Anesthesia Care: Monitoring Alpha Waves, Ensuring Brain Health

A recent study conducted by MIT focused on analyzing the brain activity of patients under general anesthesia. As patients enter unconsciousness, their brain activity slows down, and some may experience a deeper state called burst suppression, which is linked to cognitive impairments after awakening (1^✔ ✔Trusted Source
Best Practices for Postoperative Brain Health: Recommendations From the Fifth International Perioperative Neurotoxicity Working Group

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Uncovering the Pattern of Alpha Waves

The study uncovered distinct brain wave patterns in the alpha waves (with a frequency of 8 to 14 cycles per second) that could help anesthesiologists identify when patients are transitioning into a deeper state of unconsciousness. By tracking the waxing and waning of these waves, known as amplitude modulation, anesthesiologists can monitor the level of unconsciousness during anesthesia more accurately, potentially preventing patients from falling into burst suppression and reducing the risk of postoperative brain dysfunction.

The brain waves, generated by synchronized neuronal activity, oscillate at various frequencies depending on the brain's tasks. Anesthesia drugs like propofol affect these oscillations, inducing a state of unconsciousness called slow-delta-alpha (SDA) characterized by slow, delta, and alpha oscillations.

Higher doses can lead to burst suppression, evident in EEG recordings showing periods of inactivity interspersed with short bursts of low-amplitude oscillations.

Alpha Waves: A Tool to Make General Anesthesia Safe

The MIT researchers observed changes in EEG patterns as they increased the propofol dosage in patients. The alpha waves exhibited distinct waxing and waning, with increasing dosage leading to a shorter waxing period and a prolonged waning period until reaching burst suppression. Reducing the drug dosage caused an increase in alpha wave amplitude.

The study suggests that propofol may influence neuron metabolism, potentially disrupting ATP production, the cells' energy-storing molecules, eventually leading to burst suppression. This observation might explain why burst suppression is more common in elderly patients with less-regulated metabolic states.

The researchers believe these findings could enable anesthesiologists to have more precise control over a patient's unconscious state during surgery. They hope to develop an algorithm that provides a warning when a patient is approaching burst suppression, displayed on an operating room monitor. Additionally, anesthesiologists could identify these patterns in a patient's EEG to make informed decisions.

The team plans to further investigate the brain's metabolism during the transition to burst suppression using animal models.

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Reference:

1. Best Practices for Postoperative Brain Health: Recommendations From the Fifth International Perioperative Neurotoxicity Working Group - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6309612/)

Source-Medindia