Intravenous Bolus Of Dexmedetomidine Research Articles

Metabolic Manipulation and Therapeutic Hypothermia.

Hypothermia has multiple physiological effects, including decreasing metabolic rate and oxygen consumption (VO2). There are few human data about the magnitude of change in VO2 with decreases in core temperature. We aimed to quantify to magnitude of reduction in resting VO2 as we reduced core temperature in lightly sedated healthy individuals. After informed consent and physical screening, we cooled participants by rapidly infusing 20 mL/kg of cold (4°C) saline intravenously and placing surface cooling pads on the torso. We attempted to suppress shivering using a 1 mcg/kg intravenous bolus of dexmedetomidine followed by titrated infusion at 1.0 to 1.5 μg/(kg·h). We measured resting metabolic rate VO2 through indirect calorimetry at baseline (37°C) and at 36°C, 35°C, 34°C, and 33°C. Nine participants had mean age 30 (standard deviation 10) years and 7 (78%) were male. Baseline VO2 was 3.36 mL/(kg·min) (interquartile range 2.98-3.76) mL/(kg·min). VO2 was associated with core temperature and declined with each degree decrease in core temperature, unless shivering occurred. Over the entire range from 37°C to 33°C, median VO2 declined 0.7 mL/(kg·min) (20.8%) in the absence of shivering. The largest average decrease in VO2 per degree Celsius was by 0.46 mL/(kg·min) (13.7%) and occurred between 37°C and 36°C in the absence of shivering. After a participant developed shivering, core body temperature did not decrease further, and VO2 increased. In lightly sedated humans, metabolic rate decreases around 5.2% for each 1°C decrease in core temperature from 37°C to 33°C. Because the largest decrease in metabolic rate occurs between 37°C and 36°C, subclinical shivering or other homeostatic reflexes may be present at lower temperatures.

Hemodynamic Response of High- and Low-Dose Dexmedetomidine of Pediatric in General Anesthesia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Dexmedetomidine is a highly selective α2-adrenoceptor agonist, which is off-labelled use for pediatric sedation. However, the hemodynamic responses of dexmedetomidine remain unclear in the pediatric population. The primary objectives of this systematic review and meta-analysis were to examine the hemodynamic effects of high-dose and low-dose dexmedetomidine in pediatric patients undergoing surgery. EMBASE, MEDLINE, and CENTRAL were systematically searched from its inception until April 2019. All randomized clinical trials comparing high-dose (＞ 0.5 mcg/kg) and low-dose (≤ 0.5 mcg/ kg) dexmedetomidine in pediatric surgical patients were included, regardless of the types of surgeries. Observational studies, case series, and case reports were excluded. Four trials (n = 473) were included in this review. Our review demonstrated that high-dose dexmedetomidine was associated with lower heart rate than low-dose dexmedetomidine after intravenous bolus of dexmedetomidine (studies, 3; n = 274; mean difference [MD], -5 [-6 to -4]; P ＜ 0.0001) and during surgical stimulant (studies, 2; n = 153; MD, -11 [-13 to -9]; P ＜ 0.0001). In comparison to the low-dose dexmedetomidine, high-dose dexmedetomidine was also associated with a significant longer recovery time (studies, 3; n = 257; MD, 5.90 [1.56 to 10.23]; P = 0.008) but a lower incidence of emergence agitation (studies, 2; n = 153; odds ratio, 0.17 [0.03 to 0.95]; P = 0.040). In this meta-analysis, low-dose dexmedetomidine demonstrated better hemodynamic stability with shorter recovery time than high-dose dexmedetomidine. However, these findings need to be interpreted with caution due to limited published studies, a small sample size, and a high degree of heterogeneity.

Hemodynamic Response of High- and Low-Dose Dexmedetomidine of Pediatric in General Anesthesia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Dexmedetomidine is a highly selective α2-adrenoceptor agonist, which is off-labelled use for pediatric sedation. However, the hemodynamic responses of dexmedetomidine remain unclear in the pediatric population. The primary objectives of this systematic review and meta-analysis were to examine the hemodynamic effects of high-dose and low-dose dexmedetomidine in pediatric patients undergoing surgery. EMBASE, MEDLINE, and CENTRAL were systematically searched from its inception until April 2019. All randomized clinical trials comparing high-dose (＞ 0.5 mcg/kg) and low-dose (≤ 0.5 mcg/ kg) dexmedetomidine in pediatric surgical patients were included, regardless of the types of surgeries. Observational studies, case series, and case reports were excluded. Four trials (n = 473) were included in this review. Our review demonstrated that high-dose dexmedetomidine was associated with lower heart rate than low-dose dexmedetomidine after intravenous bolus of dexmedetomidine (studies, 3; n = 274; mean difference [MD], -5 [-6 to -4]; P ＜ 0.0001) and during surgical stimulant (studies, 2; n = 153; MD, -11 [-13 to -9]; P ＜ 0.0001). In comparison to the low-dose dexmedetomidine, high-dose dexmedetomidine was also associated with a significant longer recovery time (studies, 3; n = 257; MD, 5.90 [1.56 to 10.23]; P = 0.008) but a lower incidence of emergence agitation (studies, 2; n = 153; odds ratio, 0.17 [0.03 to 0.95]; P = 0.040). In this meta-analysis, low-dose dexmedetomidine demonstrated better hemodynamic stability with shorter recovery time than high-dose dexmedetomidine. However, these findings need to be interpreted with caution due to limited published studies, a small sample size, and a high degree of heterogeneity.

Effects of dexmedetomidine on the expression of inflammatory factors in children with congenital heart disease undergoing intraoperative cardiopulmonary bypass: a randomized controlled trial.

ImportanceDexmedetomidine inhibits the inflammatory response associated with cardiopulmonary bypass (CPB) and protects neural function. However, the mechanism of dexmedetomidine’s anti‐inflammatory pathway is unclear.ObjectiveTo investigate the effect of dexmedetomidine on the cognitive level and expression of inflammatory factors in children with congenital heart disease undergoing intraoperative CPB.MethodsNinety children with congenital heart disease were recruited and randomly divided into 3 groups of 30 children in each. In Group 1, a 1.0 µg·kg‐1·h‐1 intravenous bolus of dexmedetomidine was administered 10 minutes after induction of anesthesia, followed by a 0.2 µg·kg‐1·h‐1 infusion until the surgical incision. In Group 2, a 0.5 µg/kg intravenous bolus of dexmedetomidine was administered 10 minutes after induction of anesthesia, followed by a 0.1 µg·kg‐1·h‐1 infusion until the surgical incision. The control group was given physiological saline using the same method as in Groups 1 and 2. The serum levels of nuclear factor‐kappa B (NF‐κB), S‐100β protein, neuron‐specific enolase (NSE), tumor necrosis factor‐α (TNF‐α), and interleukin‐6 (IL‐6) were measured before the surgery (T1), at the end of CPB (T2), 2 hours after CPB (T3), 6 hours after CPB (T4), and 24 hours after CPB (T5). The Wechsler Intelligence Scale for children (WISC) was measured before the operation and at 3, 6, and 12 months after the operation to evaluate the neurodevelopmental state of the children.ResultsThe levels of the NF‐κB, S‐100β protein, NSE, TNF‐α, IL‐6 were significantly higher at T2, T3, or T4 than before the surgery (T1) in the control group or the dexmedetomidine groups. However, the increases of NF‐κB, TNF‐α, IL‐6, S‐100β and NSE levels were significantly smaller in the dexmedetomidine groups than those in the control group (P < 0.017). The WISC scores were similar among the three groups before or after the operation.InterpretationThe increases in NF‐κB, TNF‐α, and IL‐6 levels indicated aggravation of the inflammatory reaction and the increase S‐100β protein and NSE levels indicated that the nervous system was damaged. Administration of dexmedetomidine to children with congenital heart disease undergoing intraoperative CPB can inhibit the inflammatory response and may ameliorate the neurodevelopmental damage caused by CPB.

Effect of Intravenous Dexmedetomidine Injection(1 μg/kg)on the Intubating Conditions without Muscle Relaxants in Children after Inhalation Induction with Sevoflurane.

Objective To investigate the effect of intravenous dexmedetomidine injection(1 μg/kg)on the intubating conditions after inhalation induction with sevoflurane 8% and nitrous oxide(N2O)50% in children. Methods Totally 122 patients aged 4-10 years with an American Society of Anesthesiologists physical statusⅠ undergoing elective plastic surgery under general anesthesia were randomly divided to dexmedetomidine group(intraveneously injected with dexmedetomidine 1μg/kg)and control group(injected with normal saline)by using the random sampling table.On arrival of the operating room,anesthesia was induced with sevoflurane 8% and N2O 50% in oxygen 50%.When the patient became unconscious,the intravenous cannula 24# was inserted on the dorsum of hand.One minute later,laryngoscopy and tracheal intubation were performed.The intubating conditions were assessed by the scoring system in the previous study. Results The rates of acceptable conditions were 97% and 90% in dexmedetomidine group and in control group(P=0.143),and the rates of excellent conditions were 82% and 67%(P=0.04),respectively.In dexmedetomidine group,there were no signifi-cant differences of mean arterial presser and heart rate between the time-point of before intubation and the time-point of immediately after intubation.Conclusion Intravenous bolus of dexmedetomidine(1 μg/kg)can effectively improve the intubating conditions after inhalation induction of sevoflurane 8% and N2O 50% in children and make the hemodynamics more stable during tracheal intubation.