Correlation between the Sedation-Agitation Scale and the Bispectral Index in ventilated patients in the intensive care unit
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.
Available from: PubMed Central
- "Vet et al.  did not find a correlation between inflammation severity and COMFORT score. Trouiller et al.  and Arbour et al.  stated that the optimal measure, to monitor the pharmacodynamic endpoint, still needs to be determined. "
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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.
Available from: Ida Torunn Bjørk
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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.
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.
Available from: Jessica M Ketchum
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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.
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