BIS in Critically Ill Patients in ICU

Official title

The Comparison of Bispectral Index Parameter Between Critically Ill Patients With and Without Decreased Mental Status and Its Association With Clinical Outcomes

Overview

The Bispectral Index (BIS) is a monitor that converts brain electrical activity from EEG into a simple number from 0 to 100. A higher number means the patient is more awake, while a lower number means deeper sedation or reduced brain activity. In general, 100 means fully awake, 80 suggests light to moderate sedation, 60 is commonly used as a target for general anesthesia with a low chance of awareness, 40 indicates deep anesthesia, 20 suggests marked brain suppression with burst suppression on EEG, and 0 indicates no detectable cortical electrical activity. Although BIS was originally developed for use in the operating room, it has also been applied in the ICU to help guide sedation, avoid over- or under-sedation, and assess consciousness in patients who cannot be evaluated reliably using standard clinical scores. BIS has also been studied as a possible tool for predicting outcomes in comatose ICU patients, such as those after cardiac arrest, stroke, encephalitis, or traumatic brain injury. However, evidence is still limited for its use in predicting outcomes among ICU patients with any form of decreased consciousness. Therefore, this study was conducted to explore that role.

Detailed description

The Bispectral Index is the output of a multi-stage process that transforms the brain's electrical activity into a simplified metric. This process begins with non-invasive data acquisition and proceeds through advanced computational analysis to derive the final index.

The BIS monitor translates the EEG data into a number on a scale from 0 to 100. This index is designed to provide a direct measure of a patient's level of consciousness and response to sedation, with specific numeric ranges corresponding to general clinical states.

The generally accepted clinical correlations for the BIS scale are as follows:

* 100: This value indicates a patient who is fully awake and alert, corresponding to a state of responsiveness to a normal voice. * 80: This range is typically associated with light to moderate sedation or anxiolysis. A patient in this range may respond to loud verbal commands or mild physical stimulation, such as prodding or shaking. * 60: This value is a critical threshold often targeted for general anesthesia. It represents a low probability of explicit recall and unresponsiveness to verbal stimuli. A BIS value of less than 60 has a high sensitivity for identifying a state of drug-induced unconsciousness, making it a key target in the operating room to prevent awareness. * 40: This range signifies a deep hypnotic state, with a greater degree of cortical suppression than is typically required for general anesthesia. * 20: A BIS value in this range indicates the presence of burst suppression on the EEG. This pattern, characterized by periods of electrical activity (bursts) alternating with periods of isoelectricity (suppression), reflects a very deep level of brain suppression seen with high doses of anesthetic agents or in conditions like barbiturate coma or severe anoxic brain injury. * 0: A BIS value of 0 represents a flatline or isoelectric EEG, indicating the absence of detectable cortical electrical activity.

BIS monitoring was adapted from the operating room to the ICU to help manage the difficult task of sedating critically ill patients.

Its main goals in the ICU are to:

* Prevent the risks of over- or under-sedation. * Provide an objective number to guide medication dosage. * Assess consciousness in patients who can't be evaluated by normal methods. BIS monitoring is being used more frequently to assess the depth of sedation in ICU patients, as opposed to relying solely on clinical scoring systems.

The Bispectral Index (BIS) has been used to predict clinical outcomes in ICU patients with coma from various causes, including post-cardiac arrest, cerebrovascular disease, viral encephalitis, and traumatic brain injury. However, there is limited research on using BIS to predict outcomes for patients with any decreased level of consciousness in the ICU. Therefore, this study was initiated.

Interventions

• Other Processed EEG monitoring
  Monitor processed EEG using BIS

Primary outcome measures

• BIS value [Time frame: 24 hours following inclusion]

Secondary outcome measures (8)

• Length of stay in SICU [Time frame: Up to 90 days following inclusion]
• Length of stay in hospital [Time frame: Up to 90 days following inclusion]
• SICU discharge status [Time frame: Up to 90 days following inclusion]
• Hospital discharge status [Time frame: Up to 90 days following inclusion]
• Status at 30 days [Time frame: Up to 30 days following inclusion]
• Status at 90 days [Time frame: Up to 90 days following inclusion]
• ICU Memory [Time frame: Up to 90 days following inclusion]
• Post-traumatic Stress Disorder [Time frame: Up to 90 days following inclusion]

Eligibility criteria

Inclusion criteria

• Age≥18years
• RASS score ≤ -3 as case
• RASS score 0 to -1 as control
• Expected ICU length of stays ≥ 24hours

Exclusion criteria

• Contraindication for BIS monitoring (wound or infection at forehead)
• No space for attach BIS monitoring at forehead
• Patient with sedative drugs (Propofol, Midazolam, Dexmedetomidine)
• Patient with acute stroke
• Patient was already on EEG monitoring
• Denied by patients or patient's surrogates

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Non-randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Other

Study locations

Thailand · 1 center

• Department of Anesthesiology, Faculty of Medicine Siriraj Hospital, Mahidol University — Bangkok Noi

Publications

• Misis M, Raxach JG, Molto HP, Vega SM, Rico PS. Bispectral index monitoring for early detection of brain death. Transplant Proc. 2008 Jun;40(5):1279-81. doi: 10.1016/j.transproceed.2008.03.145. PMID 18589087
• Vivien B, Paqueron X, Le Cosquer P, Langeron O, Coriat P, Riou B. Detection of brain death onset using the bispectral index in severely comatose patients. Intensive Care Med. 2002 Apr;28(4):419-25. doi: 10.1007/s00134-002-1219-4. Epub 2002 Mar 19. PMID 11967595
• Dou L, Gao HM, Lu L, Chang WX. Bispectral index in predicting the prognosis of patients with coma in intensive care unit. World J Emerg Med. 2014;5(1):53-6. doi: 10.5847/wjem.j.issn.1920-8642.2014.01.009. PMID 25215148
• Arbas-Redondo E, Rosillo-Rodriguez SO, Merino-Argos C, Marco-Clement I, Rodriguez-Sotelo L, Martinez-Marin LA, Martin-Polo L, Velez-Salas A, Caro-Codon J, Garcia-Arribas D, Armada-Romero E, Lopez-De-Sa E. Bispectral index and suppression ratio after cardiac arrest: are they useful as bedside tools for rational treatment escalation plans? Rev Esp Cardiol (Engl Ed). 2022 Dec;75(12):992-1000. doi: 10 PMID 35570124
• Heavner MS, Gorman EF, Linn DD, Yeung SYA, Miano TA. Systematic review and meta-analysis of the correlation between bispectral index (BIS) and clinical sedation scales: Toward defining the role of BIS in critically ill patients. Pharmacotherapy. 2022 Aug;42(8):667-676. doi: 10.1002/phar.2712. Epub 2022 Jun 30. PMID 35707961
• Huespe I, Giunta D, Acosta K, Avila D, Prado E, Sanghavi D, Bisso IC, Giannasi S, Carini FC. Comparing Bispectral Index Monitoring vs Clinical Assessment for Deep Sedation in the ICU: Effects on Delirium Reduction and Sedative Drug Doses-A Randomized Trial. Chest. 2024 Oct;166(4):733-742. doi: 10.1016/j.chest.2024.05.031. Epub 2024 Jun 18. PMID 38901489
• Tasaka CL, Duby JJ, Pandya K, Wilson MD, A Hardin K. Inadequate Sedation During Therapeutic Paralysis: Use of Bispectral Index in Critically Ill Patients. Drugs Real World Outcomes. 2016 May 28;3(2):201-208. doi: 10.1007/s40801-016-0076-3. eCollection 2016 Jun. PMID 27398299
• Manning J, Chiasson M. Does Bispectral Index Monitoring Belong in the Intensive Care Unit Setting?: A Narrative Review of Evidence. Dimens Crit Care Nurs. 2025 Sep-Oct 01;44(5):231-238. doi: 10.1097/DCC.0000000000000713. PMID 40719578

Identifiers

NCT: NCT07583732 · 037/2569(IRB1)

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗