Attention-deficit/hyperactivity disorder (ADHD) in cultural context II: a comparison of the links between ADHD symptoms and waiting-related responses in Hong Kong and UK.

The concept of attention-deficit/hyperactivity disorder (ADHD) is considered to have cross-cultural validity, but direct comparisons of its psychological characteristics across cultures are limited. This study investigates whether preschool children's ADHD symptoms expressed in two cultures with different views about child behaviour and parenting, Hong Kong and the UK, show the same pattern of associations with their waiting-related abilities and reactions, an important marker of early self-regulation. A community sample of 112 preschoolers (mean age = 46.22 months; 55 from UK, 57 from HK) completed three tasks measuring different waiting elements - waiting for rewards, choosing the amount of time to wait, and having to wait unexpectedly when a task is interrupted. Participants' waiting-related behavioural and emotional reactions were coded. Parents rated their children's ADHD symptoms and delay aversion. Our findings revealed that the associations between ADHD symptoms and waiting-related responses were comparable in both UK and HK samples. This suggests that the core psychological characteristics of ADHD, particularly in relation to waiting behaviours, may exhibit similarity across cultural contexts. Future research can extend this cross-cultural analysis to other ADHD-related psychological domains and explore additional cultural settings.

Postoperative Neurocognitive Disorders After Closed-Loop Versus Manual Target Controlled-Infusion of Propofol and Remifentanil in Patients Undergoing Elective Major Noncardiac Surgery: The Randomized Controlled Postoperative Cognitive Dysfunction-Electroencephalographic-Guided Anesthetic Administration Trial.

BACKGROUND: The aim of the study was to investigate whether closed-loop compared to manual bispectral index (BIS)-guided target-controlled infusion of propofol and remifentanil could decrease the incidence of postoperative neurocognitive disorders after elective major noncardiac surgery. METHODS: Patients aged >50 admitted for elective major noncardiac surgery were included in a single-blind randomized (ratio 2:1) trial. The anesthetic protocol was allocated by randomization into either closed-loop or manual BIS-guided propofol and remifentanil titration. The BIS target range was 40-60. All patients had cognitive assessment the day before surgery and within 72 hours after surgery using a battery of neuropsychological tests. The primary outcome was the rate of postoperative neurocognitive disorders. Postoperative neurocognitive disorders were defined as a decrease >20% from baseline on at least 3 scores. Intergroup comparison of the primary outcome was performed using the χ2 test. RESULTS: A total of 143 and 61 patients were included in the closed-loop and manual groups, respectively (age: 66 [8] vs 66 [9] years). The primary outcome was observed in 18 (13%) and 10 (16%) patients of the closed-loop and manual groups, respectively (relative risk [95% confidence interval {CI}], 0.77 [0.38-1.57], P = .47). Intraoperative propofol consumption was lower (4.7 [1.4] vs 5.7 [1.4] mg·kg-1·h-1, mean difference [MD] [95% CI], -0.73 [-0.98 to -0.48], P < .0001) and the proportion of time within the BIS target range higher (84 [77-89] vs 74 [54-81]%, MD [95% CI], 0.94 [0.67-1.21], P < .0001) in the closed-loop group. CONCLUSIONS: Closed-loop compared to manual BIS-guided total intravenous anesthesia provided a significant reduction in episodes of an excessive depth of anesthesia while decreasing intraoperative propofol requirement but no evidence for a reduction of the incidence of postoperative neurocognitive disorders after elective major noncardiac surgery was observed.

Anesthetic Management Using Multiple Closed-loop Systems and Delayed Neurocognitive Recovery: A Randomized Controlled Trial.

BACKGROUND: Cognitive changes after anesthesia and surgery represent a significant public health concern. We tested the hypothesis that, in patients 60 yr or older scheduled for noncardiac surgery, automated management of anesthetic depth, cardiac blood flow, and protective lung ventilation using three independent controllers would outperform manual control of these variables. Additionally, as a result of the improved management, patients in the automated group would experience less postoperative neurocognitive impairment compared to patients having standard, manually adjusted anesthesia. METHODS: In this single-center, patient-and-evaluator-blinded, two-arm, parallel, randomized controlled, superiority study, 90 patients having noncardiac surgery under general anesthesia were randomly assigned to one of two groups. In the control group, anesthesia management was performed manually while in the closed-loop group, the titration of anesthesia, analgesia, fluids, and ventilation was performed by three independent controllers. The primary outcome was a change in a cognition score (the 30-item Montreal Cognitive Assessment) from preoperative values to those measures 1 week postsurgery. Secondary outcomes included a battery of neurocognitive tests completed at both 1 week and 3 months postsurgery as well as 30-day postsurgical outcomes. RESULTS: Forty-three controls and 44 closed-loop patients were assessed for the primary outcome. There was a difference in the cognition score compared to baseline in the control group versus the closed-loop group 1 week postsurgery (-1 [-2 to 0] vs. 0 [-1 to 1]; difference 1 [95% CI, 0 to 3], P = 0.033). Patients in the closed-loop group spent less time during surgery with a Bispectral Index less than 40, had less end-tidal hypocapnia, and had a lower fluid balance compared to the control group. CONCLUSIONS: Automated anesthetic management using the combination of three controllers outperforms manual control and may have an impact on delayed neurocognitive recovery. However, given the study design, it is not possible to determine the relative contribution of each controller on the cognition score.

Bispectral Index During Maintenance of Total Intravenous Anesthesia: Frequency of Out of Recommended Range and Impact of Patients' Characteristics: A Brief Report.

Little is known about respecting the recommended range of bispectral index (BIS) in practice. This exploratory retrospective analysis of 138 robotic surgical patients having received total intravenous anesthesia shows that BIS was between 40 and 60 during 61.3% ± 25.2% (mean ± standard deviation [SD]) of maintenance, >60 during 3.1% ± 5.5%, and <40 during 35.7% ± 26.9%. Burst suppression was present during 17.8% ± 22.2%. Female sex is associated with increased periods of BIS <40 (P = .002) as is body mass index (BMI) <26 (P = .012). Increased age is associated with increase in burst suppression (P = .005). A larger study is required to confirm the role of patients' factors on the number of periods of low BIS.

Impact of hypotension on cerebral perfusion during general anesthesia induction: A prospective observational study in adults.

INTRODUCTION: During anesthesia, decreases in mean arterial pressure (MAP) are common but the impact on possible cerebral hypoperfusion remains a matter of debate. We evaluated cerebral perfusion in patients with or without cardiovascular comorbidities (Hi-risk vs Lo-risk) during induction of general anesthesia and during hypotensive episodes. METHODS: Patients scheduled for neuroradiology procedure using standardized target-controlled Propofol-Remifentanil infusion were prospectively included. Monitoring included Transcranial Doppler (TCD) measuring mean blood velocity of the middle cerebral artery (Vm), Bispectral Index with burst suppression ratio (SR) and cerebral Near-Infrared Spectroscopy (NIRS). Hypotensive episodes were treated with a 10 µg bolus of Norepinephrine. RESULTS: Eighty-one patients were included, 37 Hi-risk and 44 Lo-risk. During induction of anesthesia, MAP and Vm decreased in all patients, with greater changes observed in Hi-risk patients compared to Lo-risk patients (-34 [38-29]% vs -17 [25-8]%, P < .001 and -39 [45-29]% vs -28 [34-19]%, P < .01 respectively). In Hi-risk patients, the MAP-decrease correlated with the Vm-decrease (r = .48, P < .01), and was associated with more frequent occurrences of SR (21 vs 5 patients, P < .01 for Hi-risk vs Lo-risk). For the MAP-increase induced by norepinephrine, the Vm-increase was greater in Hi-risk than in Lo-risk patients (+15 [8-21]% vs +4 [1-11]%, P < .01). During induction and norepinephrine boluses, NIRS values did not follow acute changes of Vm. CONCLUSION: Our results showed that Hi-risk patients had a higher decrease in MAP and Vm, and a higher occurrence of SR during induction of anesthesia than Lo-risk patients. Correction of MAP with norepinephrine increased Vm mainly in Hi-rik patients.

Behavior of a dual closed-loop controller of propofol and remifentanil guided by the bispectral index for postoperative sedation of adult cardiac surgery patients: a preliminary open study.

A dual-loop controller permits the automated titration of propofol and remifentanil during anesthesia; it has never been used in intensive care after cardiac surgery. The goal of this preliminary study was to determine the efficacy of this controller to provide postoperative sedation in 19 adult cardiac surgery patients with a Bispectral Index target of 50. Results are presented as numbers (percentages) or medians [25th-75th percentiles]. The sedation period lasted 139 min [89-205] during which the Richmond Agitation Sedation Scale was at - 5 and the Behavioral Pain Scale score at three points for all patients and observation times but one (82 out of 83 assessments). Sedation time in the range 40-60 for the Bispectral Index was 87% [57-95]; one patient had a period of electrical silence defined as Suppression Ratio at least > 10% for more than 60 s. The time between the end of infusions and tracheal extubation was 84 min [63-129]. The Richmond Agitation Sedation Scale was 0 [0-0], 0 [- 1 to 0], and 0 [0-0] respectively during the 3 h following extubation while the verbal numerical pain scores were 6 [4.5-7], 5 [4-6], and 2 [0-5]. Mean arterial pressure decreased during sedation requiring therapeutic interventions, mainly vascular filling in 15 (79%) patients. Automated sedation device was discontinued in two patients for hemodynamic instability. No patient had awareness of the postoperative sedation period. Dual closed-loop can provide postoperative sedation after cardiac surgery but the choice of the depth of sedation should take into account the risk of hypotension.

Feasibility of Fully Automated Hypnosis, Analgesia, and Fluid Management Using 2 Independent Closed-Loop Systems During Major Vascular Surgery: A Pilot Study.

Automated titration of intravenous anesthesia and analgesia using processed electroencephalography monitoring is no longer a novel concept. Closed-loop control of fluid administration to provide goal-directed fluid therapy has also been increasingly described. However, simultaneously combining 2 independent closed-loop systems together in patients undergoing major vascular surgery has not been previously detailed. The aim of this pilot study was to evaluate the clinical performance of fully automated hypnosis, analgesia, and fluid management using 2 independent closed-loop controllers in patients undergoing major vascular surgery before implementation within a larger study evaluating true patient outcomes.

Amisulpride Prevents Postoperative Nausea and Vomiting in Patients at High Risk: A Randomized, Double-blind, Placebo-controlled Trial.

BACKGROUND: Postoperative nausea and vomiting causes distress for patients and can prolong care requirements. Consensus guidelines recommend use of multiple antiemetics from different mechanistic classes as prophylaxis in patients at high risk of postoperative nausea and vomiting. The prophylactic efficacy of the dopamine D2/D3 antagonist amisulpride in combination with other antiemetics was investigated. METHODS: This double-blind, randomized, placebo-controlled, international, multicenter trial was conducted in 1,147 adult surgical patients having three or four postoperative nausea and vomiting risk factors. Patients were randomized to receive either intravenous amisulpride (5 mg) or matching placebo at induction of general anesthesia, in addition to one standard, nondopaminergic antiemetic, most commonly ondansetron or dexamethasone. Vomiting/retching, nausea, and use of rescue medication were recorded for 24 h after wound closure. The primary endpoint was complete response, defined as no emesis or rescue medication use in the 24-h postoperative period. RESULTS: Complete response occurred in 330 of 572 (57.7%) of the amisulpride group and 268 of 575 (46.6%) of the control group (difference 11.1 percentage points; 95% CI, 5.3 to 16.8; P < 0.001). The incidences of emesis (13.8% vs. 20.0%, P = 0.003), any nausea (50.0% vs. 58.3%, P = 0.002), significant nausea (37.1% vs. 47.7%, P < 0.001), and rescue medication use (40.9% vs. 49.4%, P = 0.002) were significantly lower in the amisulpride group. Adverse events and laboratory and electrocardiogram abnormalities occurred no more frequently with amisulpride than with placebo. CONCLUSIONS: Intravenous amisulpride was safe and effective as prophylaxis of postoperative nausea and vomiting when given in combination with an antiemetic from another class to adult patients at high risk for suffering postoperative nausea and vomiting undergoing elective surgery under inhalational general anesthesia. VISUAL ABSTRACT: An online visual overview is available for this article at http://links.lww.com/ALN/B727.

Does a hypnosis session reduce the required propofol dose during closed-loop anaesthesia induction?: A randomised controlled trial.

BACKGROUND: Hypnosis has a positive effect on peri-operative anxiety and pain. OBJECTIVE: The objective of this study was to assess the impact of a formal deep hypnosis session on the consumption of propofol for anaesthetic induction using automated administration of propofol guided by the bispectral index (BIS) in a closed loop. DESIGN: A 1 : 1 randomised, usual-care-controlled, single-centre trial. SETTING: Tertiary care centre in France from April 2014 to December 2015. PATIENTS: Female adult patients scheduled for outpatient gynaecological surgery under general anaesthesia. INTERVENTION: Before surgery, patients were randomised to receive either a deep hypnosis session or routine care. Anaesthetic induction was performed automatically by propofol without opioids and was assisted by the BIS in a closed loop. MAIN OUTCOME MEASURES: The primary endpoint was the propofol dose required for anaesthesia induction, defined as a BIS less than 60 for at least 30 s. RESULTS: Data for 31 patients in the hypnosis group and 35 in the control group were analysed. There was no evidence of a difference in the mean required propofol dose for anaesthetic induction between the hypnosis and the control groups (2.06 mg kg (95% confidence interval [1.68 to 2.43]) versus 1.79 mg kg (95% CI [1.54 to 2.03]), P = 0.25, respectively). CONCLUSION: The current study, which was designed to determine the effect of a deep hypnosis session on anaesthesia induction using an automated tool for propofol administration, failed to detect a difference in the required dose of propofol. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02249364.

Thoracic Epidural Analgesia With Levobupivacaine Reduces Remifentanil and Propofol Consumption Evaluated by Closed-Loop Titration Guided by the Bispectral Index: A Double-Blind Placebo-Controlled Study.

BACKGROUND: Thoracic epidural analgesia (TEA) combined with general anesthesia decreases anesthetic requirements by half when hemodynamic criteria are used for the titration of analgesia. We therefore determined the impact of TEA on anesthetic requirements, when a closed-loop controller was used allowing the automated coadministration of propofol-remifentanil guided solely by the Bispectral index. METHODS: This single-center double-blind study enrolled patients scheduled for elective posterolateral thoracotomy using TEA. Patients were randomly assigned to receive a bolus followed by a continuous infusion of levobupivacaine 0.5% (levo group) or saline 0.9% solution (saline group). General anesthesia was performed by the same automated controller. Stroke volume optimization guided by an esophageal Doppler probe was performed before randomization. The primary outcome variable was the amount of remifentanil delivered by the automated controller between skin incision and closure. Major arterial hypotension was recorded. Data are presented as medians [interquartile range] or number (%) RESULTS:: Nineteen adult patients per group completed the study. At similar depth of anesthesia evaluated by the percentage of time with the Bispectral index in the range 40-60 (85 [77-88] vs 83 [72-87]; P = .39), patients with neuraxial block required less remifentanil (0.15 [0.10-0.20] vs 0.23 [0.14-0.25], µg·kg·min; P = .03) and propofol (4.3 [3.7-4.9] vs 5.7 [4.6-7.3] mg·kg·h; P = .005). Major arterial hypotension was similar in both groups (6 [32%] vs 5 [25%]; P = .46; levo versus saline group, respectively). CONCLUSIONS: Epidurally administered levobupivacaine allowed a decrease by one-third of remifentanil requirement. After stroke volume optimization, major arterial hypotension was similar between groups.

Impact of a prophylactic combination of dexamethasone-ondansetron on postoperative nausea and vomiting in obese adult patients undergoing laparoscopic sleeve gastrectomy during closed-loop propofol-remifentanil anaesthesia: A randomised double-blind placebo-controlled study.

BACKGROUND: In obese patients, the incidence of postoperative nausea and vomiting (PONV) following sleeve gastrectomy under titration of total intravenous anaesthesia (TIVA) and the relevance of risk factors to indicate prophylaxis is unknown. OBJECTIVES: The hypothesis was that after automated TIVA, prophylaxis reduces PONV following laparoscopic sleeve gastrectomy. Our objective was to determine the incidence of PONV and evaluate the efficacy of dexamethasone and ondansetron as prophylaxis when automated intravenous anaesthesia is employed. DESIGN: A randomised, placebo-controlled, single-centre, double-blinded study. SETTING: Secondary care centre in New Caledonia from June 2013 to January 2014. PATIENTS: A total of 122 patients were randomised and 117 (92 women) were included in the analysis (58 in the prophylaxis group and 59 in the placebo group). Eligibility criteria included at least two of the known risk factors for PONV: female sex, nonsmoking status, prior history of PONV or motion sickness and expected postoperative opioid analgesia. Exclusion criteria included disorders limiting the use of the bispectral index. INTERVENTIONS: All patients received propofol and remifentanil controlled by the same automated system during induction and maintenance of general anaesthesia. The controller modifies the calculated effect-site concentrations according to bispectral index values. Patients received either intravenous dexamethasone 4 mg after tracheal intubation and ondansetron 4 mg during skin closure, or placebo. MAIN OUTCOME MEASURES: The primary endpoint was the cumulative incidences of 24-h PONV and severe PONV (vomiting or nausea with a score of ≥4 on an 11-point verbal rating scale). Data are presented as percentage (95% confidence interval). RESULTS: PONV in the first 24 h occurred in 45 (34 to 60)% of patients who received prophylaxis and 54 (41 to 67)% in the placebo group (P = 0.35). The numbers of patients who suffered severe PONV [19 (10 to 32)% in the prophylaxis group vs. 20 (11 to 33)%, P = 1, in the placebo group] and who required rescue antiemetic drugs [55 (41 to 68) vs. 63 (49 to 75)%, P = 0.46] were similar between the groups. CONCLUSION: The combination of dexamethasone and ondansetron was not effective in preventing PONV or severe PONV in obese patients undergoing laparoscopic sleeve gastrectomy after TIVA. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01876290.

Feasibility of closed-loop titration of propofol and remifentanil guided by the bispectral monitor in pediatric and adolescent patients: a prospective randomized study.

BACKGROUND: This study was designed to assess the feasibility of dual closed-loop titration of propofol and remifentanil guided solely by the Bispectral Index (BIS) monitor in pediatric and adolescent patients during anesthesia. METHODS: Children undergoing elective surgery in this single-blind randomized study were allocated into the closed-loop (auto) or manual (manual) group. Primary outcome was the percentage of time with the BIS in the range 40 to 60 (BIS40-60). Secondary outcomes were the percentage of deep (BIS<40) anesthesia and drug consumption. Data are presented as median (interquartile range) or number (%). RESULTS: Twenty-three patients (12 [10 to 14] yr) were assigned to the auto group and 19 (14 [7 to 14] yr) to the manual group. The closed-loop controller was able to provide induction and maintenance for all patients. The percentage of time with BIS40-60 was greater in the auto group (87% [75 to 96] vs. 72% [48 to 79]; P = 0.002), with a decrease in the percentage of BIS<40 (7% [2 to 17] vs. 21% [11 to 38]; P = 0.002). Propofol (2.4 [1.9 to 3.3] vs. 1.7 [1.2 to 2.8] mg/kg) and remifentanil (2.3 [2.0 to 3.0] vs. 2.5 [1.2 to 4.3] µg/kg) consumptions were similar in auto versus manual groups during induction, respectively. During maintenance, propofol consumption (8.2 [6.0 to 10.2] vs. 7.9 [7.2 to 9.1] mg kg h; P = 0.89) was similar between the two groups, but remifentanil consumption was greater in the auto group (0.39 [0.22 to 0.60] vs. 0.22 [0.17 to 0.32] µg kg min; P = 0.003). Perioperative adverse events and length of stay in the postanesthesia care unit were similar. CONCLUSION: Intraoperative automated control of hypnosis and analgesia guided by the BIS is clinically feasible in pediatric and adolescent patients and outperformed skilled manual control.

A Randomized Controlled Trial Comparison of NeuroSENSE and Bispectral Brain Monitors During Propofol-Based Versus Sevoflurane-Based General Anesthesia.

BACKGROUND: NeuroSENSE is a depth of anesthesia monitor that uses automated electroencephalogram quantification. The Wavelet-based Anesthetic Value for Central Nervous System (WAVCNS) index calculated by this monitor is based on wavelet analysis of a normalized electroencephalogram signal in the γ-frequency band. The aim of this study was to determine the extent of disagreement between the Bispectral Index (BIS) and the WAVCNS index during propofol-based and sevoflurane-based maintenance of general anesthesia in a routine surgical population. METHODS: Patients undergoing elective surgery were enrolled in the study and randomly assigned to receive either propofol or sevoflurane for the maintenance of anesthesia and remifentanil in both groups. Anesthesiologists were blinded to monitors in both groups. Discordance between the 2 monitors was assessed by the count of discrepancy in recommendation (DR) (type 1 defined as one parameter <40 and the other >60, or type 2 defined as BIS and WAVCNS values on different sides of a threshold [40 or 60]) and also by the proportion of agreement (P0) between WAVCNS and BIS, obtained every 5 seconds, in 3 categories of index (<40, 40-60, and >60). RESULTS: The analyzed data set consisted of 22 patients (36,872 data pairs) in the propofol group and 24 patients (32,826 data pairs) in the sevoflurane group. The type 1 DR rarely occurred in both the groups (<1%); however, the median (interquartile range) type 2 DR was significantly more frequent in the propofol group (20.6% [7.0-36.9] vs 4.5% [2.3-12.4]; P = 0.0005). The median difference in P0 was 11.53% (95% confidence interval, 0.57-21.32). Major disagreement between WAVCNS index and BIS was related to the weight of burst suppression pattern for the index calculation. CONCLUSIONS: Disagreement between BIS and NeuroSENSE during the maintenance of general anesthesia was worse in the propofol group than that in the sevoflurane groups. The disagreement increases during deep anesthesia or in the occurrence of burst suppression.

Comparison of the potency of different propofol formulations: a randomized, double-blind trial using closed-loop administration.

BACKGROUND: Several commercial formulations of propofol are available. The primary outcome of this study was the required dose of propofol alone or combined with lidocaine to achieve induction of general anesthesia. METHODS: This multicenter, double-blinded trial randomized patients (American Society of Anesthesiologists physical status I-III) just before elective surgery with the use of a computer-generated list. Three different propofol 1% formulations-Diprivan (Astra-Zeneca, Cheshire, United Kingdom), Propoven (Fresenius-Kabi AG, Bad Homburg, Germany), and Lipuro (B-Braun, Melshungen AG, Germany)-were compared with either placebo (saline solution) or lidocaine 1% mixed to the propofol solution. Depth of anesthesia was automatically guided by bispectral index and by a computerized closed-loop system for induction, thus avoiding dosing bias. The authors recorded the total dose of propofol and duration of induction and the patient's discomfort through a behavioral scale (facial expression, verbal response, and arm withdrawal) ranging from 0 to 6. The authors further evaluated postoperative recall of pain using a Visual Analog Scale. RESULTS: Of the 227 patients enrolled, 217 were available for analysis. Demographic characteristics were similar in each group. Propoven required a higher dose for induction (2.2 ± 0.1 mg/kg) than Diprivan (1.8 ± 0.1 mg/kg) or Lipuro (1.7 ± 0.1 mg/kg; P = 0.02). However, induction doses were similar when propofol formulations were mixed with lidocaine. Patient discomfort during injection was significantly reduced with lidocaine for every formulation: Diprivan (0.5 ± 0.3 vs. 2.3 ± 0.3), Propoven (0.4 ± 0.3 vs. 2.4 ± 0.3), and Lipuro (1.1 ± 0.3 vs. 1.4 ± 0.3), all differences significant, with P < 0.0001. No adverse effect was reported. CONCLUSION: Plain propofol formulations are not equipotent, but comparable doses were required when lidocaine was concomitantly administered.

Dexmedetomidine reduces propofol and remifentanil requirements during bispectral index-guided closed-loop anesthesia: a double-blind, placebo-controlled trial.

BACKGROUND: The α2-adrenergic agonist dexmedetomidine is a sedative and can be used as an adjunct to anesthetics. Our primary goal was thus to determine the extent to which dexmedetomidine reduces the requirement for propofol and remifentanil. METHODS: This double-blinded, randomized study (NCT00921284) used an automated dual closed-loop administration to maintain the Bispectral Index between 40 and 60. Sixty-6 ASA physical status I and II patients were given either dexmedetomidine (1 µg/kg over 10 minutes followed by a continuous infusion of 0.5 µg/kg/h throughout surgery) or comparable volumes of saline as a placebo. Propofol and remifentanil requirements were compared using nonparametric tests and expressed as medians (interquartile ranges). RESULTS: Twenty-eight patients in each group completed the study. Patients given dexmedetomidine required less propofol (1.0 [0.7-1.3] vs 1.3 [1.0-1.7] mg/kg, P = 0.002) and remifentanil (1.2 [1.0-1.4] vs 1.6 [1.1-2.8] µg/kg, P = 0.02) for anesthetic induction. The propofol dosage required for anesthetic maintenance was 29% (with a 95% confidence interval, 18-40) lower in patients given dexmedetomidine (2.2 [1.5-3.0] vs 3.1 [2.4-4.5] mg/kg/h, P = 0.005), whereas the remifentanil dosage was not significantly different (0.16 [0.09-0.17] vs 0.14 [0.13-0.21] µg/kg/h with P = 0.3). The incidence of adverse events, including hemodynamic instability and delayed recovery, was comparable with and without dexmedetomidine. The first postoperative request for morphine analgesia was delayed in patients given dexmedetomidine (median fourth hour vs first hour, P = 0.008). CONCLUSIONS: Dexmedetomidine administration significantly reduced the requirement for both propofol and remifentanil during anesthetic induction and reduced propofol use during maintenance of anesthesia. Dexmedetomidine also delayed postoperative analgesic use. Dexmedetomidine is a useful adjuvant that reduces anesthetic requirement and provides postoperative analgesia.

Automated titration of propofol and remifentanil decreases the anesthesiologist's workload during vascular or thoracic surgery: a randomized prospective study.

Closed loop target-control infusion systems using a Bispectral (BIS) signal as an input (TCI Loop) can automatically maintain intravenous anesthesia in a BIS range of 40-60 %. Our purpose was to assess to what extent such a system could decrease anesthesia workload in comparison to the use of a stand alone TCI system manually adjusted to fit the same BIS range of 40-60 % (TCI Manual). Patients scheduled for elective vascular or thoracic surgery were randomized to the TCI Loop or TCI Manual method for administering propofol and remifentanil during both induction and maintenance of general anesthesia. Assessment of workload was performed by an independent observer who quoted each time the physician looked at the BIS monitor. The number of propofol and remifentanil target modifications, the percentage of time of adequate anesthesia i.e. BIS in the range 40-60 and hemodynamic data were recorded. Eighteen patients per group were enrolled. Characteristics, duration of surgery and propofol-remifentanil consumption were similar between groups. However, the percentage of time in the BIS range 40-60 % was higher in the TCI Loop versus TCI Manual groups (94 % ± 12 vs. 74 % ± 19, p < 0.001). Mean arterial pressure was lower with TCI Manual (78 ± 6 vs. 88 ± 13 mmHg, p < 0.001). The number of times the anesthesiologist watched the controller or BIS monitor (p < 0.05) and the number of manual adjustments (p < 0.001) performed in each group was lower with TCI Loop group during induction and maintenance of anesthesia. An automated controller strikingly frees the anesthesiologist from manual intervention to adjust drug delivery.

Automatic administration of propofol and remifentanil guided by the bispectral index during rigid bronchoscopic procedures: a randomized trial.

BACKGROUND: Anesthesia for rigid bronchoscopic procedures is a demanding procedure. Automatic titration of propofol and remifentanil to maintain the bispectral index (BIS) within the recommended range (40-60) has been reported during routine surgical procedures. The aim of the present study was to evaluate its use during rigid bronchoscopy. METHODS: Patients were enrolled in a randomized study comparing manual target-controlled infusion of propofol and remifentanil (manual TCI group) with automatic titration guided by the BIS (dual-loop group). Categorical variables were compared by the Fisher's exact test, and continuous variables (median [interquartile range 25-75]) were compared by the Mann-Whitney test. RESULTS: Thirty-four patients were included in the manual TCI group and 33 were included in the dual-loop group. Baseline characteristics were well balanced between the groups. Intervention by the anesthesiologist in charge to modify propofol and/or remifentanil targets in the dual-loop group was not necessary. Percentage of time spent in the BIS interval (40-60) was similar in the manual TCI and dual-loop groups (69% [48-79] vs 70% [58-80], respectively). Durations of induction and of maintenance and propofol and remifentanil doses were also similar between groups, except for the amount of propofol needed for induction (P = 0.002). Time to tracheal extubation was also similar. No case of intraoperational awareness was detected. CONCLUSION: The present study could not establish the superiority of automatic system over manual adjustment for bronchoscopy. Further studies with a different design and a larger number of patients are required to establish the place of automatic delivery of anesthetic agents. This study was registered at ClinicalTrials.gov number, NCT00571181.

Feasibility of closed-loop titration of propofol and remifentanil guided by the spectral M-Entropy monitor.

BACKGROUND: This randomized controlled trial describes automated coadministration of propofol and remifentanil, guided by M-Entropy analysis of the electroencephalogram. The authors tested the hypothesis that a novel dual-loop controller with an M-Entropy monitor increases time spent within predetermined target entropy ranges. METHODS: Patients scheduled for elective surgery were randomly assigned in this single-blind study using a computer-generated list, to either dual-loop control using a proportional-integral-derivative controller or skilled manual control of propofol and remifentanil using target-controlled-infusion systems. In each group, propofol and remifentanil administration was titrated to a state entropy target of 50 and was subsequently targeted to values between 40 and 60. The primary outcome was the global score, which included the percentage of state entropy or response entropy in the range 40-60, the median absolute performance error and wobble. Data are presented as medians [interquartile range]. RESULTS: Thirty patients assigned to the dual-loop group and 31 assigned to the manual group completed the study. The dual-loop controller was able to provide induction and maintenance for all patients. The Global Score of State Entropy was better maintained with dual-loop than manual control (25 [19-53] vs. 44 [25-110], P = 0.043), and state entropy was more frequently maintained in the range of 40-60 (80 [60-85] vs. 60 [35-82]%, P = 0.046). Propofol (4.1 [2.9-4.9] vs. 4.5 [3.4-6.3] mg · kg(-1) · h(-1)) and remifentanil (0.18 [0.13-0.24] vs. 0.19 [0.15-0.26] µg · kg(-1) · min(-1)) consumptions and the incidence of somatic side effects were similar. CONCLUSION: Intraoperative automated control of hypnosis and analgesia guided by M-Entropy is clinically feasible and more precise than skilled manual control.