The Increasing Incidence of the Biliopancreatic Diversion with Duodenal Switch as a Surgical Weight Loss Option: Implications for Nursing Care

Introduction

Obesity continues to be a major health concern in the world today. Obesity is classified as a body mass index (BMI) of 30 or greater. According to the World Health Organization's recent data, the rate of obesity in the world is estimated at 400 million adults ¹ with the rate of obesity in the United States at 32–35%. ² This represents an increase from previous studies, and the trend does not seem to be abating. The cost of obesity care accounts for 10% of all medical spending. In 2006, per capita medical spending for an obese person was 42% higher than that of a normal weight person. ³

Comorbidities such as type 2 diabetes, hypertension, sleep apnea, hyperlipidemia, certain cancers, gastroesophageal reflux, arthritis, stroke, and heart disease are linked to obesity.^1,3–5 Weight loss alone will improve these comorbid diseases, but in the obese population, studies have shown that diet and exercise alone provide poor long-term results and that weight loss surgery shows the best lasting resolution of comorbidities.^1,3,4,6–8

Surgical weight loss options that are available today include the laparoscopic adjustable gastric banding (LAGB), vertical sleeve gastrectomy (VSG), Roux-en-Y gastric bypass (RNYGB), and the biliopancreatic diversion with duodenal switch (BPD/DS). The best long-term outcomes occur when the surgical choice is tailored to the patient. Surgical choices are determined by the following: the patient's BMI, comorbidities, individual preference, weight loss goals, and overall health. In consultation with the surgeon using the aforementioned factors, the patient and surgeon will determine which surgery is best for the individual patient.

Patients with a BMI greater than 50 are referred to as super morbidly obese. ⁹ Super morbid obesity is also associated with more obesity-related comorbidities. While the RNYGB is the most commonly performed weight loss procedure in the United States and achieves excess body weight loss of between 60 and 70%,^10,11 the recent increase in prevalence of super morbid obesity, as well as the recognition of inadequate weight loss following RNYGB in the super morbidly obese population, has prompted a growing interest in the BPD/DS. The BPD/DS has been shown to help patients achieve a higher overall weight loss, higher rates of comorbid disease resolution, and a lower weight regain rate than with the RNYGB.^3,4,9,12

Surgical Procedure

Several modifications have been done since the original biliopancreatic diversion was performed. Currently, the BPD/DS procedure includes a 60% sleeve gastrectomy with preservation of the lesser curve of the stomach and the pylorus and the neurovascular supply. The distal ileum is connected to the proximal duodenum, creating the alimentary limb, which is approximately 150 cm long, and the common channel, which is approximately 100 cm long. Recent advances in surgical technique construct the common channel length range from 100 cm to 150 cm.^1,9,13–14 Commonly, the two mesenteric defects (enteroenterostomy and Peterson's space) are closed, which reduce the risk of herniation into these spaces in the future.

The BPD/DS can be performed both open and laparoscopically, though it is now more commonly done laparoscopically. ³ The nature and complexity of this surgery usually presents greater challenges to the patient and the surgeon due to the greater level of adiposity and higher comorbidities.

Metabolic Effects

As the body of research evolves with the BPD/DS procedure, greater understanding of the metabolic effects of the surgery is being realized. Studies have been investigating the surgical effects on the gastrointestinal tract, the interaction among gut hormones, and the resolution of metabolic disease after surgery. These changes in the gastrointestinal tract affect appetite, eating behaviors, glucose homeostasis, and lipid metabolism.

The changes in the gut after the BPD/DS procedure affect the production of hormones, or peptides, that regulate appetite, gastrointestinal motility, and glucose metabolism. ¹ Hormones affected include ghrelin, cholecystokinin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and peptide tyrosine tyrosine (PYY3-36), all of which support the possibility of weight-independent hormonal effects, as evidenced by the normal fasting glucose concentrations that are achieved by many diabetics before any substantial weight loss occurs. ¹

Ghrelin is a peptide hormone mainly produced by cells in the fundus and body of the stomach. This has been called the “hunger hormone” and has been related to patient reports of increased satiety and lack of hunger after surgery. Cholecystokinin (CCK) induces postprandial satiety and is also a factor in appetite control. Released in the upper gastrointestinal tract in response to food intake, CCK signals the central nervous system to reduce the amount of food eaten. ¹ Also stimulated by CCK secretion is GLP-1.

Glucagon-like peptide-1 plays a major role in glucose homeostasis via the “incretin effect.” Its secretion is dependent on the presence of food in the lumen of the small intestine and is a very strong antihyperglycemic agent that enhances satiety, leads to delayed gastric emptying, and inhibits gastric secretion and motility.

Glucose-dependent insulinotropic polypeptide is thought to account for the stimulation of insulin release from the pancreatic beta cells. In the BPD/DS, the proximal intestine is more or less excluded from food passage, which leads to decreased GIP secretion because the nutrient stimulus is absent. The decrease in GIP levels after surgery should be beneficial from glucose homeostasis, since GIP has been shown to promote insulin resistance and hyperglycemia. ¹

Peptide tyrosine tyrosine (PYY3-36) is released in the distal intestine and reduces gastric emptying, inhibits pancreatic secretion, and decreases both gastric acid production and the total intestinal passage time. As another satiety hormone, it also leads to reduced food intake. It is thought that, in obesity, levels of PYY3-36 are reduced, which may account for exaggerated appetite. ¹

Immediate Postoperative Care and Monitoring

Early complications after surgery include anastomotic leak, infection, intestinal obstruction, strictures and bleeding, pulmonary embolism, and cardiac events.^{5,8,13,15–16} Nursing care should focus on prevention and rapid identification of these complications. Airway management and oxygenation are essential to intraoperative and postoperative management. Ensuring the head of the bed is elevated, assessing pulse oximetry, and administering supplemental oxygen are key strategies for the patient recovering from the intraoperative phase. Sleep apnea is assessed, and, if possible, patients who have continuous positive airway pressure (CPAP) machines are encouraged to use them for sleep while recovering.

Pain management is also addressed during this period. Pain assessment and management by either patient-controlled analgesia (PCA) or bolus medications are a routine responsibility of the primary nurse.

It is important to assess for increasing abdominal pain, chest pain, shortness of breath, leg pain, swelling or redness around incisions, fever, persistent tachycardia, nausea, and vomiting. These symptoms are all causes for immediate consultation with the bariatric team and quick intervention. Thromboembolic disease is a serious postoperative concern. Obesity alone is a risk factor for clotting complications, but the endothelial injury and prolonged immobility caused by long operating times—the BPD/DS may take 4 to 6 hours—can increase this clotting risk. Frequently employed prevention regimens may include early ambulation, compression stockings, intermittent pneumatic compression stockings, and medications to decrease risk of clotting such as enoxaparin administered subcutaneously. Symptoms of shortness of breath, leg pain, anxiety, and decreased pulse oximetry are all cause for immediate evaluation and intervention by the bariatric team. For those patients with very high risk factors, a prophylactic inferior vena cava filter can be placed preoperatively. ⁵

Anastomotic leaks after bariatric surgery have decreased with improved experience, but they still present a potentially deadly complication. Patients who develop postoperative anastomotic leaks are more likely to have increased hospital stays and increased mortality. ⁵ Presenting symptoms include tachycardia with a heart rate greater than 120 beats per minute, increased respiratory distress, left shoulder pain, increasing abdominal pain, and anxiety. Failure to identify and rapidly treat an anastomotic leak can result in death. Therefore nurses should have a low threshold for contacting the bariatric team if symptoms occur.

If a patient is complaining of chest pain or shortness of breath, rapid assessment is essential. These may be related to the patient's past medical history. Remember that the stress of surgery can aggravate currently existing comorbid problems such as coronary artery disease.

Long-Term Complications

Rapid weight loss is associated with the formation of cholesterol gallstones in 13–36% of patients within the first six months of surgery. ¹⁷ Most bariatric surgeons will only remove a gallbladder intraoperatively if the patient is symptomatic or if gallstones are revealed through preoperative screening. Ursodisol is a medication available to decrease the formation of gallstones after surgery, but is not universally prescribed.

Intestinal obstruction may occur after bariatric surgery, the incidence of which can vary based on the surgical approach used (i.e., open vs. laparoscopic). The surgical practice of closing potential spaces such as the enteroenterostomy and Peterson's space may also affect the incidence of obstruction. Internal hernias, adhesions, strictures, and incisional hernias can cause obstruction. Patients will typically present with abdominal pain, nausea, vomiting, abdominal distention, and possibly constipation. ¹⁷

Nutritional Complications

The risk of nutrient depletion can be high for surgeries that affect digestion and absorption of nutrients. It is thought that with the BPD/DS procedure, up to 25% of protein and 72% of fat is malabsorbed, causing deficiencies in the fat-soluble vitamins A, D, E, and K, along with zinc, thiamine, iron, and calcium. ¹⁸ Thiamine (vitamin B1) affects several organ systems. Thiamine deficiency requires early detection and prompt treatment to prevent serious irreversible neuromuscular disorders, permanent defects in learning and short-term memory, coma, and even death. Thiamine is a water-soluble vitamin that is absorbed by the proximal jejunum. Without regular and sufficient intake of thiamine, the body can become quickly depleted. In addition, a patient who underwent BPD/DS and is experiencing frequent and/or prolonged vomiting and food intolerances may not be able to take supplementation and can develop deficits very rapidly. Patients are routinely supplemented with thiamine in the form of multivitamins, thiamine itself, and/or B-complex vitamins. Caution should also be taken when a patient presents with symptoms of thiamine deficiency. Infusing solutions containing dextrose without additional vitamins and thiamine can increase glucose utilization, which can further deplete thiamine stores. ¹⁸

Anemias can occur after surgery due to several factors. Absorption of iron, which is most efficiently done in the duodenum and proximal jejunum, is bypassed with the BPD/DS. Menstruating women and individuals that have a history of chronic anemia may require additional iron supplementation. The lack of supplemental iron alone can be a cause of anemia.

Calcium and vitamin D are absorbed in the duodenum and proximal jejunum and in the jejunum and ileum, respectively. In the BPD/DS, the malabsorptive nature of the surgery can affect the absorption of these essential vitamins. This puts the patient at greater risk for bone loss and osteoporosis over time. Supplementation with calcium and vitamin D are essential for lifelong bone health. Malabsorptive surgery is a risk factor for bone loss, and bone scans may be ordered for the monitoring of ongoing bone health.

Vitamins A, E, and K along with zinc are fat-soluble vitamins that may be decreased in the patient who underwent BPD/DS secondary to the decreased intestinal fat absorption. This is caused by the delay in the mixing of gastric and pancreatic enzymes with bile until the final 50–100 cm of the ileum (common channel). Vitamin A deficiency can be responsible for visual disturbances, including night blindness. Though a rare deficiency, low levels of vitamin K can lead to bleeding disorders and disseminated intravascular coagulation. Vitamin E and zinc deficiencies have not been studied widely and are found to be readily restored with daily supplementation. All bariatric patients are encouraged to follow-up with their bariatric team to have regular laboratory studies. Supplementation is added or altered based on the individual patient's lab results.

Other Complications

Alcohol consumption is cautioned for patients that have undergone a malabsorptive procedure. Alcohol is more readily absorbed, and effects in the central nervous system may last longer. Patients should be advised to refrain from alcohol for the length of time prescribed by their bariatric team. ⁸

Pregnancy after a malabsorptive surgery is also cautioned for a period of time after surgery.^6,8 While the duration differs in the literature, most researchers agree that pregnancy should be avoided for at least one year after surgery. ⁶ The greatest danger exists to the health of both the mother and the fetus in the period of rapid weight loss. Once adaptation has occurred, after one to two years, pregnancy can be safely pursued. In fact, with weight loss, fertility often improves and pregnancy for some women is now possible when it previously was not. The risks associated with obesity and pregnancy, such as diabetes, preeclampsia, and hypertension, will all have been greatly reduced, allowing for a safer pregnancy. Nutritional values should be closely monitored during pregnancy, and supplementation should be included as needed.

Long-Term Benefits

BPD/DS surgery has been associated with a greater reduction in comorbid diseases ⁴ and a greater weight loss than with other weight loss surgeries. The overall weight loss seen with the BPD/DS averages 70–80% of excess weight.^10,11 This allows the super morbidly obese to achieve greater comorbidity reduction. One study demonstrated that markers of cardiovascular risk improved, including decreased cholesterol and triglycerides. ⁴ Additional data revealed higher rates of resolution of hypertension, diabetes, and dyslipidemia. ⁴

Quality of life studies and the patient's perception of well-being, social function, body image, and self-confidence also improved after weight loss surgery. ³ Patients report improvement in health and activities of daily living, which include playing with their children, tying shoes, and even sitting comfortably in an airplane or train. ⁷

Conclusion

The growing epidemic of obesity has led to a growing number of individuals who are now in the super morbidly obese category. Research and evidence has revealed that in this category, the traditional RNYGB may not be effective enough to restore lifelong health to individuals with a BMI greater than 50. The BPD/DS now provides a viable option to help this population realize restored health and improved quality of life. The benefits of the BPD/DS surgery do present with higher risks, however. It is essential to understand the surgery, the early and late potential complications, and the importance of lifelong monitoring for continued health.