Gastric Bypass


Catherine Spader, RN

What is gastric bypass?

Gastric bypass is a surgery that can help adults and some adolescents who are very obese (morbidly obese) lose weight. It involves attaching the stomach directly to the middle of the small intestine. This reduces the amount of calories and nutrients that are absorbed by the body. 

Gastric bypass surgery usually includes a stomach stapling procedure. Stomach stapling reduces the size of your stomach and the amount of food you can eat at one time. 

Gastric bypass has serious risks but the benefits can be significant. Benefits include long-term weight-loss and resolution of serious diseases associated with obesity, such as type 2 diabetes, hypertension, and high cholesterol. 

Gastric bypass is only one part of a complete treatment plan. Plans also include a lifelong commitment to healthy dietary and exercise habits, vitamin supplementation, and regular follow-up care. You may have less invasive treatment options with less risk of complications. Ask your doctor about all your treatment options and consider getting a second opinion before having gastric bypass. 

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Types of gastric bypass

Gastric bypass is a malabsorptive procedure. This means that it helps you lose weight by changing the normal process of digestion. Specific gastric bypass procedures include:

  • Biliopancreatic diversion with a duodenal switch (BPD-DS, duodenal switch) involves removing part of the stomach and using staples to create a smaller tube-shaped stomach (vertical sleeve gastrectomy). In another surgery, the stomach is attached to the middle of the small intestine. This bypasses a large part of the small intestine and reducing the amount of calories and nutrients absorbed into the body.

  • Roux-en-Y gastric bypass (RYGB) involves stapling the stomach to create a small pouch. The smaller stomach is attached directly to the middle of the small intestine. This allows food to bypass much of the stomach and the first section of the small intestine. It limits the amount of food that you can eat and reduces the amount of calories and nutrients that are absorbed into the body.

Why is gastric bypass performed? 

Your doctor may recommend gastric bypass to treat obesity and reduces the risk of life-threatening complications of obesity. These include diabetes, heart disease, and severe sleep apnea

Gastric bypass is not a treatment option for people who are mildly overweight. It is generally considered for adults with a body mass index (BMI) of 40 or more. This means being about 100 pounds overweight for men and 80 pounds overweight for women. Certain people who are less obese with a BMI of about 35 to 39.9 with serious weight-related health problems may have gastric bypass. 

Gastric bypass may be a treatment option if other treatments that involve less risk and fewer complications have not helped you lose weight and maintain a healthy weight. Other treatments include diet, exercise, behavioral and nutritional counseling, and medication. People typically need a psychological evaluation prior to the surgery.

Ask your doctor about all of your treatment options and consider getting a second opinion before deciding on gastric bypass. 

Who performs gastric bypass?

A general surgeon or bariatric surgeon performs gastric bypass. General surgeons specialize in the surgical treatment of a variety of diseases and conditions, including those of the stomach and intestines. Bariatric surgeons are usually general surgeons who further specialize in weight-loss surgery.  

How is gastric bypass performed?

Your gastric bypass will be performed in a hospital using one of the following approaches:

  • Minimally invasive surgery involves inserting special instruments and a laparoscope through small incisions in the abdomen. The laparoscope is a long thin camera that sends pictures of the inside of your body to a video screen viewed by your surgeon during the surgery. Minimally invasive surgery generally involves a faster recovery and less pain than open surgery. This is because it causes less trauma to tissues and organs. Your surgeon will make small incisions instead of a larger one used in open surgery. Surgical tools are threaded around muscles, tissues, and organs instead of cutting through or displacing them as in open surgery.

  • Open surgery involves making a long incision in your abdomen. Open surgery allows your surgeon to view and access the surgical area directly. Open surgery generally involves a longer recovery and more pain than minimally invasive surgery. Open surgery requires a larger incision and more cutting and displacement of muscle and other tissues than minimally invasive surgery. Despite this, open surgery may be a safer or more effective method for some patients, such as those who are very obese or have adhesions (scarring from previous surgeries).

Minimally invasive techniques may be combined with an open surgery in some cases. Additionally, your surgeon may decide after beginning a minimally invasive technique that you need open surgery to complete your surgery safely.
Your surgeon will advise you on which procedure is best for you and how long you need to stay in the hospital based on your diagnosis, age, medical history, general health, and possibly your personal preference. Learn about the different gastric bypass surgeries and ask why your surgeon will use a particular type for you.

Types of anesthesia that may be used

General anesthesia is used for gastric bypass. General anesthesia is a combination of intravenous (IV) medications and gases that put you in a deep sleep. You are unaware of the procedure and do not feel pain. 

What to expect the day of your gastric bypass

The day of your surgery, you can generally expect to:

  • Talk with a preoperative nurse. The nurse will perform an exam and ensure that all needed tests are in order. The nurse can also answer questions and will make sure you understand and sign the surgical consent form.

  • Remove all clothing and jewelry and dress in a hospital gown. It is a good idea to leave all jewelry and valuables at home or with a family member if possible. Your care team will give you blankets for modesty and warmth.

  • Talk with the anesthesiologist or nurse anesthetist about your medical history and the type of anesthesia you will have.   

  • A surgical team member will start an IV.

  • The anesthesiologist or nurse anesthetist will start your anesthesia.

  • A tube will be placed in your windpipe to protect and control breathing during general anesthesia. You will not feel or remember this or the surgery as they happen.

  • The surgical team will monitor your vital signs and other critical body functions. This occurs throughout surgery and recovery until you are alert, breathing effectively, and vital signs are stable.

What are the risks and potential complications of gastric bypass?  

As with all surgeries, gastric bypass involves risks and the possible complications. Complications may become serious and life threatening in some cases. Complications can develop during surgery or recovery.

General risks of surgery 

The general risks of surgery include: 

  • Anesthesia reaction, such as an allergic reaction and problems with breathing 

  • Bleeding or hemorrhage (heavy bleeding), which can lead to shock

  • Blood clot, in particular a deep vein thrombosis that develops in the leg or pelvis

  • Infection

Potential complications of gastric bypass

Complications of gastric bypass include:

  • Constipation

  • Damage to abdominal organs or major blood vessels

  • Dehydration

  • Difficulty swallowing (dysphagia)

  • Dumping syndrome (rapid emptying of stomach contents into the small intestine causing symptoms, such as nausea, vomiting, cramping, and abdominal pain)

  • Gallstones

  • Gastritis (irritated stomach tissue), ulcers, gastroesophageal reflux (regurgitation), and heartburn 

  • Hernias 

  • Intestinal stricture (narrowing) 

  • Leaking of digested foods and digestive juices into the abdominal cavity f