Learning objectives

• Define and classify the different types of bariatric surgery
• Describe the complications that are associated with bariatric surgery
• Anesthetic management of a patient undergoing bariatric surgery

Definition and classification

• Bariatric or weight loss surgery limits the amount of food a patient can comfortably eat or decreases the absorption of food and calories
• It is used as a later treatment option for obesity and helps to improve obesity-related conditions
  • Hypertension
  • Hyperglycemia
  • Diabetes mellitus type 2
  • Hypercholesterolemia
  • Cardiovascular disease and stroke
  • Kidney disease
  • Obstructive sleep apnea
  • Osteoarthritis
  • Non-alcohol-related fatty liver disease

Classification

• Adjustable gastric band: Placement of an inflatable silicone band around the top portion of the stomach
• Gastric bypass surgery (e.g., Roux-en-Y gastric bypass): The stomach is divided into a small upper pouch and a much larger lower “remnant” pouch, and the small intestine is rearranged to connect to both
• Sleeve gastrectomy or gastric sleeve (irreversible): The stomach is reduced to 15% of its original size via surgical removal of a large portion of the stomach along the greater curvature

Working mechanism

Each procedure exerts its effects through at least one of the three mechanisms → procedures often affect several of these mechanisms

• Restricting: Restricting food intake (e.g., gastric sleeve)
  • Reduce the size of the stomach that is available to hold a meal
  • Filling the stomach faster enables the individual to feel more full after a smaller meal
• Blocking: Decreasing nutrient absorption (e.g., Roux-en-Y gastric bypass)
  • Reduce the amount of intestine that the food passes through
  • Reduces the ability of the intestines to absorb nutrients from the food
• Mixed: Affecting cell signaling pathways
  • Alter hormones responsible for hunger (e.g., ghrelin) and satiety (e.g., leptin)

Patient characteristics

• Any age
• Males and females equally affected
• Increased incidence of
  • Diabetes mellitus
  • Cardiovascular disease
  • Respiratory disease
  • Sleep apnea syndrome

Complications

• Excess skin folds
• Malabsorption and malnutrition (e.g., vitamin and mineral deficiencies)
• Bile reflux
• Gallstones
• Kidney stones
• Blood clots in the leg (i.e., deep vein thrombosis) or lungs (i.e., pulmonary embolism)
• Infection
• Hernias
• Small bowel obstruction
• Anastomotic leaks
• Dumping syndrome 
• Hypoglycemia
• Ulcers
• Vomiting
• Gastroesophageal reflux disease
• Metabolic bone disease (e.g., osteopenia and secondary hyperparathyroidism)

Management

See also obesity considerations

Suggested reading

• Pollard BJ, Kitchen G. Handbook of Clinical Anaesthesia. 4th ed. Taylor & Francis group; 2018. Chapter 10 Abdominal surgery.

Clinical updates

Ajetunmobi et al. (A&A, 2025) report in a double-blind RCT of 120 morbidly obese adults with OSA undergoing bariatric surgery that sugammadex (2 mg/kg) did not shorten recovery versus neostigmine 2.5 mg + glycopyrrolate 0.4 mg, with similar median OR discharge times and no meaningful differences in extubation time, early recovery milestones, or perioperative complications. This implies that routine reversal can remain neostigmine-based (given similar outcomes and much lower cost), while sugammadex is best reserved for specific scenarios (e.g., deeper blockade, rapid/“rescue” reversal needs, or when anticholinesterase side effects are a concern), ideally with quantitative neuromuscular monitoring to minimize residual blockade.

• Read more about this study HERE.

Debel et al. (EJA, 2026) provide updated PROSPECT recommendations for laparoscopic sleeve gastrectomy, identifying an evidence-based, opioid-sparing analgesic regimen. In addition to paracetamol and NSAIDs/COX-2 inhibitors, the update now recommends bilateral ultrasound- or laparoscopic-guided TAP blocks and port-site local anesthetic infiltration, plus a single intra-operative dose of IV dexamethasone, while gabapentinoids are no longer advised because of side effects. Opioids should be reserved for rescue analgesia, and techniques such as QLB, ESP blocks, opioid-free anaesthesia, dexmedetomidine, magnesium, and ketamine are not recommended due to unfavourable risk–benefit profiles or insufficient evidence.