Correlation between the Sedation-Agitation Scale and the Bispectral Index in ventilated patients in the intensive care unit

ArticleinHeart & lung: the journal of critical care 38(4):336-45 · July 2009with49 Reads
DOI: 10.1016/j.hrtlng.2008.10.010 · Source: PubMed
Abstract
Oversedation masks neurologic changes and increases mortality/morbidity, whereas undersedation risks prolonged stress mobilization and patient injury. In situations such as deep sedation/analgesia, the Bispectral Index (BIS) has potential use as an adjunct to clinical assessment of sedation to help determine depth of sedation. Determining the correlation between clinical and BIS measures of sedation will help to determine the correct role of BIS in intensive care unit (ICU) practice settings. To evaluate the correlation between the clinical assessment of sedation using the Sedation-Agitation Scale (SAS) and the assessment using BIS in ventilated and sedated ICU patients. ICU patients requiring mechanical ventilation and sedation were monitored using the SAS and BIS. Nurses initiated event markers with BIS at the time of SAS assessment but were blinded to BIS scores. Data were collected on 40 subjects generating 209 paired readings. Moderate positive correlation between BIS and SAS values was shown with a Spearman Rank coefficient r value of .502 and an r(2) of .252 (P < .0001). Wide ranges of BIS scores were observed, especially in very sedated patients. Strong positive correlation was noted between BIS and electromyography with an r value of .749 (P < .0001). Age and gender significantly influenced BIS/SAS correlations. In situations in which the clinical assessment is equivocal, BIS monitoring may have an adjunctive role in sedation assessment. BIS values should be interpreted with caution, however, because electromyography activity and other factors seem to confound BIS scores. More research is necessary to determine the role of BIS monitoring in ICU practice.
    • "There was a weak correlation observed between BIS during paralysis and RASS upon emergence from paralysis but statistical significance was not achieved as we were not powered to detect such a small magnitude of correlation (Fig. 4). The correlation observed in this study was weaker than that found in most previously published studies conducted in non-paralyzed ICU patients [13][14][15][16]. The likely explanation is the difference in the ability of RASS and BIS TM to detect differences in level of sedation throughout the entire spectrum of sedation and agitation. "
    [Show abstract] [Hide abstract] ABSTRACT: Background: Patients receiving therapeutic paralysis may experience inadequate sedation due to intrinsic limitations of behavioral sedation assessment. Bispectral index (BIS™) provides an objective measure of sedation; however, the role of BIS™ is not well defined in intensive care unit (ICU) patients on neuromuscular blocking agents (NMBA). Objective: The aim of this study was to delineate the relationship between BIS™ and level of sedation for critically ill patients during therapeutic paralysis. Methods: This was a retrospective observational study conducted in ICU patients receiving continuous infusion NMBA and BIS™ monitoring. The primary endpoint was the correlation of BIS™ <60 during therapeutic paralysis with a Richmond Agitation Sedation Score (RASS) of -4 to -5 (i.e., deep or unarousable sedation) at the time of emergence from therapeutic paralysis. Results: Thirty-one patients were included in the analysis. Three of these patients (9.6 %) were inadequately sedated upon emergence from paralysis; that is, restless or agitated (RASS +1 to +2). We did not observe a correlation between BIS™ and RASS upon emergence from paralysis (r = 0.27, p = 0.14). The sensitivity of BIS™ <60 in predicting deep sedation (RASS -5 to -4) was 100 % (95 % confidence interval [CI] 0-100) with a positive predictive value of 35.7 %. The sensitivity and positive predictive value of BIS™ <60 in predicting light sedation or deeper (RASS -5 to -2) was 92.9 % (95 %CI 83.3-100) and 92.9 %, respectively. Conclusion: These results suggest that 1 in 10 critically ill patients receiving therapeutic paralysis may be inadequately sedated. BIS™ monitoring may serve as a useful adjunctive measure of sedation in critically ill patients receiving therapeutic paralysis.
    Full-text · Article · May 2016
    • "For example it is known that electromyographic (EMG) activity interferes significantly with the cerebral electrical activity. In no clinical trial, reporting wide inter individual variability, neuromuscular blockers were included explicitly in the study protocol; the only exception is Arbour R et al. [26]'s study where neuromuscular blockers were administered to two patients out of a total of forty patients. Therefore the presence of electromyographic (EMG) activity can be one of the reasons of the wide inter individual variability of the objective methods for sedation monitoring. "
    [Show abstract] [Hide abstract] ABSTRACT: In our daily practice in intensive care unit, one of the “cornerstones” is to achieve adequate sedation for every patient. Intensive care unit (ICU) patients are often sedated, and a good hypnotic monitoring is important to assure an optimal level of sedation for every patient. Sedation monitoring can be achieved using subjective or objective methods. The most recent recommendations on management of sedation were published by Critical Care Medicine in January 2013. They recommend the use of subjective methods as the primary method to monitor sedation, with the use of objective methods only in paralyzed and comatose patients, in whom subjective methods cannot be used. Unfortunately in these last recommendations, the objective methods of sedation monitoring are listed without indicating any of them as the best method actually available to assure an adequate sedation. The aim of our study is to review the characteristics of each objective method of sedation monitoring, in order to understand which is the most appropriate in the current state. We found that several objective methods are adequate to monitor the level of sedation in paralyzed or comatose patients, although the data needs to be considered with caution, Bispectral Index (BIS) is suggested as the best method for monitoring sedation in most studies.
    Full-text · Article · May 2014 · International Journal of Pediatrics
    • "Vet et al. [27] did not find a correlation between inflammation severity and COMFORT score. Trouiller et al. [64] and Arbor et al. [65] said that the optimal measure to monitor the pharmacodynamic endpoint still needs to be determined. Dosing regimens in children are based upon rather empirical extrapolations from the dosing regimens in adults. "
    [Show abstract] [Hide abstract] ABSTRACT: Midazolam is a benzodiazepine with rapid onset of action and short duration of effect. In healthy neonates the half-life (t 1/2) and the clearance (Cl) are 3.3-fold longer and 3.7-fold smaller, respectively, than in adults. The volume of distribution (Vd) is 1.1 L/kg both in neonates and adults. Midazolam is hydroxylated by CYP3A4 and CYP3A5; the activities of these enzymes surge in the liver in the first weeks of life and thus the metabolic rate of midazolam is lower in neonates than in adults. Midazolam acts as a sedative, as an antiepileptic, for those infants who are refractory to standard antiepileptic therapy, and as an anaesthetic. Information of midazolam as an anaesthetic in infants are very little. Midazolam is usually administered intravenously; when minimal sedation is required, intranasal administration of midazolam is employed. Disease affects the pharmacokinetics of midazolam in neonates; multiple organ failure reduces the Cl of midazolam and mechanical ventilation prolongs the t 1/2 of this drug. ECMO therapy increases t 1/2, Cl, and Vd of midazolam several times. The adverse effects of midazolam in neonates are scarce: pain, tenderness, and thrombophlebitis may occur. Respiratory depression and hypotension appear in a limited percentage of infants following intravenous infusion of midazolam. In conclusion, midazolam is a safe and effective drug which is employed as a sedative, as antiepileptic agent, for infants who are refractory to standard antiepileptic therapy, and as an anaesthetic.
    Full-text · Article · Feb 2014
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