Seung Ho Choi and Kazunori Kasama (eds.)Bariatric and Metabolic Surgery201410.1007/978-3-642-35591-2_2
© Springer-Verlag Berlin Heidelberg 2014
2. Preoperative Evaluation and Preparation for Patients
(1)
Department of Gastroenterological and Pediatric Surgery, Oita University Faculty of Medicine, Oita University, Oita 879-5593, Japan
Abstract
Bariatric surgery has significantly decreased overall mortality and has imparted a survival advantage to patients undergoing this surgery [21], and the number of such surgeries has now rapidly increased worldwide, even in Asia [18]. Because bariatric patients usually have uncontrolled comorbidities related to obesity and psychological problems, a multidisciplinary team approach for the systematic evaluation and management of these patients is seen as an important component of a bariatric and metabolic surgery practice. In the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) guidelines, the team leader is a surgeon who must have acquired the proper education and surgical training, and other important team members include nutritionists, psychologists with specific training and experience, psychiatrists, and medical subspecialists (endocrinologists, anesthesiologists, and cardiologists, among others) [24]. The team not only preoperatively evaluates and optimizes the patients for surgery but also provides them with preoperative teaching and perioperative care. As a result, a thorough understanding of proper patient selection, appropriate preoperative evaluation, and preparation for patients and successful outcomes of bariatric and metabolic surgery can be achieved in clinical practice. This chapter reviews issues related to preoperative evaluation and preparation for bariatric surgery.
2.1 Introduction
Bariatric surgery has significantly decreased overall mortality and has imparted a survival advantage to patients undergoing this surgery [21], and the number of such surgeries has now rapidly increased worldwide, even in Asia [18]. Because bariatric patients usually have uncontrolled comorbidities related to obesity and psychological problems, a multidisciplinary team approach for the systematic evaluation and management of these patients is seen as an important component of a bariatric and metabolic surgery practice. In the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) guidelines, the team leader is a surgeon who must have acquired the proper education and surgical training, and other important team members include nutritionists, psychologists with specific training and experience, psychiatrists, and medical subspecialists (endocrinologists, anesthesiologists, and cardiologists, among others) [24]. The team not only preoperatively evaluates and optimizes the patients for surgery but also provides them with preoperative teaching and perioperative care. As a result, a thorough understanding of proper patient selection, appropriate preoperative evaluation, and preparation for patients and successful outcomes of bariatric and metabolic surgery can be achieved in clinical practice. This chapter reviews issues related to preoperative evaluation and preparation for bariatric surgery.
2.2 Preoperative Evaluation
2.2.1 General and Medical Evaluation
Candidates for bariatric and metabolic surgery must undergo a routine preoperative evaluation similar to the workup for other major surgeries. The aims of this evaluation are to identify current issues of comorbidities related to obesity, surgical and anesthetic risks, and nutrition and to inform and educate the patients about these issues. The evaluation list includes the following items:
Hematological and laboratory analyses
Chest X-ray
Electrocardiogram
Pulmonary function test (spirometry)
Echocardiography
Abdominal computed tomography
Abdominal ultrasonography
Polysomnography
Upper gastrointestinal endoscopy
Screening of Helicobacter pylori
Esophageal pH monitoring and manometry (for gastric banding)
Hematological and laboratory analyses include a complete blood count, liver and renal function, electrolyte levels, metabolic profiles, fasting blood glucose, glycosylated hemoglobin, coagulation studies, thyroid and adrenal function, ferritin, vitamins, total iron-binding capacity, minerals, and trace elements such as iron, zinc, calcium, and magnesium. A comprehensive nutritional assessment should be performed preoperatively. The candidates frequently have deficiencies of vitamins A and D and iron [5]. These abnormalities should be corrected before the operation. Because C-peptide is a surrogate of intrinsic insulin secretion, this measurement is very important to predict remission of type 2 diabetes after bariatric and metabolic surgery [16].
Routine preoperative evaluation of left ventricular function is not recommended in noncardiac surgery [1], and transthoracic echocardiography often results in poor imaging in patients with morbid obesity. Nevertheless, preoperative assessment including echocardiography should be performed in patients with dyspnea of unknown origin, prior heart failure, and cardiomyopathy [1] and may be useful in patients with multiple obesity-related comorbidities [23]. Because decreased preoperative ejection fraction and postoperative mortality or morbidity are positively correlated [1]. Abdominal computed tomography and ultrasonography can evaluate visceral fat volume, liver size, and cholelithiasis. Hepatomegaly is cited as the most common cause to convert from a laparoscopic to an open procedure, and very low-calorie diet for 6 weeks preoperatively may be helpful to reduce liver volume and to improve access to the upper stomach when hepatomegaly is discovered [7]. Concomitant cholecystectomy for symptomatic gallbladder stones is also recommended, but prophylactic cholecystectomy for non-symptomatic gallbladder stones is still controversial [9, 25].
The anesthesiologist guidelines for patients scheduled for elective major surgery recommend considering preoperative assessment of obstructive sleep apnea with polysomnography and introducing continuous positive airway pressure [12]. Some reports recommend routine screening for obstructive sleep apnea prior to bariatric surgery [20], but the Committee of the American Society for Metabolic and Bariatric Surgery (ASMBS) does not agree with this recommendation [3].
The role of routine endoscopy for preoperative evaluation in bariatric and metabolic surgery also remains controversial. However, upper gastrointestinal endoscopy is very useful to evaluate hiatal hernia, esophagitis/gastritis, active ulcer disease, Barrett’s esophagus and other lesions with a potential for malignancy, and gastrointestinal malignancies. The guidelines from the European Association for Endoscopic Surgery recommend preoperative endoscopy or radiologic evaluation with a barium meal in all bariatric patients regardless of symptoms [26]. The SAGES guidelines recommended preoperative endoscopy when suspicion of gastric pathology exists [24]. The clinical significance of routine screening for Helicobacter pylori has not been defined for bariatric and metabolic surgery. However, preoperative eradication therapy may be advised if this infection is present [24]. Especially in Eastern Asian countries, in which gastric cancer and Helicobacter pylori infection have been epidemic and the relation has been investigated [11, 30], routine upper gastrointestinal endoscopy and screening for the infection may be necessary. Because upper gastrointestinal complications including esophageal reflux and dysmotility are associated with poor outcomes after gastric banding, esophageal pH monitoring and manometry are advised in potential gastric banding candidates [9].
Preoperative screening of deep vein thrombosis to prevent pulmonary embolism using Doppler ultrasonography and D-dimer measurement has not been established in the field of bariatric surgery. However, retrievable inferior vena cava filters are effective in preventing pulmonary embolism in high-risk patients undergoing bariatric surgery who have history of venous thromboembolism [31].
2.2.2 Psychological and Behavioral Evaluation
The psychological and behavioral evaluation of candidates for bariatric and metabolic surgery is extremely important because these candidates are more likely than the overall population to have psychiatric disorders such as depression, anxiety disorder, and personality disorder [14]. These disorders may be related to poor outcome after bariatric surgery [14]. Although consensus for a standardized protocol for the psychological and behavioral evaluation is still lacking, mental health professionals evaluate the candidates using clinical interviews, symptom inventories, objective personality/psychopathology tests, and cognitive function tests [10]. Key areas to identify may include current depressive symptoms, personality disorders, trauma history, substance abuse, or purging [6]. The relatively long evaluation process with repeated visits for several months probably helps in the more precise evaluation of the candidates. Also, smoking significantly increases operative risk and the behavioral evaluation should include it [2].
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