Gastric bypass is a type of bariatric (weight loss) surgery. It works by making the patient's stomach smaller and their digestive system shorter.
Patients normally meet their surgeon
carrying out your procedure beforehand, to discuss their surgery and care. It may be different from what is
described here, as it will be designed to meet the patient's individual needs.
Gastric bypass surgery info
Gastric
bypass is an operation to make a patient's stomach smaller, and to shorten the length
of small intestine that their food passes through. This allows the food people eat to bypass most of their stomach, and part of their small intestine – meaning
that they will only be able to eat small amounts of food, and some of the food that they eat will not be fully digested. Gastric bypass surgery can help obese people lose
weight if they are very overweight (that is morbidly obese).
Gastric bypass surgery is sometimes
called a Roux-en-Y gastric bypass (named after a surgeon called Roux). This
is the most common type of gastric bypass operation carried out in the USA and the UK.
Studies show that on average,
people lose between two-thirds and three-quarters of their excess weight in
the two years after a gastric bypass operation.
Schematic diagram showing how a gastric bypass operation is performed.
Eligibility
for a gastric bypass surgery
The doctor will only suggest
surgery if a patient has tried to lose weight in other ways (e.g with
medicines, healthy eating and exercise) for at least 6 months, and this
has not worked. Surgery will also usually only be considered if:
- A patient is morbidly obese with a body mass index
(BMI) of more than 40 or they have a BMI of over 35 and also
have a medical condition, such as diabetes or high blood
pressure, which would be likely to improve if they lose weight.
- A patient is generally fit enough to undergo surgery.
- A patient is committed to losing weight and maintaining
that weight loss by combining the surgery with lifestyle changes in the
future, and are prepared to attend regular follow-ups.
- In some areas, patients may still not be eligible for the procedure even if they meet these criteria,
due to the high demand for weight loss surgery. If their family doctor (GP) believes weight loss
surgery could be beneficial to a patient, he or she will refer the patient to a bariatric
surgeon (a doctor specialising in obesity surgery) to talk about their options.
Alternatives
to gastric bypass surgery
There are other types of
surgery available which can help people to lose excess weight by making their stomach smaller. These include gastric band and sleeve gastrectomy. The surgeon will talk about the options available and help patients to
weigh up the risks and benefits of each, to decide which is best for the patient.
Preparing
for a gastric bypass operation
The surgeon will explain how
to prepare for the operation. For example, if a patient smokes, then they will be asked to
stop, as smoking increases their risk of getting a wound infection, chest
infection or blood clot, and slows their post-operative recovery. This is particularly
important before any weight loss operation, because being very overweight
increases their risk of complications after surgery.
The surgeon may ask the patient to
follow a low-fat, low-sugar and low-carbohydrate diet with no alcohol for one
to two weeks before their operation. This helps to shrink their liver, and makes
it more likely that the surgeon will be able to complete the operation using
keyhole (laparoscopic) surgery.
A gastric bypass operation is
performed under general anaesthesia. This means the patient will be asleep
during the operation. The patient will be asked to follow
fasting instructions. This means not eating or drinking, typically for about 6 hours beforehand. However, it is important to follow the surgeon’s
advice. At the hospital, the nurse will check the heart rate and blood
pressure, and test the urine.
Patients may be asked to wear
compression stockings to help prevent blood clots forming in the veins in their legs (known as DVT - deep vein thrombosis). Patients may also be given an injection of an anticlotting medicine
called heparin (fragmin).
The surgeon will discuss with the patient what will happen before, during and after the operation, and any pain they might have. This is the patient's opportunity to understand what will happen, and they can help themselves by preparing questions to ask about the risks, benefits
and any alternatives to the procedure. This will help them to be informed, so they can give their consent for the procedure to go ahead, which they may be
asked to do so, by signing a consent form.
How is
a gastric bypass operation performed?
A gastric bypass operation
usually takes between one and three hours. The operation is usually done
using keyhole surgery (laparoscopic gastric bypass). Keyhole surgery is carried out by making small cuts in the abdomen (tummy) rather than one large cut. During a keyhole operation, the surgeon uses small instruments, guided by a special telescope with a
camera, to perform the operation.
If a patient is very overweight or
has had surgery to their abdomen previously, then the surgeon may recommend
having an open operation, which is done through a single, larger incision.
Using surgical staples, the surgeon will make a pouch out of the top of the patient's stomach, separating it from
the lower part of their stomach. The surgeon will make an opening in the
pouch and connect it to a section of the small intestine. This means the
food a patient's eat will bypass their old stomach, and the first part of their intestine. The length of small intestine which the operation bypasses can be
adjusted to make sure that when a patient reaches the right weight for their height, they will be able to eat enough to maintain that weight. The surgeon may
insert a drain, to help remove any fluid or blood which might have collected
inside the abdomen. The surgeon will close the cuts with stitches or small metal clips, and place a dressing over your
wounds.
What to
expect after a gastric bypass operation?
A patient will need to rest until the
effects of the anaesthetic have passed. They may need pain relief to help with
any discomfort as the anaesthetic wears off.
If a patient had open surgery, then they may have a catheter to drain urine from their urinary bladder into a bag (known as urinary catheter). They may also
have fine tubes coming from the wound that drain fluid into another bag, and
are usually removed after a day or two.
On the first day, patients may have
to wear special pads attached to an intermittent compression pump on their lower legs (known as flowtrons). The pump inflates the pads and encourages blood flow in the legs, helping to prevent deep vein thrombosis (DVT). Patients may also need
to wear compression stockings to help maintain their leg circulation. They will also be
encouraged to get out of bed and move around, as this helps prevent chest
infections and blood clots in their legs. They may have a nasogastric tube
fitted (a tube inserted into their nose which goes down to their stomach) to
keep their stomach pouch empty. This is usually removed the following day.
They will have a drip put into a
vein in their hand or arm to give them intravenous fluids and keep well hydrated. If they feel well enough, they can
start to drink small amounts of water soon after their operation.
Two to four days after their operation, they may have an X-ray to check that the stitches and staples are
healing well, and that there are no leaks. Patients may be asked to swallow a fluid
(known as barium) which is radio-opaque (shows up on X-ray images). If the X-ray shows
that the operation has been successful, the patient will be able to start drinking
freely, including soups and fruit juice. Patients will usually be able to go
home two to five days after their operation. They will need to arrange for
someone to drive them home.
The surgeon may use
dissolvable (absorbable) stitches. The length of time the dissolvable stitches will take
to disappear depends on what type a patient has. However, for this procedure, they
should usually disappear in 7 to 10 days. If a patient has non-dissolvable
stitches or clips, then they will need to have them taken out. The surgeon will
tell them when and where to have them removed. The nurse will give patients advice
about caring for their healing wounds before patients go home, and give them a date
for a clinic follow-up appointment.
Recovering
from a gastric bypass operation
If a patient needs pain relief (painkillers), then they can take over-the-counter painkillers such as paracetamol or
ibuprofen (neurofen). They should always read the patient information which comes with their medicine, and if they have any questions, they must ask their pharmacist for advice.
Patients will need to make major
changes to the foods they eat after their operation. They will only be able to
eat small amounts at each meal. To start with, they need to stick to liquids, and then
move onto puréed food. They may also need to take vitamin and mineral
supplements. The surgeon and dietician will give them all the information they need about what foods to eat and how much.
The patients will be asked to make other
changes to their lifestyle, such as becoming more physically active. These changes will
help them to get the most from their gastric bypass operation, and will help them to lose excess weight and keep it off. Being active will also help them to tone their muscles and improve their posture.
Patients will need to have regular
blood tests after their operation. These are to check that they are getting all
of the vitamins, minerals and nutrients they need to stay healthy.
It usually takes between 4 and 6 weeks to make a full recovery from a gastric bypass operation.
However, this varies between individuals, so it is important for patients to follow their surgeon's advice.
What
are the risks of a gastric bypass operation?
As with every procedure, there
are some risks associated with gastric bypass surgery.
Side-effects are the unwanted
but mostly temporary effects patients may get after having the operation. Patients are likely to have some bruising, pain and swelling of the skin around their wounds. They may feel sick or vomit
after eating, because the amount they are able to eat is a lot less than before
the operation. This should get better as they change their eating habits.
If a patient eats too many sugary
foods, then they can get an unpleasant sensation called "dumping". It can make people feel sick or faint, or give them abdominal pain and diarrhoea. Eating small
meals and eating little or no sugary food will help to ease these symptoms.
If a patient feels unwell after eating sugary foods, they should lie down and drink fluids only, until the feeling passes.
Complications are when problems
occur during or after the operation. The possible complications of any
operation include an unexpected reaction to the anaesthetic, excessive
bleeding or developing a blood clot, usually in a vein in your leg (DVT).
Being very overweight increases a patient's risk of complications following any operation. Patients are more likely to
have complications from having a general anaesthetic and are more at risk of
developing blood clots. If they have other conditions linked to their weight, (such as high blood pressure or diabetes mellitus), then these can also increase their risk of developing complications.
Complications specific to a
gastric bypass operation include:
- An infection in the wound or a chest infection.
- A blood clot in the lung (pulmonary embolism - PE).
- A leak at the place where the intestine is
re-joined to the stomach. This can be very serious and the patient will usually have
an operation to repair it straight away.
- The opening from the stomach into the intestine
can become narrowed, which makes it more difficult for food to pass through
it, or the stomach can become stretched. If the opening becomes narrowed, it
can usually be enlarged using a flexible telescope which patients swallow (called an
endoscope). If a patient stretches the stomach pouch by overeating, this can only be
repaired with surgery.
- A lack of protein, vitamins and minerals caused
by the change in the amount and type of food patients are able to eat after the
operation. This can affect their general health. Vitamin and mineral
supplements can help to prevent this. Patients may need to have injections of
vitamin B12.
If a patient loses weight quickly, they may develop gallstones.
These can be painful and patients may need surgery to remove them. The surgeon
may prescribe medicine to reduce the risk of developing gallstones.
During the operation, the surgeon may come across an unexpected problem and may
need to convert the keyhole operation to an open procedure. This will not affect
how well the operation works, but it may take a longer time for the patient to
recover afterwards.
Not everyone loses enough weight after gastric
bypass surgery. Inadequate weight loss is usually from not following the
correct diet or taking enough exercise. If this happens, the surgeon may
suggest another operation.
FAQs about gastric bypass surgery
What foods shall I eat after a gastric bypass
operation?
Answer
In the first month after the operation, patients will need to eat small amounts of puréed foods, while their stomach is healing. After that they can gradually start to eat solid foods.
Eating small amounts of healthy foods which are low in fat and sugar and high in
protein will help them to lose weight and keep it off.
As a gastric bypass operation
reduces the size of the stomach, patients will only be able to eat small amounts
of food at each meal.
For the first week after the operation, patients will only be able to drink fluids. Fluids can include water,
skimmed milk, hot drinks (such as tea and coffee), thin soups and fruit juices.
After the first week, and for
about three weeks after the operation, the food patients eat should be puréed.
This is because the opening out of their stomach will be quite swollen and
solid food will not be able to pass through it. Patients may be given specific
dietary advice, but the main rules to follow include:
- The food should be runny like smooth baby food. Patients can use a blender, masher or food processor to do this. Adding extra
liquid (such as gravy, sauces or fruit juice), to their food can help to make
it smoother.
- Initially, each meal must be up to 5 or 6 tablespoons in amount. Patients must eat slowly and take small mouthfuls.
- As soon as they start to feel full, they must stop eating.
The feeling of fullness patients get after a gastric bypass operation may be
different from the feeling they had before. A full stomach may give them a
heavy or tight feeling in their chest.
- Patients must drink enough water or fluids every day. They should drink 1.5 litres in 100 to 200ml glassfuls between meals, but they should not drink when they are eating a meal, and they must not drink fizzy drinks.
- After the first 4 weeks, patients can gradually start eating foods which are lumpier, but they must make sure that they chew
them very well.
- In the long term, patients must be aiming
to eat a healthy, balanced diet. This will help them to keep losing weight, and
to get all the nutrients and energy they need to stay healthy. They must make sure that they eat three balanced meals a day, they eat slowly and they stop when they feel full. Patients must also try
not to drink anything half an hour before their meals or for an hour
afterwards, as the fluid will make them feel full.
- Patients must ensure that they eat adequate
amounts of protein (such as meat, fish, pulses and eggs), and only small
amounts of carbohydrate (such as potatoes, pasta, rice and bread). Patients must eat 4 to 5 portions of fruit and vegetables a day. They should choose low-fat
foods (such as skimmed milk and low-fat cheese).
- Patients should not eat foods which contain a
lot of sugar. This may cause dumping, which can make them feel sick and faint.
- It can take up to 6 months
after the operation for people to learn which foods they can eat and to feel
confident and comfortable eating. There may be days when patients feel sick after
food and other days when they do not.
- Patients must speak to their surgeon or
dietitian for more information about the foods they can eat after their gastric
bypass operation.
Will a
further operation/ surgery needed after weight loss with gastric bypass, to
remove any excess skin?
Losing a lot of weight can cause the patient's skin to
become loose. This means that they may be left with folds of excess skin after their weight loss. Cosmetic surgery can help to reshape the parts of their body
where they have extra skin.
Most
people who have a gastric bypass operation will lose a lot of weight. On
average, people lose up to three-quarters of their excess weight in the
two years after surgery.
This amount of weight loss can
cause the skin to become loose. Once it has been stretched, skin loses its
tightness. This means that patients may be left with folds of excess skin after their weight loss. The places where this is most common are on the abdomen
(tummy), face, bottom, breasts, upper arms and thighs.
Patients may find this extra skin
uncomfortable and embarrassing. The skin in these areas can also become
irritated, painful or infected. Cosmetic surgery may help to reshape the
parts of the body where people have extra skin.
It is usual for patients to wait for between
12 and 18 months after their operation before they are able to have any cosmetic
surgery. This is to make sure that their weight is stable and it is not likely to
change significantly.
Cosmetic surgery is not suitable
for everyone, and may cause further health problems. If a patient wants to find out
more about cosmetic surgery after their gastric bypass operation, then they must discuss their options with their doctor.
Gastric
bypass surgery has a side effect called "dumping". What is
"dumping" and what do I need to do if I get this?
Dumping is an unpleasant
reaction to eating very sugary foods after having gastric bypass surgery. Patients might feel sick and faint. Patients can prevent dumping by eating the right foods.
After gastric bypass surgery, the stomach will be smaller and it will also empty more quickly than before. Sugary foods enter the patient's intestines quickly, and cause fluid to be pulled out of other tissues in their body to try and dilute it. This can be as much as 1.5 litres (three pints)
and cause the patient's blood pressure to decrease.
This fluid comes from many
parts of the body (including the blood), which is why people may feel tired and
faint. All of this extra fluid in their intestines can be painful and make their abdomen swell. When patients eat sugar, their body will also produce too much
insulin, which can also cause them to feel sweaty and faint.
To help to prevent dumping syndrome, patients must make sure that they:
- only eat small meals and stop eating before they feel full.
- rest for around 20 minutes after eating.
- eat only small amounts of carbohydrates (such as
bread, potatoes and cereals).
- only eat foods which contain very little sugar or
use artificial sweeteners instead.
- do not drink with, or immediately after, eating
If patients experience symptoms of
dumping, then they must lie down and stick to small amounts of fluids until the symptoms
have resolved.
Up to half of people who have a
gastric bypass operation may have the symptoms of dumping after their
operation. However, the symptoms usually get better as time goes on, so that
by one year after surgery, only around one in 20 people (5%) will still be affected.
If a patient is worried about their symptoms or the type of foods they must be
eating, then they must contact their dietitian or doctor for further advice.
Gastric
bypass
The
gastric bypass is a combined restrictive and malabsorptive procedure. The
first step creates a pouch, in the same position and of a similar size to
that created with the gastric band.
The
surgeon creates this pouch using metal staples that are similar to stitches.
The stomach will be cut through so that the pouch is no longer attached to
the rest of the stomach. The top section of the stomach (the pouch) will hold the food. The surgeon will count down 75–150cm from the top of the small
intestine and divide it. They will then bring up the end that is not attached
to the remaining stomach and attach it to the pouch.
Food
will now travel from the pouch straight into the small bowel. The divided end
of the small bowel which is connected to the remainder of the stomach is then
connected 75–150cm below where the other end is joined to the gastric pouch. This
allows the digestive juices (gastric and pancreatic juices) to enter the
small intestine and digest the food.
As with
the gastric band, the main effect is that the amount of food patients are able to
eat is reduced. Therefore patients will fill up quickly and stay full for longer
(after only a few mouthfuls of food). Most people find that they do not get
the same feeling of hunger that they did before the surgery. The
bypassed portion of stomach and intestine does not affect the absorption of
most of the nutrients that patients eat. However it may reduce the amount of
protein, vitamins and minerals that they absorb.
To
avoid developing a deficiency, the doctor will prescribe vitamin and mineral
supplements to the patient to take daily for life. He will also perform regular blood
tests to ensure that the patient does not develop any nutritional deficiencies.
Expectations
of weight loss
Most
people lose weight quite quickly over the first year following bypass
surgery. Patients will generally reach their target weight after 18 months. On
average, people lose 65–75% of their excess body weight. As with gastric band
surgery, there is variation in the amount of weight that people lose
following surgery.
Adherence
to dietary advice will result in greater weight loss and better weight
maintenance. The dietitian usually discusses with the patients what changes they would need
to make to their eating patterns in order to have the best weight loss results.
Advantages
- The
amount of food patients can eat is restricted.
- They are
likely to feel fuller quicker and stay fuller for longer.
- Weight
loss starts from the time of surgery.
- Weight
loss tends to be faster than following the gastric band operation.
- Patients can
lose on average 65–75% of their excess weight.
- The
average weight loss after surgery tends to be higher than after a purely
restrictive procedure (e.g. gastric band).
- It is
unusual for a patient not to lose the expected amount of weight.
- The
gastric bypass procedure is particularly effective at reducing medication requirements
and improving blood sugar control for patients affected by Type 2 Diabetes
Mellitus. A fairly recent study showed resolution of diabetes in 81% of patients 2 years
after surgery, and in 71% of patients less than 2 years after surgery
(Buchwald et al 2007 American Journal of Medicine).
Disadvantages
- The
surgery has more risks than the gastric band because it is a longer procedure
and the stomach and intestines are cut.
- Obstruction may occur where the new joins are created at the pouch and further down the
intestine — this may require a procedure (endoscopic or surgical) to widen the
area and allow food to travel through at the correct rate.
- Patients will need to take daily multivitamin and mineral supplements for life.
- Patients will be at greater risk of suffering from nutritional deficiencies such as
vitamin B12, iron and calcium.
- Patient's hair may thin, although this is temporary while they are losing weight at a rapid rate.
- Patients may
develop gallstones due to rapid weight loss, and it may be necessary to undergo a
further operation to remove their gallbladder, although this is quite rare.
- Patients may
experience dumping syndrome, a condition which occurs if they eat too much
sugar, fat or alcohol, or large amounts of food. Dumping syndrome is not considered a health
risk, but it can be quite unpleasant, with symptoms including nausea, vomiting,
diarrhoea, sweating, faintness, weakness and increased heart rate.
- Nausea
and vomiting may occur, especially in the first few days after surgery. Vomiting
is also common if patients eat too quickly or eat too much. However, patients will have better results if they follow their recommended dietary changes.
Source: NHS Choices.
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