When doing painless gastroenteroscopy, why do we do the stomach first and then the intestines?

After working for many years, clinical work is still as busy as ever: every day, I am either doing anesthesia in the operating room or in the outpatient department. When the anesthesia is over, it is time to go home.

One day, during this uneventful work, I suddenly thought of a question: when doing a gastroenteroscopy, it seems that the stomach should be examined first. So, who stipulated this?

Until this point, my brain gradually turned itself back on: I was thinking about the necessity of this.

One is to enter from the mouth, and the other is to enter from the anus. From a humanistic perspective, it seems that the mouth should enter first. So, is this the only reason? No, there must be a deeper reason~

With doubts, I immediately found the doctor in the gastroscopy room. Their answer was, there is no difference, you can do whatever you want.

Obviously, I couldn't find the answers I wanted from them.

On the way back, I was thinking: Could it be that this is what we required during anesthesia?

Since it is required by anesthesia, it is related to life safety. So, I will sort out the possible risks one by one.

Any anesthesia needs to focus on the two major systems of breathing and circulation. This is because once there is a problem, even a small problem, it will be fatal. Even if there is a problem with other systems, it will give us more time to deal with it.

Painless gastroenteroscopy anesthesia is generally performed using intravenous anesthesia. During the examination, since it is basically a non-invasive operation, the patient only needs to be unconscious. Even if gastrointestinal polyps need to be removed, since the gastrointestinal tract is not sensitive to cutting and there is almost no pain, no special analgesia is required.

This type of anesthesia is almost the smallest type of anesthesia in general anesthesia. Since the depth of anesthesia is very shallow, most patients can maintain spontaneous breathing. That state is almost the same as being asleep. After the examination, the anesthesiologist stops the drug, and the patient usually wakes up in a few minutes.

Although the most commonly used drug for this type of anesthesia has a strong circulatory inhibitory effect, a large number of studies have shown that its blood pressure reduction has a ceiling effect. Therefore, even without treatment, the changes in circulation during surgery are limited. This means that whether the stomach or the intestine is first has basically nothing to do with the circulation.

Is it breathing? With this question, we continue to analyze:

Respiratory management during painless gastroenteroscopy is indeed a headache for us anesthesiologists. It is not so bad during colonoscopy, at least we can control breathing with our heads. If we do gastroscopy, the endoscopist will compete with us for the airway position. Once something happens, it will really affect the treatment.

At this point, it seems that there is no difference in which one to do first.

Suddenly, I thought of a detail: when doing gastroscopy, the endoscopist always asks the patient to drink more than 100 ml of defoaming agent. If the patient is prone to reflux, this 100 ml is enough to cause serious consequences such as aspiration.

At this point, my thoughts became clear: the advantage of doing a gastroscopy first is that the defoaming agent in the stomach can be sucked out through the gastroscopy as soon as possible. With less content, even if there is reflux, there will be basically no consequences of aspiration; in addition, if a colonoscopy is done first, the gas injected during the colonoscopy operation will inevitably remain in the intestinal cavity. This part of the gas is likely to increase the chance of reflux by increasing abdominal pressure.

Finally, I would like to remind you that you must pay attention to fasting from food and water when doing a gastroenteroscopy. If it is a painless gastroenteroscopy, you must do the stomach first and then the intestines!