Authors: Muggleton E
Anesthesiology 144(4):1025–1026, April 2026
Summary:
This commentary challenges one of the most ingrained assumptions in anesthesiology—that hemodynamic stability reflects adequate depth of anesthesia. Building on prior research, the author argues that relying on blood pressure and heart rate as primary indicators of anesthetic depth is fundamentally flawed because these are indirect, downstream effects rather than measures of the brain, which is the true target of anesthetic agents.
Using simple clinical examples, the article illustrates the problem: a young, healthy patient may maintain stable vital signs despite inadequate anesthesia, while an older patient with comorbidities may become hypotensive with minimal anesthetic exposure. In both cases, hemodynamics provide misleading information about actual anesthetic depth.
The author emphasizes that this approach is analogous to judging treatment effectiveness by side effects rather than primary outcomes. Instead, anesthetic depth should be assessed using direct measures of brain activity, such as electroencephalography (EEG). While processed indices (e.g., BIS) have limitations, more detailed EEG analysis—such as waveform interpretation and density spectral arrays—offers a more accurate and physiologically relevant assessment.
The commentary also pushes back against common barriers to adoption, particularly cost concerns, arguing that advances in neuromonitoring technology and the ethical imperative to avoid under- or over-anesthetizing patients outweigh these objections.
Ultimately, the article calls for a shift in clinical practice—from relying on indirect physiologic markers to embracing direct neural monitoring—to improve patient safety and individualized anesthetic care.
Key Points:
- Hemodynamic parameters are unreliable indicators of anesthetic depth
- Blood pressure and heart rate reflect secondary effects, not brain activity
- EEG-based monitoring provides a more direct assessment of anesthetic effect
- Processed indices have limitations, but advanced EEG analysis is more informative
- Continued reliance on hemodynamics alone may lead to under- or over-anesthesia
What You Should Know:
This is a direct shot at how many still practice. Stable vitals do not equal adequate anesthesia. If you’re not looking at the brain, you’re guessing. The field is moving toward EEG-based monitoring—and this argues it’s time to catch up.
We would like to thank Anesthesiology for allowing us to summarize and share this article.