What is GASTRIC BYPASS and what does it involve?
The gastric bypass operation is a combination of a restrictive and malabsorptive procedure. It is a complex procedure requiring formation of a small gastric pouch using stapling devices to divide the upper stomach and produce a 20cc pouch. The upper part of the stomach is divided and joined onto the small bowel so that the main reservoir of the stomach is bypassed.A small amount of small bowel is also bypassed. The hospital stay is 3 to 5 days. Fluid is started on the first postoperative day and built up to full diet by six weeks. Compared to the gastric band, there are serious albeit uncommon complications associated with this procedure. There is also a nutritional requirement of vitamins, Iron and calcium.
The malabsorption is not as severe as with Biliopancreatic Diversion but can help maintain weight loss.
The duodenum and upper small bowel is bypassed. This can produce nutrient malabsorption and deficiency. Iron and calcium deficiencies are common and protein deficiency can occur. Supplements must be taken to prevent the metabolic effects.
What are the Complications of the gastric bypass operation?
All surgical procedures are associated with some risk. In deciding whether to undergo weight reduction surgery it is necessary to balance the risks of the procedure against the risks of obesity. The risks associated with gastric bypass are those caused by pre-existing diseases such as heart disease or high blood pressure although wound and chest infections, clots in the legs and lungs, as well as other complications, can occur. Specific complications include:
- Vomiting, reflux, diarrhoea and metabolic effects.
- Anastomotic leak from the joins in the bowel leading to peritonitis.
- Narrowing of one of the joins.
- Ulceration of the gastric pouch.
- Conversion to an open procedure, in 5% of cases.
- Small bowel obstruction can occur in the immediate post-operative period or later due to adhesions. This is one of the main causes of re-operation. The incidence of re-operation is 5%.
- Long-term metabolic side effects such as calcium deficiency with bone softening.
- Anaemia and hypo-proteinaemia
- ‘Dumping’ (an unpleasant condition with feelings of sweating, anxiety, fast pulse and nausea).
- Death in 1% of cases.
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