A comparison of propofol-to-BIS post-operative intensive care sedation by means of target controlled infusion, Bayesian-based and predictive control methods: an observational, open-label pilot study.
ABSTRACT: PURPOSE:We evaluated the feasibility and robustness of three methods for propofol-to-bispectral index (BIS) post-operative intensive care sedation, a manually-adapted target controlled infusion protocol (HUMAN), a computer-controlled predictive control strategy (EPSAC) and a computer-controlled Bayesian rule-based optimized control strategy (BAYES). METHODS:Thirty-six patients undergoing short lasting sedation following cardiac surgery were included to receive propofol to maintain a BIS between 40 and 60. Robustness of control for all groups was analysed using prediction error and spectrographic analysis. RESULTS:Although similar time courses of measured BIS were obtained in all groups, a higher median propofol effect-site concentration (CePROP) was required in the HUMAN group compared to the BAYES and EPSAC groups. The time course analysis of the remifentanil effect-site concentration (CeREMI) revealed a significant increase in CeREMI in the EPSAC group compared to BAYES and HUMAN during the case. Although similar bias and divergence in control was found in all groups, larger control inaccuracy was observed in HUMAN versus EPSAC and BAYES. Spectrographic analysis of the system behavior shows that BAYES covers the largest spectrum of frequencies, followed by EPSAC and HUMAN. CONCLUSIONS:Both computer-based control systems are feasible to be used during ICU sedation with overall tighter control than HUMAN and even with lower required CePROP. EPSAC control required higher CeREMI than BAYES or HUMAN to maintain stable control. Clinical trial number: NCT00735631.
Project description:Endoscopic submucosal dissection (ESD) is a technically difficult and lengthy procedure requiring optimal depth of sedation. The bispectral index (BIS) monitor is a non-invasive tool that objectively evaluates the depth of sedation. The purpose of this prospective randomized controlled trial was to evaluate whether BIS guided sedation with propofol and remifentanil could reduce the number of patients requiring rescue propofol, and thus reduce the incidence of sedation- and/or procedure-related complications.A total of 180 patients who underwent the ESD procedure for gastric adenoma or early gastric cancer were randomized to two groups. The control group (n=90) was monitored by the Modified Observer's Assessment of Alertness and Sedation scale and the BIS group (n=90) was monitored using BIS. The total doses of propofol and remifentanil, the need for rescue propofol, and the rates of complications were recorded.The number of patients who needed rescue propofol during the procedure was significantly higher in the control group than the BIS group (47.8% vs. 30.0%, p=0.014). There were no significant differences in the incidence of sedation- and/or procedure-related complications.BIS-guided propofol infusion combined with remifentanil reduced the number of patients requiring rescue propofol in ESD procedures. However, this finding did not lead to clinical benefits and thus BIS monitoring is of limited use during anesthesiologist-directed sedation.
Project description:OBJECTIVE:The bispectral index (BIS) has been used to monitor sedation during spinal anesthesia. We evaluated the correlation between BIS and the Observer's Assessment of Alertness/Sedation Scale (OAA/S) in patients sedated with dexmedetomidine, propofol, or midazolam. METHODS:This prospective, randomized study included 46 patients scheduled for knee arthroplasty under spinal anesthesia with sedation. The patients were randomized to receive sedation with dexmedetomidine (n?=?15), propofol (n?=?15), or midazolam (n?=?16). Correlation between BIS and OAA/S was assessed during sedation in the three groups. RESULTS:A linear correlation was observed between BIS and OAA/S, and there was no significant difference in BIS score between the groups during mild to moderate sedation status (OAA/S 3-5). During deep sedation (OAA/S 1-2), the BIS score in the midazolam group was significantly higher than that in the propofol and dexmedetomidine groups (74.4?±?11.9 vs 67.7?±? 9.5 vs 62.6?±?12.2). CONCLUSIONS:BIS values differed at the same level of sedation between different sedative agents. Objective sedation scores should therefore be used in combination with BIS values for the assessment of sedation levels during spinal anesthesia.
Project description:Introduction:Bispectral index (BIS) monitoring provides an objective, non-invasive measurement of the level of consciousness in a sedated patient. Aim:In this prospective study, we aimed to investigate the hypothesis that risk of respiratory depression could be reduced and the desired level of sedation with minimal doses of propofol could be achieved by using BIS monitoring in endoscopic retrograde cholangiopancreatography (ERCP) procedures. Material and methods:Sixty patients in the ASA 1-2 category, who were scheduled for an ERCP with sedation, were randomly divided into two groups. The procedure was performed, and sedation was administered so that the patient's Ramsay Sedation Score (RSS) would be 4-5 in the first group (group 1) and the patient's BIS value would be 65-75 in the second group (group 2). Cardiopulmonary complications, the total duration of the procedure, and the total amount of propofol administered were recorded. Results:The mean SpO2 measurements at the third minute, fifth minute, and 10th minute were higher in the BIS group (p < 0.001) (p < 0.05). The mean number of respirations during the third, fifth, 10th, and 15th minute of sedation was significantly higher in the RSS group than in the BIS group (p < 0.05). There was no difference between the groups in terms of recovery time, total propofol amount, and additional doses of bolus propofol. Conclusions:BIS monitoring during sedation with propofol for ERCP did not reduce total propofol use, but it may be an efficient guide for the timing of additional dose administration, which could reduce the risk of respiratory depression, and it could be used safely as an objective method in the follow-up of level of sedation.
Project description:There are safety issues associated with propofol use for flexible bronchoscopy (FB). The bispectral index (BIS) correlates well with the level of consciousness. The aim of this study was to show that BIS-guided propofol infusion is safe and may provide better sedation, benefiting the patients and bronchoscopists.After administering alfentanil bolus, 500 patients were randomized to either propofol infusion titrated to a BIS level of 65-75 (study group) or incremental midazolam bolus based on clinical judgment to achieve moderate sedation. The primary endpoint was safety, while the secondary endpoints were recovery time, patient tolerance, and cooperation.The proportion of patients with hypoxemia or hypotensive events were not different in the 2 groups (study vs. control groups: 39.9% vs. 35.7%, p?=?0.340; 7.4% vs. 4.4%, p?=?0.159, respectively). The mean lowest blood pressure was lower in the study group. Logistic regression revealed male gender, higher American Society of Anesthesiologists physical status, and electrocautery were associated with hypoxemia, whereas lower propofol dose for induction was associated with hypotension in the study group. The study group had better global tolerance (p<0.001), less procedural interference by movement or cough (13.6% vs. 36.1%, p<0.001; 30.0% vs. 44.2%, p?=?0.001, respectively), and shorter time to orientation and ambulation (11.7±10.2 min vs. 29.7±26.8 min, p<0.001; 30.0±18.2 min vs. 55.7±40.6 min, p<0.001, respectively) compared to the control group.BIS-guided propofol infusion combined with alfentanil for FB sedation provides excellent patient tolerance, with fast recovery and less procedure interference.ClinicalTrials. gov NCT00789815.
Project description:Several studies have suggested that the menstrual cycle has the impact on sedation. No previous study has evaluated the effects of the menstrual cycle on sedation level and propofol requirement with preoperative intravenous dexmedetomidine. Sixty-four adult fertile women receiving general anesthesia for elective gynecologic surgery were included in the study. Patients were classified into four groups on the basis of the phase of menstrual cycle and whether infused dexmedetomidine preoperatively: Group FS: the follicular phase (days 8-12) and preoperative intravenous normal saline; Group FD: the follicular phase (days 8-12) and preoperative intravenous dexmedetomidine; Group LS: the luteal phase (days 20-24) and normal saline; Group LD: the luteal phase (days 20-24) and dexmedetomidine. The patients were infused respectively dexmedetomidine at 0, 1.0, 0 and 1.0 ?g/kg over 10 min, and then propofol TCI, which was administered with target plasma concentration at 4.0 ?g/ml. BIS, heart rate, MAP were recorded until BIS to 50. In the LD group, the descent range of the BIS values was significantly sharpest among the four groups at loss of eyelash reflex. From propofol administered to loss of eyelash reflex and BIS values reach to 50, propofol requirements were significantly least and duration were shortest in the LD group among the four groups. Menstrual cycle phases affect the sedation of propofol induction with preoperative intravenous dexmedetomidine, which is deeper in the luteal phase. We should cautious of excessive sedation by propofol anesthesia with preoperative dexmedetomidine in the luteal phase.
Project description:EEG-based technologies may be limited in identifying recall under sedation (RUS). We developed a novel index, posteriorization/anteriorization (P/A) index, based on auditory evoked EEG signal and assessed whether it could differentiate between patients with or without RUS. Methods: EEG and BIS were sampled from 3 groups: 1. Patients undergoing sedation (n?=?26); 2. Awake volunteers (n?=?13, positive control for recall) 3. Patients undergoing general anesthesia (GA, n?=?12, negative control for recall). In recovery, recall was assessed using the BRICE questionnaire. Of the 26 sedated patients, 12 experienced recall. Both The P/A index and BIS differentiated between patients with recall and no recall. However, BIS differentiation may have been sensitive to the main drug used for sedation (midazolam vs. propofol) and the P/A index did not show similar drug-based sensitivity. Furthermore, only BIS results were correlated with EMG. Conclusion: This pilot study provided support for the association between P/A index and recall after sedation. Further research is needed in integrating the index into clinical use: (1) it should be derived by an easy-to-use EEG system with a better signal-to-noise ratio; (2) its applicability to other drugs must be shown.
Project description:BACKGROUND:This prospective study aimed to determine whether the bispectral index (BIS) is a valid objective tool for differentiating adequate from inadequate deep sedation in spontaneously breathing children with cerebral palsy (CP). METHODS:Propofol was titrated to increase the level of sedation with a continuous infusion of remifentanil at a rate of 0.05 ?g/kg/min while maintaining spontaneous ventilation in 22 children with spastic CP, aged 3-18 years. The depth of sedation was assessed using the University of Michigan Sedation Scale (UMSS) and the Modified Observer's Assessment of Alertness and Sedation (MOAAS) scale. Receiver operating characteristic curve analysis was performed to determine the cutoff BIS values for deep sedation, defined as a UMSS score of 3-4 and a MOAAS score of 0-1. RESULTS:The BIS values significantly changed with the increase in the level of sedation across both the UMSS and MOAAS scores (P < 0.001). The BIS values correlated with the UMSS (r = -0.795, P < 0.001) and MOAAS (r = 0.815, P < 0.001) scores. The cutoff BIS value to detect adequate deep sedation in children with CP was 61.5 (UMSS score: sensitivity 0.860, specificity 0.814; MOAAS score: sensitivity 0.794, specificity 0.811). CONCLUSIONS:The BIS value strongly correlates with the clinical sedation scales, such as the UMSS and MOAAS, during deep sedation in children with CP. Therefore, BIS monitoring can be used as a valid tool for assessing the level of propofol sedation in spontaneously breathing children with CP undergoing a botulinum toxin injection.
Project description:Aim:To compare the effects of propofol/remifentanil and meperidine/midazolam on postprocedure cognitive function. Materials and methods:A total of 100 American Society of Anesthesiologists (ASA) score I to III patients undergoing elective colonoscopy were taken into the study and divided into two groups. Exclusion criteria were patient refusal, mini mental test (MMT) <26, The Amsterdam Preoperative Anxiety and Information Scale (APAIS) >10, advanced cardiopulmonary or psychiatric disease, chronic alcohol abuse, morbid obesity, and known allergy to study drugs. In group MM, 2 mg midazolam and 20 mg meperidine was given intravenously and additional 1 to 2 mg midazolam and 20 mg meperidine (with a maximum total of 5 mg midazolam and 50 mg meperidine) was given when bispectral index (BIS) was >80. In group RP, 100 ?g/kg/minute propofol infusion and 1 ?g/kg remifentanil bolus was administered and additional 0.5 ?g/kg remifentanil bolus was given when BIS was >80. Observer's Assessment of Alertness/Sedation scale (OAA/S) and Facial Pain Score (FPS) values were recorded. Cognitive function was measured by Trieger Dot Test (TDT) and Digit Symbol Substitution Test (DSST). Results:The study was concluded with 100 patients. Heart rate was slower and BIS values were lower in group RP throughout the procedure. Blood pressure was lower in group RP without clinical significance. There was no difference concerning recovery time and visual analog scores (VASs). In group MM, TDT scores were higher and DSST scores were lower. Satisfaction was higher in group RP. Conclusion:Propofol/remifentanil combination is better than meperidine/midazolam combination concerning cognitive function in sedation for colonoscopy. Clinical significance:The addition of BIS monitorization to evaluate the depth of sedation and the negative effects of midazolam meperidine combination on postprocedural cognitive function.How to cite this article: Ekmekci P, Erkan G, Yilmaz H, Kazbek BK, Koksoy UC, Doganay G, Tüzüner F. Effect of Different Sedation Regimes on Cognitive Functions in Colonoscopy. Euroasian J Hepato-Gastroenterol 2017;7(2):158-162.
Project description:To determine whether limiting intraoperative sedation depth during spinal anesthesia for hip fracture repair in elderly patients can decrease the prevalence of postoperative delirium.We performed a double-blind, randomized controlled trial at an academic medical center of elderly patients (>or=65 years) without preoperative delirium or severe dementia who underwent hip fracture repair under spinal anesthesia with propofol sedation. Sedation depth was titrated using processed electroencephalography with the bispectral index (BIS), and patients were randomized to receive either deep (BIS, approximately 50) or light (BIS, >or=80) sedation. Postoperative delirium was assessed as defined by Diagnostic and Statistical Manual of Mental Disorders (Third Edition Revised) criteria using the Confusion Assessment Method beginning at any time from the second day after surgery.From April 2, 2005, through October 30, 2008, a total of 114 patients were randomized. The prevalence of postoperative delirium was significantly lower in the light sedation group (11/57 [19%] vs 23/57 [40%] in the deep sedation group; P=.02), indicating that 1 incident of delirium will be prevented for every 4.7 patients treated with light sedation. The mean +/- SD number of days of delirium during hospitalization was lower in the light sedation group than in the deep sedation group (0.5+/-1.5 days vs 1.4+/-4.0 days; P=.01).The use of light propofol sedation decreased the prevalence of postoperative delirium by 50% compared with deep sedation. Limiting depth of sedation during spinal anesthesia is a simple, safe, and cost-effective intervention for preventing postoperative delirium in elderly patients that could be widely and readily adopted.
Project description:To evaluate the effect of sedation depth on drug-induced sleep endoscopy (DISE).Ninety patients with obstructive sleep apnea (OSA) and 18 snorers underwent polysomnography and DISE under bispectral index (BIS)-guided propofol infusion at two different sedation levels: BIS 65-75 (light sedation) and 50-60 (deep sedation).For the patients with OSA, the percentages of velopharynx, oropharynx, hypopharynx, and larynx obstructions under light sedation were 77.8%, 63.3%, 30%, and 33.3%, respectively. Sedation depth was associated with the severity of velopharynx and oropharynx obstruction, oropharynx obstruction pattern, tongue base obstruction, epiglottis anteroposterior prolapse and folding, and arytenoid prolapse. In comparison, OSA severity was associated with the severity of velopharynx obstruction, severity of oropharynx obstruction, and arytenoid prolapse (odds ratio (95% confidence interval); 14.3 (4.7-43.4), 11.7 (4.2-32.9), and 13.2 (2.8-62.3), respectively). A good agreement was noted between similar DISE findings at different times and different observers (kappa value 0.6 to 1, respectively). A high percentage of arytenoid prolapse (46.7% among the patients with OSA under light sedation) was noted.Greater sedative depth increased upper airway collapsibility under DISE assessment. DISE under BIS-guided propofol infusion, and especially a level of 65-75, offers an objective and reproducible method to evaluate upper airway collapsibility. Some findings were induced by drug sedation and need careful interpretation. Specific arytenoid prolapse patterns were noted for which further investigations are warranted.http://www.clinicaltrials.gov, identifier: NCT01100554.A commentary on this article appears in this issue on page 965.