This study was designed to determine the optimal sedative dose of propofol to start brain magnetic resonance imaging (MRI) in children with cerebral palsy (CP).
Twenty children, aged 0.5-5 years, were administered propofol to achieve a University of Michigan Sedation Scale (UMSS) score ≥ 3 in the MRI room. The proper dose of propofol was determined using the up-and-down method.
The ED50 and ED95 for successful sedation with a UMSS ≥ 3 were 2.07 mg/kg (95% CI 1.69-2.56) and 2.69 mg/kg (95% CI 2.35-5.59). Respiratory events occurred in 5 patients and were resolved with neck extension, chin lift, or transient respiratory assistance with successful sedation.
Low dose propofol can safely facilitate the initiation of MRI in children with CP.
Cerebral palsy; MRI; Propofol
Clinical signs and patient verbal responses have traditionally been used to assess patient comfort and the depth of sedation. Recently, level-of-consciousness monitors have been used to guide sedation. The SNAP IIc is a two-lead electroencephalogram device which displays a SNAPc Index - a value derived based on both high and low frequency electroencephalogram signals. Much of the current clinical research on monitoring during sedation involves the bispectral index monitor. We compared simultaneous readings recorded by the SNAP II and bispectral index during sedation in 51 consecutive patients undergoing surgery. The anaesthesia team was blinded to the SNAP II and bispectal index values. Concurrent SNAP II and bispectral index readings displayed similarly-shaped trajectories during sedation, but further studies are needed to establish the routine clinical utility of both these monitors.
The bispectral (BIS) index has been used to interpret partial EEG recordings to predict the level of sedation and loss of consciousness in patients undergoing general anesthesia. The author has evaluated BIS technology in determining the level of sedation in patients undergoing outpatient deep sedation. These experiences are outlined in this review article. Initially, the correlation of the BIS index with traditional subjective patient evaluation using the Observer's Assessment of Alertness and Sedation (OAA/S) scale was performed in 25 subjects. In a second study, the recovery profile of 39 patients where the BIS was used to monitor sedation was compared with a control group where the monitor was not used. A strong positive relationship between the BIS and OAA/S readings was found in the initial subjects. From the recovery study, it appears that use of the BIS monitor may help titrate the level of sedation so that less drugs are used to maintain the desired level of sedation. A trend to earlier return of motor function in BIS-monitored patients was also demonstrated. BIS technology offers an objective, ordinal means of assessing the depth of sedation. This can be invaluable in comparing studies of techniques. The BIS index provides additional information to standard monitoring techniques that helps guide the administration of sedative-hypnotic agents. The trend to earlier return of motor function in BIS-monitored patients warrants further investigation.
In this issue of Critical Care, Dr Haenggi and co-workers present a study evaluating bispectral index (BIS), state entropy (SE) and response entropy in 44 patients sedated in the intensive care unit (ICU). As in recent studies attempting to correlate frontal electroencephalogram (EEG) measurements with clinical evaluations of sedative efficacy, there is considerable overlap in numerical EEG values and different clinical levels of sedation. This precludes the use of these monitors for monitoring or titrating sedation in the critically ill. Despite many attempts, no study has yet presented data showing improved outcome with the use of EEG monitors in ICU sedation. Meanwhile, clinical sedation protocols have emerged, improving important endpoints in critically ill patients needing sedation. A major underlying problem in applying EEG monitors in the ICU is that they have been developed for measuring anesthetic depth and the related risk of recall, rather than the acknowledged endpoints of sedation, namely reduction of anxiety and discomfort. Until an 'objective' monitor is developed to measure the degree of such symptoms, physicians should continue treating patients and not numbers.
Evaluating depth of sedation in the intensive care unit (ICU) is crucial for the management of mechanically ventilated patients but can be challenging in some situations. Because the depth of hypnosis is correlated with the decrease in photomotor reflex (PMR), we suggest using pupillometric video as an automated, noninvasive, simple, and reproducible technique to evaluate the depth of sedation in ICU patients. We compare the effectiveness of this procedure to the bispectral index (BIS).
Thirty-one patients requiring sedation and ventilation were included in this monocentric, observational study. The posology of hypnotics and morphinics were based on the Richmond Agitation and Sedation Scale (RASS). PMR was measured by the Neurolight® (IDMED) system and BIS value by BIS Vista® (Anandic Medical Systems). RASS, PMR, and BIS were measured three times daily in all patients. Data acquired by pupillometric video included variation in pupillary diameter (ΔPD), latency time (LT), and maximal speed of pupillary constriction (Vmax). These parameters were analyzed after having classified BIS values in three groups (<40 heavy sedation; 40 ≤ BIS ≤ 60 acceptable sedation; >60 light sedation). Exclusion criteria were neurological or ophthalmologic pathologies that could interfere with PMR.
There was a significant difference in Vmax and ΔPD between the BIS < 40 group and 40 ≤ BIS ≤ 60 groups (p < 0.0001 for each) and between the BIS < 40 and BIS > 60 groups (p < 0.0001 for each). There were no significant differences in Vmax and ΔPD between the 40 ≤ BIS ≤ 60 and BIS > 60 groups. There was no correlation between any of the BIS groups and LT.
Vmax and ΔPD seem to be relevant criteria compared with the BIS and the RASS. Pupillometric video monitoring of depth of sedation could be beneficial in ICU patients, especially for those under myorelaxant drugs, where no clinical evaluation of sedation is possible.
Sedation; Photomotor reflex; Video pupillometry; Bispectral index
OBJECTIVE: To assess the correlation between 2 clinical sedation scales and 2 electroencephalographic (EEG)–based monitors used during surgical procedures that required mild to moderate sedation.
PATIENTS AND METHODS: Patients scheduled for elective surgery participated in this institutional review board–approved study from March 2003 to February 2004. Level of sedation was determined both clinically using the Ramsay and the Observer's Assessment of Alertness/Sedation scales and with 2 EEG measures (the Bispectral Index version XP [BIS XP] or the Patient State Analyzer [PSA 4000]). Correlation between these 2 measures of sedation were tested using nonparametric statistical tests.
RESULTS: The BIS XP monitor was used in 26 patients, and the PSA 4000 monitor was used in 24 patients. The Ramsay and Observer's Assessment of Alertness/Sedation scores correlated with each other (r=−0.96; P<.001) and with both the BIS XP (r=−0.89 and r=0.91, respectively; P<.001) and the PSA 4000 (r=−0.80 and r=0.80, respectively; P<.001) values. However, this correlation was strongest only at the extremes. Between the BIS XP and PSA 4000 values of 61 and 80, the clinical sedation scores varied greatly.
CONCLUSION: On the basis of our results, these EEG-based monitors cannot reliably distinguish between light and deep sedation.
Sedative and analgesic drugs are frequently used in critically ill patients. Their overuse may prolong mechanical ventilation and length of stay in the intensive care unit. Guidelines recommend use of sedation protocols that include sedation scores and trials of sedation cessation to minimize drug use. We evaluated processed electroencephalography (response and state entropy and bispectral index) as an adjunct to monitoring effects of commonly used sedative and analgesic drugs and intratracheal suctioning.
Electrodes for monitoring bispectral index and entropy were placed on the foreheads of 44 critically ill patients requiring mechanical ventilation and who previously had no brain dysfunction. Sedation was targeted individually using the Ramsay Sedation Scale, recorded every 2 hours or more frequently. Use of and indications for sedative and analgesic drugs and intratracheal suctioning were recorded manually and using a camera. At the end of the study, processed electroencephalographical and haemodynamic variables collected before and after each drug application and tracheal suctioning were analyzed. Ramsay score was used for comparison with processed electroencephalography when assessed within 15 minutes of an intervention.
The indications for boli of sedative drugs exhibited statistically significant, albeit clinically irrelevant, differences in terms of their association with processed electroencephalographical parameters. Electroencephalographical variables decreased significantly after bolus, but a specific pattern in electroencephalographical variables before drug administration was not identified. The same was true for opiate administration. At both 30 minutes and 2 minutes before intratracheal suctioning, there was no difference in electroencephalographical or clinical signs in patients who had or had not received drugs 10 minutes before suctioning. Among patients who received drugs, electroencephalographical parameters returned to baseline more rapidly. In those cases in which Ramsay score was assessed before the event, processed electroencephalography exhibited high variation.
Unpleasant or painful stimuli and sedative and analgesic drugs are associated with significant changes in processed electroencephalographical parameters. However, clinical indications for drug administration were not reflected by these electroencephalographical parameters, and barely by sedation level before drug administration or tracheal suction. This precludes incorporation of entropy and bispectral index as target variables for sedation and analgesia protocols in critically ill patients.
Intravenous sedation during dental treatment is primarily used in outpatient clinics. Maintenance of a level of sedation sufficient to allow treatment while using the minimum dose possible and to induce faster waking is very important. The benefits of bispectral index monitoring have recently been reported for many applications, and it is expected to prove useful in intravenous sedation during dental treatment. However, because the sensor is attached to the forehead, which may be close to the site of operation, and because no neuromuscular blocking drugs are used, monitoring may be excessively interrupted by artifacts such as electromyographic input. Thus, we investigated the usefulness of bispectral index monitoring for patients under intravenous sedation during dental treatment. The incidence of "good" electroencephalograms, for which the electromyogram was less than 50 dB, signal quality index was more than 25%, and impedance was less than 10 kOhms, was 82.4% +/- 9.2%. These findings suggest that bispectral index monitoring will prove effective for intravenous sedation during dental treatment.
Sedation in children is increasingly emerging as a minimally invasive technique that may be associated with local anaesthesia or diagnostic and therapeutic procedures which do not necessarily require general anaesthesia. Standard monitoring requirements are not sufficient to ensure an effective control of pulmonary ventilation and deep sedation. Capnography in pediatric sedation assesses the effect of different drugs on the occurrence of respiratory failure and records early indicators of respiratory impairment. The Bispectral index (BIS) allows the reduction of dose requirements of anaesthetic drugs, the reduction in the time to extubation and eye opening, and the reduction in the time to discharge. In the field of pediatric sedation, capnography should be recommended to prevent respiratory complications, particularly in spontaneous ventilation. The use of the BIS index, however, needs further investigation due to a lack of evidence, especially in infants. In this paper, we will investigate the role of capnography and the BIS index in improving monitoring standards in pediatric sedation.
Neuraxial anaesthesia produces a sedative and anesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. Epidural anaesthesia was induced with 2% 2-chloroprocaine. Hemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. Sensory block level significantly predicted VRS (PK = 0.747), OAA/S score (PK = 0.748) and BIS. Bispectral index predicted VRS and OAA/S score (PK = 0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho = 0.335, P < 0.01) and sensory block (rho = 0.394, P < 0.01). The other BAEP parameters did not change during epidural anaesthesia. Hemodynamic and respiratory responses remained stable throughout the study. Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity.
Afferentation theory; Brainstem auditory evoked potentials; Chloroprocaine; Deafferentation; Epidural anaesthesia; Sedation; Sensory block
Dexmedetomidine was introduced two decades ago as a sedative and supplement to sedation in the intensive care unit for patients whose trachea was intubated. However, since that time dexmedetomidine has been commonly used as a sedative and hypnotic for patients undergoing procedures without the need for tracheal intubation. This review focuses on the application of dexmedetomidine as a sedative and/or total anesthetic in patients undergoing procedures without the need for tracheal intubation. Dexmedetomidine was used for sedation in monitored anesthesia care (MAC), airway procedures including fiberoptic bronchoscopy, dental procedures, ophthalmological procedures, head and neck procedures, neurosurgery, and vascular surgery. Additionally, dexmedetomidine was used for the sedation of pediatric patients undergoing different type of procedures such as cardiac catheterization and magnetic resonance imaging. Dexmedetomidine loading dose ranged from 0.5 to 5 μg kg−1, and infusion dose ranged from 0.2 to 10 μg kg−1 h−1. Dexmedetomidine was administered in conjunction with local anesthesia and/or other sedatives. Ketamine was administered with dexmedetomidine and opposed its bradycardiac effects. Dexmedetomidine may by useful in patients needing sedation without tracheal intubation. The literature suggests potential use of dexmedetomidine solely or as an adjunctive agent to other sedation agents. Dexmedetomidine was especially useful when spontaneous breathing was essential such as in procedures on the airway, or when sudden awakening from sedation was required such as for cooperative clinical examination during craniotomies.
dexmedetomidine; sedation; nonintubated patients
AIM: To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP).
METHODS: Fifty-nine consecutive patients with a variety of reasons for ERCP who underwent the procedure at least twice between 1 July 2010 and 30 November 2010. This was a randomized cross-over study, in which each patient underwent ERCP twice, once with BIS monitoring and once with control monitoring. Whether BIS monitoring was done during the first or second ERCP procedure was random. Patients were intermittently administered a mixed regimen including midazolam, pethidine, and propofol by trained nurses. The nurse used a routine practice to monitor sedation using the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale or the BIS monitoring. The total amount of midazolam and propofol used and serious side effects were compared between the BIS and control groups.
RESULTS: The mean total propofol dose administered was 53.1 ± 32.2 mg in the BIS group and 54.9 ± 30.8 mg in the control group (P = 0.673). The individual propofol dose received per minute during the ERCP procedure was 2.90 ± 1.83 mg/min in the BIS group and 3.44 ± 2.04 mg in the control group (P = 0.103). The median value of the MOAA/S score during the maintenance phase of sedation was comparable for the two groups. The mean BIS values throughout the procedure (from insertion to removal of the endoscope) were 76.5 ± 8.7 for all 59 patients in using the BIS monitor. No significant differences in the frequency of < 80% oxygen saturation, hypotension (< 80 mmHg), or bradycardia (< 50 beats/min) were observed between the two study groups. Four cases of poor cooperation occurred, in which the procedure should be stopped to add the propofol dose. After adding the propofol, the procedure could be conducted successfully (one case in the BIS group, three cases in the control group). The endoscopist rated patient sedation as excellent for all patients in both groups. All patients in both groups rated their level of satisfaction as high (no discomfort). During the post-procedural follow-up in the recovery area, no cases of clinically significant hypoxic episodes were recorded in either group. No other postoperative side effects related to sedation were observed in either group.
CONCLUSION: BIS monitoring trend to slighlty reduce the mean propofol dose. Nurse-administered propofol sedation under the supervision of a gastroenterologist may be considered an alternative under anesthesiologist.
Conscious sedation; Bispectral index monitors; Pancreatic neoplasm; Endoscopic retrograde cholangiopancreatography
For patients in the intensive care unit (ICU) or under monitored anesthetic care (MAC), the precise monitoring of sedation depth facilitates the optimization of dosage and prevents adverse complications from underor over-sedation. For this purpose, conventional subjective sedation scales, such as the Observer's Assessment of Alertness/Sedation (OAA/S) or the Ramsay scale, have been widely utilized. Current procedures frequently disturb the patient's comfort and compromise the already well-established sedation. Therefore, reliable objective sedation scales that do not cause disturbances would be beneficial. We aimed to determine whether spectral entropy can be used as a sedation monitor as well as determine its ability to discriminate all levels of propofol-induced sedation during gradual increments of propofol dosage.
In 25 healthy volunteers undergoing general anesthesia, the values of response entropy (RE) and state entropy (SE) corresponding to each OAA/S (5 to 1) were determined. The scores were then analyzed during each 0.5 mcg/ml- incremental increase of a propofol dose.
We observed a reduction of both RE and SE values that correlated with the OAA/S (correlation coefficient of 0.819 in RE-OAA/S and 0.753 in SE-OAA/S). The RE and SE values corresponding to awake (OAA/S score 5), light sedation (OAA/S 3-4) and deep sedation (OAA/S 1-2) displayed differences (P < 0.05).
The results indicate that spectral entropy can be utilized as a reliable objective monitor to determine the depth of propofol-induced sedation.
Entropy; Propofol; Sedation
This study investigates the possibility of a relationship between oversedation and mortality in mechanically ventilated patients. The presence of burst suppression, a pattern of severely decreased brain wave activity on the electroencephalogram, may be unintentionally induced by heavy doses of sedatives. Burst suppression has never been studied as a potential risk factor for death in patients without a known neurologic disorder or injury.
Design: Post hoc
analysis of a prospectively observational cohort study.
Medical intensive care units of a tertiary care, university-based medical center.
A total of 125 mechanically ventilated, adult, critically ill patients.
Measurements and Main Results
A validated arousal scale (Richmond Agitation-Sedation Scale) was used to measure sedation level, and the bispectral index monitor was used to capture electroencephalogram data. Burst suppression occurred in 49 of 125 patients (39%). For analysis, the patients were divided into those with burst suppression (49 of 125, 39%) and those without burst suppression (76 of 125, 61%). All baseline variables were similar between the two groups, with the overall cohort demonstrating a high severity of illness (Acute Physiology and Chronic Health Evaluation II scores of 27.4 ± 8.2) and 98% receiving sedation. Of those with burst suppression, 29 of 49 (59%) died within 6 months compared with 25 of 76 (33%) who did not demonstrate burst suppression. Using time-dependent Cox regression to adjust for clinically important covariates (age, Charlson comorbidity score, baseline dementia, Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment, coma, and delirium), patients who experienced burst suppression were found to have a statistically significant higher 6-month mortality [Hazard’s ratio = 2.04, 95% confidence interval, 1.12–3.70, p = 0.02].
The presence of burst suppression, which was unexpectedly high in this medical intensive care unit population, was an independent predictor of increased risk of death at 6 months. This association should be studied prospectively on a larger scale in mechanically ventilated, critically ill patients.
intensive care; mechanical ventilation; burst suppression; bispectral index; processed encephalogram; sedation; analgesia; delirium
The successful use of conscious sedation in patients physically dependent on centrally acting drugs is problematic for the dental anesthesiologist because of the concomitant development of tolerance to standard sedative agents. Dosage requirements necessary to adequately sedate these patients are often higher than recommended and carry an increased risk of drug overdose. The following report summarizes our experience with 18 drug-dependent patients in whom hypnosis was employed in conjunction with a standard sedation regimen. Attempts to complete various dental procedures while employing sedation alone on these patients had previously failed. All patients exhibited highly fearful or phobic behavior toward dental treatment as assessed by the Corah Dental Anxiety Scale. If an intravenous sedative regimen (midazolam or diazepam plus methohexital) was employed, hypnotic induction preceded the administration of the sedative drugs. If an intramuscular sedative regimen was employed (meperidine plus promethazine), the hypnotic induction took place after drug administration. With the combined hypno-sedative approach, treatment outcomes were judged to be good or excellent in 11 of 18 patients. Interestingly, in five of seven patients for whom the treatment outcome was rated poor or fair, the possibility of tolerance or cross-tolerance existed between a drug being abused and the sedative regimen. In contrast, this possibility existed in only 1 of 11 patients with good or excellent treatment outcomes. We conclude that hypnosis can augment the effects of sedation in this patient population. However, it is also important to choose a sedative regimen where tolerance is unlikely to exist.
Objectives. To review our sedation practice and to evaluate the clinical effectiveness of an anesthesiologist-administered intravenous sedation outside of the main operating room for pediatric upper gastrointestinal endoscopy (UGIE) in Thailand. Subjects and Methods. We undertook a retrospective review of the sedation service records of pediatric patients who underwent UGIE. All endoscopies were performed by a pediatric gastroenterologist. All sedation was administered by staff anesthesiologist or anesthetic personnel. Results. A total of 168 patients (94 boys and 74 girls), with age from 4 months to 12 years, underwent 176 UGIE procedures. Of these, 142 UGIE procedures were performed with intravenous sedation (IVS). The mean sedation time was 23.2 ± 10.0 minutes. Propofol was the most common sedative drugs used. Mean dose of propofol, midazolam and fentanyl was 10.0 ± 7.5 mg/kg/hr, 0.2 ± 0.2 mg/kg/hr, and 2.5 ± 1.2 mcg/kg/hr, respectively. Complications relatively occurred frequently. All sedations were successful. However, two patients became more deeply than intended and required unplanned endotracheal intubation. Conclusion. The study shows the clinical effectiveness of an anesthesiologist-administered IVS outside of the main operating room for pediatric UGIE in Thailand. All complications are relatively high. We recommend the use of more sensitive equipments such as end tidal CO2 and carefully select more appropriate patients.
Objective assessment of sedation depth is a valuable target. Spectral entropy is an anesthetic depth monitor based on the analysis of the electroencephalogram signal.
To evaluate the performance of spectral entropy as an objective measure of sedation state in midazolam-premedicated patients and to correlate it with a clinically assessed sedation score.
Settings and Design:
This prospective double-blind placebo-controlled study was performed in King Fahd Hospital of the university.
Eighty adult ASA I–II patients were randomly assigned into 4 groups. Patients were premedicated using 0.02, 0.04, or 0.06 mg/kg midazolam or saline intramuscularly. The effect of these doses on the Observer's Assessment of Alertness and Sedation (OAA/S) scale, hemodynamic variables, response entropy (RE), and state entropy (SE), was evaluated at 10, 20, and 30 min after premedication.
Spearman Rank-order correlation analysis to examine the relation between OAA/S and entropy. The ability of spectral entropy to predict the depth of sedation was evaluated using Smith prediction probability.
Midazolam doses ≥0.04 mg/kg produced significant decreases in RE, SE, and OAA/S scores. There was a strong correlation between midazolam dose and OAA/S scale, RE, and SE since Spearman Rank R values were 0.792, 0.822, and 0.745, respectively (P<0.001). In addition, RE and SE were strong predictors of OAA/S level during midazolam sedation with no significant difference in prediction between the 2 entropy components.
Spectral entropy is a reliable measure for the sedative premedication. It may be used to objectively assess the adequacy of midazolam premedication and to determine the dose requirement.
Monitoring; depth of anaesthesia; observer's assessment of alertness and sedation; premedication; midazolam; sedation
Background. Ketamine sedation has been found superior by physician report to traditional sedation regimens for pediatric endoscopy. Goal. To objectively compare sedation with ketamine versus midazolam/fentanyl for children undergoing gastrointestinal endoscopy. Study. Patients received one of two regimens and were independently monitored using a standardized rating scale. Results. There were 2 episodes of laryngospasm during ketamine sedation. Univariate analyses showed patients sedated with ketamine (n = 17) moved more (median 25% of procedure time versus 8%, P = .03) and required similar low levels of restraint (0.83% versus 0.25%, P = .4) as patients sedated with midazolam/fentanyl (n = 20). Age-adjusted analyses suggested that patients sedated with ketamine were comparably more quiet (P = .002). Conclusions. A pilot trial of ketamine at our institution was associated with episodes of laryngospasm. In addition, children sedated with ketamine moved and required restraint similarly to patients sedated with midazolam/fentanyl. Physician perceptions may be affected by the fact that children who received ketamine were less likely to vocalize distress.
To assess whether monitoring sedation status using bispectral index (BIS) as an adjunct to clinical evaluation was associated with a reduction in the total amount of sedative drug used in a 12 h period.
Prospective randomized controlled clinical trial.
Tertiary care neurocritical care unit.
Sixty-seven mechanically ventilated adult patients receiving continuous intravenous sedation with propofol.
Sedation monitoring using clinical assessment with the Ramsay scale (Ramsay-alone group) or clinical assessment plus BIS monitoring (BIS-augmentation group). Subjects were randomized to Ramsay-alone (n = 35), or BIS-augmentation (n = 32). Nurses adjusted the dose of propofol to a Ramsay of 4, or a Ramsay of 4 and BIS between 60 and 70.
Measurements and Main Results
Patients in the BIS-augmentation group received significantly less propofol by volume (93.5 ml vs. 157.8 ml, respectively; P < .015), and had lower infusion rates (14.6 vs. 27.9 mcg/kg/min; P = .003). There is a lower risk of propofol infusion exceeding manufacturer’s recommended dosing guides in the BIS-augmentation group versus the Ramsay-alone group (0 vs. 23%, P = .0052). The BIS-augmentation group woke up much quicker than those in the Ramsay-alone group (1.2 vs. 7.5 min; P < .0001).
BIS-augmented sedation monitoring resulted in a marked reduction in the total dose of sedative used to achieve the same level of clinical sedation resulting in shortened time to wake up without any measurable adverse effects. Physiologic sedation assessment tools may provide a useful means of improving the care of sedated critically ill patients.
Sedation assessment; Nursing care; Critical care; Neurofunction monitoring; Neurocritical care
Moderate to deep sedation is generally used for endoscopic retrograde cholangiopancreatography (ERCP). The depth of sedation is usually judged by clinical assessment and electroencephalography-guided monitoring. The aim of this study was to compare the clinical efficacy of clinical assessment and NarcotrendTM monitoring during deep-sedated ERCP.
One hundred patients who underwent ERCP in a single year were randomly assigned to either group C or group N. Patients in group C (52) were sedated using the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale. Patients in group N (48) were sedated using the NarcotrendTM system. The MOAA/S scale 1 or 2 and the NarcotrendTM index 47–56 to 57–64 were maintained during the procedure. The primary outcome variable of the study was the successful completion of the endoscopic procedure. The secondary outcome variables were the total dose of propofol used during the procedure, complications during and immediately after procedure, and recovery time.
All endoscopies were completed successfully. The mean total dose of propofol in group C was significantly lower than that in group N. However, the mean dose of propofol, expressed as dose/kg or dose/kg/h in both groups, was not significantly different (P = 0.497, 0.136). Recovery time, patient tolerance and satisfaction, and endoscopist satisfaction were comparable between the two groups. All sedation-related adverse events during and immediately after the procedure, such as hypotension, hypertension, tachycardia, bradycardia, transient hypoxia, and upper airway obstruction, in group C (62.2%) were significantly higher than in group N (37.5%) (P = 0.028).
Clinical assessment and NarcotrendTM-guided sedation using propofol for deep sedation demonstrated comparable propofol dose and recovery time. Both monitoring systems were equally safe and effective. However, the NarcotrendTM-guided sedation showed lower hemodynamic changes and fewer complications compared with the clinical assessment-guided sedation.
deep sedation; endoscopic retrograde cholangiopancreatography; clinical assessment; NarcotrendTM monitoring
Brain function monitors have improved safety and efficiency in general anesthesia; however, they have not been adequately tested for guiding conscious sedation for periodontal surgical procedures. This study evaluated the patient state index (PSI) obtained from the SEDline monitor (Sedline Inc., San Diego, CA) to determine its capacity to improve the safety and efficiency of intravenous conscious sedation during outpatient periodontal surgery. Twenty-one patients at the periodontics clinic of Baylor College of Dentistry were admitted to the study in 2009 and sedated to a moderate level using midazolam and fentanyl during periodontal surgery. The PSI monitoring was blinded from the clinician, and the following data were collected: vital signs, Ramsay sedation scale (RSS), medications administered, adverse events, PSI, electroencephalography, and the patients' perspective through visual analogue scales. The data were correlated to evaluate the PSI's ability to assess the level of sedation. Results showed that the RSS and PSI did not correlate (r = −0.25) unless high values associated with electromyographical (EMG) activity were corrected (r = −0.47). Oxygen desaturation did not correlate with the PSI (r = −0.08). Satisfaction (r = −0.57) and amnesia (r = −0.55) both increased as the average PSI decreased. In conclusion, within the limits of this study, PSI appears to correlate with amnesia, allowing a practitioner to titrate medications to that effect. It did not provide advance warning of adverse events and had inherent inaccuracies due to EMG activity during oral surgery. The PSI has the potential to increase safety and efficiency in conscious sedation but requires further development to eliminate EMG activity from confounding the score.
Most clinicians give sedatives and analgesics according to their professional experience and the patient's estimated need for sedation. However, this approach is prone to error. Inadequate monitoring of sedation and analgesia may contribute to adverse outcomes and complications. With this in mind, data obtained continuously using nonstimulating methods such as bispectral index (BIS) may have benefits in comparison with clinical monitoring of sedation. The aim of this prospective observational trial was to evaluate the use of electroencephalographic (EEG) BIS for monitoring sedation in paediatric intensive care unit (PICU) patients.
Forty paediatric patients (<18 years) were sedated for mechanical ventilation in a cardiac surgical and general PICU. In each paediatric patient BIS and COMFORT score were obtained. The study protocol did not influence ongoing PICU therapy. BIS and corresponding COMFORT score were collected three times for each patient. Measurements with the best starting EEG impedances were analyzed further. Deep sedation was defined as a COMFORT score between 8 and 16, and light sedation as a score between 17 and 26. Biometric and physiological data, and Pediatric Risk of Mortality III scores were also recorded.
There was a good correlation (Spearman's rho 0.651; P = 0.001) between BIS and COMFORT score in the presence of deep sedation and low starting impedance. Receiver operating characteristic (ROC) analysis revealed best discrimination between deep and light sedation at a BIS level of 83.
In the presence of deep sedation, BIS correlated satisfactorily with COMFORT score results if low EEG impedances were guaranteed.
bispectral index; electroencephalography; intensive care unit; paediatric; sedation
Propofol induced sedation with bispectral index (BIS) monitoring has been reported to lead to higher satisfaction in patients and endoscopists during endoscopic submucosal dissection (ESD) procedures. There are no data, however, regarding the efficacy of midazolam and meperidine (M/M) induced sedation with BIS monitoring during ESD. The purpose of this study was to evaluate whether M/M induced sedation with BIS monitoring could improve satisfaction and reduce the dose of M/M required during ESD.
Between September 2009 and January 2010, 56 patients were prospectively enrolled and randomly assigned to a BIS group (n=28) and a non-BIS group (n=28). Patient and endoscopist satisfaction scores were assessed using the visual analog scale (0 to 100) following the ESD.
The mean satisfaction scores did not significantly differ between the BIS and non-BIS groups (92.3±16.3 vs 93.3±15.5, p=0.53) or endoscopists (83.1±15.4 vs 80.0±16.7, p=0.52). Although the mean meperidine dose did not differ (62.5±27.6 vs 51.0±17.3, p=0.18) between the two groups, the mean dose of midazolam in the non-BIS group was lower than in the BIS group (6.8±2.0 vs 5.4±2.1, p=0.01).
BIS monitoring during ESD did not increase the satisfaction of endoscopists or patients and did not lead to an M/M dose reduction. These results demonstrate that BIS monitoring provides no additional benefit to M/M induced sedation during ESD.
Bispectral index monitoring; Satisfaction; Midazolam; Endoscopic submucosal dissection
Oral midazolam is being used for conscious sedation in dentistry with little documentation assessing its efficacy. In order to accumulate preliminary data, a randomized, double-blind, controlled, crossover, multi-site pilot study was conducted. The objective was to determine if 0.6 mg/kg of oral midazolam was an equally effective or superior means of achieving conscious sedation in the uncooperative pediatric dental patient, compared with a commonly used agent, 50 mg/kg of oral chloral hydrate. Twenty-three children in three clinics who required dentistry with local anesthetic and were determined to exhibit behavior rated as "negative" or "definitely negative" based on the Frankl scale were assessed. They were evaluated with respect to acceptance of medication; initial level of anxiety at each appointment; level of sedation prior to and acceptance of local anesthetic; movement and crying during the procedure; and overall behavior. The results showed that the group randomly assigned to receive midazolam had a significantly greater initial level of anxiety for that appointment (P < 0.02), a finding that could clearly confound further determination of the efficacy of these drugs. Patients given oral midazolam had an increased level of sedation prior to the administration of local anesthetic compared with those given chloral hydrate (P < 0.015). No statistically significant differences were noted in any of the other parameters. The age of the patient was found to have no correlation with the difference in overall behavior (r = -0.09). These preliminary data warrant further clinical trials.
Bispectral Index (BIS) has been used to monitor level of “sedation” based on the electroencephalogram (EEG). Patients evaluated for surgery to control a seizure disorder undergo Wada testing, during which one hemisphere is rendered functionally inactive after injecting a short-acting barbiturate. We surmised that the BIS values would reflect these functional changes. Eight epileptic patients were enrolled. A full array of 21 EEG electrodes and 2 BIS XP (Quatro) strips over each frontal region of the scalp were applied. The EEG was continuously recorded. BIS values from each hemisphere were recorded every minute. Angiography was performed by advancing a catheter into each internal carotid artery. Amobarbital or methohexital was injected until the patient developed a hemiparesis. The EEG confirmed a significant lateralized cortical effect of the barbiturate. Repeated measures analysis of variance was used to analyze the differences between the BIS values from monitor electrode strips placed on the left (left BIS) and the right (right BIS) sides of the head as well as the differences in the left and right BIS values before and after each injection of the barbiturate. Injection of barbiturate into either the left or right internal carotid artery produced a significant change on the 21-electrode EEG. However, there was no difference between left BIS to right BIS values (P = 0.84). With repeated injections of barbiturates, some patients became sedated. At these times, both left BIS and right BIS values decreased together before and after injection of barbiturate. The BIS monitor was unable to distinguish significant hemispheric EEG and clinical functional changes except when the patient became sedated.