Modified Observer's Assessment Of Alertness/Sedation Scale Research Articles

Quantified Ataxic Breathing Can Detect Opioid-Induced Respiratory Depression Earlier in Normal Volunteers Infused with Remifentanil.

Ataxic breathing (AB) is a well-known manifestation of opioid effects in animals and humans, but is not routinely included in monitoring for opioid-induced respiratory depression (OIRD). We quantified AB in normal volunteers receiving increasing doses of remifentanil. We used a support vector machine (SVM) learning approach with features derived from a modified Poincaré plot. We tested the hypothesis that AB may be found when bradypnea and reduced mental status are not present. Twenty-six healthy volunteers (13 female) received escalating target effect-site concentrations of remifentanil with a low baseline dose of propofol to simulate typical breathing patterns in drowsy patients who had received parenteral opioids. We derived respiratory rate (RR) from respiratory inductance plethysmography, mental alertness from the Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S), and AB severity on a 0 to 4 scale (categories ranging from none to severe) from the SVM. The primary outcome measure was sensitivity and specificity for AB to detect OIRD. All respiratory measurements were obtained from unperturbed subjects during steady state in 121 assessments with complete data. The sensitivity of AB for detecting OIRD by the conventional method was 92% and specificity was 28%. As expected, 69 (72%) of the instances not diagnosed as OIRD using conventional measures were observed to have at least moderate AB. AB was frequently present in the absence of traditionally detected OIRD as defined by reduced mental alertness (MOAA/S score of <4) and bradypnea (RR <8 breaths/min). These results justify the need for future trials to explore replicability with other opioids and clinical utility of AB as an add-on measure in recognizing OIRD.

Efficacy and safety of remimazolam versus propofol for intraoperative sedation during regional anesthesia: A phase II, multicenter, randomized, active-controlled, single-blind clinical trial.

This study aimed to evaluate the efficacy and safety of remimazolam for intraoperative sedation during regional anesthesia. It was a phase II-multicenter, randomized, single-blind, parallel-group, active-controlled clinical trial (No. ChiCTR2100054956). From May 6, 2021 to July 4, 2021, patients were randomly enrolled from 17 hospitals in China. A total of 105 patients aged 18-65 years who underwent selective surgery under regional anesthesia were included. Patients received different sedatives with different dosages: 0.1 mg/kg remimazolam (HR), 0.05 mg/kg remimazolam (LR), or 1.0 mg/kg propofol (P) group, followed by a maintenance infusion. Main outcome measures included the efficacy of sedation measured by Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) levels (1-4, 1-3, 2-3, 3, and 2-4) during the sedation procedure (the duration percentage) and incidence of adverse reactions. It showed that the duration percentage of MOAA/S levels 1-4 was 100.0 [8.1]% (median [interquartile range]), 89.9 [20.2]%, 100.0 [7.7]% in the HR, LR, and P groups, respectively. The percentage of patients in the HR, LR, and P groups who achieved MOAA/S levels 1-4 within 3 min after administration was 85.7%, 58.8%, and 82.9%, respectively. However, the time to recovery from anesthesia after withdrawal of sedatives (7.9 ± 5.7 min), incidence of anterograde amnesia (75%), and adverse effects were not statistically significant among the three groups. These findings suggest that a loading dose of remimazolam 0.1 mg/kg followed by a maintenance infusion of 0-3 mg/kg/h provides adequate sedation for patients under regional anesthesia without increasing adverse reactions.

Intranasal dexmedetomidine is an effective sedative agent for electroencephalography in children

BackgroundIntranasal dexmedetomidine (DEX), as a novel sedation method, has been used in many clinical examinations of infants and children. However, the safety and efficacy of this method for electroencephalography (EEG) in children is limited. In this study, we performed a large-scale clinical case analysis of patients who received this sedation method. The purpose of this study was to evaluate the safety and efficacy of intranasal DEX for sedation in children during EEG.MethodsThis was a retrospective study. The inclusion criteria were children who underwent EEG from October 2016 to October 2018 at the Children’s Hospital affiliated with Chongqing Medical University. All the children received 2.5 μg·kg− 1 of intranasal DEX for sedation during the procedure. We used the Modified Observer Assessment of Alertness/Sedation Scale (MOAA/S) and the Modified Aldrete score (MAS) to evaluate the effects of the treatment on sedation and resuscitation. The sex, age, weight, American Society of Anesthesiologists physical status (ASAPS), vital signs, sedation onset and recovery times, sedation success rate, and adverse patient events were recorded.ResultsA total of 3475 cases were collected and analysed in this study. The success rate of the initial dose was 87.0% (3024/3475 cases), and the success rate of intranasal sedation rescue was 60.8% (274/451 cases). The median sedation onset time was 19 mins (IQR: 17–22 min), and the sedation recovery time was 41 mins (IQR: 36–47 min). The total incidence of adverse events was 0.95% (33/3475 cases), and no serious adverse events occurred.ConclusionsIntranasal DEX (2.5 μg·kg− 1) can be safely and effectively used for EEG sedation in children.

Effects of etomidate on bispectral index scale and spectral entropy during induction of anesthesia by means of the raw electroencephalographic and electromyographic characteristics.

BackgroundEtomidate frequently induces myoclonus, so it may affect electromyographics (EMG). And EMG commonly has an effect on the bispectral index scale (BIS) and spectral entropy. This study was performed to compare the effect of etomidate on BIS, response entropy (RE) and state entropy (SE) during induction of anesthesia.MethodsFifty patients (ASA I or II) scheduled for elective surgery were included in this study. Anesthesia was induced with etomidate (0.3 mg/kg) and rocuronium (0.6 mg/kg). Patients also inhaled 4 vol% sevoflurane and 100% oxygen and, then intubated. BIS, RE, SE and Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) were measured 4 times (before injection of etomidate [T0], at loss of eyelash reflex [T1], 90 seconds after rocuronium injection [T2], and after intubation [T3]). We also checked whether myoclonus occurred.ResultsBaseline values (T0) were 93.1 ± 4.7 for BIS, 95.8 ± 3.7 for RE and, 87.3 ± 3.5 for SE. In comparison with T0, there were significantly differences in BIS (50.2 ± 16.3), RE (76.8 ± 18.5) and SE (66.3 ± 17.4) at T1 (all P < 0.05). There were no significant differences at T2 and T3. Thirty one patients had myoclonus. At the occurrence of myoclonus, RE and SE values significantly increased but not BIS (P < 0.05).ConclusionsIn patients with myoclonus, at the loss of consciousness, spectral entropy did not decrease where as BIS did, suggesting that BIS may evaluate hypnotic levels better than spectral entropy during induction of anesthesia with etomidate.

Bi-spectral index, entropy and predicted plasma propofol concentrations with target controlled infusions in Indian patients

Many processed electroencephalographic signals are used now to help the anaesthesiologist titrate the depth of sedation. We investigated the relationship between target plasma propofol concentration and objective end-points of sedation- Bispectral Index (BIS), State Entropy (SE) and Response Entropy (RE)-at clinical end-points as assessed by Modified Observer Assessment of Alertness/sedation Scale (MOAAS) in Indian patients. Eighteen ASA 1 and 2 Indian adult patients scheduled to undergo elective surgery were included. The target control infusion (TCI) of propofol was administered using 'Diprifusor'. The level of sedation was assessed using MOAAS by the anaesthesiologist. BIS, SE, RE were recorded throughout. TCI was started at 0.5μg/ml and increased by 0.5μg/ml every 6min till MOAAS scores reached 0 or there was sustained BIS value less than 30. The EC(50) and EC(95) of predicted plasma propofol concentration for loss of consciousness (assessed by loss of response to verbal command), were 2.3 and 2.8μg/ml respectively and for loss of response to painful stimuli (trapezius squeeze) were 4.0 and 5.0μg/ml respectively. The BIS and entropy values (EC(50) and EC(95)) for loss of consciousness and response to painful stimuli in Indian patients were estimated. The preliminary relation of target plasma propofol concentration with BIS was found to be BIS=100.5-16.4 × (Target concentration). The target plasma propofol concentrations required to produce unconsciousness and loss of response to painful stimuli in Indian patients have been estimated. Also, the relations between target plasma concentration and objective measures of different levels of anaesthesia have been established.

Comparison of Entropy and Bispectral Index during Propofol and Fentanyl Sedation in Monitored Anaesthesia Care

Comparison of entropy (state entropy [SE] and response entropy [RE]) with the bispectral index (BIS) during propofol sedation in monitored anaesthesia care (MAC) was carried out in patients undergoing hand surgery. Thirty candidates for elective hand surgery were pre-medicated with midazolam 0.06 mg/kg and atropine 0.01 mg/kg. Sedation was induced with intravenous propofol and fentanyl was also administered. The Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) was used to determine sedation level and pain was maintained at < 4 on a 0 - 10 verbal rating scale. The BIS, entropy, MOAA/S and pain values were recorded before initiation of sedation (control), during initiation of sedation, during surgery, and for 30 min after the end of surgery and anaesthesia. On initiation of sedation, entropy decreased more rapidly than BIS. At 10 min after initiation of sedation, the mean +/- SD values for MOAA/S, BIS, RE and SE were 3.00 +/- 0.36, 85.45 +/- 0.15, 74.00 +/- 0.60 and 72.02 +/- 0.12, respectively. During recovery, BIS and RE and SE increased in parallel with MOAA/S. It is concluded that entropy monitoring is as reliable as BIS monitoring in MAC.

Bispectral Index Monitoring for Nurse-Administered Propofol Sedation During Upper Endoscopic Ultrasound: A Prospective, Randomized Controlled Trial

Bispectral index monitoring (BIS) is a quantitative assessment of brain cortical activity. The aim of this study was to determine if BIS-guided nurse-administered propofol sedation would decrease by > or = 20% both recovery time and propofol dose compared to standard propofol sedation for endoscopic ultrasound (EUS). Prospectively, eligible outpatients were randomized to BIS-guided or standard propofol sedation during EUS. Propofol was given by nurses in intermittent boluses with sedation targeted at a BIS score of < 65-75. For the control group, the nurse was blinded to BIS scores and sedation was titrated to a modified observer's assessment of alertness/sedation scale (MOAA/S) score < or = 3. Of 50 patients enrolled, data for 44 randomized to BIS-guidance (n = 24) and the control group (n = 20) were evaluated. Between the BIS-guided and control group there was no difference between the mean procedure duration, total propofol dose, recovery time, mean intraoperative MOAA/S, and mean BIS score. Compared to standard propofol sedation for EUS, BIS-guided propofol sedation offers no significant decrease in postprocedure recovery times or propofol doses.

A reply

We would like to thank Dr Crocker and colleagues for their interest in our study. We are happy to respond to the queries that they raised. Firstly, in the Modified Observer's Assessment of Alertness/Sedation (OAAS) scale, level 1 describes a patient who responds to painful trapezius squeeze, and level 2 corresponds to a patient who responds to mild prodding or shaking. We did not want to apply painful stimuli to assess the alertness or sedation status of our patients. Therefore, level 2 was defined by us as a patient who does not respond to mild prodding or shaking, and this level was then regarded as a surrogate for loss of consciousness. We agree with Crocker et al. that we actually used a modified OAAS scale. Second, we are aware that one limitation of our study was the lack of measurements of propofol plasma concentrations; this was pointed out by us in the discussion of our paper. It remains unclear, however, whether plasma concentrations would have improved the validity of our findings. Finally, alcohol and nicotine consumption may indeed be linked in some individuals. Thus, we cannot rule out that in our study cohort, alcohol consumption was a confounding factor. In the absence of valid data on the impact of alcohol consumption on the hypnotic efficacy of propofol, this assumption, however, remains speculative.

Comparative evaluation of the cerebral state index and the bispectral index during target-controlled infusion of propofol

Cerebral state index (CSI) has recently been introduced as an intra-operative monitor of anaesthetic depth. We compared the performance of the CSI to the bispectral index (BIS) in measuring depth of anaesthesia during target-controlled infusion (TCI) of propofol. Twenty Chinese patients undergoing general anaesthesia were recruited. CSI and BIS, and predicted effect-site concentration of propofol were recorded. The level of sedation was tested by Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS) every 20 s during stepwise increase (TCI, 0.5 microg ml(-1)) of propofol. The loss of verbal contact (LVC) and loss of response (LOR) were defined by MOAAS values of 2-3 and less than 2, respectively. Baseline variability and the prediction probability (P(K)) were calculated for the BIS and CSI. The values of BIS(05) and CSI(05), BIS(50) and CSI(50), BIS(95) and CSI(95) were calculated at each end-point (LVC and LOR). Baseline variability of CSI was more than that of BIS. Both CSI and BIS showed a high prediction probability for the steps awake vs LVC, awake vs LOR, and LVC vs LOR, and good correlations with MOAAS values. Despite larger baseline variation, CSI performed as well as BIS in terms of P(K) values and correlations with step changes in sedation.

The Influences of Clonidine Premedication on the Bispectral Index and Hemodynamics during the Induction of Anesthesia and Endotracheal Intubation with Propofol

Background: The bispectral index (BIS) has been used as an indicator of a sedative state. In this study, we investigated the influence of intravenous clonidine 2 or 3/kg on the bispectral index and cardiovascular response to anesthetic induction. Methods: The study design is prospective, randomized and double-blind. Ninety patients scheduled to undergo elective surgery under general anesthesia were divided into 3 groups. Each group received no premedication (group 1, n = 30), clonidine 2/kg (group 2, n = 30) and clonidine 3/kg (group 3, n = 30). The sedation and responsiveness scores of the Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS/S) were measured before induction and the BIS, blood pressure, and heart rate were measured at before induction, after propofol injection, and after intubation. Results: The BIS was significantly lower in groups 2 and 3 than in group 1 before anesthetic induction and intubation. Mean blood pressure was significantly lower in groups 2 and 3 than in group 1 before anesthetic induction, after propofol infusion and after intubation. Heart rate was also significantly lower in groups 2 and 3 than in group 1 after intubation. The sedation score and MOAAS/S were significantly lower in groups 2 and 3 than in group 1. Conclusions: Clonidine-premedicated patients appear to maintain stable hemodynamics during anesthetic induction and intubation. The bispectral index can be objectively used in clonidine-premedicated patients when evaluating the degree of sedation.