46.7%) in the placebo group and one subject (3.3%) in the DEX group reported nausea (P<.001). Postoperative vomiting was not observed in any of the subjects. Premedication with DEX can be considered a viable treatment option for reducing postoperative pain and postoperative nausea after bimaxillary orthognathic surgery.

EFFECT OF NEBULISED DEXMEDETOMIDINE IN BLUNTING HAEMODYNAMIC RESPONSE TO INTUBATION- A RANDOMIZED DOUBLE BLIND CONTROLLED STUDY

BACKGROUND: Dexmedetomidine, an alpha-2 agonist, has been used for attenuation of he- modynamic response to laryngoscopy but not through the nebulized route. We evaluated the effects of preoperative dexmedetomidine nebulization on the hemodynamic response to laryngoscopy and intubation. To evaluate the AIM: effects of nebulised dexmedetomidine as a premedication in Blunting the haemodynamic response to laryngoscopy and tracheal intubation. After MATERIALS AND METHODS: written informed consent and ethics committee approval, 50 patientsBelonging to ASA status I or II were randomly allocated to two groups.Patients not Giving consent,predicted airway difculty and uncontrolled hypertension were Excluded. All the patients were monitored by ASA standard monitors.They were Randomized into two groups- C and D Group C received 5 ml of normal saline and Group D received 5 ml of dexmedetomidine at a dose of 1 μg/kg as nebulisation 10 mins prior to induction.Then the patients were premedicated and induced with Propofol and intubated after giving a non depolarizing muscle relaxant. Vital monitoring like HR,SBP,DBP,MAP,SPO2,was noted at baseline, post nebulization ,post intubation at 1,5,10 minutes. Demographic details and surgery cha RESULTS: racteristics were comparable between the Groups.Heart rate between the two groups were comparable.The MAP,SBP and DBP values after intubation were lower in group D, which was statistically Signicant(P&lt;0.05).The mean dose of propofol for induction was also lower in Group D. To conclude,nebulised CONCLUSION: dexmedetomidine effectively blunts the pressor response To laryngoscopy and intubation with no serious adverse effects

Comparison of Intravenous Versus Nebulized Dexmedetomidine for Laryngoscopy and Intubation-Induced Sympathoadrenal Stress Response Attenuation.

Nebulized dexmedetomidine has been used for procedural sedation and allaying separation anxiety in children. Literature regarding its use in the attenuation of laryngoscopy and intubation response via the nebulized route is scarce. We evaluated preoperative dexmedetomidine nebulization on the hemodynamic response arising from laryngoscopy/intubation, hemodynamics, analgesic consumption, and postoperative sore throat. The primary objective was to evaluate/compare the hemodynamic effects of preoperative intravenous and nebulized dexmedetomidine on laryngoscopy/intubation and compare the efficacy of the two routes in blunting the sympathoadrenal response. The secondary objective was to evaluate their effects on intraoperative analgesic consumption and incidence and sore throat postoperatively. 120 ASA I & II adult patients undergoing elective surgeries requiring tracheal intubation were randomized to receive intravenous dexmedetomidine (1 µg/kg over 10 minutes) and nebulized dexmedetomidine (1 µg/kg in 3 - 4 mL of 0.9% saline), 30 min before anesthesia induction. Heart rate and non-invasive blood pressure were monitored for 10 min following laryngoscopy and then throughout the surgery. Intraoperative analgesic consumption, postoperative sore throat, and recovery from anesthesia were assessed. No significant hemodynamic difference was found between the two groups till three minutes. Then, the difference turned significant owing to a greater fall in the heart rate and mean arterial pressure in the intravenous group. Nebulized dexmedetomidine exhibited a lesser tendency of hypo/hypertension and brady/tachycardia, while hemodynamics was more stable. There was lesser sore throat and sedation in the nebulized group. Intraoperative analgesic and propofol consumption was comparable between the two groups. Nebulized dexmedetomidine attenuated laryngoscopy and intubation response, although to a lesser extent than the intravenous group in equivalent doses. However, the nebulized route provided greater hemodynamic stability in the intraoperative period and lesser sedation/sore throat postoperatively without an increase in adverse effects. Nebulized dexmedetomidine may provide a more holistic and viable alternative in patients who poorly tolerate hypotension, bradycardia, and sedation.

Preoperative dexmedetomidine and intraoperative bradycardia in laparoscopic cholecystectomy: a meta-analysis with trial sequential analysis.

BackgroundWhile laparoscopic surgical procedures have various advantages over traditional open techniques, artificial pneumoperitoneum is associated with severe bradycardia and cardiac arrest. Dexmedetomidine, an imidazole derivative that selectively binds to α2-receptors and has sedative and analgesic properties, can cause hypotension and bradycardia. Our primary aim was to assess the association between dexmedetomidine use and intraoperative bradycardia during laparoscopic cholecystectomy. MethodsWe performed a systematic review with a meta-analysis and trial sequential analysis using the following PICOS: adult patients undergoing endotracheal intubation for laparoscopic cholecystectomy (P); intravenous dexmedetomidine before tracheal intubation (I); no intervention or placebo administration (C); intraoperative bradycardia (primary outcome), intraoperative hypotension, hemodynamics at intubation (systolic blood pressure, mean arterial pressure, heart rate), dose needed for induction of anesthesia, total anesthesia requirements (both hypnotics and opioids) throughout the procedure, and percentage of patients requiring postoperative analgesics and experiencing postoperative nausea and vomiting and/or shivering (O); randomized controlled trials (S). ResultsFifteen studies were included in the meta-analysis (980 patients). Compared to patients that did not receive dexmedetomidine, those who did had a higher risk of developing intraoperative bradycardia (RR: 2.81, 95% CI [1.34, 5.91]) and hypotension (1.66 [0.92, 2.98]); however, they required a lower dose of intraoperative anesthetics and had a lower incidence of postoperative nausea and vomiting. In the trial sequential analysis for bradycardia, the cumulative z-score crossed the monitoring boundary for harm at the tenth trial.ConclusionsPatients undergoing laparoscopic cholecystectomy who receive dexmedetomidine during tracheal intubation are more likely to develop intraoperative bradycardia and hypotension.

Effect of Preoperative Dexmedetomidine on Prevalence of Postoperative Cognitive Dysfunction in Elderly Patients Candidate for Orthopedic Surgery under General Anesthesia

Background: Postoperative cognitive dysfunction (POCD) is amongst the most critical complications after surgery. This study shows the effect of dexmedetomidine on the prevalence of postoperative cognitive impairment. Methods: In this double-blinded clinical trial study, patients aged 60-80 years undergoing pelvic and femoral orthopedic surgery were randomly assigned in one of the two groups of the course, i.e., Dexmedetomidine (DEX) or normal saline (NS). We infuse One hour before anesthesia, one µg/kg dexmedetomidine in the group (DEX), and the same volume of normal saline (NS). Mini-Mental State Examination test (MMSE) was applied to evaluate the patients' cognitive condition, One day before the surgery, 24 and 72 hours after the surgery. Results: There was no significant difference between the two groups in terms of age, sex, duration of anesthesia, duration of surgery, and the amount of bleeding during operation (P&gt;0.0). The postoperative hematocrit level was lower than the preoperative level in the group (DEX) (P&lt;0.05). There was no significant difference in MMSE test scores pre and postoperatively between the two groups (P&gt;0.05). Conclusion: Dexmedetomidine infused before surgery has no preventive effect on POCD in elderly patients undergoing pelvic and femoral orthopedic surgery under general anesthesia.

Effect of Intravenous Dexmedetomidine on Intraocular Pressure in Patients Undergoing Glaucoma Surgery Under Local Anesthesia: A Pilot Study.

Preoperative intravenous (IV) dexmedetomidine produced a 33% reduction in intraocular pressure (IOP) within 15 minutes of administration in patients with glaucoma. To evaluate the effect of preoperative IV dexmedetomidine on IOP in adult patients undergoing glaucoma surgery under local anesthesia. In a prospective interventional case series, 12 patients with uncontrolled IOP (IOP>24 mm Hg in both the eyes) with the systemic status of American Society of Anesthesiologists (ASA) classification I-II, received IV dexmedetomidine 0.6 µg/kg 30 minutes preoperatively. The IOP of the nonsurgical eye (measured with Perkins tonometer), the heart rate (HR), and blood pressure (BP) were recorded 5 minutes prior, 15 minutes and 2 hours after IV dexmedetomidine administration, and were compared using analysis of variance and Tukey honestly significant difference tests. There were 4 women and 8 men with a mean age (±SD) of 60.6±10.4 years. The mean number of antiglaucoma medications was 4.3±1.3. The mean pre-dexmedetomidine IOP was 31.5±5.6 mm Hg. At 15 minutes post-dexmedetomidine administration, the mean and percentage drop in IOP were 10.2±3.2 mm Hg (P=0.001) and 33%±11%, respectively. The mean and percentage drop in systolic BP were 18±20 mm Hg (P=0.01) and 12%±14%, and drop in diastolic BP were 6.5±10 mm Hg (P=0.05) and 7%±11%, respectively. The mean and percentage drop in HR were 2±0.6 bpm (P=0.48) and 2%±13%, respectively. None of the subjects experienced any medication-related adverse effects. At 2 hours, the mean and percentage drop in IOP were 5.3±3 mm Hg and 17%±11%, respectively. In the small sample of (ASA I-II) patients studied, preoperative dexmedetomidine produced a significant drop in IOP (33%) within 15 minutes of IV administration in patients with glaucoma that was reversing at 2 hours, with a good safety profile.

Effect of preoperative dexmedetomidine nebulization on the hemodynamic response to laryngoscopy and intubation: a randomized control trial.

BackgroundDexmedetomidine, an alpha-2 agonist, has been used for attenuation of hemodynamic response to laryngoscopy but not through the nebulized route. We evaluated the effects of preoperative dexmedetomidine nebulization on the hemodynamic response to laryngoscopy and intubation and examined the intraoperative anesthetic-analgesic requirements and recovery outcomes.MethodsOverall, 120 American Society of Anesthesiologists I & II adult patients (of either gender) undergoing elective surgeries and requiring tracheal intubation, were randomized to receive nebulized dexmedetomidine (1 µg/kg in 3–4 ml of 0.9% saline) or 0.9% saline (3–4 ml), 30 min before anesthesia induction. Heart rate (HR) and non-invasive systolic blood pressure (SBP) were monitored for 10 min following laryngoscopy.ResultsAfter laryngoscopy, linear mixed effect modelling showed significantly lower trend of increase in HR in the dexmedetomidine group versus saline (P = 0.012); however, there was no difference in the SBP changes between the two groups (P = 0.904). Induction dose of propofol (P < 0.001), intraoperative fentanyl consumption (P = 0.007), and isoflurane requirements (P = 0.013) were significantly lower in the dexmedetomidine group. There was no difference in the 2 h incidence of postoperative nausea and vomiting (PONV) (P = 0.612) or sore-throat (P = 0.741).ConclusionsNebulized dexmedetomidine at 1 µg/kg attenuated the increase in HR but not SBP following laryngoscopy and reduced the intraoperative anesthetic and analgesic consumption. There was no effect on early PONV, sore-throat, or increase in incidence of adverse effects. Nebulized dexmedetomidine may represent a favorable alternative to the intravenous route in short duration surgeries.

Application effect of preoperative intranasal dexmedetomidine in pediatric anesthesia

Objective To observe the clinical effects of preoperative intranasal dexmedetomidine in pediatric anesthesia. Methods From April 2014 to April 2017, 40 pediatric patients who accepted elective circumcision, ASAⅠ, aged 2 to 10 years in Wenjiang Branch of Sichan Provincial People's Hospital were divided into two groups, with 20 cases in each group.The test group received intranasal dexmedetomidine 1μg/kg, and the control group received intranasal equal volume of saline 30 min before surgery.HR, SpO2, BP were monitored and recorded before intranasal(T0), 5min after intranasal(T1), 10min after intranasal(T2), 20min after intranasal(T3), 30min after intranasal(T4). The sedation score was assessed after 30 min of administration.The restless score was observed after waking. Results ANOVA analysis showed that there were significant differences in SBP(F=14.54, P<0.05) and DBP(F=22.69, P<0.05) between the two groups, and the SBP(F=13.77, P<0.05), DBP(F=10.48, P<0.05), HR(F=5.13, P<0.05) had interaction effects.Compared with those of the control group, the heart rate and the diastolic pressure of the test group were decreased at T2~T4(all P<0.05). The sedation score of the test group was superior than that of the control group(t=-9.131, P<0.05), and the postoperative agitation score was lower than that of the control group(t=3.387, P<0.05). Conclusion Intranasal dexmedetomidine can provide satisfactory sedative effects without affecting the vital signs of children and significantly reducing the postoperative agitation. Key words: Dexmedetomidine; Intranasal; Pediatric anesthesia; Preoperative; Circumcision

The influence of dexmedetomidine on remifentanil‑induced hyperalgesia and the sex differences

In the clinical settings, patients often develop opioid-induced hyperalgesia (OIH) after utilization of high dose intra-operative remifentanil. Systemic α2 agonists, including dexmedetomidine, are believed to reduce pain and opioid requirements after surgery, thus decreasing the incidence of hyperalgesia. The present study aimed to investigate the effect of dexmedetomidine on remifentanil-induced hyperalgesia and explored the sex differences. A total of 48 patients (24 male, 24 female) with an American Society of Anesthesiologists physical status of I-II that were undergoing thyroidectomy were randomly assigned to one of the following six groups: Male controlled group (MC) and female controlled group (FC) (group MC, n=8 and group FC, n=8), which received a preoperative placebo of 0.2 µg.kg-1 normal saline and intraoperative remifentanil 0.2 µg.kg-1.min-1; male and female group with low-dose dexmedetomidine (group MD1, n=8 and group FD1, n=8), which received preoperative dexmedetomidine 0.2 µg.kg-1 and intraoperative remifentanil 0.2 µg.kg-1.min-1; and male and female groups with high-dose dexmedetomidine (group MD2, n=8 and group FD2, n=8), which received dexmedetomidine 0.6 µg.kg-1 and intraoperative remifentanil 0.2 µg.kg-1.min-1. Result indicated that the visual analog scale (VAS) scores and morphine dosing frequency were significantly higher in MC and FC groups compared with the other same sex groups. Furthermore, the mechanical hyperalgesia threshold and patients' analgesia satisfaction score after surgery were significantly lower in MC and FC groups. Notably, the frequency of post-operative chills, nausea and vomiting were significantly lower in groups MD1, MD2, FD1 and FD2. The present findings indicated that low- and high-dose dexmedetomidine injection significantly decreased the patient's risk of enhanced pain intensity and increased postoperative morphine dosing caused by remifentanil-induced hyperalgesia. These findings suggest that the influence of dexmedetomidine displayed minimal significant differences between sex. Trial registration no., IRB2018-YX-001 (Name of registry: Institutional Medical Ethics Committee of Tianjin Medical University General Hospital; date of registration: February 1, 2016).

Tracheal extubation in deeply anesthetized pediatric patients after tonsillectomy: a comparison of high-concentration sevoflurane alone and low-concentration sevoflurane in combination with dexmedetomidine pre-medication

BackgroundDexmedetomidine can facilitate a smooth extubation process and reduce the requirement of sevoflurane and emergence agitation when administrated perioperatively. We aimed to observe the extubation process and the recovery characteristics in pediatric patients undergoing tonsillectomy while anesthetized with either high-concentration sevoflurane alone or low-concentration sevoflurane combined with pre-medication of single dose of intravenous dexmedetomidine.MethodsSeventy-five patients (ASA I or II, aged 3–7 years) undergoing tonsillectomy were randomized into three equal groups: to receive intravenous saline (Group D0), dexmedetomidine 1 μg/kg (Group D1), or dexmedetomidine 2 μg/kg (Group D2) approximately 10 min before anesthesia. Before the end of surgery, sevoflurane were adjusted to 1.5 times, 1.0 time and 0.8 times the minimal effective concentration in groups D0, D1 and D2, respectively. The sevoflurane concentration for each group was maintained for at least 10 min before the tracheal deep-extubation was performed. The extubation event, recovery characteristics and post-op respiratory complications were recorded.ResultsAll tracheal tubes in three groups were removed successfully during deep anesthesia. Nine patients in Group D0, three patients in Group D1, and two patients in Group D2 required oral airway to maintain a patent airway after extubation. The frequency of oral airway usage in groups D1 and D2 were significantly lower than that in Group D0. The percentages of patients with ED and the requirements of fentanyl in groups D1 and D2 were also significantly lower than those in Group D0. The time from extubation to spontaneous eye opening in Group D2 was longer than that in groups D0 and D1. The times of post-anesthesia care unit discharge in groups D0 and D2 were longer than that in Group D1. No other respiratory complications and vomiting were observed.ConclusionA single dose of intravenous dexmedetomidine as pre-medication in combination with low-concentration sevoflurane at the end of surgery provided safe and smooth deep extubation condition and it also lowered the emergence agitation in sevoflurane-anaesthetized children undergoing tonsillectomy. Preoperative dexmedetomidine at 1 μg/kg did not prolong postoperative recovery time.Trial registrationChinese Clinical Trial Registry (ChiCTR): ChiCTR-IOR-16008423, date of registration: 06 may 2016.

Role of Low Dose Preoperative Dexmedetomidine in Preventing Tourniquet Induced Hypertension in Paediatric Orthopaedic upper Limb Surgeries during General Anaesthesia

Role of Low Dose Preoperative Dexmedetomidine in Preventing Tourniquet Induced Hypertension in Paediatric Orthopaedic upper Limb Surgeries during General Anaesthesia

Effectiveness of preoperative intranasal dexmedetomidine compared with oral midazolam for the prevention of emergence delirium in pediatric patients undergoing general anesthesia: a systematic review protocol.

This review aims to identify the effectiveness of preoperative intranasal dexmedetomidine compared with oral midazolam for the prevention of emergence delirium in pediatric patients undergoing general anesthesia.

Induced hypotension in ambulatory functional endoscopic sinus surgery: A comparison between dexmedetomidine and clonidine as premedication. A prospective, double-blind, and randomized study.

Background:Functional endoscopic sinus surgery (FESS) is the mainstay of a therapeutic technique for nasal pathologies. This study is to compare the ability of preoperative dexmedetomidine versus clonidine for producing controlled hypotensive anesthesia during FESS in adults in an ambulatory care setting.Materials and Methods:Sixty patients (25-50 years) posted for ambulatory FESS procedures under general anesthesia were randomly divided into Group C and D (n = 33 each) receiving dexmedetomidine 1 μg/kg and clonidine 1.5 μg/kg, respectively; both diluted in 100 ml saline solution 15 min before anesthetic induction. Nasal bleeding and surgeon's satisfaction score; amount and number of patients receiving fentanyl and nitroglycerine for analgesia and deliberate hypotension, duration of hypotension, post anesthesia care unit (PACU) and hospital stay; hemodynamic parameters and side effects were recorded for each patient.Results:Number and dosage of nitroglycerine used was significantly (P = 0.034 and 0.0001 respectively) lower in Group D compared to that in Group C. Similarly, number of patients requiring fentanyl and dosage of same was significantly lower in Group D. But, the duration of controlled hypotension was almost similar in both the groups. Group D patients suffered from significantly less nasal bleeding and surgeon's satisfaction score was also high in this group. Discharge from PACU was significantly earlier in Group D, but hospital discharge timing was quite comparable among two groups. Intraoperative hemodynamics was significantly lower in Group D (P < 0.05) without any appreciable side effects.Conclusion:Dexmedetomidine found to be providing more effectively controlled hypotension and analgesia, and thus, allowing less nasal bleeding as well as more surgeons’ satisfaction score.

Clinical study to evaluate the role of preoperative dexmedetomidine in attenuation of hemodynamic response to direct laryngoscopy and tracheal intubation

ObjectivesDexmedetomidine, an α2 agonist, has been evaluated for its hypnotic, analgesic, and anxiolytic properties in the intraoperative period and critical care setting. However, data on the effect of dexmedetomidine on attenuation of pressor response to direct laryngoscopy and tracheal intubation are limited. We studied the effect of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg on hemodynamic responses to tracheal intubation, and dose requirements of anesthetics for induction and their adverse effects. MethodsEighty adult patients scheduled for elective surgery under general anesthesia requiring tracheal intubation were included. Patients were randomized into two groups: dexmedetomidine and placebo (n = 40 each). The study drug was administered intravenously over a period of 10 minutes prior to induction. Direct laryngoscopy and endotracheal intubation were performed. Hemodynamic parameters, the total dose of propofol, and adverse effects were recorded during induction and postintubation periods for 15 minutes. ResultsThe maximum percentage increase in the heart rate after intubation was 19.6% less in the dexmedetomidine group than that in the placebo group (12.96% vs. 32.57%). The maximum percentage increases in systolic blood pressure, diastolic blood pressure, and mean blood pressure after intubation were significantly lower in the dexmedetomidine group than in the placebo group (12.38% vs. 45.63%, 19.36% vs. 60.36%, and 15.34% vs. 50.33%, respectively). There was a significant reduction of the mean total dose of propofol required for induction, 1.04 mg/kg in the dexmedetomidine group versus 2.01 mg/kg in the placebo group (p < 0.001). No serious side effects or adverse reactions were observed in either group. ConclusionAdministration of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg resulted in significant attenuation of the rise in the heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure, until 5 minutes postintubation. It significantly reduced the dose requirements of propofol for induction and caused minimal side effects.

Good vagal tone, a tourniquet and dexmedetomidine: Recipe for disaster.

Sir, Arthroscopic repairs of the cruciate ligaments of the knee are fairly common place surgeries. Both anterior and posterior ligaments are commonly repaired at the same sitting, resulting in prolonged surgery and consequently, tourniquet time. These injuries are common among young, fit athletic individuals. The vagal tone may be increased in these individuals.[1] Though many patients undergoing surgery are curious about the procedure and refuse sedation in order to watch the procedure live, some are quite anxious and demand sedation. A 31-year-old footballer was posted for arthroscopic repair of both ligaments of the right knee. The patient (American society of Anaesthesiologists physical status I) though was willing for a spinal anaesthetic, requested deep sedation as he was very anxious. Baseline heart rate was 55/min and non-invasive blood pressure (NIBP) 113/71 mm of Hg. Spinal anaesthesia was administered with 17.5 mg of bupivacaine 0.5% heavy plus 25 μg of fentanyl in sitting position and midline projection via a 26 gauge Quincke needle. Sensory block height achieved was till T6 after 5 min. A pneumatic tourniquet was applied around the thigh and inflated to 300 mmHg. Midazolam 3 mg intravenous (IV) was administered just before incision and patient became drowsy but remained anxious and restless. Dexmedetomidine IV (Xamdex®100 μg/ml, 2 ml ampoule, Abbott) was started at 0.5 μg/kg/h, avoiding the loading dose as midazolam had already been given. The patient became sedated in about 10 min. Oxygen was started via polymask. The surgery prolonged beyond the default tourniquet alarm time of 60 min; the surgeon needed an additional hour and the tourniquet time was increased accordingly. The patient remained well sedated; the heart rate had dipped to about 47–52 beats/min, but the blood pressure (BP) remained stable. After 2 h, the surgeon was requested to deflate the tourniquet temporarily but disagreed since he had only a few minutes to complete the procedure. Dexmedetomidine infusion was discontinued at this time. However, completion took another 30 min and the tourniquet was deflated at 150 min. Seconds after the deflation, the patient's heart rate started dropping and when it reached 30 beats/min, injection atropine 0.6 mg IV was administered. The patient, who had awakened and become communicative after the dexmedetomidine infusion was terminated, became unresponsive. This was followed by sudden asystole on the monitor, as can be seen from the photograph of the monitor trend screen [Figure 1].Figure 1: Photograph of monitor trend screen showing asystolic arrest (yellow arrow) and recoveryQRS complexes reappeared after about 10 s and after about 30 s heart rate was 60/min. The patient became responsive and oriented, with no recall of events. After 1 min, the patient was calm, cooperative and completely stable. There was no NIBP reading at the point of asystole, but readings, while the heart rate improved, were in normal range. Post-procedure, the patient was monitored for 24 h and was discharged after 3 days. Young athletic persons manifest high vagal tone with low resting heart rates. Neuraxial blocks may also cause bradycardia and hypotension. Dexmedetomidine also causes significant bradycardia. Though prolonged use of the tourniquet is associated with a slow rise in heart rate and BP, this effect may be obtunded by other factors such as dexmedetomidine and antihypertensive drug use. Lu et al.[2] demonstrated that pre-operative dexmedetomidine prevents tourniquet-induced hypertension in patients under general anaesthesia. In our case, basal heart rate was low, but no bradycardia or hypotension occurred after spinal anaesthetic. Though dexmedetomidine infusion brought down the heart rate by about 5–7 beats, both heart rate and NIBP remained stable. Tourniquet release is associated with sudden haemodynamic changes including rate and rhythm changes, hypotension, pulmonary oedema,[3] pulmonary embolism,[45] and cardiac arrest.[67] In this case, the prolonged tourniquet for 150 min, along with the basal vagal tone and the continuing effect of the dexmedetomidine led to the asystolic arrest; fortunately, in the absence of pre-existing heart disease, response to intervention was prompt. This combination should be avoided; if inescapable, constant monitoring and use of emergency drugs and equipment can save the day.

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.

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

Preoperative dexmedetomidine attenuates hemodynamic responses to hydrodissection in patients undergoing robotic thyroidectomy

Percutaneous tunneling (hydrodissection) in the neck and anterior chest in patients undergoing robotic thyroidectomy leads to significant hemodynamic responses such as increases in blood pressure and heart rate. We evaluated whether a single preoperative dexmedetomidine injection attenuated hemodynamic responses to hydrodissection by reducing the half-maximal effective concentration (EC50) of remifentanil needed to maintain hemodynamic stability during hydrodissection. Forty-one patients undergoing robot-assisted endoscopic thyroidectomy were randomly allocated to one of the two groups-group D (n=22) and group C (n=19) patients received dexmedetomidine 1µg/kg and normal saline for 10min before anesthetic induction, respectively. The EC50 of remifentanil for hemodynamic stability during hydrodissection was determined using Dixon's up-and-down method with initial dose (4and 5ng/mL in groups D and C, respectively). The concentration of remifentanil for consecutive patients in each group was determined by the response of the previous patient, using increments or decrements of 0.5ng/mL. Hemodynamic stability during hydrodissection was defined as increased systolic blood pressure <20% of baseline. The EC50 of remifentanil for maintaining hemodynamic stability during hydrodissection was 0.8ng/mL in group D and 7.3ng/mL in group C (p=0.002). A single preoperative dexmedetomidine injection attenuated hydrodissection-induced hemodynamic responses in patients undergoing robotic thyroidectomy.