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Crit Care. 2010; 14(Suppl 1): P489.
Published online 2010 March 1. doi:  10.1186/cc8721
PMCID: PMC2934021

Assessment of correlation between Bispectral Index monitorization and sedation scales used in the intensive care unit


The level of sedation should be monitored as the depth of sedation can affect the rate of related complications, length of hospital stay and costs [1]. The recent study aims to monitor the depth of sedation of patients in the ICU using the Ramsay Sedation Scale (RSS), Richmond Agitation Sedation Scale (RASS), Sedation Agitation Scale (SAS) and Adaptation To Intensive Care Environment scale (ATICE) and to assess the correlation between these scales and Bispectral Index (BIS) scores and to compare the correlation coefficients of these scales with each other.


After approval from the hospital ethics committee, 30 mechanically ventilated patients who required sedation in the ICU were enrolled into the study. Patients who are quadriplegic or need muscle paralysis are excluded. The choice of sedative agent and the dose regimen that will be used are left to consultant ICU staff different from the investigators. Demographic data and APACHE II scores of the patients were registered. BIS, RSS, RASS, SAS, ATICE scores, mean arterial pressure, heart rate, and peripheral oxygen saturation values (SpO2) of the patients were registered before the initiation of the sedation and in 2-hour intervals after initiation of the sedation.


Male/female ratio was 22/8, mean of ages and body weights of the patients were 57.3 ± 15.8 years and 69.6 ± 14.3 kg, respectively. The median of APACHE II scores was 14 (4 to 23). Mean arterial pressure, heart rate and SpO2 changes were insignificant after initiation of sedation compared with the beginning (P > 0.05). BIS, RASS, SAS scores were significantly lower, RSS scores were significantly higher in all intervals compared with the beginning (P < 0.05). Significant change was not observed for ATICE scores compared with the beginning value (P > 0.05). Statistically significant correlation was observed between all scoring systems and BIS values (P < 0.05). Significantly highest correlation was found between BIS-RSS and BIS-RASS (r = 0.758 and r = 0.750, respectively), comparing correlation between BIS-SAS (r = 0.656) and BIS-ATICE (r = 0.565) (P < 0.05). Also, correlation between BIS-SAS was significantly higher than BIS-ATICE correlation (P < 0.05).


All scales assessed in this study showed significant correlation with BIS. The significantly highest correlation was found between BIS-RSS and BIS-RASS and lowest correlation between BIS-ATICE.


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