Correlation between the Sedation-Agitation Scale and the Bispectral Index in ventilated patients in the intensive care unit.
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.
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ABSTRACT: To describe intensive care nurses' perceptions of unit and personal sedation practice in the context of nursing and medical treatment of adult intensive care patients sedated and ventilated for more than 24 hours. Self-administered questionnaire. Three general ICUs in three university hospitals in Norway. Eighty-six questionnaires were returned (response rate 47%). Continuous infusions of fentanyl and midazolam were perceived as most common and nurses often gave both analgesics and sedatives prior to care. Daily interruption of sedation or analgesia-based sedation was not perceived as practice in the units. MAAS was most commonly used, whilst protocols or objective scoring systems were not. Documentation of sedation levels was fairly routine, whereas documentation of patient needs was not perceived as important. Collaboration with physicians was viewed as most important, whilst no significance was assigned to collaboration with relatives. The study shows that a focus on analgesia-based sedation and continual control of the sedation level should be considered in order to decrease the risk of oversedation. Inclusion of relatives' opinions, increased collaboration between nurses and physicians, and implementation of sedation tools, may contribute to even better patient outcome and should be focus in further studies.Intensive & critical care nursing: the official journal of the British Association of Critical Care Nurses 10/2010; 26(5):270-7. DOI:10.1016/j.iccn.2010.06.006
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ABSTRACT: Actigraphic data during simulated participant movements were evaluated to differentiate among patient behavior states. Arm and leg actigraphic data were collected on 30 volunteers who simulated 3 behavioral states (calm, restless, agitated) for 10 minutes; counts of observed participant movements (head, torso, extremities) were documented. The mean age of participants was 34.7 years, and 60% were female. Average movement was significantly different among the states (P < .0001; calm [mean = .48], restless [mean = 2.16], agitated [mean = 3.75]). Mean actigraphic measures were significantly different among states for both arm (P < .0001; calm [mean = 6.8], restless [mean = 28.5], agitated [mean = 52.6]) and leg (P < .0001; calm [mean = 3.5], restless [mean = 18.7], agitated [mean = 37.7]). Distinct levels of behavioral states were successfully simulated. Actigraphic data can provide an objective indicator of patient activity over a variety of behavioral states, and these data may offer a standard for comparison among these states.Heart & lung: the journal of critical care 05/2011; 40(3):e52-9. DOI:10.1016/j.hrtlng.2009.12.013 · 1.32 Impact Factor
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ABSTRACT: This study tested the hypothesis that the bispectral index (BIS) is reliable relative to clinical judgment for estimating sedation level during daily propofol spontaneous awakening trials (SATs) in trauma patients. This was a prospective observational trial with waiver of consent conducted in the intensive care unit of Level I trauma center in 94 mechanically ventilated trauma patients sedated with propofol alone or in combination with midazolam. BIS, Richmond Agitation Sedation Scale (RASS), electromyography, and heart rate variability, as a test of autonomic function, were measured for 45 minutes during daily SATs. Data were evaluated with analysis of variance, linear regression, and nonparametric tests. The BIS wave form coincided almost exactly with propofol on/off. Steady-state BIS correlated with RASS (p < 0.0001) and with propofol dose (p < 0.0001), but the strengths of association were relatively low (all r(2) < 0.5). BIS wave form was not altered by age, heart rate, or heart rate variability and was similar with propofol alone or propofol plus midazolam, but the presence of brain injury or the use of paralytics shifted the curve downward (both p < 0.001). The overall test characteristics for BIS versus RASS without neuromuscular blockade were sensitivity: 90% versus 77% (p = 0.034); specificity: 90% versus 75% (p = 0.021); positive predictive value: 90% versus 76% (p = 0.021), and negative predictive value: 90% versus 76% (p = 0.021). In the first trial in trauma patients and largest trial in any surgical population, the (1) BIS was reliable and has advantages over RASS of being continuous and objective, at least during a propofol SAT; (2) BIS interpretation remains somewhat subjective in patients receiving paralytic agents or with traumatic brain injury.The Journal of trauma 07/2011; 71(5):1415-21. DOI:10.1097/TA.0b013e3182178b8b · 2.96 Impact Factor