General Anesthesia – Surgery & Fasting

General Anesthesia – Surgery & Fasting

November 20, 2020

Usually, before having a general anesthetic, patients are not allowed anything to eat or drink. This is because when the anesthetic is used, the human body’s reflexes are temporarily stopped.

If a patient’s stomach has food and drink in it, there’s a risk of vomiting or bringing up food into the throat. If this happens, the food could get into the lungs and affect breathing, as well as causing damage to the lungs.

While some may argue that fasting is a necessity, that may not be true. The requirement for fasting before surgery was recommended by the American Society of Anesthesiologists (ASA), which published updated guidelines in 2011 for patients undergoing general anesthesia to reduce the risk of aspiration pneumonia.

General anesthesia is the key consideration because, in its absence, there is little risk of aspiration pneumonia, except upper gastrointestinal endoscopy; in those receiving light sedation, postoperative nausea and vomiting also are rare. Finally, fasting does not guarantee gastric emptying, according to Daniel Terveen, MD.

Another important consideration is that requiring fasting by elderly patients scheduled to undergo cataract surgery alters their normal routine, which can impact those with diabetes or other comorbidities, possibly leading to dehydration and altered blood glucose levels as well as causing significant stress.

Analyzing Cases

Terveen, along with a group of colleagues that included Chris Bender, CRNA, conducted a study to determine how the absence of preoperative fasting affected patient satisfaction with the surgical experience. Both Terveen and Bender are with Vance Thompson Vision in Sioux Falls, South Dakota.

A total of 200 patients who received oral sedation before undergoing routine cataract surgery were included in a prospective case-control study. Half the patients followed the ASA fasting guidelines, and 100 patients were not required to fast— to determine the patient levels of comfort and the postoperative incidence rates of nausea and vomiting.

The postoperative patient satisfaction was scored on a scale from 1 to 5, with 1 indicating very dissatisfied and 5 indicating very satisfied. “The preoperative and postoperative scores were both very high in the fasting and nonfasting groups, but we found a clinically significant difference in the preoperative satisfaction levels between the groups,” Terveen said.

“The patients who did not fast preoperatively had a better experience by maintaining their normal routines and were not as concerned about the effects of stopping their medications.” One episode of nausea and vomiting occurred in each group, and no aspiration occurred in either group.

The investigators concluded that eliminating preoperative fasting requirements increased patient satisfaction preoperatively, with no increased risks of nausea and vomiting or aspiration.

It does not have to cross the corneal and conjunctival barriers; instead, the surgeon places it under the iris and near the ciliary body, where the inflammatory cascade begins. When we participated in the Dexycu clinical trials, we noticed how quiet the anterior chambers appeared postoperatively, with hardly any cell or flare on postoperative day 1.

We attribute this to not only the site of injection but also the timing. With topical drops, although we instruct the patient to instill the steroid 4 times a day starting several hours after surgery or starting the next morning if the eye is patched at the time of surgery, the reality is that family members may still need to make a trip to the pharmacy, or the patient may go home and fall asleep before instilling the drops.

It can be from 12 to 24 hours or more before the first dose of topical steroid is delivered to the eye, compared with just a few seconds when the surgeon injects Dexycu after the case.

There is a bit of a learning curve for the proper injection technique for Dexycu; there is also the possibility of migration of the dexamethasone spherule onto the IOL optic or onto the iris, where it becomes visible until its absorption within a few days.

With intraoperative sustained-release steroids— perhaps coupled with other injected or sustained-release drugs—we can eliminate the gambles of patient adherence. This has the potential to greatly enhance the patient experience, improve practice flow, and provide the surgeon with more control over unwanted postoperative complications.