PURPOSE: Sedation is measured in the ICU using clinical scoring systems. Bispectral Index (BIS) analyses the EEG and translates it into a value reflecting the depth of hypnotic state. The current study evaluates the role of BIS in management of sedation in the ICU.
METHODS: In a prospective cross over study, 14 MICU patients, ages between 18-85 yrs were initially managed clinically with observation of the BIS for 4 hours. Patients were then crossed over and had their sedation titrated using the BIS as a guide to keep the BIS score between 50-70.
RESULTS: Ramsey sedation scale did not change between the observational & treatment arms of the study (5 ± 1). Average BIS was 53.3 ± 12.7 at the beginning & was guided by titration of sedatives to 59.8 ± 14.8. The difference of 6.6 was statistically significant (p < 0.004). The dose of sedatives was changed in 12 of the 14 patients (87%) with the use of BIS monitoring. The correlation between the Ramsey sedation scale and the BIS score was not strong. During the observation arm of the study the correlation coefficient between BIS and RSS was −0.40 and during the treatment arm −0.42.
CONCLUSION: Ramsey Sedation Scale & Bispectral Index do not have a strong correlation. BIS monitoring lead to a statistically significant increase in the BIS score but the clinical change in the level of sedation was not significant.
CLINICAL IMPLICATIONS: Use of BIS lead to a change in level of sedatives in 87% of patients and was associated with an average decrease in the dose of propofol by 5.2 mcg/kg/min. This decrease while not significant clinically would lead to a reduction in the use of propofol by 524 mg per day in an average 70 kg patient. This would lead to a average daily cost savings of $40-80.00 per patient. The use of BIS in the intensive care unit needs to be studied further.
DISCLOSURE: Akram Khan, None.