In this pre-annual meeting research round-up, Dr. Akhtar highlights studies that underscore “the opportunity for us to reduce the amount of anesthetic we use in elderly patients” and two studies in the works that may one day help make anesthetic management more “brain centric.”
May 10, 2018
by Sandra Gordon for ASA
“If we go by the recommendations, most of our elderly patients get more anesthetic than they require,” says Shamsudden Akhtar, M.D., associate professor in the department of anesthesiology and pharmacology at the Yale School of Medicine, who will moderate the discussion: “Practical Management of High-Risk Geriatric Patient: Brain, Heart-Lung and Kidneys” at the ANESTHESIOLOGY® 2018 annual meeting in October. To reduce the amount of anesthetic in elderly patients and, consequently, the risk of postoperative delirium, awareness is key.
Less Can Be More
- Does intravenous induction dosing among patients undergoing gastrointestinal surgical procedures follow current recommendations: a study of contemporary practice, which involved 1,869 adult patients receiving general anesthesia for GI procedures from February 2013 to January 2014, found that the administered dose of anesthetic induction agents is significantly higher than recommended for patients 65 years and older.
- A Retrospective Observational Study of Anesthetic Induction Dosing Practices in Female Elderly Surgical Patients: Are We Overdosing Older Patients? This retrospective, observational study involving 768 patients in a tertiary-care academic hospital found that older patients received lower doses of propofol and midazolam than younger patients. However, practitioners still consistently exceeded FDA recommended doses of propofol and fentanyl.
- Association Between Age and Dosing of Volatile Anesthetics in 2 Academic Hospitals. This retrospective cross-sectional study of 7,878 patients receiving a single potent volatile anesthetic at two academic hospitals found that patients 65 years and older received a decreased dose of anesthetic, but the age-adjusted doses were higher than predicted.
- Propofol Use in the Elderly Population: Prevalence of Overdose and Association with 30-Day Mortality. This retrospective study of 17,540 patients, 23 percent of whom were 65 years and older, found that median propofol dose in those 65 years and older for induction was 1.8 (1.4–2.2 mg/kg), which is above the recommended dose of 1–1.5 mg/kg. However, the median dose was not associated with a greater 30-day postsurgical mortality rate.
Brain Monitoring and Delirium Prevention
Can monitoring brain activity with EEG or BIS monitors during surgery in older patients impact the incidence of postsurgical delirium? “Studies are currently underway that will be instructive for us,” Dr. Akhtar says.
Here are two to put on your radar:
- Protocol for the Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES). The ENGAGES trial, which involves 1,232 patients 60 years and older, hypothesizes that administering anesthesia under EEG guidance will prevent postoperative delirium and other complications, including falls and a decreased quality of life. Patients are randomized to one of two groups: general anesthesia with clinicians blinded to EEG monitoring and EEG guidance of anesthetic agent. Postoperative delirium within five days, falls at one and 12 months, and health-related quality of life at one and 12 months will be compared between groups.
- Rational and Design of the Balanced Anesthesia Study: A Prospective Randomized Clinical Trial of Two Levels of Anesthetic Depth on Patient Outcome After Major Surgery seeks to determine if “light” anesthesia, defined as a BIS target of 50, will reduce all-cause mortality within one year of surgery compared to “deep” anesthesia, defined by a BIS target of 35, in surgical patients 60 years and older who require general anesthesia.
“We’re moving into an area, especially when we’re dealing with so many elderly patients — patients 80 years and older with many comorbidities—that we have to pay greater attention to how much anesthetic we give them,” Dr. Akhtar says. To reduce the risk of postoperative delirium, the results of these and other studies will contribute to the body of evidence weighing in on how much anesthetic is required to maintain blood pressure or the cardiovascular system versus how much is required for the brain during surgery for elderly patients.
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