Surgical Treatment for Obesity

Copyright © 2005 by the Wound, Ostomy and Continence Nurses Society J WOCN ■ November/December 2005 393 In the United States, obesity has reached epidemic proportions. Serious medical complications, impaired quality of life, and premature mortality are all associated with obesity. Medical conditions such as type 2 diabetes mellitus, hypertension, hyperlipidemia, or sleep apnea can improve or be cured with weight loss.1 Medical treatment programs focused on diet, behavior modification, and/or pharmacologic intervention have met with limited long-term success. Although surgical treatments for obesity have become popular in recent years, they should only be used as a last resort for weight loss. Not all patients can be considered appropriate candidates for surgery; therefore, guidelines based on criteria from the National Institutes of Health should be used preoperatively to help identify suitable persons.2 Most individuals who opt for weight-loss surgery have usually struggled for many years with losing weight and keeping it off, but surgery alone will not ensure successful weight loss. Patient education is imperative for longterm success. Moreover, any such educational regimen should include information on diet, vitamin and mineral supplementation, and lifestyle changes, as well as expected weight-loss results and improvements in comorbid conditions. Patients must be willing to commit to a long-term follow-up program intended to promote successful weight loss and weight maintenance and to prevent metabolic and nutritional complications.

In the United States, obesity has reached epidemic proportions. Serious medical complications, impaired quality of life, and premature mortality are all associated with obesity. Medical conditions such as type 2 diabetes mellitus, hypertension, hyperlipidemia, or sleep apnea can improve or be cured with weight loss. 1 Medical treatment programs focused on diet, behavior modification, and/or pharmacologic intervention have met with limited long-term success. Although surgical treatments for obesity have become popular in recent years, they should only be used as a last resort for weight loss. Not all patients can be considered appropriate candidates for surgery; therefore, guidelines based on criteria from the National Institutes of Health should be used preoperatively to help identify suitable persons. 2 Most individuals who opt for weight-loss surgery have usually struggled for many years with losing weight and keeping it off, but surgery alone will not ensure successful weight loss. Patient education is imperative for longterm success. Moreover, any such educational regimen should include information on diet, vitamin and mineral supplementation, and lifestyle changes, as well as expected weight-loss results and improvements in comorbid conditions. Patients must be willing to commit to a long-term follow-up program intended to promote successful weight loss and weight maintenance and to prevent metabolic and nutritional complications.
O besity, a chronic disease manifested by an excess of body fat, has reached epidemic proportions. 3 In the United States, 127 million adults are overweight, 60 million are obese, and 9 million are classified as morbidly obese. 4 An increase in weight related comorbidities has paralleled this rise in obesity, prompting the US Centers for Disease Control and Prevention to rank obesity as America's number one health threat in 2004 (Figure 1). In addition, obesity is now the second leading cause of preventable death, resulting in more than 400,000 deaths annually. 5 It is projected that obesity will surpass tobacco use and become first on the list for preventable death in the year 2005.
The etiology of obesity is multifactorial. Environmental, metabolic, genetic, hormonal, and neurologic factors all The etiology of obesity is multifactorial.
Environmental, metabolic, genetic, hormonal, and neurologic factors all contribute to varying degrees.
contribute to varying degrees. The simple explanation is that weight gain is caused by consuming more calories than the body expends with excess calories stored as adipose tissue.
Body mass index (BMI) is the most widely accepted classification of weight status. To calculate an individual's BMI, the body weight in kilograms is divided by height in meters squared. Charts and online sites are available for rapid calculation of BMI. 6 BMI is not only used to diagnose and classify obesity, but it also can estimate health risk. Morbidity and mortality will increase proportionately to an individual's BMI (Table 1). However, obesity-related health risk is also influenced by the distribution of body fat. 7 Patients who exhibit central obesity (the "apple" shape) are at increased risk for cardiovascular disease and diabetes. A peripheral fat distribution pattern (the "pear" shape) is associated with abdominal hernia, venous stasis disease, and degenerative joint problems. The individual's level of physical fitness is another factor that influences risk. People who are obese who are active and exhibit higher levels of fitness are at lower risk for developing cardiovascular disease or diabetes. The onset of overweight/obesity will also contribute; the earlier the onset of weight problems, the higher the risk for developing associated comorbidities. Finally, ethnicity will also have an influence. For example, Asians are at greater risk for cardiovascular disease and/or diabetes compared to whites at the same BMI.
Weight loss and managing obesity provides for shortterm and long-term healthcare benefits. Unfortunately, medical weight-loss programs encompassing dietary counseling, exercise programs, behavior modification, and/or pharmacotherapy demonstrate only modest results that are not sustained in the long-term. 8 In addition, patients classified as morbidly obese are usually refractory to these medical weight-loss modalities. Although surgical treatment for weight loss is seen by many as a last resort, current data suggest morbid obesity is best treated with bariatric or weight-loss surgery. 2 In a recently published meta-analysis, a substantial majority of patients who were obese demonstrated complete resolution or improvement in type 2 diabetes, hyperlipidemia, sleep apnea, and/or hypertension with weight loss after bariatric surgery. 9 As increasing numbers of people who are morbidly obese undergo surgical treatment for their obesity, it becomes increasingly important for healthcare providers, including the WOC nurse, to be knowledgeable about the various surgical procedures and the effect they may have on patients' nutrition, vitamin, and mineral status. WOC nurses face unique challenges as they care for the obese patient, especially when consulted regarding skin breakdown and wound care. 10 Nutrition related issues will vary depending on the surgical procedure, as well as where the patient is in his or her postoperative course. Recommendations regarding nutrition supplements will need to be made based on surgical anatomy.

Surgical Treatment of Obesity
In 1991, the National Institutes of Health (NIH) established guidelines for the surgical treatment of obesity 2 (Figure 2). In addition to the NIH criteria, many bariatric surgery programs have additional guidelines whose aim is to decrease operative risk and establish patient accountability. For example, patients may be asked to eliminate tobacco use. Women of child-bearing age are asked to commit to the use of birth control for the first 18 to 24 months after surgery. This is done to protect the health of the fetus, as well as to ensure optimal weight loss results for the patient. Because they must follow strict dietary guidelines after surgery, it is also imperative for individuals to show they have the capacity to follow a diet and establish regular mealtimes. Therefore, patients may be asked to lose a predetermined amount of weight before surgery to demonstrate compliance, as well as their ability to follow a diet plan. This can frequently be accomplished by eliminating fast foods, high caloric liquids, and caffeine from the diet. In addition, preoperative weight loss of 10% or more of body weight may also reduce    The bariatric surgery team works with the patient to establish lifelong health behavior modifications beginning in the preoperative period, because these changes will set the stage for life after surgery. 12 Many patients will look to the surgery as a "new lease on life"; this philosophy may increase their level of readiness for making necessary lifestyle changes. 13 Patients are asked to be personally accountable for following program guidelines and to assume ownership for the choices they make.

■ Surgical Procedures for Weight Loss
There are several different surgical procedures currently performed for weight loss, each achieving results by differing mechanisms of action. The laparoscopic adjustable gastric band (lap-band) ( Figure 3) and vertical-banded gastroplasty (VBG) are restrictive procedures; the biliopancreatic diversion (BPD) and duodenal switch (DS) ( Figure 4) are malabsorptive procedures; and the Roux-en-y gastric bypass (RYGB) ( Figure 5) is a procedure that combines both modalities. 14-17 These procedures can be performed via either the morbidity. 1 Patients should not be at their heaviest lifetime weight at the time of their surgery.

■ Preoperative Evaluation and Education
Before surgery, all patients are required to undergo a psychologic evaluation. The purpose of this evaluation is to ensure Before surgery, all patients are required to undergo a psychological evaluation . . . patients must be emotionally prepared to manage the postsurgical lifestyle and dietary changes.
that the patient has a thorough understanding of all aspects of the surgical procedure and its risks. 11 In addition, patients must be emotionally prepared to manage the postsurgical lifestyle and dietary changes. The meeting with the psychologist will focus on: Ⅲ Previous weight loss efforts and their results. Ⅲ Current diet and conditions that influence eating behavior. Ⅲ Factors that have contributed to previous success and failure in weight control.
Depending on the patient's medical history, consults with other medical specialists, such as a cardiologist or pulmonologist, may be indicated. Tests commonly required before surgery include a cardiac stress test, echocardiogram, and/or sleep study to evaluate for sleep apnea.
Extensive patient education begins before surgery, using a variety of teaching methods, including group lectures, individual counseling, and the provision of written materials. Patient education is imperative for successful and safe weight loss and should include information on diet, vitamin and mineral supplementation, and lifestyle changes, as well as expected weight-loss results and improvement in comorbid conditions. Individuals are also encouraged to attend support group meetings where patients who have had bariatric surgery will provide those undergoing bariatric surgery a realistic view of how their life will change after surgery.
Patients must understand that weight-loss surgery is not a panacea. Bariatric surgery provides individuals with a "tool" that can be used to achieve long-term weight loss. This understanding should begin with the first patient encounter and must be a universal message delivered by all members of the bariatric surgery team. It is important that team members and the patient establish mutually realistic expectations focused on anticipated weight-loss results, as well as the resolution of comorbidities, improved functional capacity, and quality of life. 12  open or laparoscopic approach, with the majority being done laparoscopically because this approach offers the advantages of a shorter hospital stay and less pain ( Table 2).
The restrictive procedures result in weight loss by reducing the size of the stomach, thereby limiting the amount of food and subsequently the number of calories an individual is able to consume. Before surgery, the stomach volume is 1 L; after a restrictive procedure, the small gastric pouch has a capacity of 15 mL. In addition, the outlet from the pouch is small, delaying the emptying of food and contributing to a sense of fullness. Therefore, after either of these procedures, despite a small portion size, patients experience an early sense of satiety followed by a prolonged sense of satisfaction.
The BPD and DS, both less commonly performed procedures in the United States, alter the mechanism of calorie absorption because during these surgeries the majority of small bowel is bypassed (only 1.5 feet is available for absorption after surgery vs 7 to 9 feet before surgery). 14 Individuals who have had a BPD or DS eat a larger volume of food, but because the majority of calories are not absorbed, weight loss will occur. As a consequence of the malabsorption of nutrients, after a BPD or DS, patients will experience frequent loose stools and are at increased risk for protein malnutrition, vitamin and mineral deficiencies, and poorer quality of life.
The RYGB, presently recognized as the "gold standard," is a combination procedure that restricts the volume of food eaten and limits absorption of nutrients. To a lesser degree, malabsorption is less likely with RYGB surgery than with the BPD or DS. 14 The RYGB procedure offers the best combination of weight loss coupled with the fewest nutritional risks. Because this is a restrictive procedure, when an individual consumes a meal, he or she will experience an early sense of satiety. However, unlike the purely restrictive procedures, if the RYGB patient consumes foods high in sugar or fat (greater than 10 g of sugar or fat/serving) he or she will experience symptoms of the "dumping syndrome." 14 Within 30 minutes of consuming sugar, patients will become diaphoretic, experience heart  palpitations, and become flushed and tremulous. Shortly after these initial symptoms, the patient will have severe abdominal cramping and explosive diarrhea. A common response after experiencing a dumping episode is, "I felt like I was dying." If a high-fat meal is consumed, patients will experience nausea, flatulence, and loose stools. These symptoms are a mechanism of 2 factors: first, rebound hypoglycemia resulting from the rapid absorption of sugar from the roux limb; second, the presence of sugar and/or fat in the roux limb triggers an osmotic pull of fluid from the vascular space into this portion of the small bowel. Because of the strongly negative feedback patients receive, they learn to avoid high-calorie foods, particularly those that contain sugar and fat.

■ Postoperative Recovery
Patients' postoperative care after weight-loss surgery will vary among bariatric surgery programs. The use of standing orders and clinical pathways will provide a program with direction, facilitate adherence to program guidelines, and allow for the evaluation of outcomes. Protocols should be in place that addresses perioperative care, diet progression, pain management, and deep venous thrombosis prophylaxis.
For example, at the Medical College of Wisconsin, prophylaxis for deep venous thrombosis includes early ambulation, the use of sequential compression devices, and anticoagulation. On the first postoperative day, patients will undergo a limited gastrointestinal swallow study to evaluate for an anastomotic leak or obstruction ( Figure 6). Once the examination has been determined to be normal, patients will begin sipping water and for their evening meal will receive a pureed diet. After lunch on the second postoperative day, if the diet is tolerated and adequate liquids (64 oz) are consumed, the patient is discharged home according to the clinical pathway. Patients who have undergone a laparoscopic RYGB are typically hospitalized for 2 days; when the procedure is performed using an open approach, patients are usually discharged on postoperative day 4.

■ Risks and Benefits of Roux-en-y Gastric Bypass Surgery
Roux-en-y gastric bypass (RYGB) surgery is not without risk, and patients need to understand both the potential bene-

Procedure Description
Roux-en-y gastric bypass (combination procedure) (see Figure 5) Laparoscopic adjustable gastric band (restrictive procedure) (see Figure 3) Vertical banded gastroplasty (restrictive procedure) Biliopancreatic diversion; duodenal switch (malabsorptive procedures) (see Figure 4) The stomach is divided and separated with a stapler, and a 15-mL gastric pouch is created. The small intestine is then cut approximately 2 feet below the stomach and, a gastrojejunostomy is formed with a 10-mm outlet allowing food to empty slowly from the pouch. The lower part of the stomach is bypassed, but the digestive juices, bile, and stomach acid flows normally, eventually mixing with and digesting food where they meet at the jejunojejunostomy. An inflatable band is placed around the upper stomach to create a small gastric pouch. The band is connected to an implanted reservoir in the abdominal wall. The reservoir can be accessed with a needle and saline injected to inflate or deflate the band affecting the emptying time of the pouch. The upper stomach near the esophagus is stapled vertically to create a small pouch. A band is placed to restrict the outlet from the pouch delaying the emptying of food. In general, three main components: a. Partial gastrectomy done to decrease acid and prevent ulcer b. Biliopancreatic limb-remainder of small bowel; diverts digestive juices c. Nutrient or common limb-portion of small bowel where absorption occurs (50-100 cm in length); biliopancreatic limb empties digestive juices to mix with food stuffs.
fits and the complications that may occur (Table 3). [18][19][20][21][22] Mortality rates of 0.5% (1 in every 200 cases) after gastric bypass are reported in the literature. An anastomotic leak, cent meta-analysis, type 2 diabetes mellitus was resolved or improved in 86% of patients who had undergone weightloss surgery. Hypertension resolved or improved in 78.5% and hyperlipidemia improved in 70% of patients postoperatively. Individuals with obstructive sleep apnea also saw their condition resolve or improve 83.6% of the time. 9 ■ Diet Progression, Metabolic and

Diet Progression
The first year after surgery is the ideal time during which patients can begin to establish a new lifestyle; it is also the time frame when individuals are at their greatest risk for dehydration, nausea and vomiting, and protein malnutrition. 14 It is therefore critical that patients have available to them and participate in a postsurgery follow-up program designed to promote lifestyle changes and minimize nutritional complications. 12,14 Because of changes in their metabolic milieu during the first 3 to 6 months after surgery, individuals are not typically hungry; thus, this is the most opportune time to institute and reinforce a healthier way of eating. Mealtimes are structured: 3 meals per day, spaced approximately 5 hours apart with the majority of meals eaten at home, and no between-meal snacks. To reduce calories and avoid "dumping" symptoms, patients are instructed to keep their diet low in fat and sugar and limit their intake either to 10 g or less per serving. During this first year, patients relearn how to eat and drink; therefore, what had once been a behavior requiring little thought becomes a conscious activity.
As the capacity of their pouch changes, how and what individuals eat and drink will change during the first year. The pouch will always remain 15 mL, but with time when a meal is eaten it will be able to stretch, reaching a maximum capacity of 180-200 mL (still less than a "normal" stomach capacity of 1 L). The goal of diet progression during the first 6 months, therefore, is to prevent dehydration and protein malnutrition and to minimize gastrointestinal symptoms triggered by poor dietary choices. Later goals are mechanical manipulation of the pouch to control hunger and weight maintenance (Table 4). Patients are asked to keep a dietary log to document their liquid and protein intake, both as a monitoring tool and a means to incorporate new eating habits into their daily lives.

Dehydration
In the first months after RYGB, there is a physiologic as well as a mechanical risk for dehydration. Early after surgery the patient will enter a ketotic state wherein fat is burned for energy and fluid requirements are increased (water is needed for this chemical reaction). After weightloss surgery, patients require a minimum of 64 oz of liquid or they will rapidly dehydrate. The early and predominant symptom of dehydration is nausea. The nausea that patients experience furthers to compound the problem, be-  one of the most catastrophic postoperative complications, may contribute to a prolonged hospital stay and lead to possible reoperation. Leak rates are reported to range from 0.72 to 4.3% and can contribute to other infectious complications, such as intraabdominal abscess. Wound infection rates in an open procedure are reported to be as high as 9.0%, whereas with the laparoscopic approach, the incidence falls to 1.5-5.0%, which is an advantage of this technique. It is anticipated that patients will lose 60-80% of their excess body weight during the first 18-24 months after RYGB surgery. [18][19][20][21][22] To calculate a patient's excess body weight, his or her ideal body weight is subtracted from his or her actual weight. In the first month after surgery, patients will lose approximately 10% of their preoperative weight. During each of the next 5 months, patients will loose an average 10-15 lb per month. Weight loss will slow during the course of the second half of the first year, with patients losing half as much weight as they lost during the first 6 months. For example, if a patient lost 100 lb during the first 6 months, he or she may lose approximately 50 pounds during the following 6 months. The majority of weight loss will occur within the first year after surgery.

Surgical Morbidity and Mortality
Improvement will begin to be seen in the patient's comorbid health conditions as the weight is lost. 9,20,21 In a re-cause they typically drink less in response to this symptom. In addition to this physiologic risk, during the early postoperative period, patients are also mechanically restricted and therefore cannot drink more than 1 oz every 15 minutes by taking small frequent sips of liquid. Therefore, if patients are unable to meet their minimum fluid requirement, it becomes physically impossible to make up the deficit, and they may require IV fluids. At the first sign of nausea, patients are instructed to begin to "drink through their symptoms" to avoid worsening dehydration. If they are successful, their nausea will subside and they will maintain their hydration status.

Nausea and Vomiting
Nausea and vomiting after RYGB are not only caused by dehydration but also can be triggered by eating meals too quickly, overeating, reclining immediately after a meal, or consuming foods that are high in fats and/or sugar. Timing of liquid intake is also important in preventing nausea; if patients drink with their meals or in proximity to mealtime, they will experience nausea and/or vomiting. Patients need to understand what caused their symptoms and then make the appropriate adjustment to avoid symptoms in the future. Antiemetics are ineffective in treating nausea in these situations. If patients experience an episode of nausea and/or vomiting (not related to dehydration), they are taught to withhold any liquids or solids until their symptoms subside. Once their symptoms have resolved, they are directed to first suck on a sugar-free Popsicle or ice chips. Patients will then progress to sips of water followed by drinking, after which their diet will gradually be advanced over the next 24 hours. If at any time a patient's symptoms are irretractable, a limited upper gastrointestinal radiologic examination may be indicated to rule out an obstruction.

Protein Intake
To avoid entering a starvation state and to preserve lean muscle mass after RYGB, patients will need to have a minimum protein intake of 60 g/day. 14 Some bariatric surgery programs will advocate the use of protein supplements or small frequent meals to achieve this goal. Because highcalorie liquids and between-meal snacks will slow weight loss and may lead to weight regain in the future, in the authors' program patients are taught from the beginning Nausea and vomiting after RYGB not only is caused by dehydration but also can be triggered by eating meals too quickly, overeating, reclining immediately after a meal, or consuming foods that are high in fats and/or sugar. how to accomplish an intake of 60 g/day (3 meals per day). Initially, when the patient's volume of food eaten is restricted by the small volume of the pouch, their food items can be fortified with powdered milk or egg whites (the protein content is increased without increasing the volume).
There are also new low-carbohydrate/high-protein milks and yogurts available, which are good food choices for RYGB patients.

Exercise
To maximize weight loss and preserve lean muscle mass, patients need to be physically active after undergoing bariatric surgery. One hour of planned exercise of a moderate intensity per day is the ideal goal. Walking is encouraged if patients do not have joint problems; otherwise, water exercise is an excellent option.

■ Long Term Follow-up
Long-term risks attributable to weight-loss surgery include vitamin and mineral deficiencies, cholelithiasis (in those patients with a gallbladder), and weight regain. [23][24][25][26][27] During the first 6 months after weight-loss surgery (the period when patients experience rapid weight loss) patients are at an increased risk for forming gallstones (bile becomes saturated with cholesterol). To minimize this risk, patients can be placed on 300 mg of ursodiol twice a day. Studies have shown a significant decrease in gallstone formation and symptomatic cholecystitis with ursodiol prophylaxis. 24,25 Several authors have reported on the incidence of vitamin deficiencies after RYGB. Observational studies have demonstrated that iron deficiency can occur in 20-49% of patients and B 12 deficiency in 26-70%; non-hemolytic anemia was identified in 18-54% of patients within the first year of surgery. 23,26,27 To prevent anemia, lifelong vitamin and mineral supplementation is therefore suggested after RYGB. 14 It is recommended that patients take a multivitamin with minerals, 500 µg of oral vitamin B 12 , and 1000-1200 mg of calcium daily. Menstruating women may also require additional iron supplementation to prevent irondeficiency anemia. Monitoring vitamin and mineral status, as well as nonhemolytic anemia evaluation, should occur routinely after weight-loss surgery.
Regular office visits provide patients the opportunity to receive ongoing education and counseling focused on exercise and diet; regular office visits also provide healthcare practitioners the opportunity to monitor their patient's nutritional and metabolic status. At the Medical College of Wisconsin, patients are followed for a minimum of 5 years, because an individual's chance for ongoing success increases if his or her weight can be maintained for that time period. Weight maintenance depends on the patient's adherence to diet, regular physical activity, and selfmonitoring of weight and food intake. 28 To prevent weight regain, patients must avoid consuming high-calorie liquids, drinking liquids with meals, and snacking between meals. If individuals drink liquids with their meals, they will "flush" the solid food out of their pouch and delay achieving fullness. Such "flushing," therefore, allows a patient to eat more, which leads to the consumption of more calories, with weight regain being the result. A patient's attendance in a support group where facilitating lifestyle change, weight loss, and weight maintenance are the focus, is therefore encouraged.

■ Summary
Long-term success after bariatric surgery depends on patients being well educated in how their surgery will promote weight loss and the lifestyle changes they must make to accomplish this goal. Personal accountability on behalf of the patient is a necessary component. A team of healthcare professionals must be available to provide bariatric surgery patients with ongoing education and support. With a patient's commitment to lifestyle change and the provision of necessary support personnel, weight loss can be significant and maintained lifelong.
✔ Roux-en-y Gastric Bypass will provide patients with a tool which can be used to achieve long-term weight loss and minimize obesity-related health risks.
✔ Education of the patient is necessary to ensure success and minimize complications after weight-loss surgery.
✔ A multidisciplinary bariatric team will promote success and provide necessary support for patients.

KEY POINTS
Regul ar office visits provide patients the opportunity to receive ongoing education and counseling focused on exercise and diet; regular office visits also provide healthcare practitioners the opportunity to monitor their patient's nutritional and metabolic status.