Brain Monitoring With Electroencephalography and the Electroencephalogram-Derived Bispectral Index During Cardiac Surgery

Abstract

Cardiac surgery presents particular challenges for the anesthesiologist. In addition to standard and advanced monitors typically used during cardiac surgery, anesthesiologists may consider monitoring the brain with raw or processed electroencephalography (EEG). There is strong evidence that a protocol incorporating the processed EEG Bispectral Index (BIS) decreases the incidence intraoperative awareness compared with standard practice. However there is conflicting evidence that incorporating the BIS into cardiac anesthesia practice improves "fast-tracking," decreases anesthetic drug use, or detects cerebral ischemia. Recent research, including many cardiac surgical patients, shows that a protocol based on BIS monitoring is not superior to a protocol based on end tidal anesthetic concentration monitoring in preventing awareness. There has been a resurgence of interest in the anesthesia literature in limited montage EEG monitoring, including nonproprietary processed indices. This has been accompanied by research showing that with structured training, anesthesiologists can glean useful information from the raw EEG trace. In this review, we discuss both the hypothesized benefits and limitations of BIS and frontal channel EEG monitoring in the cardiac surgical population.

Monitoring the brain: processed electroencephalogram and peri‐operative outcomes

“…Regardless of the utility of pEEG devices, clinicians can glean important information from the unprocessed EEG waveform . Efforts to educate anaesthetists about the EEG and its underlying neurobiology should proceed in tandem with advances in pEEG technology .…”

Mitral Valve Replacement in a Patient with Porcelain Aorta after Previous Myocardial Revascularization

“…Four minutes after asystole, the surgery replacement procedure was started, with surgical access for the left conventional atriotomy, the aortic valve did not present insufficiency during the procedure, this allowed this to the surgeon to have a good surgical vision, the stenotic valve was replaced with the traditional technique, has been used the Medtronic Hancock ™ II Model T510C biological valve prosthesis size 25 mm (Figure 3), CO2 was administered with a 2.5 l / min flow in the field during the procedure; for the prophylaxis of air embolism. Bispectral index (bis) monitor remained at the value of 38 no modification of anesthesia was necessary [8], during bolus administration of K + Cl and throughout the procedure. The asystole was maintained for 43 minutes (Figure 1), the replacement was 36 minutes, before the left atrium was closed, a endocavitary aspirator was inserted; at the same time the heating of the patient was started, and they were administered 10 units of insulin actrapid ® ; to lower potassium levels with 30 ml of 33% glucose solution.…”

Identifying neurophysiological features associated with anesthetic state in newborn mice and humans

“…While power at high frequency oscillations is reduced (>40 Hz), power at slower frequencies (<15 Hz) is enhanced ( 15 ). The computations underling proprietary indexes such as the Bispectral index or Narcotrend are thought to take advantage of these phenomena ( 18 ). However, in preterm and term neonates for the first weeks of life, EEG during sleep-wake cycles is weakly correlated with behavioral states and shows characteristic bursts or spontaneous activity transients ( 19, 20 ).…”