I heard a recent presentation at a resident conference about complications during cardiac surgery, including large stroke. One of the discussion points that came up was the use of cerebral oximetry during cardiac surgery to potentially detect and/or prevent neurologic injury and stroke. Should it be used routinely? Does it actually have the ability to detect ongoing or acute cerebral ischemia during surgery? Some of my colleagues and I continued to discuss it over the next few days. The next week, I took care of a patient for routine aortocoronary bypass, and cerebral oximetry came up during surgery when the surgeon requested that we use it for all of his cases. He then commented to his resident that cerebral oximetry “is the standard of care for heart surgery.” I wasn’t so sure, and have been thinking about it since: Is cerebral oximetry the standard of care or not?

What a complicated question! The first task in deciding is to define the “standard of care.” We use this very important phrase, but I would guess that many are not able to accurately define what it means. In medical malpractice law, the “standard of care” is the minimally competent care that physicians must provide to meet the quality of care that is required by law.1 Of course, that statement requires further clarification: What is “minimally competent care?” We can ask ourselves: What would a similarly qualified and reasonable medical professional do under similar circumstances? If someone of equal training, experience, and qualifications found themselves in a similar situation, what would they do? This isn’t perfect, but it gets us closer to understanding what it means to be using the “standard of care.”

There are endless discussions one could have regarding various aspects of anesthetic practice that might be considered to be the “standard of care.” For example, consider pulse oximetry. Pulse oximetry was developed in the 1970’s and has been accepted as a “standard of care” monitor since 1989 when it was included in the American Society of Anesthesiologists’ (ASA) “Standards for Basic Anesthetic Monitoring.”2 I can confidently assume that 100% of anesthesiologists today would agree without question that pulse oximetry is considered to be the standard of care for any anesthetic that is conducted today. But can the same be said of cerebral oximetry?

Cerebral oximetry is commonly used during cardiac surgery that utilizes cardiopulmonary bypass and aims to monitor cerebral oxygenation and detect cerebral “desaturation” events. The goal of cerebral oximetry use is identifying and treating cerebral ischemia and, hopefully, preventing post-operative neurological complications. This goal sounds wonderful, but is cerebral oximetry effective and does it improve outcomes? These are the key questions and, until they can be answered, I think the jury is still out on cerebral oximetry’s inclusion in the “standard of care” club.

What do the experts and guidelines say? On my review, I discovered that existing guidelines are surprisingly quiet on the subject of cerebral oximetry. The ASA does not offer any guidelines or consensus statements that mention cerebral oximetry. The same goes for the Society of Cardiovascular Anesthesiologists and the Society for Neuroscience in Anesthesiology and Critical Care. In 2020 the American Society of Enhanced Recovery and the Perioperative Quality Initiative published a joint consensus statement on the role of cerebral oximetry in perioperative outcomes.3 In their statement, there was an agreement that “there is insufficient evidence to recommend using intraoperative cerebral oximetry to reduce mortality or organ-specific morbidity after cardiac surgery” and that “there is insufficient evidence to recommend using intraoperative cerebral oximetry to improve outcomes after noncardiac surgery.