Reasonable and good bowel preparation has a decisive role in preventing postoperative infection in colorectal surgery, which shows the importance of bowel preparation. What are the key points to note sometimes? Let’s see what the article says. Yan Fu, Department of Anorectal Medicine, Taihe Hospital, Shiyan City
Diet preparation
1-3 days before surgery, we should have a light diet with little or no residue, and a liquid diet on the night of the first day before surgery.
Mechanical bowel preparation
That is, cleanse the solids in the intestinal lumen by physical methods to reduce the potential sources of contamination visible to the naked eye.
1. Retrograde bowel cleansing method
Oral laxative such as 50% magnesium sulfate 30 ml or castor oil 30 ml is started three days before the operation and clean enema is given the night before the operation until the excreted stool is clear.
Advantages: the effect is exact, once accepted by most surgeons, and is still widely used in primary hospitals.
Disadvantages: (1) It can lead to dehydration and electrolyte imbalance. (2) It can lead to malnutrition, physical depletion of the patient and reduced tolerance to surgery. (3) It is difficult to cleanse the proximal end of intestinal obstruction. (4) Due to high-pressure counter-current enema, repeated stimulation of tumor increases its chance of metastasis. (5) The shed tumor cells are flushed to the proximal end of the mouth, which may cause local implantation and metastasis or increase the chance of recurrence.
2. Parallel intestinal cleansing method
Commonly used drugs are oral magnesium sulfate, oral mannitol and senna.
a. Oral magnesium sulfate
Hypertonic laxative, not absorbed by the intestine. It takes effect 2-8 hours after taking the drug, and the effect lasts 1-4 hours, and oral magnesium sulfate must drink a lot of water (>2500 ml) at the same time, so as to accelerate and enhance its laxative effect.
Advantages: simple and easy to use, strong effect.
Disadvantages: astringent and bitter taste, easy to cause vomiting, stomach fullness and discomfort, and cause dehydration. Contraindicated in cardiac and renal insufficiency.
b. Oral mannitol
Advantages: simple and easy, fast-acting, strong diarrheal action, because of its sweet taste, easier to accept than oral magnesium sulfate.
Disadvantages: (1) For tumors with large ring-shaped masses protruding into the intestinal lumen, mannitol may cause complete intestinal obstruction. (2) The production of large amounts of E. coli in the intestinal cavity after the use of mannitol may increase infection. (3) Mannitol may produce a large amount of methane gas in the intestine, which may cause an explosion when using an electric knife intraoperatively.
(4) It is contraindicated in patients with diabetes mellitus.
c. Senna
Advantages: mild action, no special odor.
Disadvantages: individual differences, the action time is too long, there are adverse reactions leading to abdominal pain, upper gastrointestinal bleeding, etc.
3. Whole intestine irrigation method
The irrigation solution is an oral isotonic electrolyte solution, which is instilled in large quantities for a short period of time to make it exceed the absorption capacity of the small intestine, expand the volume of the intestinal lumen and stimulate an increase in intestinal peristalsis, thus causing diarrhea and flushing the intestine.
The irrigation is started the afternoon before the operation, with fasting for about 8 hours before the irrigation, a gastric tube is inserted, and the patient is seated in a reclining chair with a toilet bucket. Sedative medication may be added if necessary.
The lavage solution is warmed to about 37°C and then injected through the gastric tube at a rate of 50-70 ml/min, 3000-4000 ml per hour, after about half an hour the patient starts to defecate, and after about 90 minutes a clear liquid without fecal residue is discharged.
Advantages: this method does not require prolonged dietary restriction, the entire gastrointestinal tract is cleansed, and water intoxication does not occur.
Disadvantages: contraindicated in cases of mechanical intestinal obstruction, cardiac and renal insufficiency, poor general condition.
Oral antibiotic intestinal preparation
This means that bacteria adhering to the surface of the intestinal mucosa and mucus are inhibited by oral non-absorbable antibiotics.
Adult stool contains a large number of bacteria, more than a hundred species, and a large number of adhesions to the intestinal mucosal surface, so simply cleaning the intestinal contents does not reduce the number of bacteria remaining in the intestine to a level sufficient to avoid infection.
Commonly used antibiotics are: metronidazole, haloperidol, gentamicin, erythromycin, streptomycin, kanamycin, etc.
Principles of antibiotic intestinal preparation application: short duration, broad spectrum, high efficiency, low toxicity, and non-absorption in the intestine.
Observation points
1. Adverse reactions
Mainly observe whether the patient can tolerate the discomfort that may occur in the intestinal preparation, including abdominal pain, abdominal distension, nausea, vomiting and hunger. Also pay attention to psychological comfort to relieve their stress before surgery and during intestinal preparation.
2. Blood electrolyte levels
Pay attention to the preoperative review of blood electrolyte levels and provide timely correction for electrolyte disorders.
3. Intestinal cleanliness
It is best to have no fecal water, no flatulence and intestinal atrophy.