The Influence of Sedation Level Guided by Bispectral Index on Therapeutic Effects for Patients with Severe Traumatic Brain Injury

BACKGROUND: Sedation therapy is vital for treating severe traumatic brain injury (TBI). Yet, types of sedation assessment tools and sedation levels that are suitable for sedation treatment have not been investigated. OBJECTIVE: To investigate the influence of different sedation levels guided by the Bispectral Index (BIS) on the therapeutic effects for severe TBI. METHODS: According to inclusion, exclusion, and rejection criteria, 35 patients were prospectively included and divided into Richmond Agitation Sedation Scale (RASS), BIS(I), and BIS(II) groups. The RASS group was controlled the level of sedation to within -2 or -3, and the BIS(I) and (II) groups within the range of 40-50 and 50-60, respectively. In addition to clinical data, RASS, BIS, and intracranial pressure (ICP) values were collected. RASS and ICP variability were introduced to investigate the different of sedative control effect with or without BIS monitor, and the control effect of ICP between different sedation levels. Statistical analysis was performed to estimate the effectiveness of different sedation levels guided by BIS in sedation treatment within 72 hours. RESULTS: There were no significant differences in de-mographics among the 3 groups. RASS variability of the BIS(I) and (II) groups was significantly lower than that of the RASS group (P < 0.05), and in the BIS(I) group it was insignificantly lower than in the BIS(II) group. The ICP of the BIS(I) and (II) groups declined to < 13.5 mm Hg significantly earlier than that of the RASS group (P < 0.05), and the difference between BIS(I) and (II) was insignificant. ICP variability of RASS group was higher than those of the BIS(I) and (II) groups (P < 0.05), and ICP variability of the BIS(I) group was significantly lower than that of the BIS(II) group (P < 0.05). Differences in days in the neurosurgery intensive care unit and outcomes among the 3 groups were insignificant. CONCLUSIONS: BIS is more reliable than RASS for maintaining a stable sedation status and ICP. Deeper sedation levels (BIS 40-50) cause ICP to decrease more quickly, with lower ICP variability.