Laparoscopic Gastric Banding

Obesity is defined as a BMI >30 kg/m²; extreme obesity has a BMI >40, super obese BMI >50, and super-super obese BMI >60. Increased BMI is associated with increased incidence of a multitude of medical conditions, such as cardiovascular disease, respiratory compromise, cancer, diabetes, HTN, and hypercholesterolemia. For every 13.5 kg of fat gained, an estimated 25 miles of neovascularization occurs to provide sufficient blood flow to tissues, and this translates into an increased cardiac output of 0.1 L/min/kg of fat (so 10 kg fat increases the CO by 1 L/min).

Ideal body weight (IBW) is

• Men: Height in cm minus 100
• Women: Height in cm minus 105
• IBW is associated with the lowest morbidity and mortality.

Cardiac: Systemic HTN, cardiomegaly, CHF, CAD, pulmonary hypertension

Resp: Restrictive pattern with decreased lung volumes and capacities, arterial hypoxemia may cause Polycythemia

Obesity hypoventilation syndrome (Pickwickian syndrome differentiates from obstructive sleep apnea by CHF)

Liver: Abnormal liver function tests, fatty liver infiltration.

Metabolic: Insulin resistance, hypercholesterolemia leading to cardiac disease/gallstones. Drug metabolism may be altered

GI: Increased intraabdominal pressure, gastric volume, and acidity, with an increased incidence of hiatal hernia. The patient may have an increased risk of aspiration (controversial), but consider premedication with an H2 blocker, promotility drugs, and antacids.

Surgical options

Malabsorptive: Jejunoileal and biliopancreatic bypass are rarely used

Restrictive: Vertical banded gastroplasty (VBG), gastric banding including adjustable gastric banding (AGB)

Roux-en-Y gastric bypass (RYGB) combines gastric restriction with minimal malabsorption

VBG, AGB, and RYGB can all be performed laparoscopically, and this approach has been proven to decrease overall morbidity

Pts are usually <65 years and >100 lbs above their IBW

Surgical approach

Laparoscopically due to decreased pain, earlier ambulation, earlier discharge, quicker return to regular activities, and reduced wound complications compared to the open approach

Open approach in patients with previous upper abdominal surgery, pts who cannot tolerate Pneumoperitoneum (CHF, severe CAD, and pulmonary disease), or revision bariatric surgery

The surgery is performed with 5 or 6 small abdominal incisions using Pneumoperitoneum. Profound muscle relaxation is essential to facilitate optimal surgical conditions and minimize the risk of injury to internal organs/vessels. There will be multiple position changes, so ensure patient safety and monitor airway position closely

Position

Supine, possible split leg for surgical access. Ensure proper pressure point padding, use of safety belts, and possibly a bean bag

Preoperative Considerations

Antibiotics

Cefoxitin – 3^rd generation, crosses BBB and is suitable for Gram Negative organisms

Surgical Time

2-4 hrs

EBL

<50 mL

Anesthetic considerations

Pharmacology

Highly lipophilic drugs have an increased volume of distribution and prolonged elimination

TBW dosing: midazolam, thiopental, propofol, fentanyl, sufentanil, cisatracurium, succinylcholine

IBW dosing: remifentanil, vecuronium (note prolonged duration), rocuronium

Renal clearance increased due to increased renal blood flow (increased CO) and increased GFR

Desflurane undergoes hepatic metabolism of 0.02%, and it has low blood gas solubility (0.42%), which enables quick change in anesthetic level. Note tachycardia (from lung nociceptors) if induction is too rapid. It has respiratory pungency. Oil: gas coefficient is 19, meaning desflurane will not build up in fatty tissues

Pneumoperitoneum       

• Provides a view of the surgical area, room for instruments to move
• There is a high risk for complications as the inferior vena cava, aorta, iliac arteries, and veins, as well as bladder, bowel, and uterus are close to the infraumbilical site
• Gas embolism symptoms: hypotension, dysrhythmias, cyanosis, pulmonary edema, Millwheel murmur
  • Release Pneumoperitoneum, place on the left side and aspirate air if possible
• Risk of pneumothorax due to barotrauma (increased PIP due to decreased pulmonary compliance)
• Left shoulder pain (CO₂)
  • Alleviate with three big breaths after CO₂ is released before the closure of the abdominal wall

Advantages: Decreased post-op pain, less post-op pulmonary impairment, reduction in post-op ileus, shorter hospital stay, earlier ambulation, and smaller incision