Objective To observe the effects of two different intranasal dexmedetomidine doses as premedication on the ECof sevoflurane for successful laryngeal mask airway placement in children. Methods Children aged 3-6 years, of American Society of Anesthesiologists physical status 1, and scheduled for plastic surgery were enrolled in this study. Children were assigned to receive either spray administration of intranasal dexmedetomidine 1 μg/kg (group D1, n=21) or 2 μg/kg (group D2, n=20) approximately 30 minutes before anesthesia. Anesthesia was induced with sevoflurane up to 8% in 100% O, with fresh gas flow set to 6 L/min. After the pupil fixed to the middle position, sevoflurane dial setting was reduced to 5% and fresh gas flow reduced to 3 L/min. The endtidal sevofluran (ET) concentration for laryngeal mask airway insertion sustained for 10 minutes after vein intubation, which was determined according to the Dixon's up and down method. The initial endtidal sevoflurane concentration in each group was set at 2%. ETwas increased/decreased (1:1.2) in the next patient according to the response to laryngeal mask airway insertion. Bispectral index, mask acceptance, all response to laryngeal mask airway insertion, and ETof laryngeal mask airway insertion of children were recorded. Results The bispectral index value was 77.4±3.6 in group D2, which was significantly lower than that (87.4±1.9) in group D1 when children entered operation room (P<0.05). Mask acceptance was 76.2% in group D1 and 90.0% in group D2. The ECof sevoflurane for laryngeal mask airway insertion was 1.09% (95% CI=0.89%-1.28%) in group D2, which was lower than 1.59% (95% CI=1.41%-1.78%) in group D1 (P<0.05). Conclusion Compared with the dose of 1 μg/kg, spray administration of intranasal dexmedetomidine 2 μg/kg as premedication can reduce the sevoflurane ECfor successful laryngeal mask airway placement in children.
Administration, Intranasal ; Anesthesia ; Anesthetics, Inhalation ; administration & dosage ; Child ; Child, Preschool ; Dexmedetomidine ; administration & dosage ; Humans ; Laryngeal Masks ; Methyl Ethers ; administration & dosage

BACKGROUND: Dexmedemomidine, a highly selective alpha-2 adrenoreceptor agonist has an analgesic and sedative effect without causing respiratory depression. In this study, we compared the duration of brachial plexus block (BPB), the time at which the patient first feels pain after performing BPB, the need for use of analgesics, and the occurrence rate of complications while continuous infusion with dexmedetomidine was used for sedation in patients undergoing BPB, to a control group, who were only infused with normal saline. METHODS: BPB was performed in 48 patients scheduled for upper limb surgery. Infraclavicular approach was provided with 40 ml of 1.5% mepivacaine and 200 microg of epinephrine using nerve stimulator. After verification of successful block, dexmedetomidine group received dexmedetomidine (loading dose 0.1 microg/kg/min for the first 10 minutes followed by a maintenance dose of 0.005 microg/kg/min as required to maintain bispectral index 60-80). In the control group, normal saline was infused at a rate of 10 ml/hr. The duration of BPB, the time at which the patient first feels pain after performing BPB, frequency of complication, and the use of analgesics of the both groups were checked. RESULTS: The motor and sensory block duration, and the time at which the patient first feels pain after BPB were longer in the dexmedetomidine group compared to the control group. And the need for analgesics were less in the dexmedetomidine group. CONCLUSIONS: Intravenous administration of dexmedetomidine prolongs the duration of BPB.
Administration, Intravenous ; Analgesics ; Brachial Plexus ; Dexmedetomidine ; Epinephrine ; Humans ; Hypnotics and Sedatives ; Mepivacaine ; Respiratory Insufficiency ; Upper Extremity

OBJECTIVETo investigate the effect of different doses of dexmedetomidine (Dex) on early postoperative cognitive dysfunction in elderly patients undergoing laparoscopic surgery for colorectal cancer.

METHODSEighty ASAI-III elderly patients (over 65 years) were randomized equally into 4 groups including a control group without dexmedetomidine and 3 dexmedetomidine groups (groups D1, D2, and D3) with loading dexmedetomidine doses of 0.2, 0.5, and 0.8 µg/kg and maintenance doses of 0.2, 0.5, and 0.8 µg·kg(-1)·h(-1), respectively. Dex was discontinued 30 min before the end of surgery. The time of operation, adverse reactions, time from the end of surgery to spontaneous breathing recovery (TR), time from spontaneous breathing recovery to opening eyes (TO), and time from opening eyes to extubation (TE) were recorded. Mini-Mental State (MMSE) test was used to assess the cognitive function 1 day before and at 1 day and 3 days after the operation.

RESULTSThe incidence of postoperative cognitive dysfunction (POCD) was significantly lower in groups D2 and D3 than in the control group and group D1 (P<0.05). The incidences of hypotension and bradycardia were the highest in group D3 (P<0.05), which also had longer significantly TO and TE than the other 3 groups (P<0.05).

CONCLUSIONDexmedetomidine with a loading dose of 0.5 µg/kg followed by maintenance doses of 0.5 and 0.8 µg·kg(-1)·h(-1) (preferentially 0.5 µg·kg(-1)·h(-1)) can reduce the incidence of POCD in elderly patients undergoing laparoscopic surgery for colorectal cancer.

Aged ; Cognition ; drug effects ; Colorectal Neoplasms ; surgery ; Dexmedetomidine ; administration & dosage ; Humans ; Laparoscopy ; Postoperative Complications ; Respiration

OBJECTIVETo evaluate the influence of small-dose dexmedetomidine infusion on recovery of patients undergoing vertebral operation.

METHODSSixty ASA I-II patients undergoing vertebral operation were randomly divided into two groups (n=30). In group I, dexmedetomidine infusion was pumped at the rate of 0.5 µg·kg(-1)·h(-1) from tracheal intubation to incision suture, and in group II, 0.9%saline was pumped instead. The mean arterial pressure, heart rate, Riker Sedation-Agitation Scale and Ramesay sedation score were recorded at the time points of autonomous respiration (T1), eye opening (T2), extubation (T3), 1 min after extubation (T4), 10 min after extubation (T5), and 30 min after extubation (T6).

RESULTSThe recovery time of autonomous respiration and eye opening time in group I were significantly longer than those in group II, and the extubation time was significantly shorter in group I (P<0.05). Riker Sedation-Agitation Scale scores in group II were significantly higher than those in group I at T2 and T4, and Ramesay sedation scores in group I were significantly higher than those in group II at T1, T2 and T5 (P<0.05). The mean arterial pressure and heart rate at each time point was significantly lower in group I than in group II (P<0.05), especially at T3 and T4 (P<0.01). In both groups, the mean arterial pressure and heart rate at T3 and T4 were significantly higher than those at rest (P<0.05).

CONCLUSIONSSmall-dose dexmedetomidine infusion can reduce dysphoria and lower the risks during recovery from general anesthesia following vertebral operation.

Adult ; Aged ; Anesthesia Recovery Period ; Dexmedetomidine ; administration & dosage ; pharmacology ; Humans ; Middle Aged ; Spine ; surgery

OBJECTIVE: To compare the median effective dose (ED) of intranasal dexmedetomidine for procedural sedation in uncooperative pediatric patients with acyanotic congenital heart disease before and after cardiac surgery. METHODS: We prospectively recruited 47 children (22 in preoperative group and 25 in postoperative group) who needed sedation for transthoracic echocardiography (TTE). A modified up-and-down sequential study design was employed to determine dexmedetomidine dose for each patient with a starting dose of 2 μg/kg in both groups; dexmedetomidine doses for subsequent subjects were determined according to the responses from the previous subject using the up-and-down method at a 0.25 μg/kg interval. The ED was determined using probit regression. The onset time, examination time, wake-up time and adverse effects were measured, and the safety was evaluated in terms of changes in vital signs every 5 min. RESULTS: The ED value of intranasal dexmedetomidine for sedation was 1.84 μg/kg (95% : 1.68-2.00 μg/kg) in children with congenital heart disease before cardiac surgery, and 3.38 μg/kg (95% : 3.21-3.54 μg/kg) after the surgery. No significant difference was found between the two groups in the demographic variables, onset time, examination time, wake-up time, or adverse effects. CONCLUSIONS In children with acyanotic congenital heart disease, the ED of intranasal dexmedetomidine for TTE sedation increases to 3.38 μg/ kg after cardiac surgery from the preoperative value of 1.84 μg/kg.
Administration, Intranasal ; Cardiac Surgical Procedures ; Child ; Dexmedetomidine ; Heart Defects, Congenital ; surgery ; Humans ; Hypnotics and Sedatives

OBJECTIVETo determine the 50% effective concentration (EC(50) ) of dexmedetomidine (DEX) as an adjuvant for achieving the minimal effect in combined spinal-epidural anesthesia (CSEA) with Narcotrend.

METHODSThirty ASA class I-II patients undergoing CSEA were allocated to receive 0.5% bupivacaine injection (2 ml) in the subarachnoid space, followed by a target-controlled infusion of DEX for at least 60 min. The target concentration of DEX was adjusted according to the response of the previous patient using a double-blind, up-and-down sequential method. The initial DEX concentration of the first patient was 0.5 ng/ml. An Observers Assessment of Alertness/Sedation Scale (OAA/S) score of no more than 3 within 30 min defined an effective sedation. The Narcotrend index (NTI) related to the OAA/S score was recorded as well. The correlation between Narcotrend and OAA/S score was analyzed.

RESULTSThe EC(50) of DEX as an adjuvant in CSEA was 0.35∓0.07 ng/ml. The NTI was positively correlated to the OAA/S score (r=0.967, P=0.000). The regression equation was OAA/S =-3.922+0.094NTI (F=401.710, P=0.000).

CONCLUSIONWe suggest a novel protocol using DEX as a adjunct in CSEA. The EC(50) % of DEX to result in ideal sedation (OAA/S≤3) was 0.35∓0.07 ng/ml. NTI may serve as an objective index for sedation assessment in CSEA.

Adult ; Anesthesia, Epidural ; Anesthesia, Spinal ; Dexmedetomidine ; administration & dosage ; Humans ; Middle Aged

Objective To compare two spray administration of intranasal dexmedetomidine (DEX) doses for premedication in children. Methods In this prospective,randomized,double-blind study,41 children aged 3-6 years were enrolled. Children were assigned to receive either spray administration of intranasal DEX 1 μg/kg (Group D1) or 2 μg/kg (Group D2). The Ramsay Sedation Scale scores were evaluated at 5 min intervals. Sedation status at separation from patient was also evaluated. Heart rate (HR) and saturation of peripheral oxygen (SpO) were recorded before and every 15 min after drug administration. Results The median sedation onset time was 30 min and 20 min in group D1 and group D2,respectively. Compared with the children in group D1,those in group D2 were significantly more sedated when they were separated from their parents (61.9% vs. 95.0%,respectively)(χ=5.549,P=0.010). In Group D2,the HR decreased by 15.8% (t=2.415,P=0.021) 30 min after the spray administration of intranasal DEX. Compared with the baseline values,there was no significant difference in both groups in terms of SpO(t=-1.426,P=0.162;t=-1.096,P=0.280)and HR in group D1 (t=-0.299,P=0.767) 30 min after the spray administration of intranasal DEX. Conclusion Spray administration of intranasal DEX 2 μg/kg provides superior sedation in children.
Administration, Intranasal ; Anesthesia ; methods ; Child ; Child, Preschool ; Dexmedetomidine ; administration & dosage ; Double-Blind Method ; Female ; Heart Rate ; Humans ; Hypnotics and Sedatives ; administration & dosage ; Male ; Oxygen ; analysis ; Prospective Studies

OBJECTIVE: To observe the preoperative sedation, the status of separation from parents, compliance with the mask, hemodynamic parameters and postoperative agitation of intranasal dexmedetomidine (DEX) premedication on children undergoing dental rehabilitation under general anesthesia. METHODS: In the study, 60 children of American Society of Anesthesiology classification (ASA I-II), aged 2-9 years, were randomly assigned to one of two equal groups. Thirty minutes before operation, control group received intranasal placebo (0.9% saline) 0.02 mL/kg, and DEX group received intranasal DEX 2 μg/kg. The preoperative sedation score, the status of separation from parents, compliance with the mask and hemodynamic parameters were recorded by an anesthesiologists until anesthesia induction. Recovery conditions, postoperative agitation were also recorded. RESULTS: There was no significant difference between the two groups in patient characteristics, operation time, extubation time and recovery time. Compared with the children in control group, those in DEX group were significantly more sedated when they were separated from their parents (56.7% vs. 26.7%, P<0.05). Satisfactory compliance with mask application was 40% in control group vs. 73.3% in DEX group (P<0.05). There was no significant difference between the two groups regarding the incidences of postoperative agitation and oxygen saturation (SpO₂). Compared with control group, the heart rate (HR) of DEX group was decreased after 20 minutes of drug administration [(97.13±12.93) beats/min vs.(104.53±11.97) beats/min, P<0.05]. The changes of the HR and SpO2 in the two groups were within the normal range. There were no incidences of bradycardia and hypoxemia in either of the groups during study observation. CONCLUSION Premedication with intranasal DEX 2 μg/kg for children undergoing dental rehabilitation under general anesthesia produces good preoperative sedation. The levels of sedation, scores of parental separation and compliance with the mask were satisfied. The children have good recovery conditions, and no obvious postoperative agitation and respiratory depression after DEX administration. Intranasal DEX 2 μg/kg is an effective and safe alternative for premedication in children.
Administration, Intranasal ; Anesthesia, General ; Child ; Child, Preschool ; Dental Restoration, Permanent/methods* ; Dexmedetomidine/administration & dosage* ; Double-Blind Method ; Heart Rate ; Humans ; Hypnotics and Sedatives/administration & dosage*

OBJECTIVETo determine the minimum alveolar concentration (EC(50) and EC(95)) of sevoflurane in body movement response to surgical incision during combined anesthesia with dexmedetomidine, sevoflurane and fentanyl.

METHODSTwenty-six ASA class I or II patients (aged 18-60 years) underwent selective surgery for lumbar disc herniation under general anesthesia with the combination of with dexmedetomidine, sevoflurane and fentanyl. All the patients received infusion with 0.5 mg/kg dexmedetomidine for 10 min before anesthesia induction with intravenous injection of 3 µg/kg fentanyl 8% sevoflurane inhalation. Upon loss of consciousness, sevoflurane concentration was reduced to 5% with intravenous injection of 1-2 mg/kg succinylcholine, and intubation was started after muscles relaxation. Anesthesia was maintained by sevoflurane and dexmedetomidine (0.2 µg·kg(-1)·h(-1)). Before the surgery, a steady state end-tidal sevoflurane concentration was maintained for at least 10 min. The first patient of the series was tested with 1.5% sevoflurane, and the concentration was adjusted according to modified Dixons up-and-down method (with a step size of 0.2%). Probit analysis was used for calculating EC(50), EC(95) and the 95% confidence interval (CI).

RESULTSThe EC(50) of sevoflurane was 0.94% (95%CI of 0.76%-1.07% ) and EC(95) was 1.23% (95%CI 1.09%-2.05% ).

CONCLUSIONThe EC(50) and EC(95) of sevoflurane are 0.94% and 1.23%, respectively, for suppressing body movement in response to surgical incision during combined anesthesia with sevoflurane, dexmedetomidine and fentanyl.

Adolescent ; Adult ; Anesthesia ; methods ; Anesthetics ; administration & dosage ; Dexmedetomidine ; administration & dosage ; Female ; Fentanyl ; administration & dosage ; Humans ; Male ; Methyl Ethers ; pharmacokinetics ; Middle Aged ; Pulmonary Alveoli ; metabolism ; Reference Values ; Young Adult

OBJECTIVETo assess the effects of dexmedetomidine (Dex) on propofol dosage in target-controlled infusion (TCI) and hemodynamics in patients undergoing laparoscopic surgery under general anesthesia.

METHODSSixty patients undergoing laparoscopic surgery under general anesthesia were randomly divided into control group (n=30) and the Dex group (n=30). The patients in Dex group received a loading dose of Dex (1 µg/kg, infused within 10 min) before the surgery followed by continuous infusion at the rate of 0.3 µg·kg(-1)·h(-1) till the end of the surgery, and the control patients received saline infusion in the same manner. Heart rate, blood pressure, bispectral index (BIS), and propofol dose in TCI were recorded during induction and maintenance of anesthesia. The incidence of hypotension and bradycardia were observed during and after the surgery.

RESULTSNo difference was found in the incidence of hypotension and bradycardia between the control group and Dex group (P>0.05), but heart rate and blood pressure were lower in Dex group during extubation (P<0.05). The dose of propofol in TCI was significantly less in Dex group than in the control group (P<0.05).

CONCLUSIONDex can reduce hemodynamic abnormalities caused by extubation and decrease the dosage of propofol in TCI, and may serve as an ideal adjuvant drug for general anesthesia.

Anesthesia, General ; Blood Pressure ; Bradycardia ; Dexmedetomidine ; therapeutic use ; Heart Rate ; Hemodynamics ; Humans ; Hypotension ; Laparoscopy ; Propofol ; administration & dosage ; therapeutic use