Perspective:

Numerous factors may explain findings from this large clinical trial that appear to contradict earlier animal data and smaller trial results. First, experimental findings in animals are frequently not reproducible in human patients, despite expectations. Second, in previous anesthetic preconditioning protocols, the degree of myocardial protection depended upon adherence to anesthetic administration techniques that differ distinctly from methods used in real-world clinical practice, raising the possibility that protocol standardization could have produced conditions conferring greater protection. Third, the markedly lower overall mortality and complication rates of the MYRIAD study population, compared to those in previous studies that showed outcome benefit from volatile anesthetic, raises the possibility that any protective effect of an intervention that acts by limiting ischemia-mediated injury may not be measurable in a low-risk population.

Despite the findings from the MYRIAD group, and lack of consistently proven mortality benefit in high-risk CABG patients, volatile anesthetics will maintain a prominent role in management of patients undergoing a variety of surgical procedures including CABG, since they enable the anesthesiologist, on a real-time basis, to measure end-expired and estimate central nervous system anesthetic concentrations, and in turn, to make timely adjustments to minimize the risk of circulatory depression due to excessive dosing, and to minimize risk of unintended movement or awareness with recall due to underdosing. Modern volatile anesthetics have the additional advantage of low solubility in blood and tissues, a feature that allows rapid, predictable recovery, even after lengthy surgery.