Ileus and obstruction follow abdominal surgery

After a laparatomy the normal muscular action of a patient's gut is usually absent for 6 to 72 hours. The return of his bowel sounds is a sign that his gut is starting to work normally again, and that it is time to remove his nasogastric tube. His gut may fail to work as the result of: (1) Paralytic ileus, which is a prolongation of the normal postoperative inactivity of the gut. This is the commonest cause, especially after an operation for abdominal sepsis. (2) Obstruction due to sepsis which has caused loops of small gut to mat together and obstruct. (3) Mechanical obstruction due to adhesions. Distinguishing between these three causes is difficult because: (a) postoperative obstruction may cause little or no pain, and (b) a recent abdominal incision makes careful abdominal palpation more difficult. (c) Organising pus eventually becomes fibrous adhesions so there is no sharp distinction between (2) and (3). Postoperative intussusception is a rare cause of obstruction, but it must be operated on.

If a patient's abdomen is silent and steadily distends after an abdominal operation, how long can you wait before you decide that his distension is caused by some mechanical obstruction that you should try to relieve? Perhaps his gut is being kinked by a fibrinous adhesion or an inflammatory mass? A way out of this problem is to treat him symptomatically for ileus and obstruction, and not to operate for 7 to 10 days, or until you are forced to. This will give an inflammatory mass time to resolve. You may however be forced to operate earlier, if there are signs of peritoneal irritation (which could be due to a leaking anastomosis or to new infection), or some mechanical obstruction unrelated to the original operation (see below).

NJOROGE aged 10 had a splenectomy for a ruptured spleen. On the 3rd postoperative day he was clearly not well. He had obstructive bowel sounds, some colicky pain, and a moderate amount of fluid was coming up his nasogastric tube. He was immediatly operated on and an intussusception was found. LESSON Don't wait too long before you reopen an abdomen, be guided by the whole clinical picture. Early mechanical obstruction like this is rare; ileus is more usual early. Fig. 10-19 INTESTINAL OBSTRUCTION AND PARALYTIC ILEUS. The passage of intestinal contents down the gut can be prevented by a mechanical obstruction, or by a functional disturbance of the motility of the gut (paralytic ileus). The physiological effects are much the same in both and are shown here. Adapted from a drawing by Frank Netter, with the kind permission of GIBA-GEIGY Ltd, Basle (Switzerland).

POSTOPERATIVE GUT OBSTRUCTION OR ILEUS? This is the patient whose bowel sounds do not return after an operation.

DIAGNOSIS. After a messy operation with much pus and spillage, expect ileus. After a clean one severe ileus is unlikely; if his gut obstructs the cause is more likely to be mechanical. Ileus tends to occur earlier and mechanical obstruction later.

Examine him twice a day asking these questions: Has he any pain? Is his girth increasing or decreasing? How much fluid is being aspirated? Have his bowel sounds returned? Is he passing any flatus? Does he have signs of peritonitis? Is his general condition deteriorating?

The signs of mechanical obstruction requiring surgery are[md]colicky abdominal pain, an increasing girth, a large volume of gastric aspirate, no flatus, and X-rays showing fluid levels. Typically, absent bowel sounds indicate ileus, and ''tinkling' ones indicate mechanical obstruction. If he has little pain, and X-rays show gas filled loops with fluid levels all through his large and small gut, he is more likely to have ileus.

If he distended progressively from Day 1 and is still distended on Day 5, he probably has ileus. The normal postoperative musclar inactivity usually starts to resolve after 72 hours, but may last 7 to 14 days or more in the presence of infection, metabolic imbalance, impaired renal function or severe general illness.

If he was all right until Day 5, and then started distending, he probably has a mechanical obstruction, especially if he has colic, ''tinkling' bowel sounds, distension, vomiting, no fever and a normal white count. The tinkling bowel sounds may be intermittent, so you may have to listen for a long time.

If at Day 5 his abdomen is silent and painless, he is febrile and he has a raised white count, he probably has ileus. If he has no fever, a normal white count, and tinkling bowel sounds, suspect a mechanical obstruction.

If he does not pass flatus when he has had bowel sounds or gas pains for some hours, or he has coliky pain, or X-rays show distended small gut and collapsed large gut, suspect mechanical obstruction.

If normal bowel function starts, and then stops again, or he vomits or distends, or you aspirate progressively more fluid, even several litres a day, suspect mechanical obstruction. If at the same time he has diarrhoea, he may have a pelvic abscess, or uncommonly staphylococcal enterocolitis, or he may have a partial obstruction, which allows some fluid to pass and obstructs the rest. Maintaining his fluid balance will be difficult. If you have excluded enterocolitis, you may have to operate.

NONOPERATIVE TREATMENT. ''Suck and drip' him diligently (9.9). Hypokalaemia aggravates ileus, so take care to give him potassium supplements to replace the potassium he loses in the intestinal secretions that you suck up his nasogastric tube[md]see A 15.5. He needs about 40 mmol/day plus any extra potassium he loses through the tube.

OPERATION. Proceed as for obstruction due to adhesions in Section 10.7. Take great care not to exert traction on previous anastomoses. Decompress his upper small gut before you close his abdomen.