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Dr. Pralobh Kumar Singh
Dr. Manish Kumar Singh
Dr. Zia Arshad
Dr. Gyan Prakash Singh


electrophysiological monitoring, mechanical ventilation, intensive care unit, sedation, bispectral index


Background: Adequate sedation is required for smooth ventilation of patients on invasive mechanical ventilation. Under sedation may result in prolonged stress mobilization and patient harm, whereas over sedation obscures neurologic abnormalities and increases mortality and morbidity. In instances such as deep sedation/analgesia, the Bispectral Index (BIS) may be used as an auxiliary to clinical assessment of sedation to assist in determining depth of sedation. Determining the correlation between clinical and BIS measurements of sedation will assist in determining the appropriate role of BIS in intensive care unit (ICU). The aim of the present study to monitor depth of sedation of patients in ICU using Riker Sedation Agitation Scale (RSAS) and to assess the correlation between RSAS & BIS.

Methods: The present observational study was conducted from May 2022 to April 2023. 47 cases that required mechanical ventilation and sedation with a baseline intact brain function were enrolled as per inclusion-exclusion criteria. Patients of either of 18 years or older who required mechanical ventilation and sedation with a baseline intact brain function and willing to participate were included in the study. Patients with age less than 18 years, diagnosed or suspected condition that resulted in a decreased level of consciousness or reduced blood flow/oxygen supply of the brain, i.e., prolong seizure activity, encephalopathic state, hypoxemia with PaO2 less than 55 mm Hg, altering level of consciousness, and severe ischemic or hemorrhagic stroke were excluded from study. Patients with clinical states such as drug overdose producing alterations in level of consciousness, severe anemia impairing consciousness, and severe alkalotic/ acidotic states, patients with birth injuries impairing neurologic function such as cerebral palsy were not included in study. The BIS and RSAS measurement was done before initiation of sedation & in 4-hour intervals after initiation of sedation up to 24 hours.

Results: At all the periods of observation correlation between BIS and RSAS were highly significant and level of correlation was strong to very strong/perfect.

Conclusion: BIS monitoring may play an additional function in sedation assessment in cases where the clinical assessment is ambiguous. BIS results must be taken with caution, however, because electromyography activity and other variables appear to confuse BIS scores. Additional research is required to determine the clinical utility of BIS monitoring in ICU practice.

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1. Tonner PH, Weiler N, Paris A, Scholz J: Sedation and analgesia in the intensive care unit. Curr Opin Anaesthesiol. 2003, 16:113-21. 10.1097/00001503-200304000-00003
2. De Jonghe B, Cook D, Appere-De-Vecchi C, Guyatt G, Meade M, Outin H: Using and understanding sedation scoring systems: a systematic review. Intensive Care Med. 2000, 26:275-85. 10.1007/s001340051150
3. Avidan MS, Jacobsohn E, Glick D, et al.: Prevention of intraoperative awareness in a high-risk surgical population. N Engl J Med. 2011, 365:591-600.
4. Avidan MS, Zhang L, Burnside BA, et al.: Anesthesia awareness and the bispectral index. N Engl J Med. 2008, 13:1097-108. 10.1056/NEJMoa0707361
5. Zhang C, Xu L, Ma YQ, et al.: Bispectral index monitoring prevent awareness during total intravenous anesthesia: a prospective, randomized, double-blinded, multi-center controlled trial. Chin Med J (Engl. 2011, 124:3664-9. 10.1007/s00540-010-1050-y
6. Arbour R, Waterhouse J, Seckel MA, et al.: Correlation between the Sedation-Agitation Scale and the Bispectral Index in ventilated patients in the intensive care unit. Heart & Lung. 38:336-345. 10.1016/j.hrtlng.2008.10.010
7. Aspect Medical Systems. Technology overview: bispectral in- dex. Newton, MA: Aspect Medical Systems, Inc. 1997,
8. Flaishon R, Windsor A, Sigl J, et al.: Recovery of consciousness after thiopental or propofol. Bispectral index and isolated forearm technique. Anesthesiology. 1997, 86:613-9. 10.1097/00000542-199703000-00013
9. Simmons LE, Riker RR, Prato BS, Fraser GL: Assessing sedation during intensive care unit mechanical ventilation with the Bispectral Index and the Sedation-Agitation Scale. Crit Care Med. 1999, 27:1499-504. 10.1097/00003246-199908000-00016
10. Dahaba AA, Lischnig U, Kronthaler R, et al.: Bispectral-index-guided versus clinically guided remifentanil/propofol analgesia/sedation for interventional radiological procedures: an observer-blinded randomized study. Anesthesia & Analgesia. 103:378-384. 10.1213/
11. Manyam SC, Gupta DK, Johnson KB, et al.: When is a bispec- tral index of 60 too low? Rational processed electroencepha- lographic targets are dependent on the sedative-opioid ratio. Anesthesiology. 2007, 106:472-83. 10.1097/00000542-200703000-00011
12. Mondello E, Siliotti R, Noto G, et al.: Bispectral Index in ICU: correlation with Ramsay Score on assessment of sedation level. Journal of. 10.1023/a:1021250320103
13. Riess ML, Graefe UA, Goeters C, Van Aken H, Bone HG: Sedation as- sessment in critically ill patients with bispectral index. Eur J Anaesth. 2002, 19:18-22. 10.1017/s0265021502000030
14. Jacobi J, Fraser GL, Coursin DB, et al.: Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult. Crit Care Med. 2002, 30:119-41. 10.1097/00003246-200201000-00020
15. Vivien B, Di Maria S, Ouattara A, et al.: Overestimation of Bispectral Index in sedated intensive care unit patients revealed by administration of muscle relaxant. The. Journal of the American Society of Anesthesiologists. 99:9-17. 10.1097/00000542-200307000-00006
16. Frenzel D, Greim CA, Sommer C, et al.: Is the bispectral index appropriate for monitoring the sedation level of mechani- cally ventilated surgical ICU patients?. Intensive Care Med. 2002, 28:178-83. 10.1007/s00134- 001-1183-4
17. LeBlanc JM, Dasta JF, Kane-Gill SL: Role of the bispectral index in sedation monitoring in the ICU. Ann Pharmacother. 2006, 40:490-500. 10.1345/aph.1E491
18. Trouiller P, Fangio P, Paugam-Burtz C, et al.: Frequency and clinical impact of preserved bispectral index activity during deep sedation in mechanically ventilated ICU patients. Intensive Care Med. 2009, 35:2096- 2104. 10.1007/s00134-009-1636-8
19. Riker RR, Picard JT, Fraser GL: Prospective evaluation of the Sedation-Agitation Scale for adult critically ill patients. Crit Care Med. 1999, 27:1325-1329. 10.1097/00003246-199907000-00022
20. De Deyne C, Struys M, Decruyenaere J, et al.: Use of continuous bispectral EEG monitoring to assess depth of sedation in ICU patients. Intensive care medicine. 24:1294-1298. 10.1007/s001340050765.