Gastric Bypass Surgery: What to Expect on the Day of Surgery

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Gastric bypass surgery is typically performed by a bariatric surgeon in a hospital under general anesthesia. The procedure takes under two hours, and the hospital stay is two to three days.

Below is an overview of what else you can expect before, during, and after gastric bypass surgery.

Before the Surgery

On the day of your gastric bypass surgery, you will first be taken to a pre-operative room where you will change into a hospital gown.

Once you are dressed, a nurse will check your vital signs and place a peripheral IV in your arm. This IV is used to give you fluids and medications (e.g., an antibiotic and anesthesia drugs) prior to and during the surgery.

To prevent blood clots, inflatable compression devices will likely be placed on your legs at this time. You may also be given a shot of blood-thinning medication.

Next, your anesthesiologist and your surgical team will come to greet you and briefly review the surgery with you. You may need to sign additional consent forms at this time.

Finally, you will be taken into the operating room where you will be given medication to put you to sleep. You will not feel any pain or have any memory of the operation.

During the Surgery

In most cases, gastric bypass surgery is performed laparoscopically. This means that the surgeon uses long, thin instruments to operate through tiny incisions made in your abdomen. If the surgery is performed openly, the stomach and small intestines are accessed through a large incision in the abdomen.

Laparoscopic gastric bypass surgery generally takes approximately 90 minutes to perform. Here is a general breakdown of the surgery from start to finish:

Starting Anesthesia

Once you are in the operating room, an anesthesiologist will insert a tube through your mouth and into your airway. This tube is connected to a ventilator, which helps with breathing during surgery. A urinary catheter will also be placed.

During the entire surgery, the anesthesiologist will remain in the operating room to monitor your vital signs and adjust your anesthesia medications, accordingly.

Creating the Stomach Pouch

After cleaning the skin of your abdomen, your surgeon will start the surgery by making multiple incisions in your upper abdomen. Long, thin surgical instruments, including one with an attached camera and light, will be inserted through these incisions.

Next, a pouch 30-milliliter (mL) in volume will be created from the top part of the stomach (the portion closest to the esophagus, where foods travel from your mouth). This new stomach pouch will then be removed from the rest of the stomach. The remaining "old" stomach will be stapled closed.

Dividing the Small Intestines

After creating the new stomach pouch, the surgeon will make an incision in the small intestines, dividing it into two parts. The lower part, called the jejunum, will be pulled up and connected to the newly formed stomach pouch. The remaining upper part, called the duodenum, will be attached to a lower part of the jejunum (below where the stomach is attached).

Stopping Anesthesia

Once the surgery is complete, the surgeon will close the abdominal incisions with dissolvable sutures or surgical staples. The breathing tube will be removed, anesthesia will be stopped, and you will be taken to a recovery room.

After the Surgery

While in the recovery room, a post-operative care nurse will monitor your vital signs. Once you are awake, alert, and stable (about one to two hours after surgery), you will be moved to a hospital room where you can expect to stay for approximately two to five nights.

Laparoscopic gastric bypass surgery typically requires a shorter hospital stay than open surgery. As you recover in your hospital room, you can expect the following on the first day or so after surgery:

  • You will get out of bed and begin walking around (a physical therapist will assist you).
  • You will start drinking clear liquids (e.g., broths, water, decaffeinated coffee and tea, and sugar-free popsicles or jello).
  • Your urinary catheter will be removed.
  • You will be transitioned over to oral pain medication from pain medication that goes through your vein.
  • You will use a special breathing device (called an incentive spirometer) several times throughout the day to keep your lungs strong and healthy.

In preparing for discharge, you will be given various instructions to follow at home. These instructions will include recommendations on incision site care and activity restrictions.

Before leaving the hospital, you will also meet with a nutritionist to review your diet plan. This plan will involve gradually progressing from consuming only clear liquids (week one) to eating solid foods (beginning around eight weeks, with just soft foods to start).

During your recovery, your surgeon and nutritionist will also advise you on the following:

  • Drinking 2 liters of water a day.
  • Taking your vitamin supplements (complex multivitamin, calcium, vitamin D, iron, vitamin C, and vitamin B12).
  • Following certain dietary guidelines (e.g., not drinking liquids at meals and avoiding carbonated drinks and all foods high in sugar or fat).
  • Consuming the correct amount of protein daily (around 60 grams), which often requires supplementing in between meals with a protein shake.

A Word From Verywell

Getting through gastric bypass surgery is only the first step in a lifelong journey of healthy living. As you navigate the highs and lows of undergoing and recovering from surgery, be sure to reach out to your surgical team with any questions or concerns. It's also a good idea to surround yourself with support, whether that's a partner, friend, neighbor, or member from a bariatric surgery support group.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. University of California San Francisco Health. Recovery from bariatric surgery.

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  7. University of Pittsburgh Medical Center. Phase 4: Stabilization diet for post-bariatric surgery patients.

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.