Dose Of Dexmedetomidine For Sedation Research Articles

A pilot study of ADRA2A genotype association with doses of dexmedetomidine for sedation in pediatric patients.

Study ObjectiveDexmedetomidine is titrated to achieve sedation in the pediatric and cardiovascular intensive care units (PICU and CVICU). In adults, dexmedetomidine response has been associated with an ADRA2A polymorphism (rs1800544); CC genotype is associated with an increased sedative response compared with GC and GG. To date, this has not been studied in children.DesignWe conducted a pilot study to determine whether ADRA2A genotype is associated with dexmedetomidine dose in children.Measurements and Main ResultsForty intubated PICU or CVICU patients who received dexmedetomidine as a continuous infusion for at least 2 days were genotyped for ADRA2A with a custom‐designed TaqMan® Assay. Ten (25%) subjects were wildtype (GG), 15 (37.5%) were heterozygous (GC), and 15 (37.5%) were homozygous (CC) variant. The maximum dexmedetomidine doses (mCg/kg/h) were not different between genotype groups CC (1, 0.3–1.2), GC (1, 0.3–1.3), and GG (0.8, 0.3–1.2), (p = 0.37); neither were mean dexmedetomidine doses for these respective genotype groups 0.68 (0.24–1.07), 0.72 (0.22–0.98), 0.58 (0.3–0.94), (p = 0.67).ConclusionsThese findings did not confirm the results from adult studies where ADRA2A polymorphisms correlate with dexmedetomidine response, therefore highlighting the need for pediatric studies to validate PGx findings in adults prior to implementation in pediatrics.

Dose Comparison of Dexmedetomidine Sedation following Spinal Anesthesia: Parturient versus Nonpregnant Women-A Randomized Trial.

Background This study was designed to investigate and compare the effective doses of dexmedetomidine for sedation in parturient patients who underwent Cesarean section (CS) and nonpregnant women who underwent elective gynecologic surgery. Methods The study comprised 60 females aged between 25 and 35. They were divided into two groups. The parturient group received a bolus dose of dexmedetomidine over 15 min after the delivery of the fetus and placenta. In the nonpregnant women group, a bolus of dexmedetomidine was administered intravenously upon the completion of spinal anesthesia. The subsequent dose required by patients in each group was then determined through a modified two-stage Dixon up-and-down sequential method. Probit analysis was used to calculate the ED50 and the ED95 of dexmedetomidine for adequate sedation. Results The ED50 of dexmedetomidine for adequate sedation in parturient patients was 1.58 μg/kg (1.51–1.66 μg/kg); in nonpregnant women, it was 0.96 μg/kg (0.91–1.01 μg/kg) (95% CI). The ED95 of dexmedetomidine in parturients was 1.80 μg/kg (1.70–2.16) μg/kg and that of nonpregnant women was 1.10 μg/kg (1.04–1.30 μg/kg) (95% CI). The ED50 in parturients was significantly higher than that in nonpregnant women (P < 0.05). Conclusion The ED50 of dexmedetomidine for target sedation in parturients who received spinal anesthesia for CS is greater than 1.5 times that in nonpregnant women who received spinal anesthesia for lower abdominal gynecologic surgery. This study postulates that the dose of dexmedetomidine required to achieve optimal sedation following spinal anesthesia is much higher in parturients than in nonpregnant women undergoing gynecologic surgeries. This trial is registered with NCT02111421.

Comparison of efficacy of different doses of dexmedetomidine for sedation in patients with Parkinson′s disease undergoing deep brain stimulation surgery

Objective To compare the efficacy of different doses of dexmedetomidine for sedation in patients with Parkinson′s disease(PD) undergoing deep brain stimulation(DBS) surgery. Methods Seventy-five patients of both sexes with PD, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, aged 48-72 yr, with body mass index of 18-24 kg/m2, undergoing elective DBS surgery, were divided into 3 groups(n=25 each) using a random number table method: different doses of dexmedetomidine groups(D1-3 groups). Dexmedetomidine was intravenously infused in a loading dose of 0.5 μg/kg at 10 min before local infiltration anesthesia with 0.25 % ropivacaine 10-20 ml, followed by an infusion of 0.3, 0.5 and 0.8 μg·kg-1·h-1 in D1-3 groups, respectively.The infusion of dexmedetomidine was suspended during neurological test, the patients were awakened, and dexmedetomidine was infused at 0.3, 0.5 and 0.8 μg·kg-1·h-1 until the end of the surgery after the test.Bispectral index(BIS) value was recorded immediately before anesthesia(T0), immediately after administration prior to wake-up(T1) and during neurological test(T2). The wake-up time and adverse reactions such as requirement for rescue analgesics, pulse oxygen saturation(SpO2)<90% and snoring were recorded. Results Compared with group D1, the requirement for rescue analgesics and BIS value at T1, 2 were significantly decreased in D2 and D3 groups, and the wake-up time was significantly prolonged, and the incidence of SpO2<90% and snoring was increased in group D3 (P<0.05 or 0.01). Compared with group D2, the requirement for rescue analgesics and BIS value at T1 were significantly decreased, the wake-up time was prolonged, and the incidence of SpO2<90% and snoring was increased in group D3(P<0.05 or 0.01). Conclusion Dexmedetomidine 0.5 μg·kg-1·h-1 can produce good sedative efficacy and safety for DBS surgery in patients with PD. Key words: Dose-response relationship, drug; Dexmedetomidine; Conscious sedation; Parkinson disease; Electric stimulation

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.

Optimal dose of dexmedetomidine for sedation during epidural anesthesia

Optimal dose of dexmedetomidine for sedation during epidural anesthesia

Comparison of two loading doses of dexmedetomidine for sedation during spinal anesthesia

Comparison of two loading doses of dexmedetomidine for sedation during spinal anesthesia

Dexmedetomidine and ketamine sedation for muscle biopsies in patients with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) possesses many potential challenges for anesthetic care. Invasive and noninvasive procedures with corresponding sedation or general anesthesia are frequent and necessary for affected patients. There remains a need for a better agent or agents for procedural sedation in patients with comorbid diseases. This study prospectively evaluated a combination of ketamine with two different doses of dexmedetomidine for sedation during muscle biopsy in patients with DMD. Dexmedetomidine 1.0 or 0.5 μg·kg(-1) was administered as a loading dose over 3 min followed by a continuous infusion of 1.0 or 0.5 μg·kg·h(-1). Ketamine (1 mg·kg(-1)) was administered along with the dexmedetomidine loading dose. As the procedure commenced, additional doses of ketamine (0.5 mg·kg(-1)) were administered as needed. Sedation scores, hemodynamic data, operative times, and recovery times were recorded. The study cohort included a total of 53 bicep, deltoid, or anterior tibialis muscle biopsies in 19 boys including 24 in the dexmedetomidine 1.0 μg·kg(-1) group and 29 in the dexmedetomidine 0.5 μg·kg(-1) group. Mean age and weight were 9.7 ± 1.4 years and 33.3 ± 7.7 kg in the dexmedetomidine 1.0 μg·kg(-1) group and 8.8 ± 1.8 years and 30.2 ± 10.8 kg in the dexmedetomidine 0.5 μg·kg(-1) group. No significant changes in blood pressure were noted. A decrease in heart rate (HR) occurred after the loading dose of dexmedetomidine in both groups. The HR was significantly lower in the dexmedetomidine 1.0 μg·kg(-1) group compared with the dexmedetomidine 0.5 μg·kg(-1) group. Total recovery time to discharge was significantly shorter in the dexmedetomidine 0.5 μg·kg(-1) group than the dexmedetomidine 1.0 μg·kg(-1) group (146 ± 65 vs 174 ± 58 min; P = 0.03), although the total ketamine dose was significantly greater in the dexmedetomidine 0.5 μg·kg(-1) group (3.7 ± 1.0 vs 2.0 ± 0.5 mg·kg(-1); P < 0.01). There were no episodes of apnea or hypoventilation; however, a jaw thrust was needed in one patient in the dexmedetomidine 1.0 μg·kg(-1) group. The combination of dexmedetomidine and ketamine is safe and effective for moderately painful procedures with limited respiratory and cardiovascular effects in a high-risk patient population. Dexmedetomidine 0.5 μg·kg(-1) as a loading dose with ketamine followed by a continuous infusion of dexmedetomidine at 0.5 μg·kg(-1) ·h(-1) achieved an adequate sedation level with shorter total recovery times in the perioperative unit compared with a higher dose regimen of dexmedetomidine (1.0 μg·kg(-1) loading dose followed by an infusion at 1.0 μg·kg(-1) ·h(-1)).

Dexmedetomidine ameliorates monitored anaesthesia care.

Background and Aims:Monitored anaesthesia care (MAC) is meant for procedures under local anaesthesia. Various drugs have been used for this purpose. The recently introduced alpha2 agonist, dexmedetomidine provides “conscious sedation” with adequate analgesia and minimal respiratory depression. Hence, the safety and efficacy of two doses of dexmedetomidine for sedation and analgesia were evaluated.Methods:A total of 90 patients were distributed in three groups of 30 each: Dexmedetomidine 0.5 μg/kg (DL), dexmedetomidine 1.0 μg/kg (DH) and normal saline (C). The initial loading dose was followed by maintenance infusion of 0.2-0.7 μg/kg/h of dexmedetomidine or equivalent volume of saline. Study drug was started at least 15 min before placement of local anaesthesia. Drugs were titrated to a target level of sedation (=3 on Ramsay sedation scale [RSS]). Midazolam 0.02 mg/kg for RSS < 3 and fentanyl 0.5 μg/kg were supplemented as required. The statistical analysis was performed using Chi-square test and mean and anova analysis.Results:In groups DL and DH fewer patients required supplemental midazolam, 56.7% (17/30) and 40% (12/30), compared with control, where 86.7% (26/30)needed midazolam supplements. P = 0.000. Both groups DL and DH required significantly less fentanyl (84.8 and 83.9 μg) versus control (144.2 μg). There was significantly increased ease of achieving and maintaining targeted sedation and analgesia in both dexmedetomidine groups when compared with placebo (P = 0.001). Adverse events observed with dexmedetomidine were bradycardia and hypotension.Conclusions:Dexmedetomidine in the doses studied was considered safe and effective sedative and analgesic for patients undergoing procedures under MAC.

Nasotracheal Fiberoptic Intubation: Patient Comfort, Intubating Conditions and Hemodynamic Stability During Conscious Sedation with Different Doses of Dexmedetomidine

The study aims to evaluate the efficacy of two doses of dexmedetomidine for sedation during awake fiberoptic intubation (AFOI). The study was designed in a prospective, randomized, double-blinded manner and carried out in an academic medical university. Forty young co-operative patients aged 15–45 years of either sex belonging to ASA class I-II, planned for elective maxillo-facial surgery formed the study group. All patients received midazolam 0.05 mg/kg, glycopyrrolate 0.2 mg, ondansetron 4 mg, and ranitidine 50 mg IV 15 min before as premedication, oxygen by nasal cannula, and topical local anesthetics to the airway. Patients were randomly assigned to one of the groups; dexmedetomedine 1 μg/kg IV (Group L), or dexmedetomidine 1.5 μg/kg IV (Group H). Observer’s Assessment of Alertness/Sedation (OAA/S) was assessed. Primary outcome measurements were: HR, MAP, SpO2 and EtCO2 and secondary outcome measurements were: intubation scores by vocal cord movement, coughing and limb movement, fiberoptic intubation comfort score, nasotracheal intubation score and airway obstruction score. On the first post-operative day, recall, level of discomfort during fiberoptic intubation, adverse events and satisfaction score were also assessed. There were no significant hemodynamic differences between the two groups. OAA/S was significantly better with dexmedetomidine 1.5 μg/kg (p < 0.05) and patients were significantly calmer, more cooperative and satisfied during awake fiberoptic intubation with dexmedetomidine 1.5 μg/kg with fewer transient adverse effects. Dexmedetomidine 1.5 μg/kg proved to be more effective for sedation for awake fiberoptic intubation.

Optimal dose of dexmedetomidine for sedation during spinal anesthesia

BackgroundSedation in spinal anesthesia can reduce patient's anxiety and discomfort. Dexmedetomidine has a sedative, hypnotic, analgesic, and minimal respiratory depression effect. However, use of the dexmedetomidine is associated with prolonged recovery. This study was designed to investigate the optimal dose of intravenous dexmedetomidine for proper sedation with minimal recovery time in spinal anesthesia.MethodsOne hundred twenty eight patients, aged 20-70 years (58.8 ± 0.7), were recruited. After performing the spinal anesthesia with hyperbaric bupivacaine (13 mg), a loading dose of dexmedetomidine (1 µg/kg) was administered for 10 min, followed by the maintenance infusion of the following: Group A (n = 33; normal saline), Group B (n = 35; dexmedetomidine 0.2 µg/kg/hr), and Group C (n = 39; dexmedetomidine 0.4 µg/kg/hr). Heart rate, blood pressure, and the bispectral index score (BIS) were recorded during the operation. In the recovery room, modified aldrete score (MAS) was measured.ResultsThere were no significant differences in mean blood pressure and heart rate among the three groups. BIS was not significantly different among the three groups from baseline to 60 min after the infusion of dexmedetomidine. BIS were significantly increased in Group A after 70 and 80 min, and Group A and B after 90, 100, 110 min of dexmedetomidine infusion (P < 0.05). MAS was higher in Group A as compared to Group B and C, within 30 min after admission in the recovery room (P < 0.05).ConclusionsThe loading dose (1 µg/kg/10 min) of dexmedetomidine was sufficient for surgery of less than 60 min. Dexmedetomidine infusion followed by maintenance dose (0.2 µg/kg/hr) was sufficient for surgery within 90 min.

Monitored Anesthesia Care with Dexmedetomidine: A Prospective, Randomized, Double-Blind, Multicenter Trial

Dexmedetomidine (DEX) is increasingly being used as a sedative for monitored anesthesia care (MAC) because of its analgesic properties, "cooperative sedation," and lack of respiratory depression. In this randomized, multicenter, double-blind, Phase III Food and Drug Administration study, we evaluated the safety and efficacy of two doses of DEX for sedation of patients undergoing a broad range of surgical or diagnostic procedures requiring MAC. Three hundred twenty-six patients were randomized 2:2:1 to DEX 0.5 microg/kg, DEX 1 microg/kg, or saline placebo initial loading dose, followed by a maintenance infusion of 0.2-1.0 microg x kg(-1) x h(-1) of DEX (or equivalent volume of saline) titrated to a targeted level of sedation (< or = 4 on the Observer's Assessment of Alertness/Sedation Scale [OAA/S]). Study drug was started at least 15 min before placement of regional or local anesthetic block. Midazolam was given for OAA/S > 4 and fentanyl for pain. The primary end-point was the percentage of patients not requiring rescue midazolam. Significantly fewer patients in the 0.5- and 1-microg/kg DEX groups required supplemental midazolam compared with placebo (59.7% [80/134], 45.7% [59/129] vs 96.8% [61/63], respectively; P < 0.001) and at lower doses to achieve an OAA/S < or = 4 before and during surgery compared with the saline group (1.4 and 0.9 mg vs 4.1 mg, respectively; P < 0.001, each group compared with placebo). Both DEX groups required significantly less fentanyl (84.8 and 83.6 microg vs 144.4 microg, respectively; P < 0.001, for both DEX groups versus placebo) for all surgical subtypes. Anesthesiologists indicated significantly increased ease of achieving and maintaining targeted sedation in both DEX groups compared with placebo with midazolam (P < 0.001). Patient satisfaction was significantly higher with DEX (P < or = 0.009, both groups versus placebo). Common adverse events with DEX were protocol-defined bradycardia and hypotension that were predominately mild to moderate in severity. The incidence of clinically significant respiratory depression (defined as a respiratory rate of < 8 or an oxygen saturation of < 90%) was lower in DEX-treated patients (P = 0.018, for both groups versus placebo). DEX is an effective baseline sedative for patients undergoing MAC for a broad range of surgical procedures providing better patient satisfaction, less opioid requirements, and less respiratory depression than placebo rescued with midazolam and fentanyl.