CBR AM cheat sheet

NIH 1991 consensus criteria for bariatric surgery: BMI ≥40, or BMI ≥35 with obesity-related comorbidity; requires documented failed nonsurgical attempts and acceptable operative risk.

Asian populations use lower thresholds (often BMI ≥27.5 with comorbidity, ≥32.5 without) because cardiometabolic risk rises at lower BMI than in White populations.

Absolute contraindications: uncontrolled severe psychiatric illness, active substance use, inability to comply with lifelong diet/supplement follow-up, and lack of understanding of risks.

Required preoperative workup: CBC, CMP with liver enzymes, HbA1c, lipid panel, TSH, iron studies, vitamin B12, 25-OH vitamin D, and pregnancy testing in patients of childbearing potential.

A 6-12 month medically supervised diet is not an evidence-based predictor of postoperative weight loss; it is used to demonstrate behavioral readiness and satisfy payer rules, not to select on weight-loss response.

Preoperative very-low-calorie diet (typically 800-1000 kcal/day for 2-4 weeks) reduces liver volume and left liver lobe size, easing laparoscopic exposure.

Obstructive sleep apnea screening: STOP-BANG score ≥3 warrants further evaluation; untreated severe OSA raises perioperative respiratory risk and should be optimized before surgery.

Helicobacter pylori testing and eradication is recommended before gastric bypass where prevalence is high, reducing marginal ulcer risk; routine endoscopy is indicated for alarm symptoms, not universally.

Sleeve gastrectomy removes ~75-80% of the stomach along the greater curvature, leaving a tubular conduit of roughly 60-100 mL; it is restrictive with neurohormonal (ghrelin) effects.

Roux-en-Y gastric bypass creates a 15-30 mL gastric pouch, a Roux limb (typically 75-150 cm) and a biliopancreatic limb; it combines restriction with malabsorption and dumping physiology.

Laparoscopic adjustable gastric banding is purely restrictive, has the highest long-term reoperation rate among common procedures, and is now used infrequently.

Biliopancreatic diversion with duodenal switch gives the greatest durable weight loss but carries the highest risk of protein-calorie malnutrition and fat-soluble vitamin deficiency.

One-anastomosis gastric bypass (mini-gastric bypass) uses a single loop gastrojejunostomy; its long-term risk of biliary reflux and esophageal metaplasia remains under surveillance.

Leak after sleeve gastrectomy most often occurs at the proximal staple line near the angle of His; after bypass, at the gastrojejunostomy.

Conversion of sleeve to bypass is a common revisional option for refractory reflux or inadequate weight loss; each revision carries higher leak and complication rates than the primary operation.

Informed consent must cover expected percent total weight loss, micronutrient supplementation for life, dumping risk, and the possibility of revisional surgery.

Postoperative progression: clear liquids (day 0-1), full liquids (1-2 weeks), pureed (2-4 weeks), soft solids, then regular texture; advance only as tolerated.

Protein target is 60-80 g/day (often up to 1.0-1.5 g/kg ideal body weight); protein intake is the strongest dietary predictor of lean mass preservation.

Fluids: at least 1.5-2 L/day, sipped in small volumes; no drinking 15-30 minutes before or after meals to avoid pouch distension and early satiety.

Dumping syndrome is triggered by high-sugar, high-osmolar foods; management is low-sugar, high-protein, high-fiber meals, fluids between meals, and lying down after eating for late dumping.

Lifelong micronutrients: multivitamin with minerals, vitamin B12 (oral 350-500 mcg/day or intramuscular), vitamin D plus calcium citrate (1200-1500 mg/day), and iron.

Thiamine (vitamin B1) deficiency risk rises with persistent vomiting; untreated Wernicke encephalopathy is a neurologic emergency requiring immediate parenteral thiamine.

Avoid alcohol: altered pharmacokinetics, higher blood alcohol peaks, and increased risk of transfer addiction and liver injury.

Pregnancy should be delayed 12-18 months postoperatively; screen for iron, folate, B12, and vitamin D deficiency and provide additional supplementation.

Postoperative leak presents with tachycardia (often >120), fever, abdominal pain, or respiratory distress; tachycardia is the earliest and most sensitive sign.

Anastomotic stricture after bypass causes progressive dysphagia and vomiting of solid food; treat with endoscopic balloon dilation.

Marginal ulcer typically presents 1-3 months postoperatively with epigastric pain; risk factors include NSAIDs, smoking, and H. pylori; treat with proton pump inhibitors.

Small bowel obstruction after Roux-en-Y bypass may be internal hernia; CT imaging is the study of choice, and surgical exploration is indicated when suspected.

Dumping syndrome: early (10-30 min) is osmotic and vagal; late (1-3 h) is reactive hypoglycemia from exaggerated insulin response; differentiate by timing.

Bowel obstruction after bypass may be internal hernia; CT imaging is the study of choice, and surgical exploration is indicated when suspected.

Rapid weight loss raises gallstone risk; consider prophylactic ursodiol for high-risk patients, and counsel on symptoms of cholecystitis.

Venous thromboembolism prophylaxis: early ambulation, mechanical compression, and risk-stratified chemoprophylaxis; obesity is an independent VTE risk factor.

Preoperative psychological evaluation screens for active psychiatric illness, eating disorders (especially binge-eating disorder), substance use, and cognitive capacity to consent.

Active substance use disorder and uncontrolled severe psychiatric illness are contraindications until treated and stable; documented stability is required before surgery.

Binge-eating disorder is common and is associated with poorer weight loss and more loss-of-control eating postoperatively; treat with cognitive behavioral therapy.

Alcohol use disorder risk increases after surgery due to altered tolerance; screen with AUDIT-C at follow-up and counsel on abstinence or strict limits.

Depression and anxiety frequently persist or worsen after surgery; screen with PHQ-9 and GAD-7 at intervals and refer for treatment.

Eating behavior after surgery shifts toward grazing and loss-of-control eating; structured meals and behavioral monitoring reduce these patterns.

Support groups and behavioral programs improve adherence to diet and supplement regimens; attendance should be encouraged, not required for eligibility.

Suicide risk is elevated in bariatric populations; routine mental health screening and prompt referral are part of postoperative care.

Type 2 diabetes remits in a substantial proportion of patients after surgery; medication doses (insulin, sulfonylureas) must be reduced or stopped early to prevent hypoglycemia.

Antihypertensive medications often require reduction as weight falls; monitor blood pressure and renal function and deprescribe as indicated.

After gastric bypass, extended-release and enteric-coated formulations may be poorly absorbed; prefer immediate-release alternatives where possible.

NSAIDs increase marginal ulcer and anastomotic ulcer risk; avoid or use with caution and gastroprotection after bypass.

Dose adjustment is required for narrow-therapeutic-index drugs (warfarin, levothyroxine, phenytoin, lithium); monitor levels and clinical response.

Levothyroxine absorption may change after bypass; recheck TSH 6-8 weeks after surgery and after dose changes.

Obesity increases risk of VTE, OSA, and nonalcoholic fatty liver disease; optimize these before and after surgery with appropriate therapy (e.g., CPAP).

Diabetes remission criteria often use HbA1c <6.5% and fasting glucose <126 mg/dL off medications for at least one year; document medication status.

Lifelong follow-up is recommended at least annually and more frequently in the first 1-2 years; monitor weight, nutrition labs, and comorbidity status.

Expected weight loss: sleeve and bypass typically achieve 25-35% total weight loss at 1-2 years; some regain is common after 2-5 years.

Weight regain evaluation: assess dietary patterns, portion size, grazing, alcohol use, mental health, and anatomical causes (pouch dilation, fistula, band slippage).

Laboratory monitoring includes CBC, CMP, iron studies, B12, folate, 25-OH vitamin D, calcium, PTH, and lipid panel at scheduled intervals.

Micronutrient deficiencies (iron, B12, vitamin D, thiamine) are common and may be asymptomatic; treat and replete before symptoms develop.

Physical activity target: at least 150 minutes/week of moderate activity plus resistance training to preserve lean mass.

Pregnancy should be delayed 12-18 months and requires nutritional monitoring and supplementation throughout.

Long-term data show durable comorbidity improvement and reduced mortality compared with nonsurgical management, but adherence to follow-up is essential.

Accreditation standards (e.g., MBSAQIP) require a multidisciplinary team, defined pathways, data collection, and quality reporting.

Program structure includes surgeon, dietitian, nurse, psychologist or behavioral health, and care coordinator; each role has defined responsibilities.

Standardized perioperative pathways (enhanced recovery protocols) reduce length of stay and complications; include early ambulation, opioid-sparing analgesia, and early oral intake.

Quality metrics include 30-day readmission, reoperation, leak rate, VTE, mortality, and nutritional deficiency rates; track and report them regularly.

Informed consent documentation must include risks, benefits, alternatives, and expected follow-up requirements, signed by the patient.

Patient selection criteria and exclusion documentation should be standardized to reduce variation and support payer authorization.

Safety programs include medication reconciliation, allergy verification, and pregnancy screening before surgery.

Continuous quality improvement uses audit and feedback, root-cause analysis of adverse events, and staff education to improve outcomes.

Surgical safety checklist (WHO-style) reduces errors: verify patient identity, procedure, site, allergies, and availability of blood products before incision.

Venous thromboembolism prophylaxis: risk-stratify, use mechanical compression plus chemoprophylaxis, and encourage early ambulation.

Anastomotic leak is a surgical emergency; early recognition and prompt reoperation reduce mortality.

Medication safety: reconcile all medications, verify allergies, and adjust doses for altered absorption after bypass.

Infection prevention: appropriate antibiotic prophylaxis, sterile technique, and glycemic control reduce surgical site infection.

Falls and pressure injuries are preventable; assess mobility and skin integrity in patients with obesity.

Adverse event reporting and root-cause analysis drive system improvement; nonpunitive reporting culture increases event capture.

Patient education on warning signs (fever, tachycardia, pain, vomiting) enables early presentation and reduces severe complications.