Anesthetic Considerations for Endobariatric Procedures: Primary and Revisional Options

Introduction

Endobariatric procedures have emerged as a groundbreaking approach to address obesity through minimally invasive techniques. These procedures can serve as primary weight loss options or as revisions for patients with a history of bariatric surgery. The safe and comfortable execution of these procedures necessitates meticulous anesthetic management. This article will delve into the history of endobariatric procedures, explore primary and revisional options, address airway concerns in obese patients, discuss airway management devices, and emphasize pharmacological considerations regarding drug lipid solubility for obese patients.

History of Endobariatric Procedures

The development of endobariatric procedures marks a significant advancement in the field of bariatric medicine. These techniques have evolved over the years to offer less invasive alternatives to traditional bariatric surgery. Here’s a brief historical overview:

• 1980s: Introduction of intragastric balloons as a non-surgical weight loss approach.
• 2000s: Advancements in endoscopic techniques led to the development of procedures like endoscopic sleeve gastroplasty (ESG) and the primary obesity surgery endoluminal (POSE) procedure.
• 2010s: Growing acceptance of endobariatric techniques, with an emphasis on refining and expanding the range of procedures available, including revisional options.

Details of Primary Endobariatric Procedures

1. POSE (Primary Obesity Surgery Endoluminal):

• Description: POSE is an incisionless procedure that creates gastric plications, reducing gastric volume and promoting satiety.
• Anesthesia Considerations: General endotracheal anesthesia (GETA) is often employed due to the procedure’s duration. Risks include intraprocedural bleeding and postprocedural pain.
• Dosing Basis: Water-soluble drugs may be preferred due to their predictable onset and recovery profiles, such as propofol and dexmedetomidine.

1. ESG (Endoscopic Sleeve Gastroplasty):

• Description: ESG remodels the greater curvature of the stomach through full-thickness sutures, reducing gastric capacity and delaying gastric emptying.
• Anesthesia Considerations: ESG typically requires GETA with full-thickness suturing. Postprocedural pain may necessitate a prolonged recovery.
• Dosing Basis: Water-soluble drugs like propofol and dexmedetomidine are suitable for their precise control of sedation levels and avoidance of lipid accumulation in adipose tissue.

1. Intragastric Balloon Insertion:

• Description: Intragastric balloon insertion induces gastroparesis for weight loss. The type of balloon used dictates the anesthesia approach, whether gas- or fluid-filled.
• Anesthesia Considerations: Deep propofol sedation (Monitored Anesthesia Care, MAC) is suitable for balloon insertion. However, fluid-filled balloon removal often necessitates GETA to puncture and release saline.
• Dosing Basis: Water-soluble drugs like propofol may be preferable for precise sedation control, while lipid-soluble drugs may be used for deeper sedation during balloon insertion.

1. AspireAssist Device:

• Description: The AspireAssist device allows patients to aspirate ingested food portions from the stomach. It is suitable for individuals with a BMI of 35-55 kg/m².
• Anesthesia Considerations: Deep sedation is employed for device insertion and removal.
• Dosing Basis: Water-soluble drugs like propofol are often used for sedation, but dosing may vary based on patient requirements.

1. Gastric Botulinum Toxin Injection:

• Description: This procedure involves the injection of botulinum toxin into the stomach lining to induce gastroparesis and early satiety. It is effective when combined with diet and exercise.
• Anesthesia Considerations: Deep sedation is typically sufficient for the injection procedure.
• Dosing Basis: Water-soluble drugs may be preferred for their predictability in sedation and minimal lipid accumulation.

Details of Revisional Endobariatric Procedures

1. TORe (Transoral Outlet Reduction):

• Description: TORe is used in patients who have previously undergone Roux-en-Y gastric bypass. It narrows the gastrojejunal anastomosis and reduces the size of the gastric pouch.
• Anesthesia Considerations: TORe typically requires GETA with endoscopic suturing.
• Dosing Basis: Water-soluble drugs may be the choice due to their precise control during a potentially prolonged procedure.

1. ROSE (Restorative Obesity Surgery Endoluminal):

• Description: Similar to TORe, ROSE focuses on reducing the size of the gastric pouch in patients with previous bariatric surgery.
• Anesthesia Considerations: GETA with endoscopic suturing is the common approach.
• Dosing Basis: Water-soluble drugs are suitable for their predictability and control during the procedure.

1. Mucosal Ablation (Argon Plasma Coagulation):

• Description: This procedure involves the application of argon laser coagulation to the anastomotic outlet.
• Anesthesia Considerations: Deep sedation is typically sufficient. Multiple sittings may be required.
• Dosing Basis: Water-soluble drugs are commonly used for better control during the procedure.

Airway Concerns in Obese Patients

Obesity presents distinct airway concerns that require careful consideration during anesthesia:

• Increased Upper Airway Tissue: Excess adipose tissue in the neck and throat region narrows the upper airway, making obese patients more susceptible to airway obstruction.
• Decreased Airway Patency: Reduced muscle tone and compliance in the upper airway, particularly the pharynx, can lead to partial or complete airway collapse.
• Obstructive Sleep Apnea (OSA): Obesity is a significant risk factor for OSA, where patients experience repetitive episodes of upper airway obstruction during sleep.
• Short Neck and Limited Neck Mobility: Obese patients may have short, thick necks with limited mobility, making optimal head and neck positioning challenging for airway management.

Airway Management Devices

To address airway concerns in obese patients, various airway management devices are utilized:

• Supraglottic Airway Devices (SADs): Devices like the Laryngeal Mask Airway (LMA) are favored for their ease of placement and ability to seal the airway above the glottis, reducing the risk of aspiration.
• Video Laryngoscopes: These devices provide a clear view of the glottis and vocal cords during intubation, especially beneficial for managing difficult airways.
• Nasopharyngeal Airway: Nasopharyngeal airways help maintain airway patency and provide high-flow oxygen, reducing the risk of hypoxemia.
• High-Flow Nasal Cannula (HFNC): HFNC delivers high-flow oxygen through nasal prongs, minimizing dead space and improving oxygenation.
• Continuous Positive Airway Pressure (CPAP): CPAP delivers continuous positive pressure to the airway, preventing airway collapse and enhancing oxygenation in patients with OSA.

Pharmacological Considerations Based on Drug Lipid

Solubility

Anesthetic dosing for obese patients should consider the lipid solubility of drugs to optimize their effects and minimize airway-related complications:

Water-Soluble Drugs:

• Propofol: 1-2.5 mg/kg IV – Rapid onset and recovery; may require lower doses in obese patients.
• Dexmedetomidine: Loading: 1 mcg/kg over 10 minutes, Maintenance: 0.2-1.4 mcg/kg/hr – Causes minimal respiratory depression.

Lipid-Soluble Drugs:

• Midazolam: 0.02-0.05 mg/kg – Administer slowly to minimize respiratory depression.
• Ketamine: 1-2 mg/kg IV – Useful for induction but may increase salivation.
• Etomidate: 0.2-0.6 mg/kg IV – Minimal cardiovascular effects, suitable for induction.
• Remifentanil: Initial bolus: 1-2 mcg/kg, Continuous infusion tailored to patient response – Adjust infusion rate to maintain analgesia during the procedure.

Types of Anesthesia

The choice of anesthesia depends on the procedure and patient factors:

1. General Endotracheal Anesthesia (GETA): Commonly used for primary endobariatric procedures, such as POSE and ESG, due to their time-consuming nature and specific risks. Water-soluble drugs may be favored for precise control.
2. Monitored Anesthesia Care (MAC) or Deep Sedation: Often used for procedures like intragastric balloon insertion, AspireAssist device insertion and removal, and gastric botulinum toxin injection, with dosing adjusted based on the patient’s requirements.
3. Postoperative Nausea and Vomiting (PONV) Management: PONV is common in endobariatric procedures, and aggressive pharmacotherapy is used to manage it. Drug selection may consider the lipid solubility of the drugs used.
4. Adjustment for Morbidly Obese Patients: Dosing may be adjusted for morbidly obese patients, with lower doses of lipid-soluble drugs in some cases, and water-soluble drugs for precise control in others.
5. Avoidance of Inhalational Anesthetics: Inhalational anesthetics are avoided due to the increased risk of PONV, and water-soluble drugs may be preferred for alternative sedation.
6. Intermittent Positive Pressure Ventilation (IPPV): IPPV is employed, and settings are adjusted to maintain acceptable end-tidal CO2 (EtCO2).
7. Reversal of Neuromuscular Blockade: Neuromuscular blockade with rocuronium is reversed using sugammadex, adjusted based on patient response.
8. Prophylactic Medications: Prophylactic medications like ondansetron and dexamethasone are used to prevent PONV, with dosing adjusted to patient needs.
9. Postprocedural Pain Management: Patients may experience postprocedural pain, but hospital admission is typically not required for pain management or monitoring. Pain management medications are chosen based on patient response and needs.

Conclusion

Endobariatric procedures offer a less invasive approach to weight loss in obese patients. Anesthesia providers must be well-versed in the specific requirements and potential risks associated with each procedure to ensure patient safety and optimal outcomes. Tailoring the anesthetic approach to the procedure type, patient characteristics, and the lipid solubility of drugs is essential for successful management. Attention to airway management, choice of airway devices, pharmacological considerations, and anesthesia type, all while considering lipid solubility, is vital for the safe and effective execution of endobariatric procedures. Close monitoring and a well-coordinated medical team are integral to successful anesthesia management for this patient population.