Effects of Intravenous Dexmedetomidine in Humans

Dexmedetomidine attenuates the increase of ultrasonographic optic nerve sheath diameter as a surrogate for intracranial pressure in patients undergoing robot-assisted laparoscopic prostatectomy: A randomized double-blind controlled trial

BACKGROUND

Pneumoperitoneum and steep Trendelenburg position during robot-assisted laparoscopic prostatectomy (RALP) can increase intracranial pressure (ICP). Dexmedetomidine, a highly selective alpha-2 adrenergic receptor agonist, can cause cerebral vasoconstriction and decrease cerebral blood flow by stimulating the postsynaptic alpha-2 adrenergic receptors on cerebral blood vessels. However, the effects of dexmedetomidine on ICP are controversial and have not been evaluated during RALP under the establishment of pneumoperitoneum in the steep Trendelenburg position. Therefore, we evaluated the effect of dexmedetomidine on optic nerve sheath diameter (ONSD) as a surrogate for assessing ICP during RALP.

METHODS

Patients were randomly allocated to receive dexmedetomidine (n = 63) (loading dose, 1 μg/kg for 10 minutes and continuous infusion, 0.4 μg/kg/hr) or normal saline (n = 63). The ONSD was measured at 10 minutes after induction of anesthesia in the supine position (T1), 30 minutes (T2) and 60 minutes (T3) after establishment of pneumoperitoneum in the steep Trendelenburg position, and at closing the skin in the supine position (T4). Hemodynamic and respiratory variables were measured at every time point.

RESULTS

ONSDs at T2, T3, and T4 were significantly smaller in the dexmedetomidine group than in the control group (5.26 ± 0.25 mm vs 5.71 ± 0.26 mm, 5.29 ± 0.24 mm vs 5.81 ± 0.23 mm, and 4.97 ± 0.24 mm vs 5.15 ± 0.28 mm, all P <.001). ONSDs at T2, T3, and T4 were significantly increased compared to T1 in both groups. Hemodynamic and respiratory variables, except heart rate, did not significantly differ between the 2 groups. The bradycardia and atropine administration were not significantly different between the 2 groups.

CONCLUSION

Dexmedetomidine attenuates the increase of ONSD during RALP, suggesting that intraoperative dexmedetomidine administration may effectively attenuate the ICP increase during pneumoperitoneum in the Trendelenburg position.

Practicalities of Total Intravenous Anesthesia and Target-controlled Infusion in Children

Propofol administered in conjunction with an opioid such as remifentanil is used to provide total intravenous anesthesia for children. Drugs can be given as infusion controlled manually by the physician or as automated target-controlled infusion that targets plasma or effect site. Smart pumps programmed with pharmacokinetic parameter estimates administer drugs to a preset plasma concentration. A linking rate constant parameter (keo) allows estimation of effect site concentration. There are two parameter sets, named after the first author describing them, that are commonly used in pediatric target-controlled infusion for propofol (Absalom and Kataria) and one for remifentanil (Minto). Propofol validation studies suggest that these parameter estimates are satisfactory for the majority of children. Recommended target concentrations for both propofol and remifentanil depend on the type of surgery, the degree of surgical stimulation, the use of local anesthetic blocks, and the ventilatory status of the patient. The use of processed electroencephalographic monitoring is helpful in pediatric total intravenous anesthesia and target-controlled infusion anesthesia, particularly in the presence of neuromuscular blockade.

Dexmedetomidine: present and future directions

Dexmedetomidine is a potent, highly selective α-2 adrenoceptor agonist, with sedative, analgesic, anxiolytic, sympatholytic, and opioid-sparing properties. Dexmedetomidine induces a unique sedative response, which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Dexmedetomidine may produce less delirium than other sedatives or even prevent delirium. The analgesic effect of dexmedetomidine is not strong; however, it can be administered as a useful analgesic adjuvant. As an anesthetic adjuvant, dexmedetomidine decreases the need for opioids, inhalational anesthetics, and intravenous anesthetics. The sympatholytic effect of dexmedetomidine may provide stable hemodynamics during the perioperative period. Dexmedetomidine-induced cooperative sedation with minimal respiratory depression provides safe and acceptable conditions during neurosurgical procedures in awake patients and awake fiberoptic intubation. Despite the lack of pediatric labelling, dexmedetomidine has been widely studied for pediatric use in various applications. Most adverse events associated with dexmedetomidine occur during or shortly after a loading infusion. There are some case reports of dexmedetomidine-related cardiac arrest following severe bradycardia. Some extended applications of dexmedetomidine discussed in this review are promising, but still limited, and further research is required. The pharmacological properties and possible adverse effects of dexmedetomidine should be well understood by the anesthesiologist prior to use. Moreover, it is necessary to select patients carefully and to determine the appropriate dosage of dexmedetomidine to ensure patient safety.

Cooling to Facilitate Metabolic Suppression in Healthy Individuals

BACKGROUND: Carbon dioxide (CO₂) toxicity could be catastrophic for astronauts. Suppressing metabolism by lowering body temperature decreases CO₂ production and may facilitate rescue in the event of a crippled ship. Lowering body temperature requires shivering suppression. We evaluated dexmedetomidine to facilitate cooling of healthy individuals.METHODS: Following consent, we administered a 1 mcg · kg^-1 bolus of dexmedetomidine followed by continuous infusion (0.5-1.4 mcg · kg^-1 · h^-1) for 3 h of cooling. We cooled subjects using a bolus of 30 cc · kg^-1 of 4°C saline followed by surface cooling. We measured vital signs, thermal and comfort scales, sedation, and shivering for 3 h and during recovery. ANOVA evaluated changes in measures over time.RESULTS: Nine subjects completed the study. Mean age was 31 (SD 8) yr, mean mass was 71 (SD 14) kg, height of 168 (SD 9) cm, and body mass index of 25 (SD 3). Median time to 1°C drop in core temperature was 16 (IQR 15, 32) min. Temperature changed over time with median lowest temperature being 33.1°C (IQR 32.8°C, 34.1°C). Neither heart rate nor diastolic blood pressures changed over time. Systolic blood pressure decreased over time. Subjects responded to verbal stimuli and completed tasks throughout the protocol. During cooling and maintenance, subjects reported discomfort and the sensation of being cold.CONCLUSION: Dexmedetomidine facilitates shivering suppression during prolonged cooling in healthy individuals. Subjects are easily roused, have mild decreases in systolic blood pressure, and note sensations of discomfort and cold. Cooling to suppress metabolism is a feasible countermeasure to prolong astronaut endurance.Rittenberger JC, Flickinger KL, Weissman A, Repine M, Elmer J, Guyette FX, Callaway CW. Cooling to facilitate metabolic suppression in healthy individuals. Aerosp Med Hum Perform. 2019; 90(5):475-479.

Patient-controlled Intravenous Analgesia With Combination of Dexmedetomidine and Sufentanil on Patients After Abdominal Operation: A Prospective, Randomized, Controlled, Blinded, Multicenter Clinical Study

Objective:

To investigate the effect of combination of dexmedetomidine and sufentanil on patient-controlled intravenous analgesia (PCIA) in patients after abdominal operation and to assess the safety and validity of this treatment.

Methods:

This is a prospective, randomized controlled, blinded, multicenter clinical study. A total of 210 patients from 9 clinical research centers underwent selective abdominal operation with general anesthesia were enrolled in the study, including laparoscopic-assisted abdominal operation on stomach, intestines or open surgery on stomach, intestines, kidneys and liver, the American Society of Anesthesiologists status I to II. Patients were randomly assigned into 2 groups: control group (group C) sufentanil 100 μg+normal saline 100 mL in total and test group (group D) sufentanil 100 μg+ dexmedetomidine 200 μg+normal saline 100 mL in total. PCIA was set as follow: background infusion of sufentanil 2 μg/h, bolus dose of sufentanil 2 μg, lockout interval 5 minutes. Main measure indices were analgesic consumption, pressing times and effective pressing times of analgesic pump, usage count, and consumption of remedy drug. Validity indices were visual analog scale (VAS) scores and patient satisfaction. Drug safety indices were hemodynamic parameters, drug side effects, and anal exhaust time.

Results:

In total, 203 cases were analyzed. Seven cases were eliminated for incomplete data record. The total consumption of sufentanil (μg) in 24 hours after operation of group C and group D were 56.9±21.5 and 49.8±15.5, respectively, and the difference was statistically significant (P<0.05). Pressing times of analgesic pump in 24 hours after operation of group C and group D were 9.47±16.07 and 5.02±5.56 times, respectively, and the difference was statistically significant (P<0.05). Effective pressing times of analgesic pump in 24 hours after operation of group C and group D were 7.8±9.7 and 4.57±5.02 times, respectively, and the difference was statistically significant (P<0.05). Resting VAS scores and movement VAS scores at 2, 4, 8, and 24 hours postoperatively were statistically different (P<0.05). Usage times of rescue drug (pethidine) of group C and group D were 9 and 1, mean rank 118.13 and 85.71, respectively, and the difference was statistically significant (P<0.05). Mean rank of general satisfaction of group C and group D were 98.99 and 105.04, respectively, and the difference was statistically significant (P<0.05). Incidence rate of nausea in group C and group D within 24 hours after surgery was 25% and 12.5%, and of vomiting 18.2% and 6.25%, respectively and of vomiting and the difference was statistically significant.

Conclusions:

Compared with sufentanil PCIA alone, the combination of dexmedetomidine and sufentanil for PCIA after abdominal operation could reduce sufentanil consumption, decrease VAS scores, lower the rate of nausea and vomiting, and improve patient satisfaction.

Anesthetic Efficacy of Dexmedetomidine versus Midazolam When Combined with Remifentanil for Percutaneous Transluminal Angioplasty in Patients with Peripheral Artery Disease

Anesthesia for percutaneous transluminal angioplasty (PTA) involves a high-risk population having a broad spectrum of pain character and intensity. This study delved the anesthetic efficacy of dexmedetomidine versus midazolam, when used with remifentanil. Seventy patients scheduled for femoropopliteal PTA were randomized into two groups receiving either intermittent midazolam boluses (0.03–0.05 mg/kg) (MR group) or dexmedetomidine 0.2–0.7 μg/kg/h after a loading dose of 1.0 μg/kg for 10 min (DR group), both with remifentanil. The primary endpoint was the patients’ satisfaction (1–5, 5; extremely satisfied). Secondary endpoints included postprocedural pain scores (0–10, 10; worst imaginable pain) and adverse events. The satisfaction level of patients was significantly greater in the DR group compared with the MR group (4.0 [3.0, 5.0] versus 4.0 [2.0, 5.0] p = 0.021). The number of patients having a postprocedural pain score of at least 3 was significantly greater in the MR group compared with the DR group (10 [29%] versus 2 [6%], p = 0.013). The number of patients with hypotensive episodes was higher in the DR group (5 [14.7%] versus 0, p = 0.025), which could all be restored with ephedrine. The use of dexmedetomidine in conjunction with remifentanil may be a safe option that provides excellent patient satisfaction while potentially attenuating postprocedural pain.

Dexmedetomidine in the Management of Awake Fiberoptic Intubation

Awake Fibreoptic Intubation (AFOI) is, nowadays, the gold standard in predicted difficult airway management. Numerous practice guidelines have been developed to assist clinicians facing with a difficult airway. If conducted without sedation, it is common that this procedure may lead to high patient discomfort and severe hemodynamic responses. Sedation is frequently used to make the process more tolerable to patients even if it is not always easy to strike a balance between patient comfort, safety, co-operation, and good intubating conditions. In the last years, many drugs and drug combinations have been described. This minireview aims to discuss the evidence supporting the use of Dexmedetomidine (DEX) in the AFOI management.

Acute Management of Hypertension Following Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is responsible for approximately 15% of strokes annually in the United States, with nearly 1 in 3 of these patients dying without ever leaving the hospital. Because this disproportionate mortality risk has been stagnant for nearly 3 decades, a main area of research has been focused on the optimal strategies to reduce mortality and improve functional outcomes. The acute hypertensive response following ICH has been shown to facilitate ICH expansion and is a strong predictor of mortality. Rapidly reducing blood pressure was once thought to induce cerebral ischemia, though has been found to be safe in certain patient populations. Clinicians must work quickly to determine whether specific patient populations may benefit from acute lowering of systolic blood pressure (SBP) following ICH. This review provides nurses with a summary of the available literature on blood pressure control following ICH. It focuses on intravenous and oral antihypertensive medications available in the United States that may be utilized to acutely lower SBP, as well as medications outside of the antihypertensive class used during the acute setting that may reduce SBP.

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 dexmedetomidine vs. remifentanil combined with sevoflurane during radiofrequency ablation of hepatocellular carcinoma: a randomized controlled trial

BACKGROUND

Remifentanil is widely used for ultrasound-guided percutaneous radiofrequency ablation (RFA) of small hepatocellular carcinoma (HCC). We determined whether dexmedetomidine could be an alternative to remifentanil for RFA of HCC under general anesthesia with sevoflurane.

METHODS

We prospectively randomized patients scheduled to undergo RFA for HCC to a dexmedetomidine (DEX) group or remifentanil (REMI) group (47 patients each). In the DEX group, a bolus infusion (0.4 μg kg^- 1) was started 15 min before anesthesia induction and continued at 0.2 μg kg^- 1 h^- 1 until 10 min before the end of surgery. In the REMI group, 3 μg kg^- 1 h^- 1 of remifentanil was administered from 15 min before anesthesia induction to the end of the surgery. The primary endpoint was postoperative pain intensity. Secondary endpoints included analgesic requirement, postoperative liver function, patient comfort, and hemodynamic changes. Group allocation was concealed from patients and data analysts but not from anesthesiologists.

RESULTS

Postoperative pain intensity, analgesic consumption, comfort, liver function, and time to emergence and extubation did not differ between the two groups. Heart rate, but not mean arterial pressure, was significantly lower in the DEX group than in the REMI group, at 1 min after intubation and from 30 min after the start of the surgery until anesthesia recovery. Sevoflurane concentration and dosage were significantly lower in the DEX group than in the REMI group.

CONCLUSION

During RFA for HCC, low-dose dexmedetomidine reduced the heart rate and need for inhalational anesthetics, without exacerbating postoperative discomfort or liver dysfunction. Although it did not exhibit outstanding advantages over remifentanil in terms of pain management, dexmedetomidine could be a safe alternative adjuvant for RFA under sevoflurane anesthesia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-OPC-15006613 . Registered on 16 June 2015.

Effect of a low-dose dexmedetomidine infusion on intraoperative hemodynamics, anesthetic requirements and recovery profile in patients undergoing lumbar spine surgery

Background and Aims

Dexmedetomidine has been used as an anesthetic adjuvant; however, hypotension is a concern especially in prone patients. The aim of the study was to evaluate the effect of a low-dose dexmedetomidine infusion on intraoperative hemodynamics, blood loss, anesthetic requirements, and recovery profile in patients undergoing lumbar spine surgery in the prone position.

Material and Methods

The study was conducted in a randomized double-blinded manner in 60 patients scheduled for one- or two-level lumbar laminectomy. After administration of general anesthesia, patients were placed in prone position and allocated to either of two groups of 30 patients each. Patients in Group A received dexmedetomidine infusion at the rate of 0.3 μg kg^-1 hr^-1, whereas, group B patients received a saline infusion. The depth of anesthesia was guided by Bispectral index (BIS) monitoring, maintaining BIS between 40 and 60.

Results

The demographic profile and duration of surgery in both groups were similar. Mean heart rate was statistically similar in both the groups. Mean blood pressure was lower in group A, though the difference was significant only for the initial 30 min. The mean end-tidal sevoflurane requirement in group A was significantly less than that in group B (P = 0.003). Patients in group A had better recovery profile with mean emergence, extubation, and recovery times of 8.08 ± 3.48 min, 9.37 ± 3.64 min, and 11.65 ± 4.03 min, respectively, as compared with 11.27 ± 3.05 min, 12.24 ± 2.39 min, and 14.90 ± 2.63 min, respectively, in group B (P < 0.001). Mean intraoperative blood loss in group A of 263.47 ± 58.66 mL was significantly lower than 347.67 ± 72.90 ml in group B (P = 0.0001).

Conclusion

Group A patients had stable hemodynamic parameters, reduced intraoperative blood loss, less anesthetic requirement, and could be extubated earlier as compared with group B patients.

Efficacy of dexmedetomidine as an adjunct in aiding video laryngoscope-assisted assessment of vocal cord movements at extubation following total thyroidectomy

Background:

Assessment of vocal cord movements following total thyroidectomy diagnoses recurrent laryngeal nerve injury. Use of videoscope along with sedatives may blunt hemodynamic responses seen with the conduct of direct laryngoscopy for assessing vocal cord mobility.

Aims:

The primary objective of this study was to assess changes in mean arterial pressure (MAP) during vocal cord assessment following total thyroidectomy using video laryngoscope, with and without the use of dexmedetomidine as an adjunct. Secondary objectives included assessment of changes in heart rate (HR), patient reactivity score along with ease of laryngoscopy and vocal cord visibility.

Settings and Design:

This randomized, prospective, unblinded study was conducted in 54 patients at a tertiary care center.

Materials and Methods:

Group D received dexmedetomidine 0.5 μg/kg, once the thyroid was removed. Group S did not receive dexmedetomidine. Hemodynamic response at extubation, patient reactivity, ease of laryngoscopy, and ease of vocal cord assessment were noted.

Statistical Analysis Used:

Chi-square test and Independent t-test.

Results:

Baseline HR, systolic blood pressure (SBP), and MAP were comparable between the groups. However subsequently, Group D had significantly lower HR and SBP at the time of extubation and at 3 and 6 min later. MAP at extubation and at 3 min later was comparable, but at 6 min, Group D had significantly lower values. In both groups, patient reactivity scores, ease of laryngoscopy, and vocal cord visibility were comparable (P > 0.05).

Conclusion:

Dexmedetomidine 0.5 μg/kg when used as an adjunct clinically improved conditions for assessing vocal cord mobility with significant attenuation of associated hemodynamic responses.

Dexmedetomidine pharmacodynamics in healthy volunteers: 2. Haemodynamic profile

Background

Dexmedetomidine, a selective α 2 -adrenoreceptor agonist, has unique characteristics, with little respiratory depression and rousability during sedations. We characterized the haemodynamic properties of dexmedetomidine by developing a pharmacokinetic-pharmacodynamic (PKPD) model with a focus on changes in mean arterial blood pressure (MAP) and heart rate.

Methods

Dexmedetomidine was delivered i.v. to 18 healthy volunteers in a step-up fashion by target-controlled infusion using the Dyck model. Exploratory PKPD modelling and covariate analysis were conducted in NONMEM.

Results

Our model adequately describes dexmedetomidine-induced hypotension, hypertension, and bradycardia, with a greater effective concentration for the hypertensive effect. Changes in MAP were best described by a double-sigmoidal E max model with hysteresis. Covariate analysis revealed no significant covariates apart from age on the baseline MAP in the population pharmacokinetic model used to develop this PKPD model. Simulations revealed good general agreement with published descriptive studies of haemodynamics after dexmedetomedine infusion.

Conclusions

The present integrated PKPD model should allow tighter control over the desired level of sedation, while limiting potential haemodynamic side-effects.

Clinical trial registration

NCT01879865.

A retrospective comparison of propofol to dexmedetomidine for pediatric magnetic resonance imaging sedation in patients with mucopolysaccharidosis type II

BACKGROUND

Mucopolysaccharidosis type II patients are reported to have an elevated incidence of difficult airway. Propofol is a commonly used sedative for magnetic resonance imaging in pediatric patients, but patients who receive it may exhibit dose-dependent upper airway obstruction and respiratory depression. Dexmedetomidine also provides adequate procedural sedation with a relatively low risk of airway obstruction. Accordingly, we introduced the use of dexmedetomidine in our practice to reduce the risk of airway obstruction during magnetic resonance imaging procedures.

AIMS

The aim of this study was to evaluate the incidence of artificial airway interventions in patients sedated with propofol and compare it to that in patients sedated with dexmedetomidine in patients with mucopolysaccharidosis type II during magnetic resonance imaging procedures.

METHODS

All mucopolysaccharidosis type II patients undergoing magnetic resonance imaging at our institution between April 2014 and February 2018 were included in this study. The patients were divided into two groups according to whether they were managed before and after the introduction of dexmedetomidine: those who were sedated with propofol (group P) and those who were sedated with dexmedetomidine (group D).

RESULTS

Forty-six sedations were performed in 27 patients. Artificial airway interventions were significantly more frequent during propofol-based than dexmedetomidine-based sedation: 14 of 32 (43.8%) in group P and 1 of 14 (7.1%) in group D (odds ratio, 10.11; 95% confidence interval, 1.18-86.85; P = 0.018). Time to awake and time to discharge were similar between groups. Changes in hemodynamic variables also did not significantly differ between groups.

CONCLUSION

Dexmedetomidine provides an adequate level of sedation and is associated with lower rates of artificial airway interventions compared to propofol. Therefore, dexmedetomidine may offer advantages for preserving the native airway compared to propofol when administered during magnetic resonance imaging scans in patients with mucopolysaccharidosis type II.

The correlation of heart rate between natural sleep and dexmedetomidine sedation

Background

Sedation by dexmedetomidine, like natural sleep, often causes bradycardia. We explored the nature of heart rate (HR) changes as they occur during natural sleep versus those occurring during dexmedetomidine sedation.

Methods

The present study included 30 patients who were scheduled to undergo elective surgery with spinal anesthesia. To assess HR and sedation, a pulse oximeter and bispectral index (BIS) monitor were attached to the patient in the ward and the operating room. After measuring HR and BIS at baseline, as the patients slept and once their BIS was below 70, HR and BIS were measured at 5-minute intervals during sleep. Baseline HR and BIS were also recorded before spinal anesthesia measured at 5-minute intervals after dexmedetomidine injection.

Results

During natural sleep, HR changes ranged from 2 to 19 beats/min (13.4 ± 4.4 beats/min), while in dexmedetomidine sedation, HR ranged from 9 to 40 beats/min (25.4 ± 8.5 beats/min). Decrease in HR was significantly correlated between natural sleep and dexmedetomidine sedation (R² = 0.41, P < 0.001). The lowest HR was reached in 66 min during natural sleep (59 beats/min) and in 13 min with dexmedetomidine sedation (55 beats/min). The time to reach minimum HR was significantly different (P < 0.001), but there was no difference in the lowest HR obtained (P = 0.09).

Conclusions

There was a correlation between the change in HR during natural sleep and dexmedetomidine sedation. The bradycardia that occurs when using dexmedetomidine may be a normal physiologic change, that can be monitored rather than corrected.

Comparative Evaluation of Different Doses of Intravenous Dexmedetomidine on Hemodynamic Response during Laryngoscopy and Endotracheal Intubation in Geriatric Patients Undergoing Spine Surgeries: A Prospective, Double-Blind Study

BACKGROUND

Dexmedetomidine, a selective alpha 2 (α2)-adrenergic receptor agonist, has been used to blunt the hemodynamic response associated with laryngoscopy and tracheal intubation, which is a common concern for the anesthesiologist, especially in high-risk patients and geriatric age group.

AIM AND OBJECTIVES

The current study is to evaluate and compare the effects of different doses of dexmedetomidine in controlling hemodynamic response during tracheal intubation in geriatric patients.

MATERIALS AND METHODS

After getting approval from the Ethical Committee, 90 patients of the American Society of Anesthesiologist Physical Status Classes I and II, aged ≥60 years, were randomly assigned into three groups: Group I (normal saline, n = 30), Group II - dexmedetomidine (0.50 μg/kg, n = 30), and Group III - dexmedetomidine (1.00 μg/kg, n = 30). Dexmedetomidine was infused for 10 min before induction. Data were recorded as before infusion (T0), at the end of infusion (T1), before tracheal intubation (T2), at the moment of tracheal intubation (T3) 5 min after tracheal intubation (T4), and 10 min after tracheal intubation (T5). Modified observer's assessment of alertness/sedation scale score was observed at the time of T0 and T1. All statistical analyses were done using SPSS version 22.

RESULTS

Mean systolic blood pressure was statistically significantly (P < 0.05) more among Group I compared to Group II and III at T2, T3, and T4. Mean heart rate (HR) value was significantly (P < 0.05) more among Group I compared to Group III from T1 to T5, whereas there was no significant change in HR between Group I and Group II and at T4 and T5 h was comparable in Group II and Group III.

CONCLUSION

This study concluded that more acceptable hemodynamic changes were seen with 0.50 μg/kg dexmedetomidine when compared with 1.0 μg/kg dexmedetomidine during intubation. A lower dose besides being cost-effective is also free of side effects associated with the higher dose of 1 μg/kg dexmedetomidine.

Dexmedetomidine attenuates the positive chronotropic effects of intravenous atropine in patients with bradycardia during spinal anaesthesia: a retrospective study

INTRODUCTION

Dexmedetomidine is a sedative used during spinal anaesthesia. However, it frequently induces bradycardia. Although intravenous atropine is often used for treating bradycardia during regional anaesthesia, the response to atropine might be attenuated by concomitantly administering sedatives.

METHODS

We examined the effects of atropine used for treating bradycardia during spinal anaesthesia among patients receiving dexmedetomidine (D group), propofol (P group), or neither (nonDnonP group) for sedation, retrospectively.

RESULTS

A total of 108 patients were included. Heart rate was significantly slower at all time points in the D group (n = 69) than in the nonDnonP group (n = 14) (p <  0.025 for all). On the other hand, heart rate was significantly slower only 60 min after administration of atropine in the P group (n = 25) than in the nonDnonP group (p = 0.002). There were differences in the overall values of heart rate (including all the values from time 0 to 60 min) among the three groups (p = 0.026).

CONCLUSIONS

The positive chronotropic effects of atropine might be attenuated with the use of dexmedetomidine or propofol during spinal anaesthesia. Although atropine may be administered when bradycardia occurs, a dose of atropine might result in an insufficient effect against the bradycardia. The sufficient number of subjects may change the results of the investigation, and large-scale randomised controlled trials will be necessary.

Comparison of upper airway patency in patients with mild obstructive sleep apnea during dexmedetomidine or propofol sedation: a prospective, randomized, controlled trial

Background

In addition to propofol, dexmedetomidine is a suitable alternative for intraoperative sedation in procedures requiring regional anesthesia. To date, however, little is known about the influences of each drug on upper airway patency. Accordingly, the authors investigated differences between dexmedetomidine and propofol sedation in the occurrence of upper airway obstruction and requirements for airway intervention in patients with mild obstructive sleep apnea.

Methods

Patients with an apnea/hypopnea index of 5–14/h according to Watch-PAT 200 analysis were enrolled in this study. Spinal anesthesia was routinely performed for surgery. Intraoperative sedation was initiated using either dexmedetomidine or propofol infusion at a level of modified observer’s assessment of alertness/sedation scale 3. The primary outcome was the proportion of patients exhibiting signs of upper airway obstruction. A sign of upper airway obstruction was defined as no detection of end-tidal carbon dioxide for at least 10 s despite respiratory efforts.

Results

A total of 50 patients were included in the final analysis (dexmedetomidine [n = 26]; propofol [n = 24]). During the intraoperative sedation period, there was a significantly lower proportion of patients exhibiting signs of upper airway obstruction in the dexmedetomidine group than in the propofol group (11.5% vs. 41.7%, P = 0.035). An artificial airway was inserted in 1 patients (3.8%) and 5 patient (20.8%) in the dexmedetomidine and propofol groups, respectively (P = 0.093).

Conclusion

Dexmedetomidine sedation was associated with a lower incidence of upper airway obstruction than propofol sedation in patients with mild obstructive sleep apnea.

Trial registration number

Clinical trials.gov (NCT02993718): Retrospectively registered.

Recent Trends in the Practice of Procedural Sedation Under Local Anesthesia for Catheter Ablation, Gastrointestinal Endoscopy, and Endoscopic Surgery in Japan: A Retrospective Database Study in Clinical Practice from 2012 to 2015

OBJECTIVES

To investigate changes in sedation practice during 2012-2015, using a large health claims database, for catheter ablation (CA), gastrointestinal endoscopic examination (EE), and surgery (ES) after dexmedetomidine (DEX) was approved for procedural sedation in 2013. We assessed the trends of sedative utilization, sedative-analgesic combinations, and, additionally, incidence of complications from 2012 to 2015.

METHODS

Using the database provided by Medical Data Vision Co., Ltd. (Tokyo, Japan), annual utilization proportions of the sedatives and sedative-analgesic combinations and occurrence of complications were calculated in patients with a record of local anesthesia and CA, EE, and/or ES but without general anesthesia used on the same day. The sedatives studied were DEX, propofol (PF), midazolam (MDZ), diazepam, flunitrazepam, thiamylal (TIA), thiopental (TIO), and ketamine.

RESULTS

DEX was used most often for CA, followed by PF. From 2012 to 2015, the proportion of DEX increased from 30 to 36%, and that of PF slightly decreased from 29 to 27%. The order of utilization proportions did not change for EE or ES. The use of benzodiazepines, particularly MDZ, predominated. The top five sedative-analgesic combination patterns changed during the study period for CA, but not for EE or ES. The most common complications with CA, EE, and ES were bradycardia, nausea and vomiting, and respiratory depression, respectively. There were no changes in the complications' trends for the procedures.

CONCLUSION

The approved use of DEX for procedural sedation resulted in changes for CA, but not for EE or ES. The complication trends did not change.

Replacement of dexmedetomidine loading with midazolam for sedation in elderly patients with spinal anesthesia

BACKGROUND

Dexmedetomidine is an effective sedative during spinal anesthesia. However, it requires a loading dose, which can result in transient hypertension, hypotension, bradycardia, and/or sinus arrest. In addition, the time required to reach an appropriate depth of sedation may cause anxiety to the patients. Therefore, we examined whether an intravenous bolus of midazolam could replace the loading dose of dexmedetomidine for sedation during surgery in elderly patients who received spinal anesthesia.

METHODS

Patients aged over 60 years who scheduled to undergo total knee arthroplasty under spinal anesthesia were enrolled in this study. The patients were randomized into 2 groups. Patients in dexmedetomidine group (group D) (n = 20) were administered a loading dose of dexmedetomidine (1.0 μg/kg over 10 min) intravenously followed by dexmedetomidine maintenance (0.5 μg/kg/h). Patients in group MD (n = 20) were administered an intravenous midazolam (0.05 mg/kg) followed by dexmedetomidine maintenance (0.5 μg/kg/h) intravenously. Heart rate (HR), mean arterial blood pressure (MBP), peripheral oxygen saturation (SpO2), and patient state index (PSI) were recorded. Ramsay sedation scale (RSS) scores were evaluated at 10 minutes after drug administration and the end of surgery.

RESULTS

A total of 40 subjects were enrolled in the present study. At baseline, there was no between-group difference in HR. Ten minutes after drug administration, group D had lower HR than group MD (62.1 ± 9.4 versus 69.6 ± 13.4, P = .047). PSI was significantly lower in group MD at 10 minutes after drug administration (82.8 ± 13.0 versus 72.0 ± 16.0, P = .024); there was no between-group difference at 30 and 60 minutes, and lower values in group D at the end of surgery (70.2 ± 22.6 versus 79.7 ± 10.9, P = .011). The RSS score showed statistically significantly deeper sedation in group MD 10 minutes after drug administration, but no difference at the end of surgery.

CONCLUSIONS

An intravenous bolus of midazolam is a viable alternative to dexmedetomidine loading for sedation during surgery in elderly patients who received spinal anesthesia. This is especially effective for patients who are at high risk for bradycardia or who want a faster sedation.

Effective dose of dexmedetomidine as an adjuvant sedative to peripheral nerve blockade in elderly patients

Background

The median effective dose (ED₅₀) of sedative dexmedetomidine adjuvant to peripheral nerve block (PNB) has not yet been verified in elderly patients. This study assessed the ED₅₀ of intravenous dexmedetomidine for sedation in elderly patients who were undergoing total knee arthroplasty (TKA) with PNB.

Methods

Forty‐two patients aged 65–85 years were included and stratified into two groups according to age: young‐old group (aged 65–74 years) and middle‐old group (aged 75–85 years). After the PNB was performed, a pre‐calculated dose of dexmedetomidine was administered for 10 min. The Observer's Assessment of Alertness/Sedation scale, bispectral index score, blood pressure and heart rate were recorded. ED₅₀ values of dexmedetomidine for adequate sedation were estimated by the up‐and‐down method of Dixon and probit regression.

Results

The ED₅₀ of single‐dose dexmedetomidine adjuvant to PNB was 0.57 μg/kg (95% confidence interval [CI], 0.47–0.65) in the young‐old group and 0.38 μg/kg (95% CI, 0.28–0.46) in the middle‐old group. The ED₅₀ of dexmedetomidine differed significantly between the two groups (P < 0.001). In addition, no significant adverse hemodynamic or hypoxemic effects were noted.

Conclusion

We determined the ED₅₀ for sedation using intravenous dexmedetomidine adjuvant to PNB in elderly patients. The ED₅₀ of dexmedetomidine in the middle‐old group decreased by 33% compared with that in the young‐old group with a mean age difference of 11 years between the two groups.

Comparison of the effect of intravenous dexmedetomidine and lignocaine spray instilled into the endotracheal tube on extubation response in patients undergoing spine surgery

Background: In spine surgery rapid emergence and extubation with haemodynamic stability is crucial for early neurological examination. Here, we have studied the effect of α2 agonist – dexmedetomidine intravenous (IV) and lignocaine spray instilled into the endotracheal tube at the end of the procedure to attenuate the extubation responses. Methods: A total of 45 patients undergoing spine surgery were randomly allocated in three groups. After the return of spontaneous respiration, Group-D: Dexmedetomidine 0.3 mcg/kg IV, Group-L: 10% lignocaine spray 1.5 mg/kg through endotracheal route and Group-P: Normal saline IV given over 60 s. Haemodynamic responses (systolic blood pressure, diastolic blood pressure, mean arterial pressure [MAP], heart rate [HR] and SpO2) were recorded before and after administration of drugs and also duration of emergence, extubation, quality of extubation and post-operative sedation level were evaluated. Results: The increase in MAP and HR during extubation was significantly less in Group-D than Group-L and Group-P, 2 min after administration of the respective drugs (P < 0.05). There were no significant differences in the grade of a cough after extubation and post-operative sedation level. Conclusion: Dexmedetomidine (0.3 mcg/kg) attenuates haemodynamic response better than lignocaine spray (1.5 mg/kg) during emergence and extubation. It also provides smooth extubation and easy recovery without any post-operative sedative effect.

To evaluate the effects of dexmedetomidine on intraocular pressure and haemodynamic changes in response to laryngoscopy and tracheal intubation

Background: The most important prerequisites for neurosurgeries are brain relaxation, need of stable haemodynamics with less fluctuation in intracranial pressure and speedy recovery from anaesthesia. Endotracheal intubation is the major stressful stimuli that can elicit a marked pressor response. Various drugs have been used to attenuate these reflexes. Dexmedetomidine, a highly selective alpha 2-adrenoceptor agonist, have neuroprotective, cardioprotective, and sedative effects so it is potentially useful during neuroanaesthesia. This is a prospective randomised control trial carried out to see whether administration of Dexmedetomidine prior to intubation can attenuate the various haemodynamic responses, intraocular pressure (IOP) and the requirement of induction dose of propofol in control and study group. Materials and Methods: Fifty patients (ASA grade 1, 2) scheduled for intracranial tumour surgeries were divided into two groups (25 each). Group D received Dexmedetomidine 0.8 μg/kg i.v. over 10 mins and group C received 20 ml saline. Anaesthesia induced with Propofol, dose adjusted using bispectral index monitor. The groups were compared with IOP, Heart rate (HR), Mean arterial pressure (MAP), and dose of Propofol required for induction. Results: Groups were well matched for their demographic data and pre-operative. IOP in both the eyes decreases significantly after premedication and remained below baseline even after 10th min of intubation in group D while in Group C; it increased significantly after intubation and remained above baseline. The difference between groups was also statistically significant. HR and MAP decreased significantly in patients of group D compared to group C ( P< 0.05). Patients were more haemodynamicaly stable at all time points after premedication in group D ( P< 0.05). Propofol requirements for induction was lesser in group D (P < 0.05). Bradycardia and hypotension incidences were higher in group D. Conclusion: Dexmedetomidine premedication decreases the sympathoadrenal effect on IOP and haemodynamic parameters during laryngoscopy/intubation and decreases the requirement of propofol for induction of general anaesthesia.

A Comparative Study of the Amount of Bleeding and Hemodynamic Changes between Dexmedetomidine Infusion and Remifentanil Infusion for Controlled Hypotensive Anesthesia in Lumbar Discopathy Surgery: A Double-Blind, Randomized, Clinical Trial

Background

The aim of this study was to compare the volume of blood loss and hemodynamic changes in patients undergoing lumbar discopathy, after continuous infusions of dexmedetomidine versus remifentanil during anesthesia with controlled low blood pressure.

Methods

In this randomized double-blind clinical trial, 60 patients aged 20 to 65 years were randomly assigned to control and intervention groups. The intervention group received a continuous infusion of dexmedetomidine at 0.3 - 0.7 µg/kg/hour plus propofol at 50 - 100 µg/kg/minute. The control group was given a continuous infusion of remifentanil at 0.1 to 1 µg/kg/minute plus the same dose of propofol as above. The primary outcome was the amount of patient's bleeding during surgery, and secondary outcomes were changes in the patient's systolic blood pressure, diastolic blood pressure, mean arterial pressure, and urinary output.

Results

Univariate and multivariate analyses of the main outcome in the control and intervention groups showed that there was no significant difference between the two drugs with regards to the volume of blood loss, mean arterial pressure, and systolic and diastolic blood pressure. Postoperative side effects were significantly lower in the intervention group (P = 0.002).

Conclusions

Administration of dexmedetomidine plus propofol in comparison with remifentanil plus propofol did not show any significant difference regarding blood loss and hemodynamic changes; however, it reduced some side effects after surgery and decreased analgesic requirement in the postoperative period. Taken together, the findings of this study do not support strong recommendations for dexmedetomidine infusion for all patients and the decision should be taken with caution on basis of the anesthesiologist’s expert opinion and the patient’s condition during surgery.

Subcutaneously administered dexmedetomidine is efficiently absorbed and is associated with attenuated cardiovascular effects in healthy volunteers

PURPOSE

Palliative care patients often need sedation to alleviate intractable anxiety, stress, and pain. Dexmedetomidine is used for sedation of intensive care patients, but there is no prior information on its subcutaneous (SC) administration, a route that would be favored in palliative care. We compared the pharmacokinetics and cardiovascular, sympatholytic, and sedative effects of SC and intravenously (IV) administered dexmedetomidine in healthy volunteers.

METHODS

An open two-period, cross-over design with balanced randomization was used. Ten male subjects were randomized to receive 1 μg/kg dexmedetomidine both IV and SC. Concentrations of dexmedetomidine and catecholamines in plasma were measured. Pharmacokinetic variables were calculated with non-compartmental methods. In addition, cardiovascular and sedative drug effects were monitored.

RESULTS

Eight subjects completed both treatment periods. Peak concentrations of dexmedetomidine were observed 15 min after SC administration (median; range 15-240). The mean bioavailability of SC dexmedetomidine was 81% (AUC_0-∞ ratio × 100%, range 49-97%). The mean (SD) peak concentration of dexmedetomidine in plasma was 0.3 (0.1) ng/ml, and plasma concentrations associated with sedative effects (i.e., > 0.2 ng/ml) were maintained for 4 h after SC dosing. Plasma noradrenaline concentrations were significantly lower (P < 0.001) within 3 h after IV than after SC administration. Subjective scores for vigilance and performance were significantly lower 0-60 min after IV than SC dosing (P < 0.001 for both). The onset of the cardiovascular, sympatholytic, and sedative effects of dexmedetomidine was clearly less abrupt after SC than IV administration.

CONCLUSIONS

Dexmedetomidine is relatively rapidly and efficiently absorbed after SC administration. Subcutaneous dexmedetomidine may be a feasible alternative in palliative sedation, and causes attenuated cardiovascular effects compared to IV administration. CLINICALTRIALS.

GOV IDENTIFIER

NCT02724098 . EUDRA CT number 2015-004698-34 .

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.

Effects of an Intraoperative Dexmedetomidine Bolus on the Postoperative Blood Pressure and Pain Subsequent to Craniotomy for Supratentorial Tumors

BACKGROUND

Control of emergence hypertension and pain is important after craniotomy for monitoring the neurological status. This prospective double-blinded study investigated the hemodynamics after a single bolus of dexmedetomidine (DEX) infusion administered to the patient undergoing craniotomy under general anesthesia, and its effect on emergence hypertension and postsurgical pain.

METHODS

Adult patients scheduled for elective surgery for supratentorial tumors were randomized to receive a 10-minute intraoperative DEX infusion of 0.4 μg/kg (small dose, n=43) or 0.8 μg/kg (medium dose, n=46), or normal saline (vehicle control, n=45), ∼60 minutes before the end of anesthesia.

RESULTS

A transient increase in the blood pressure associated with DEX was observed; 53.5% and 91.3% of the patients in the small-dose and the medium-dose groups, respectively, required treatment. Emergence mean arterial pressure and heart rates were significantly lower in the DEX groups compared with the control group. Incidence rates of postoperative hypertension in the small-dose (16.3%) and the medium-dose groups (15.2%) were significantly lower relative to that of the control group (35.6%). Patients who received DEX had a lower Verbal Numerical Rating Scale (VNRS) score in the neurosurgical ICU than the control group, and postsurgical pain (VNRS≥4) was lower in the medium-dose group (41.3%) than in the control group (71.1%). No shivering was observed in the medium-dose group, which was significantly less than that of the other 2 groups.

CONCLUSIONS

An intraoperative bolus of DEX risks a transient increase in mean arterial pressure, but controls emergence hypertension effectively. Dose-related reductions in postsurgical pain and shivering were observed.

Assessment the effect of dexmedetomidine on incidence of paradoxical hypertension after surgical repair of aortic coarctation in pediatric patients

OBJECTIVE

The aim of the study was to assess the effect of dexmedetomidine on the incidence of paradoxical hypertension in patients undergoing aortic coarctation repair.

DESIGN

Randomized observational study.

SETTING

University hospital and cardiac center.

PATIENTS

The study included 108 pediatric patients with isolated aortic coarctation.

METHODS

The patients were classified into two groups (each = 54): Group D: the patients received dexmedetomidine as a loading dose of 0.5 μg/kg over 10 min followed by infusion 0.3 μg/kg/h during surgery and continued for the first 48 postoperative hours. Group C: The patients received an equal amount of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly. The collected data included the heart rate, systolic and diastolic arterial blood pressure, incidence, onset, severity and treatment of paradoxical hypertension, fentanyl dose and end-tidal sevoflurane concentration, amount of blood loss and urine output.

MAIN RESULTS

The heart rate, systolic and diastolic blood pressure decreased significantly with dexmedetomidine than Group C (P < 0.05). The incidence and severity of the paradoxical hypertension was lower with dexmedetomidine than Group C (P = 0.011, P = 0.017, respectively). The onset the paradoxical hypertension was earlier in Group C than dexmedetomidine (P = 0.026). The dose of fentanyl and sevoflurane concentration decreased significantly with dexmedetomidine (P = 0.034, P = 0.026, respectively). The blood loss decreased with dexmedetomidine (P = 0.020) and the urine output increased with dexmedetomidine (P = 0.024). The incidence of hypotension and bradycardia was more with dexmedetomidine (P < 0.05).

CONCLUSION

Dexmedetomidine is safe in pediatric patients undergoing aortic coarctation repair. It minimized the incidence and severity of paradoxical hypertension. It decreased the required antihypertensive medications.

Can sedation using a combination of propofol and dexmedetomidine enhance the satisfaction of the endoscopist in endoscopic submucosal dissection?

BACKGROUND AND STUDY AIMS

 The aim of this pilot randomized controlled trial was to evaluate and compare the satisfaction of the endoscopist along with the effectiveness and safety of sedation between sedation protocol using a combination of propofol (PF) and dexmedetomidine (DEX) (Combination group) and sedation protocol using PF alone (PF group) during gastric endoscopic submucosal dissection (ESD).

PATIENTS AND METHODS

Fifty-eight patients with gastric neoplasias scheduled for gastric ESD were enrolled and randomly assigned to the two groups. The satisfaction scores of the endoscopists and the parameters for the effectiveness and safety of sedation were evaluated by comparisons between the two groups.

RESULTS

The satisfaction scores of the endoscopists, which were measured using a visual analogue scale, were significantly higher in the Combination group than in the PF group (88 vs. 69, P  = 0.003). The maintenance dose of PF was lower in the Combination group than in the PF group (2 mg/kg/h vs. 5 mg/kg/h, P  < 0.001), and the number of rescue PF injections was fewer in the Combination group than in the PF group (2 times vs. 6 times, P  < 0.001). The incidence of bradycardia (defined as a pulse rate ≤ 45 bpm) in the Combination group was higher than that in the PF group (37.9 % vs. 10.3 %, P  = 0.029).

CONCLUSIONS

This study suggests that gastroenterologist-directed sedation using a combination of PF and DEX during gastric ESD can enhance the satisfaction levels of endoscopists by providing stable sedation with an acceptable safety profile.

A Comparison of Oral Midazolam-ketamine, Dexmedetomidine-fentanyl, and Dexmedetomidine-ketamine Combinations as Sedative Agents in Pediatric Dentistry: A Triple-Blinded Randomized Controlled Trial

Introduction:

It is common to encounter a patient who is anxious to the magnitude that precludes the possibility of provision of dental treatment. This study aims to evaluate and compare the sedative effect of oral combinations of midazolam-ketamine (MK), dexmedetomidine-fentanyl (DF), and dexmedetomidine-ketamine (DK) in a group of uncooperative children requiring dental treatment.

Methodology:

This was a prospective, randomized, triple-blind study where 36 children who were 3–9 year old with American Society of Anesthesiologists –I status and presenting early childhood caries were randomly assigned to: Group A – 0.3 mg/kg of M and 5 mg/kg K, Group B – 2 ug/kg of D with 3 ug/kg of F, and Group C – 2ug/kg of D with 5 mg/kg of K in 1 mL honey. Patients' blood pressure, heart rate, and oxygen saturation were recorded from the start of the procedure till discharge. Patients' behavior, sedation status, and wake-up behavior were evaluated with Modified Observer Assessment of Alertness and Sedation Scale and ease of treatment completion by Houpt scale.

Results:

Hemodynamic changes were statistically insignificant in all three groups. 72.8% of patients in Group A and 58.3% of patients in Group B were successfully sedated during treatment. Behavior improvement was seen in all three groups during treatment with statistically insignificant difference in behavior scores produced by Group C. Ease of treatment completion was moderately better with Group A.

Conclusion:

Oral DK has a comparable sedative property with oral MK combination. Oral DF promises to be a potential sedative agent for children due to its successful anxiolysis.

Efficacy and safety of dexmedetomidine infusion for patients undergoing awake craniotomy: An observational study

Background:

The goal of awake craniotomy is to maintain adequate sedation, analgesia, respiratory, and hemodynamic stability and also to provide a cooperative patient for neurologic testing. An observational study carried out to evaluate the efficacy of dexmedetomidine sedation for awake craniotomy.

Materials and Methods:

Adult patients with age >18 year who underwent awake craniotomy for intracranial tumor surgery were enrolled. Those who were uncooperative and had difficult airway were excluded from the study. In the operating room, the patients received a bolus dose of dexmedetomidine 1 μg/kg followed by an infusion of 0.2–0.7 μg/kg/h (bispectral index target 60–80). Once the patients were sedated, scalp block was given with bupivacaine 0.25%. The data on hemodynamics at various stages of the procedure, intraoperative complications, total amount of fentanyl used, intravenous fluids required, blood loss and transfusion, duration of surgery, Intensive Care Unit (ICU), and hospital stay were collected. The patients were assessed for Glasgow outcome scale (GOS) score and patient satisfaction score (PSS).

Results:

A total of 27 patients underwent awake craniotomy during a period of 2 years. Most common intraoperative complication was seizures; observed in five patients (18.5%). None of these patients experienced any episode of desaturation. Two patients had tight brain for which propofol boluses were administered. The average fentanyl consumption was 161.5 ± 85.0 μg. The duration of surgery, ICU, and hospital stays were 231.5 ± 90.5 min, 14.5 ± 3.5 h, and 4.7 ± 1.5 days, respectively. The overall PSS was 8 and GOS was good in all the patients.

Conclusion:

The use of dexmedetomidine infusion with regional scalp block in patients undergoing awake craniotomy is safe and efficacious. The absence of major complications and higher PSS makes it close to an ideal agent for craniotomy in awake state.

A Comparative Study Evaluating Effects of Intravenous Sedation by Dexmedetomidine and Propofol on Patient Hemodynamics and Postoperative Outcomes in Cardiac Surgery

Background

The use of intravenous sedation during cardiac surgery to reduce awareness has been practised routinely during past few years and the two most commonly used drugs include propofol and dexmedetomidine, but their effects on hemodynamics and postoperative outcomes in cardiac surgery is continually being evaluated.

Aims

The aim of this study was to compare the effects of anesthesia by dexmedetomidine and propofol on the hemodynamic variables and postoperative outcomes in patients who were planned for elective cardiac surgery.

Settings

Cardiac operating room of a tertiary care hospital.

Design

A prospective, randomized controlled, double-blind clinical trial.

Materials and Methods

Sixty patients were randomized to receive either a continuous infusion of propofol (0.25-1 mg/kg/h) or dexmedetomidine bolus of 1 μg/kg over 10 min followed by infusion (0.2-0.6 μg/kg/h) after induction of anesthesia. The anesthesia technique and physiological monitoring including bispectral index monitoring were similar among both the groups. Hemodynamic variables (mean heart rate [HR], mean arterial pressure [MAP]) were noted at predefined time intervals, intraoperative vasopressor or inotrope requirements and postoperative outcomes including postoperative ventilation time and length of stay in the Intensive Care Unit (ICU) were also recorded.

Statistical Analysis

Statistics was done using SPSS V 20 (IBM, NY) using Student's t-test, analysis of variance, and Mann-Whitney U-test, and a P < 0.05 was considered to indicate a significant difference.

Results and Conclusions

HR and MAP were significantly less in dexmedetomidine group compared to propofol group (P < 0.05). Both the groups had a similar requirement of vasopressors and inotropes. The duration of postoperative ventilation and length of stay in the ICU were significantly shorter in the dexmedetomidine group (P < 0.05). The risk of delirium was significantly less in dexmedetomidine group (P < 0.05). From our study we concluded, that the perioperative infusion of dexmedetomidine produces better hemodynamic stability, reduces the risk of postoperative delirium, and leads to shorter ICU stay.

Comparison of Intranasal Dexmedetomidine Compared to Midazolam as a Premedication in Pediatrics with Congenital Heart Disease Undergoing Cardiac Catheterization

Background:

The intranasal route is a reliable way to administer preanesthetics and sedatives to children. The aim of this study was to compare the anxiolytic and sedative effect of intranasal dexmedetomidine and midazolam as a premedication in pediatrics with simple congenital heart disease undergoing cardiac catheterization.

Patients and Methods:

Sixty children 3–6 years old of either sex with simple congenital heart disease undergoing cardiac catheterization were randomly allocated into two groups: Dexmedetomidine group who received intranasal dexmedetomidine (0.1 μg/kg) and midazolam group who received intranasal midazolam (0.2 mg/kg) 30 min before induction. Heart rate, mean arterial blood pressure, and oxygen saturation were monitored up to 30 min after drug administration. The sedation score, anxiety score, and child-parent separation score were recorded until the child taken to the operating room. The postoperative agitation score was also observed.

Results and Conclusion:

The premedication of children with intranasal dexmedetomidine attained satisfactory and significant sedation and lower anxiety level with better parental separation than those who received intranasal midazolam.

A Combination of Dexmedetomidine and Lidocaine Is a Cardiovascularly Safe Dental Local Anesthetic for Hypertensive Rats Treated With a Nonselective β-Adrenergic Antagonist

Hypertensive patients receiving nonselective β-adrenergic antagonists are vulnerable to hypertension and bradycardia when injected with dental local anesthetic formulations containing epinephrine. Dexmedetomidine (DEX), an α₂-adrenergic agonist, has been reported to prolong and enhance the local anesthetic effects of lidocaine. The cardiovascular effects of the DEX-lidocaine combination have not yet been investigated in the presence of nonselective β-adrenergic antagonists. Therefore, we assessed the cardiovascular effects of the DEX-lidocaine combination in spontaneously hypertensive rats (SHR) treated with a nonselective β-adrenergic antagonist (propranolol). We injected propranolol-treated rats with various concentrations of DEX alone, 100 μg/kg epinephrine alone, or 5 μg/kg DEX combined with 2% lidocaine and measured their blood pressure (BP) and heart rates (HR) to assess the cardiovascular effects. The BP of propranolol-treated SHR was significantly increased by treatment with 100 μg/kg epinephrine alone. The BP and HR of propranolol-treated SHR were not significantly changed by treatment with low concentrations of DEX, but they were significantly decreased by treatment with a high concentration of DEX (50 μg/kg). Moreover, there was no significant difference in the BP and HR of propranolol-treated SHR after the injection of a combination of 5 μg/kg DEX and 2% lidocaine. Thus, the DEX-lidocaine combination may be an acceptable addition to dental local anesthetic solutions from a cardiovascular standpoint for hypertensive patients receiving nonselective β-adrenergic antagonists.