Scientific research tries to isolate elements to identify causes and effects. This is a challenge that requires researchers to limit the scope of their questions. The findings, even when they are clear and consistent, indicate results that are often too limited for general audiences to understand. That’s why media reports based on scientific research usually generalize from the specific to create a bigger picture—and miss the point.
This explanation is necessary because we are about to string together several separate study findings to provide context for a recommendation. We acknowledge that each study has to be taken on its own merits, and that no two of these studies were intended to complement or contradict each other. They are simply points that can be used to form a line.
Importance of Anesthesia
Anesthesia enables clinicians to perform procedures that would be difficult or impossible with fully alert patients. Anesthetists are trusted members of every surgical team, enabling clinicians to concentrate on their specialties.
Anesthetists work to achieve the right depth of sedation for each stage of a procedure. They rely on training, experience, judgment, and the information they get from other clinicians. Sedation monitoring, a relatively recent innovation, helps them validate their decisions.
Anesthesia has inherent risks. Too little sedation can lead to patient awareness, in which the patient is conscious during a medical procedure. Even if the narcotics used block the sensation of pain, they may reduce or eliminate muscle movement, so the patient is unable to move or speak—and may feel anything from concern to terror.
Too much sedation has other negative effects. A patient who receives too much anesthetic or for too long—or both—will often have more trouble during recovery. Problems range from slower recovery rates to long-term memory loss to elevated risk of death six months after surgery. While there is no direct cause and effect for these outcomes, the correlation is high enough that anesthetists take these risks into account.
Anesthesia and Pediatrics
These risks especially affect pediatric and neonate patients, and women during the third trimester of pregnancy. On 27 April 2017, the U.S. Food and Drug Administration (FDA) issued a warning that exposure to some general anesthetic and sedation medicines “for lengthy periods of time or over multiple surgeries or procedures may negatively affect brain development in children younger than 3 years.” This heightened caution inspired a study by the Mayo Clinic.
Mayo Anesthesia Safety in Kids (MASK) Study
This study involved neuropsychological testing of 997 children, all born in the same county within a span of 13 years. Some had been exposed to anesthesia multiple times, some once, and some never. Subjects underwent neuropsychological testing at ages 8–12 or 15–20; the primary outcome was the Full-Scale intelligence quotient standard score of the Wechsler Abbreviated Scale of Intelligence. Secondary outcomes included individual domains from a comprehensive neuropsychological assessment and parent reports.
The primary outcome of intelligence quotient did not differ significantly according to exposure status; multiply exposed and singly exposed children scoring 1.3 points (95% CI, −3.8 to 1.2; P = 0.32) and 0.5 points (95% CI, −2.8 to 1.9; P = 0.70) lower than unexposed children, respectively. For secondary outcomes, processing speed and fine motor abilities were decreased in multiply but not singly exposed children; other domains did not differ. The parents of multiply exposed children reported increased problems related to executive function, behavior, and reading.
Traditional methods of monitoring depth of anesthesia include clinical signs, lower esophageal contractility, and heart rate variability. These methods depend on the expertise of each anesthetist, and on the standard of care for each facility.
Clinicians recognize the potential value of monitoring depth of anesthesia, and medical device companies have developed several technologies for it in the past 30 years. Most of these measure brain electrical activity (EEG). One drawback to this approach is interference: Electromyography (EMG) signals, which are often high in pediatric patients, can distort EEG readings.
One device uses proprietary signal processing algorithms to detect and classify EEG. The Narcotrend Compact-M monitor applies a scale of 100 (conscious) to 0 (very deep hypnosis, EEG suppression) to help clinicians adjust anesthesia according to patient age. The Narcotrend Compact-M monitor is indicated for use with pediatric patients from the first day of life.
Clinical Studies on Narcotrend and Pediatric Patients
The Narcotrend Compact-M monitor provides reliable depth of anesthesia measurements for patients of any age. For more information, read a brief summary covering four clinical studies focused on pediatric use.