A Hard Look At The Scientific Evidence for What Doctors and Hospitals Ask Patients To Do Before Surgery
A Hard Look At The Scientific Evidence for What Doctors and Hospitals Ask Patients To Do Before Surgery
Science does not support much of what I was told to do before my thirteenth surgery.
A Hard Look At The Scientific Evidence for What Doctors and Hospitals Ask Patients To Do Before Surgery
Science does not support much of what I was told to do before my thirteenth surgery.
After twelve operations, I know the drill well: “Nothing to eat or drink after midnight,” and “No blood thinners for ten to fourteen days before surgery.” Those are only two of the time-honored diktats that patients are told to follow to ensure the safety of their operations.
But what is the scientific evidence supporting these instructions? Following the pandemic, we were told to “follow the science” or look only at “evidence-based results.” And that is what I did. I am a skeptic by nature and believe it is not only wise but necessary to ask if how we practice medicine needs revising.
The following is only a partial list of my pre-operative instructions. It is not meant to be a guideline or advice on what to do before surgery.
Nothing To Eat Or Drink After Midnight
The origin of this has to do with the risk of a patient aspirating their stomach contents while under sedation and before a breathing tube is inserted into their airway. Stomach contents are, by their nature, acidic. If a patient throws up due to sedative drugs, they are not able to clear their airway, and the caustic contents can flow from the food pipe and stomach into the lungs, causing severe pneumonia.
The most acidic substances have a pH of 1 and the most alkaline 14. Gastric (stomach) juices in an empty stomach have a pH of 1.5, which is low enough to destroy delicate lung tissue. A full stomach has a pH of 2–6. MD Anderson Cancer Institute busted this NPO after-midnight myth in 2023. (NPO is derived from the Latin nil per os or nothing by mouth.)
Despite the literal meaning, NPO doesn’t always mean you can’t eat or drink anything. Patients should be encouraged to drink clear liquids up to two hours before anesthesia.
And there are good reasons to keep patients hydrated. Blood pressure can get dangerously low, especially if you are fasting for 12–18 hours, and it can be difficult to start an IV (intravenous) line before surgery to provide hydration.
The NPO after-midnight standard is inflexible. It does not distinguish between someone having a major operation or procedure, like a colonoscopy. The NPO time is fixed and the same and ignores whether the operation/procedure starts at 7 AM or 3 PM.
This is purely for the convenience of the hospital and the doctors. They don’t trust the patient to follow complicated instructions, so they use “one size fits” all. However, the scientific evidence no longer supports this rigid instruction.
My pre-operative nurse also told me nonsensical things like make sure I don’t swallow any water after brushing my teeth in the morning—like, a few drops of water will make a difference!
Other than healthcare convenience, there is a basic distrust of the patients. There seems to be an assumption that patients are all dumb and, therefore, the simplest instructions work best. And there is a real fear of medical malpractice. Should a medical mishap or mistake occur before, during, or after surgery, it is easier to blame the patient for not following instructions rather than updating pre-operative medical directions.
Stop All Vitamins And Supplements Two Weeks Before Surgery
Aspirin and other blood-thinning drugs should be stopped seven days before surgery to prevent post-operative bleeding. Some vitamins and supplements also “thin” the blood, albeit not as strong as aspirin or other prescribed drugs. Vitamin E is the most common vitamin that makes blood thinner.
I have Crohn’s colitis, and this causes me not to absorb many vitamins and minerals in my diet, and my blood levels for some of these are low. Therefore, I have been prescribed them as a supplement. However, my vitamins and supplements, Vitamin D3, Calcium, Vitamin B12, and zinc, do not affect blood’s ability to clot normally. Yet, I was told to stop them. Why? Again, the assumption is that patients are not smart enough to know which ones they take have this side effect. Thus, it is simpler to tell them to stop them all.
Surgical Site Infections
Surgical Site Infections (SSI) are a dreaded complication after surgery. It delays wound healing and the success of the operation. In extreme cases, it may also lead to blood poisoning by bacteria, known as sepsis, which has a high rate of death.
Medicare and other insurers grade doctors and hospitals for their SSI rates, which becomes public information. Hence, hospitals have become overly cautious and worried about infections to the point where they instruct patients to do things with little or no scientific merit.
I was given a bottle of chlorhexidine gluconate (CHG) to scrub my body starting three days before surgery. No data shows that CHG is more effective at infection prevention than plain soap.
There is a moderate quality of evidence that bathing with CHG soap does not significantly reduce SSI rates compared to bathing with plain soap.
And it gets even worse than the soap we are told to use. I was instructed to place clean sheets on the bed two days before surgery. There is no good evidence this is necessary. (Although sheets should generally be changed every week.)
And I was told not to let pets sleep in the bed before surgery. My small dog does this, but she says above the covers. Regardless, there is no data to support these instructions.
All of these excess minutiae may confuse patients with too many instructions, and there is a risk of them not following any. The medical system’s intent is like the analogy of “throwing poop at the wall and hoping some of it sticks.” If patients are told to go overboard in following directions that have little scientific proof, then there is a chance they will follow some of it.
I am not downplaying the seriousness of SSI. However, after twelve operations, I did not follow many of these extreme directives and have yet to have any infection. I am only one person, and conclusions can’t be drawn. However, decent clinical trials examining what patients are told to do are lacking.
Takeaways
Many pre-operative instructions need to be updated, and scientific scrutiny has failed. They have stayed the same for decades and, in some cases, become even more draconian.
The NPO after midnight commandment is probably the most egregious and fails to recognize studies that it should be modified and individualized.
Prohibiting necessary vitamins, minerals, and blood thinners for excessive periods before surgery should be more logical, individualized, and not all-encompassing.
Surgical Site Infections are a serious problem. However, robust scientific trials have yet to study much of what patients are told to do before surgery to prevent them.
The culture surrounding pre-operative directions stems from distrust of patients, convenience for the hospitals and doctors, and the real fear of malpractice claims.
It is time for the medical establishment to move into the 21st century with pre-operative instructions. Science is not static, and there is always a need to objectively test how medicine is practiced and how it impacts patients.
