A comparison of four sedation techniques for pediatric dental surgery

Background: We prospectively assessed the efficacy and side effects of four sedation techniques in our dental clinic: oral midazolam, intranasal (IN) midazolam, IN midazolam combined with oral transmucosal fentanyl citrate (OTFC), and IN midazolam combined with IN sufentanil. Materials & Methods: With IRB approval, a nonrandomized open label study of moderate sedation in children undergoing dental surgery was administered during a 6 ‐month period. The sedation regimen was rotated daily at the anesthesiologist’s discretion. Each sedation was monitored by a research nurse who assessed the quality of sedation and the frequency of complications. All children were monitored during the procedure and recovery for at least 20 min, before discharge based on the University of Michigan Sedation and Ohio State behavior rating scores. Results: One hundred and two children were sedated in the dental clinic during this period. The sedation was successful in 73% (range 64% to 88%) of the children. The time to onset was greatest with OTFC (37 min) and least with IN midazolam (17 min) compared with the other two groups (20 and 30 min). Recovery after OTFC was prolonged (39 min) significantly compared with the other three groups (26.5–30 min). Efficacy of sedation and frequency of complications (9% incidence of nausea and 6% of mild hemoglobin desaturation) were similar among the groups. Conclusions: All four sedation regimens were equally effective in this cohort of healthy children. The onset and recovery with OTFC was significantly delayed compared with the other regimens. The frequency of side effects was small; there were no side effects in the PO midazolam group.     

Bispectral Index compared to Ramsay score for sedation monitoring in intensive care units

AIM: Continuous monitoring is of paramount importance in order to obtain a correct level of sedation in ICU patients. Clinical scoring systems, although simple and inexpensive, are often inadequate in evaluating the patient level of consciousness. Among instrumental tools for sedation monitoring, Bispectral Index (BIS) is now widely used due to its reliability and applicability. Nevertheless some doubts still exist regarding its usefulness in ICU. METHODS: Sedation, obtained with propofol or midazolam, was monitored with Ramsay scale and BIS in 40 patients admitted in ICU for postoperative monitoring after major abdominal or vascular surgery. A correlation between Ramsay score and BIS values was searched using Pearson test. RESULTS: A good correlation between Ramsay score and BIS values was observed. At the deeper levels of sedation a wide range of BIS values corresponds to Ramsay score 6, indicating various levels of central nervous system depression that are not identified by clinical evaluation. CONCLUSIONS: BIS monitoring is useful in ICU patients and allows a finest differentiation of sedation level in deeply sedated ICU patients.     

Bispectral index monitoring of sedation depth in pediatric dental patients

The bispectral index (BIS) monitor records electroencephalogram waveforms and provides an objective measure of the hypnotic effect of a sedative drug on brain activity. The aim of this pilot study was to use the BIS monitor to evaluate the depth of procedural sedation in pediatric dental patients and to assess if the BIS monitor readings correlate with a validated pediatric sedation scale, the University of Michigan Sedation Scale (UMSS), in determining the level of sedation in these patients. Thirty-five pediatric dental patients requiring sedation were studied prospectively. A baseline BIS reading was obtained and during the procedure an independent observer recorded the BIS every 5 minutes. The operator, who was blinded to the BIS results, determined the UMSS scale at the same 5-minute interval. The patients were monitored postoperatively for 1 hour. There was a significant but moderate correlation between BIS values and UMSS scores (Spearman's rank correlation r = -0.574, P < .0001). Percentage of agreement and kappa coefficient using all the observations were also calculated. The percentage of agreement was 37.8%, the kappa coefficient was 0.18 (P < .0001), and the weighted kappa coefficient 0.26 (P < .0001). A lack of correlation was noted between the deeper levels of UMSS sedation scores and BIS values. This study demonstrated a significant correlation between BIS values and the UMSS score in pediatric dental patients undergoing mild to moderate sedation. Based on our results, it appears that the BIS monitor may be useful during mild or moderate sedations to establish the level of sedation objectively without the need to stimulate the patient.     

BIS在小儿监测中的研究进展

目前，脑电双频谱指数（BIS）已被广泛应用于成人镇静状态与麻醉深度的监测，但小儿大脑发育成熟度与成人比有一定差异，因此BIS在小儿监测的应用特性备受关注。通过对这一领域研究现状进行综述以供参考。     

Bispectral index (BIS) monitoring during propofol-induced sedation and anaesthesia

One may have to use a monitor of cortical suppression to maintain the optimal level of sedation and hypnosis. The bispectral index (BIS), a processed EEG parameter, which incorporates coupling along with the frequency and amplitude of EEG waveforms, has been proposed as a measure of the pharmacodynamic anaesthetic effect on the central nervous system. The numerical value of BIS varies from 0 to 100 (no cerebral activity to fully awake patient). In order to achieve the desired level of propofol sedation or hypnosis, a target concentration of propofol at the effect site or in the blood must be delivered. Alternately, one may use BIS monitoring to monitor hypnosis or sedation levels or to reflect propofol concentrations in the blood. Significant correlations between plasma propofol concentrations and BIS values (r = 0.68-0.78) have been reported by many investigators. During propofol-induced sedation, BIS values may be maintained above 75 to prevent airway obstruction and hypoxia. During propofol intravenous anaesthesia, BIS values from 40 to 60 have been proposed to maintain the desired level of hypnosis, with values below 50 associated with an insignificant probability of recall. However, the major limitation of the BIS monitor (monitor of hypnosis) relates to the fact that balanced anaesthesia comprises hypnosis, areflexia and analgesia and requires the administration of hypnotic agents, muscle relaxants and analgesics to achieve the desired clinical effects. Therefore, besides using the BIS value guidelines, one may also consider the haemodynamic, autonomic and somatic responses of the patient, the anaesthetic technique and the surgical interventions before deriving definite conclusions about the overall anaesthetic state of the patient.     

Relative reliability of the auditory evoked potential and Bispectral Index for monitoring sedation level in surgical intensive care patients

Sedation is an important adjunct therapy for patients in the intensive care unit. The objective of the present study was to observe correlation between an established subjective measure, the Ramsay Sedation Scale, and two objective tools for monitoring critically ill patients: the Bispectral Index (BIS) and auditory evoked potential. Ninety patients undergoing major surgery scheduled for postoperative mechanical ventilation and continuous sedation with propofol and fentanyl were selected. Electrodes for determining BIS and auditory evoked potential were placed on the foreheads of all patients according to manufacturer's specifications at least six hours after patients' arrival at the intensive care unit. Ramsay Sedation Scale, BIS, signal quality index, composite A-line autoregressive index (AAI) and electromyographic activities were recorded every five minutes for 30 minutes. BIS and AAI showed good correlation amongst readings (r(s)=0.697, P <0.01). Both were significantly influenced by electromyographic activities (BIS, r(s)=0.735, P <0.01; AAI, r(s)=0.856, P <0.01). Comparison of BIS and AAI revealed an acceptable correlation between electroencephalogram variables and the Ramsay Sedation Scale (BIS, tau=-0.689; AAI, tau=-0.621; P <0.01). In conclusion, the auditory evoked potential and BIS monitors revealed an acceptable correlation with the Ramsay Sedation Scale. However, the BIS and auditory evoked potential monitors do not perform adequately as a substitute in the assessment of sedated intensive care unit patients. These monitors could be used as part of an integrated approach for the evaluation of those patients especially when the subjective scales do not work well in the setting of neuromuscular blockade or may not be sufficiently sensitive to evaluate very deep sedation.     

A comparison of midazolam and diazepam for intravenous sedation in dentistry

In a randomised cross-over trial, midazolam, a new water soluble benzodiazepine was compared with the conventional diazepam preparation (Valium) in 34 patients aged 16-45 years who were undergoing outpatient conservation dentistry. Midazolam hydrochloride (0.17 mg/kg) was virtually free of venous complications and showed advantages over diazepam (0.32 mg/kg) in providing a faster onset of action, higher incidence of amnesia and more rapid recovery. Midazolam produced a higher incidence of respiratory side effects hiccough (17.6% compared with 2.9%), brief apnoea following induction (11.8% compared with 5.8%), and airway obstruction during maintenance (8.8% compared with 0%). These may be related to the greater potency of midazolam as suggested by the smaller total dose required. Cardiovascular changes and operating conditions were similar.     

A comparison of two sedation techniques for neuroradiology

Two groups of 25 patients were sedated during neuroradiological investigation. The first group was sedated with fentanyl and midazolam while the other was given fentanyl and a two-stage infusion of propofol in a subanaesthetic dose. Both techniques resulted in satisfactory sedation and recovery, although those who received propofol were more likely to recall their journey from the X-ray department back to the ward. Sedation in both groups resulted in unacceptable PaO2 values in some patients which could subsequently be corrected by administration of supplementary oxygen.     

Closed loop control of sedation for colonoscopy using the Bispectral Index

Sixteen patients undergoing colonoscopy were sedated with propofol using a closed-loop control system guided by the Bispectral Index (BIS). Propofol administration, via a target-controlled infusion, was controlled by a proportional-integral-differential control algorithm. The median (range) propofol target concentration during closed-loop control was 2.3 (1.7-3.6) microg.ml(-1). The performance characteristics of the system were excellent, with a median absolute performance error of 7 (1-15). Patients were drowsy yet rousable, with a median (range) BIS set-point of 80 (75-85). No patient became apnoeic, required airway support or became haemodynamically unstable whilst sedated. Eight patients moaned or moved during colonoscopy and four had recall. Median (range) time to full consciousness was 4 (2-20) min after the end of closed-loop control. Patient and surgeon satisfaction were high. We conclude that BIS may be a suitable control variable for closed-loop control of sedation with propofol.     

Bispectral EEG index monitoring of high-dose nitrous oxide and low-dose sevoflurane sedation

This single-blind controlled clinical study characterized the effects of 30-70% nitrous oxide (N2O) and 0.2-0.8% sevoflurane conscious sedation on quantitative electroencephalographic (EEG) readings of 22 healthy dental students as measured by the bispectral index (BIS). The study verified the 2 previously published BIS/N2O investigations showing no correlation between N2O dosage up to 70% and BIS. Observer's Assessment of Alertness and Sedation scores (OAA/S), however, correlated well with increasing doses of N2O from approximately 35 to 70%. A near linear dose-response relationship was established between OAA/S and end tidal (ET) sevoflurane concentrations of 0.4-0.7%. Only at the highest level of end tidal sevoflurane recorded, 0.7%, was statistically significant BIS depression seen. Subjects evaluated the acceptability of the sedative effect of the 2 gases, showing a slight preference for N2O. Comparable partial anterograde amnesia and sedation (OAA/S) were produced by both agents in administered concentrations of 40-70% N2O and 0.6-0.8% sevoflurane. Female subjects exhibited better memory and significantly less amnesia than males. No statistically significant changes occurred in any of the monitored vital signs. EMG readings demonstrated a statistically significant difference from control values only at the highest, 0.7%, ET concentration of sevoflurane. BIS does not appear useful for evaluating the level of nitrous oxide sedation in the dental setting but may have some value in assessing depth of sedation at deeper levels of sevoflurane sedation.     

New parameters of skin conductance compared with Bispectral Index monitoring to assess emergence from total intravenous anaesthesia

Background: Arousal after total i.v. anaesthesia (TIVA) has been reportedto be detectable by monitoring the number of fluctuations persecond (NFSC), a parameter of skin conductance (SC). However,compared with monitoring of the bispectral index (BIS^®),the predictive probability of NFSC was significantly lower.The aim of this study was to determine the value of the twonew, not yet published parameters of SC, area under the curve(AUC) methods A and B, for monitoring emergence from TIVA comparedwith monitoring of NFSC and BIS^®. Methods: Twenty-five patients undergoing surgery were investigated. NFSC,AUC A, AUC B, BIS^®, and haemodynamic parameters (mean arterialpressure and heart rate) were recorded simultaneously. The performanceof the monitoring devices in distinguishing between the clinicalstates ‘steady-state anaesthesia’, ‘firstclinical reaction’, and ‘extubation’ werecompared using the method of prediction probability (Pk) calculation. Results: BIS^® showed the best performance in distinguishing between‘steady-state anaesthesia’ vs ‘first reaction’(Pk BIS^® 0.95; NFSC 0.73; AUC A 0.54; AUC B 0.62) and ‘steady-stateanaesthesia’ vs ‘extubation’ (Pk BIS^®0.99; NFSC 0.73; AUC A 0.71; AUC B 0.67). However, the timefrom first BIS^®>60/SC>0 to a first clinical reactionwas significantly shorter for BIS^® (median BIS^® 180s; NFSC 780 s; AUC A 750 s; AUC B 690 s; P < 0.001). Conclusions: AUC A and AUC B did not improve accuracy of SC monitoring inpatients waking after TIVA.     

Bispectral index monitoring during sedation with sevoflurane, midazolam, and propofol.

BACKGROUND: Bispectral Index (BIS) has been used to measure sedation depth. Ideally, to guide anesthetic management, range of BIS scores at different sedation levels should not overlap, and BIS should be independent of drug used. This study assessed ability of BIS to predict sedation depth between sevoflurane, propofol, and midazolam. Quality of recovery was also compared. METHODS: Patients undergoing surgery with local or regional anesthesia and sedation were randomized to sevoflurane (n = 23), midazolam (n = 21), or propofol (n = 22). Sedation was titrated to Observers's Assessment of Alertness-Sedation score of 3 (responds slowly to voice). BIS and Observers's Assessment of Alertness-Sedation were measured every 5 min. BIS prediction probability (PK) was compared between drugs. Recovery was assessed by BIS and Digit Symbol Substitution and memory tests. RESULTS: Bispectral Index of responders to voice was significantly different from nonresponders (86 +/- 10 vs. 74 +/- 14, mean +/- SD; P < 0.001) However, wide variability and overlap in BIS were observed (25th-75th percentile, responders vs. non-responders: 79-96 vs. 65-83). BIS of responders was different for sevoflurane versus propofol and midazolam. BIS was a better predictor of propofol sedation than sevoflurane or midazolam (PK = 0.87 +/- 0.11, 0.76 +/- 0.01, and 0.69 +/- 0.02, respectively; P < 0.05). At 10 min after the procedure, 76, 48, and 24% of sevoflurane, propofol, midazolam patients, respectively, returned to baseline Digit Symbol Substitution scores (P < 0.05). Excitement-disinhibition occurred in 70, 36, and 5% of sevoflurane, propofol, and midazolam patients, respectively (P < 0.05). CONCLUSION: Individual BIS scores demonstrate significant variability, making it difficult to predict sedation depth. The relation between BIS and sedation depth may not be independent of anesthetic agent. Quality of recovery was similar between drugs, but excitement occurred frequently with sevoflurane.     

Bispectral index monitoring in fast track pediatric cardiac surgery

BACKGROUND: We evaluated the changes in the bispectral index (BIS) as a potential indicator of level of consciousness in infants and children undergoing fast track cardiac surgery. METHODS: Twenty-one children undergoing fast track cardiac surgery were recruited into this study. Anesthesia was maintained with inhaled sevoflurane and intravenous fentanyl 10 microg x kg(-1). Cardiopulmonary bypass (CPB) with mild hypothermia and an immediate tracheal extubation protocol were used. BIS was recorded throughout the operation. RESULTS: In average, BIS was kept almost under 70 with 0.5-3.0% of sevoflurane. During rewarming from mild hypothermia, BIS increased temporarily over 70 in about a half of children. We, therefore, treated them by increasing sevoflurane concentration. Nineteen children were extubated in the operating room, and two patients were extubated in ICU within three hours after surgery. CONCLUSIONS: BIS was kept within the level of adequate sedation during surgery. However, since the increase in BIS during the rewarming phase could reflect light anesthesia, caution should be taken around this phase.     

Bispectral index monitoring: comparison of two types of electrode

Bis-monitoring is a new method of monitoring anaesthetic depth. Bis-monitoring is easy to perform, but the Bis-monitor and the original, disposable electrodes are expensive. The aim of this study was to determine whether the original Zipprep electrodes could be replaced by the much cheaper electrocardiogram electrodes. We compared bispectral index measurements, conducted using both types of electrode in the same patients before anaesthesia, and during light and deep anaesthesia, in patients randomly allocated to receive either sevoflurane or propofol anaesthesia. We found very good agreement between the measurements from the two different sets of electrodes. The impedance in the electrocardiogram electrodes was higher than in the Zipprep electrodes, but this did not affect the bispectral index. No other problems with either type of electrode were detected. It is concluded that Zipprep electrodes can be replaced by electrocardiogram electrodes in normal clinical practice.     

脑电双频指数引导下右美托咪啶和咪达唑仑用于下肢手术镇静的比较

目的 比较和评估右美托咪啶(dexmedetomidine,DEX)和咪达唑仑用于骨科下肢手术中镇静的效果和安全性.方法 骨科下肢手术患者52例,均接受腰硬联合麻醉,按镇静方法 完全随机分为两组:D组27例,以DEX0.5μg·kg-1·h-1静脉恒速输注(负荷量0.5 μg/kg);M组25例,以咪达唑仑50 μg·...     

A comparison of dexmedetomidine and midazolam for sedation in third molar surgery

This randomised, double-blind study compared dexmedetomidine and midazolam for intravenous sedation during third molar surgery under local anaesthesia. Sixty patients received either dexmedetomidine (up to 1 microg x kg(-1)) or midazolam (up to 5 mg), which was infused until the Ramsay Sedation Score was four or the maximum dose limit was reached. Intra-operative vital signs, postoperative pain scores and analgesic consumption, amnesia, and satisfaction scores for patients and surgeons, were recorded. Sedation was achieved by median (IQR (range)) doses of 47 microg (39-52 (25-76)) or 0.88 microg x kg(-1) (0.75-1.0 (0.6-1.0)) dexmedetomidine, and 3.6 mg (3.3-4.4 (1.9-5.0)) or 0.07 mg x kg(-1) (0.055-0.085 (0.017-0.12)) midazolam. Heart rate and blood pressure during surgery were lower in dexmedetomidine group. There was no significant difference in satisfaction or pain scores. Midazolam was associated with greater amnesia. Dexmedetomidine produces comparable sedation to midazolam.     

Transurethral surgery using intravesical bupivacaine and intravenous sedation.

We report our experience using intravesical 0.5% bupivacaine as a topical anesthetic along with intravenous fentanyl and midazolam sedation to perform a variety of transurethral procedures in 78 patients. We achieved adequate pain control in all patients and observed no anesthetic complications. Use of this combination of intravesical topical anesthesia and intravenous sedation provided safe, adequate anesthesia to our patients undergoing various transurethral procedures in an outpatient clinic setting.