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How Brain Function Monitoring Technology During General Anesthesia Can Help Improve Patient Outcomes

Brain Function Monitoring Technology During General Anesthesia
Postoperative delirium (POD) is common and costly:
  • Of all surgical patients, 37 to 46 percent are affected by POD.1
  • Risk increases up to 87 percent depending on the patient age and type of surgery.1
  • In-hospital POD costs the U.S. healthcare system $150 billion per year.2
Fortunately, POD is preventable in up to 40 percent of cases with proper screening, identification of risk factors, and implementation of evidence-based monitoring methods in the OR.2 Organizations such as the European Society of Anaesthesiology (ESA) and the Enhanced Recovery After Surgery (ERAS®*) Society have released best practice and position statements for brain function monitoring.3,4
This blog post explains the need for monitoring, patient-specific anesthesia titration, and intended benefits of technology-guided anesthetic dosing.
Related: Check out a timeline and list of organizations that support the use of brain function monitoring technology (processed EEG monitoring) during surgical procedures involving anesthesia.

Addressing the Risk of Postoperative Delirium

In 2017, the ESA released guidelines for prevention and treatment of POD that recommend monitoring depth of anesthesia during surgery.3
The ESA guidelines committee task force reviewed the evidence related to delirium in the postoperative period and concluded:
  • POD is a common complication that requires prevention and immediate treatment.
  • Prevention is important and possible, and it should be a key priority.
  • Providers must focus on the prevention of POD, not just treatment of it after the fact. 
  • All patients, regardless of age, should be monitored.3
  • Monitoring of depth of anesthesia and avoiding deep anesthesia are strongly recommended.3
The message of the ESA guideline is very clear. As players in the healthcare industry, we all have to work together to reduce the incidence of POD.3
Related: Learn more about the ESA guidelines and minimizing POD

Brain Monitoring Technology for Enhanced Recovery Protocols

The ERAS®* Society suggests brain monitoring technology for enhanced recovery protocols to avoid complications associated with too much or too little anesthesia. Since 2013, the society has published recommendations for procedures such as colorectal surgery, gastrointestinal surgery, bariatric surgery, gynecologic oncology surgery, and esophagectomy.

“Just Right” Anesthesia Titration 

The common use of anesthetic agents requires new approaches in monitoring to ensure good outcomes, particularly as each patient has a unique sensitivity to anesthesia. Achieving and maintaining the right anesthetic effect provides peace of mind that each patient is receiving the safe dosage for the best possible outcome. 
When the anesthetic dose is too deep, EEG suppression is an independent factor for POD.5  When the dose is too light, there can be an increased incidence of intraoperative awareness.6
With “just right” dosing enabled by Bispectral Index™ (BIS™) brain function monitoring technology, studies have found: 
  • Anesthetic drug use is decreased up to 23 percent.7,8,9
  • Wake-up time is up to 40 percent faster.8
  • Postoperative nausea and vomiting may be reduced up to 37.5 percent.9,10
  • Outcomes are improved and patient satisfaction is increased.9,10
Related: How can you optimize anesthesia delivery for each patient? Learn about the most widely studied consciousness monitoring system available.

Brain Function Monitoring Insights

You can improve patient experience and help mitigate risk using BIS™ technology to monitor the anesthetic effect on a patient’s brain. The potential benefits of maintaining BIS™ monitoring values in the range of 40 to 60 by adjusting anesthetic levels and administration include:
  • Patient-specific drug titration (a 50 percent reduction in propofol administration during hypothermic cardiopulmonary bypass).11
  • Faster wake-up, recovery, and discharge from the PACU.7
  • Lowered incidence of intraoperative awareness (approximately 80 percent lower compared to routine care in total intravenous, inhaled, and balanced anesthesia patients).6,12,13
  • May reduce delirium by an average of 36 percent.1,14–16
Learn more about how to use brain function monitoring technology to help reduce postoperative complications and improve outcomes for your patients.
Related: Read the clinical evidence about guided anesthesia delivery.

1. Whitlock E, Vannucci A, Avidan M. Postoperative delirium. Minerva Anestesiol. 2011 April; 77(4): 448–456.
2. American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults. Postoperative delirium in older adults: Best practice statement from the American Geriatrics Society. Intraoperative Measures to Prevent Delirium. J Am Coll Surg. 2014; 220(2):136–148.e1.
3. Aldecoa C, Bettelli G, Bilotta F, et al. European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium. Eur J Anaesthesiol. 2017;34(4):192–214.
4. Gustafsson UO, Scott MJ, Schwenk W, et al. Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations. World J Surg. 2013;37(2):259–284.
5. Fritz BA, Kalarickal PL, Maybrier HR, et al. Intraoperative electroencephalogram suppression predicts postoperative delirium. Anesth Analg. 2016;122(1):234–242.
6. Zhang C, Xu L, Ma Y, et al. Bispectral index monitoring prevents awareness during total intravenous anesthesia: a prospective, randomized, double-blinded, multi-center controlled trial. Chin Med J. 2011;124(22):3664-3669.
7. Gan TJ, Glass PS, Windsor A, et al. Bispectral index monitoring allows faster emergence and improved recovery from propofol, alfentanil, and nitrous oxide anesthesia. BIS Utility Study Group. Anesthesiology. 1997;87:808-15.
8. Punjasawadwong Y, Boonjeungmonkol N, Phongchiewboon A. Bispectral index for improving anaesthetic delivery and postoperative recovery. Cochrane Database Syst Rev. 2014;(6):CD003843.
9. Liu SS. Effects of bispectral index monitoring on ambulatory anesthesia: a meta-analysis of randomized controlled trials and a cost analysis. Anesthesiology. 2004;101(2):311-315.
10. Luginbuhl M, Wuthrich S, Petersen-Felix S, et al. Different benefits of bispectral index (BIS) in desflurane and propofol anesthesia. Acta Anaesthesiol Scand. 2003;47:165-173.
11. Chiu CL, Ong G, Majid AA. Impact of bispectral index monitoring on propofol administration in patients undergoing cardiopulmonary bypass. Anaesthesia Intensive Care. 2007;35:342-347.
12. Myles PS, Leslie K, McNeil J, et al. Bispectral index monitoring to prevent awareness during anesthesia: the B-Aware randomised controlled trial. Lancet. 2004;363(9423):1757-1763.
13. Ekman A, Lindholm ML, Lennmarken, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand. 2004;48(1):20-26.
14. Chan MT, Cheng BC, Lee TM, et al. BIS-guided anesthesia decreases postoperative delirium and cognitive decline. J Neurosurg Anesthesiol. 2013; 25: 33-42.
15. Radtke FM, Franck M, Lendner J, et al. Monitoring depth of anaesthesia in a randomized trial decreases the rate of postoperative delirium but not postoperative cognitive dysfunction. Br J Anaesth. 2013; 110: i98-105.
16. Sieber FE, Zakriya KJ, Gottschalk A, et al. Sedation depth during spinal anesthesia and the development of postoperative delirium in elderly patients undergoing hip fracture repair. Mayo Clin Proc. 2010 Jan;85(1):18-26.

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TOPIC: BIS™ Brain MonitoringOperating Room

About the Author

Connor Fox is a Product Specialist for BIS™ brain monitoring technology and INVOS™ regional oximeter at Medtronic.

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