Perioperative management - Laparoscopic gastric bypass

Like all other approaches in the treatment of obesity, surgical measures are not addressing the cause of obesity because this is complex and still largely unknown. Based on the guidelines in developed countries, surgery is considered in patients with a BMI ≥ 35 kg/m² and severe comorbidities, such as diabetes, or a BMI ≥ 40 kg/m² and in whom conventional treatment regimens had proved unsuccessful.

The following parameters must be considered when choosing a procedure:

1. • Patients baseline weight (BMI)
   • Expected weight loss (EWL)
   • Compliance
   • Age
   • Family planning not yet completed in women
   • Comorbidities (particularly diabetes )
   • Surgical risk

Other factors to consider include:

1. • Gender
   • Occupation
   • Eating habits 

• Debilitating disease
• Pregnancy
• Lack of compliance
• Gastric and duodenal disorders 

Since bleeding in the gastric remnant cannot be treated endoscopically, laparoscopic gastric bypass is contraindicated in patients on

• lifelong anticoagulants (warfarin or ASA)
• chronic analgesics (ulcerogenic)

Risk evaluation plays a key role in bariatric surgery. In addition to the standard diagnostic workup (ECG, chest x-ray, lab panels), this always includes pulmonary function testing and assessment of the nutritional status. Endoscopy of the stomach is particularly important in resection procedures such as gastric bypass. Radiology , on the other hand, provides additional information only in around 5% of patients. Routine polysomnography is standard practice in US departments where between 77% and 88% of patients suffer from sleep apnea.

Preoperative measures with physical conditioning are initiated already prior to hospitalization: No smoking, liquid diet at least two days before admission (ideally two weeks) and discontinuation of medication that could increase the risk (metformin, oral anticoagulants etc.).
Preoperative intestinal preparation is also recommended in gastric bypass.  In general, preoperative hygiene measures are like those in other types of procedures, paying special attention to intertriginous areas, acute inflammatory crural ulcers, and diabetic changes in the lower extremities. Antithrombotic weight.adapted medication is initiated on the day of surgery.

The patients must be given comprehensive information since they will undergo an elective procedure. In addition to the general surgical risks associated with laparoscopy and the conversion to laparotomy, this must include the specific risks ranging from the intraoperative risks, short- and long-term sequelae through the need for transfusion and the mortality risk.  At present, there is no standard format for obtaining informed consent.

You can find a detailed informed consent example here.

Since gastric bypass can only be performed by laparoscopy or laparotomy, this requires either general anesthesia or general anesthesia in pneumoperitoneum

In principle, endoscopy-assisted intubation should be possible in obese patients. Video laryngoscopy substantially facilitates intubation.

Ileus positioning

Maximum relaxation is required throughout the entire operation to assure maximum range of motion in the surgical field, which is already constricted by the abdominal and visceral fat. In addition, the anesthetist should note that the rather upright position of the patient, almost sitting (anti-Trendelenburg position), may require increased ventilation pressure, possibly PEEP ventilation.

Central venous catheter

In high-volume centers it is generally possible to forgo a central venous catheter (CVC) since in extremely obese patients this is associated with its own morbidity. However, in lower-volume centers and for longer operating times a CVC is recommended. Furthermore, a CVC provides good venous access during the critical first 24-28 postoperative hours when the peripheral venous situation is generally precarious.

Inserting the CVC peripherally into the brachial or radial vein will avoid the risk of pneumothorax.

Gastric tube

A nasogastric tube must be in place during the operation and moved as directed by the surgeon when fashioning the gastrojejunostomy. This requires absolute coordination via the laparoscope monitor since the nasogastric tube must be advanced carefully through the anastomosis being fashioned while avoiding perforation. The completed anastomosis is leak tested with methylene blue. This also requires close coordination with the surgeon. After the leak test, the tube should be repositioned to rule out inadvertent suture fixation. If necessary, the tube may be left for up to 24 hours in the anastomosis but must then be removed to avoid pressure ulceration. However, usually the nasogastric tube can be carefully removed following successful leakage testing. Do not withdraw the tube too fast since that could result in perforation or rupture of the anastomosis in the event of inadvertent intraoperative suture fixation of the tube.

Place the patient in an anti-Trendelenburg position on the bariatric operating table certified for the patient weight. These tables should also be equipped with side extensions to accommodate very wide patients. Position the video monitors above the patient’s shoulders on the left and right. Abduct both arms. Spread both legs.

In Europe the most common surgeon position between the patient’s spread legs is ergonomically best (“French position”). Unless working with a voice-controlled camera this procedure requires a camera assistant. A pneumatic liver retractor on the patient‘s right side holds in place the left hepatic lobe. The scrub nurse stands to the left of the surgeon.

• Basic laparoscopy set
• Two-step trocar system with Verres needle or another type of access trocar
• Two 5 mm trocars (possibly extra-long)
• Three 12 mm trocars (possibly extra-long)
• Possibly, a 15 mm trocar for the staplers
• Dissection device (Ultracision® or LigaSure™)
• Electrocautery unit
• Selection of laparoscopic staplers (3-4 blue cartridges for the stomach and two white cartridges for the small intestine)
• Two Babcock forceps or other atraumatic graspers to measure the small intestine
• Two needle holders 
• Scissors and, possibly, traumatic graspers
• A 30° laparoscope is recommended
• High-volume insufflators
• Stabilizer for liver retractor

Postoperative analgesia:

Intravenous, non-ulcerogenic standard medication will generally suffice.

Follow this link to PROSPECT (Procedures Specific Postoperative Pain Management)

Follow this link to the current German guideline Behandlung akuter perioperativer und posttraumatischer Schmerzen [Treatment of acute perioperative and posttraumatic pain].

Postoperative care:

• Postoperative monitoring: Since tachycardia is sometimes the only sign of significant problems in these patients, postoperative monitoring on the IMC/ICU is recommended.
• Bronchopulmonary hygiene: The high rate of atelectasis and low oxygen saturation seen in his patient population mandates intensive bronchopulmonary hygiene PT measures.
• Upper GI series with water-soluble contrast agent (diatrizoic acid) An upper GI study can be undertaken on postoperative day 2. If no leakage or stenosis is seen remove the nasogastric tube if not already done intraoperatively. Some centers do not carry out routine x-ray studies and others do not leave the tube in situ postoperatively, without any discernible negative consequences. Vitamin replacement: Vitamin replacement is initiated after postoperative week 3. This comprises a daily dose of multivitamin tablets, vitamin B12 100 mg and calcium carbonate.
• Iron replacement: Iron replacement is recommended in menstruating women.
• Gallstones: In patients still with their gallbladder, the administration of certain bile acids during the first six postoperative months may reduce gallstone development from almost 40% to 3%.
• Sports: Since physical activity is a decisive factor for the long-term success of the operation, encourage the patient at each follow-up visit to exercise a lot. Recommended are running, cycling or aerobics five times a week for at least 30 minutes. In primary wound healing, a muscle building weight-training program for the upper body may also be recommended after postoperative week 6. During the first year all patients are seen for follow-up visits every three months  to monitor their appropriate dietary and exercise lifestyle.
• Follow-up visits: At least twice yearly for an indefinite period.

Deep venous thrombosis prophylaxis: 

Unless contraindicated, the moderate risk of thromboembolism (surgical operating time > 30 min) calls for prophylactic physical measures and low-molecular-weight heparin, possibly adapted to weight or dispositional risk, until full ambulation is reached. Furthermore, patients should wear thigh-high compression stockings.

Note: Renal function, HIT II (history, platelet check)

Follow this link to the current German guideline Leitlinie Prophylaxe der venösen Thromboembolie [Guideline on prophylaxis in venous thromboembolism].

Ambulation: 

Start already in the evening of the day of surgery; increasing ambulation is desirable but lifting objects weighing more than around 3 kg should be avoided until postoperative week 6.

Physical therapy: 

Possible prophylactic respiratory therapy for pneumonia.

Diet: 

Nutrition can be slowly initiated on postoperative day 2, starting with water (< 30 ml/h). As soon as the patients can tolerate sips of water, increase their fluid intake to 60 ml/h and offer them 60 ml of a standard enteral solution with their favorite flavor three times daily. Instruct patients to avoid solid food for the time being. In general, drinks rich in carbohydrates are outdated. Medication should only be taken as powder or solution. The gradual transition from soft to solid food can be initiated four weeks after surgery , starting with boiled chicken and fish. It is possible that patients will not tolerate meat for some time. Instruct the patients to chew their food thoroughly and pause between bites. They should stop eating once they start to feel full. Patients should eat three meals daily and not skip any meals. Snacks, if at all taken, should be low in calories, such as pure popcorn, celery or carrots.

Bowel movement:

Patients in the immediate postoperative phase may experience both constipation and diarrhea. As a rule, these can be managed with standard measures. At times lactose intolerance may be revealed. Assuring adequate fluid intake by patients is paramount Persistent diarrhea with severe flatulence may be a sign of high oral fat intake. Occasionally, there may also be transient disruption of the normal intestinal microbiome which should resolve upon resumption of a normal diet. Close follow-up by a trained medical nutritionist is recommended in such cases.

Work disability: 

Patients are normally discharged on postoperative day 3 to 5 provided that their fluid intake is adequate.