Bispectral Index compared to Ramsay score for sedation monitoring in intensive care units

Abstract

Aim: Continuous monitoring is of paramount importance in order to obtain a correct level of sedation in ICU patients. Clinical scoring systems, although simple and inexpensive, are often inadequate in evaluating the patient level of consciousness. Among instrumental tools for sedation monitoring, Bispectral Index (BIS) is now widely used due to its reliability and applicability. Nevertheless some doubts still exist regarding its usefulness in ICU.

Methods: Sedation, obtained with propofol or midazolam, was monitored with Ramsay scale and BIS in 40 patients admitted in ICU for postoperative monitoring after major abdominal or vascular surgery. A correlation between Ramsay score and BIS values was searched using Pearson test.

Results: A good correlation between Ramsay score and BIS values was observed. At the deeper levels of sedation a wide range of BIS values corresponds to Ramsay score 6, indicating various levels of central nervous system depression that are not identified by clinical evaluation.

Conclusions: BIS monitoring is useful in ICU patients and allows a finest differentiation of sedation level in deeply sedated ICU patients.