Bariatric surgical patients are inherently at risk for PONV
Bariatric surgical patients carry several the risk factors for PONV. The majority of weight loss surgery patients are female, their pain is managed with opioids, and the procedure may be performed laparoscopically. Their obese body habitus contributes to longer duration surgery. Coexisting diabetes may result in delayed gastric emptying due to gastroparesis. Additionally, anatomical origins of PONV during bariatric surgeries are thought to be caused by gastric manipulation and incisions made through afferent branches of the vagus nerve. The vagal nerves are one of the main peripheral afferent pathways for triggering PONV. This combination of risk factors put the bariatric patient at high risk of PONV, possibly greater than 70%. Despite triple prophylaxis, up to 42% of these patients still require rescue anti-emetics.
Jeopardized outcomes and decreased patient satisfaction
PONV can jeopardize surgical outcomes by impacting hydration status, electrolyte balance, aspiration risk, intracranial and intraocular pressures, wound dehiscence, and esophageal rupture. Additionally, nausea and vomiting are the most common reasons for hospital readmission following bariatric surgery, increasing healthcare expenditures.
Review of bariatric procedures
Restrictive Procedures
Gastric Bands: Silicone device placed at the top of the stomach that limits the amount a person can eat. Size of the pouch made can be adjusted with fluid injections through a port under the skin. The patient ay need several adjustments. Pros: Low risk of complications, faster to discharge, easily removed if needed. However, slower and less weight loss, risk of band movement and stomach erosion, and may result in enlargement of esophagus. Higher rate of re-operations. Patients usually go home same day.
Gastric Sleeve: Stomach is freed from organs around it, titanium staples placed to reduce stomach by 80% (about size of banana). Portion of the stomach that secretes hunger hormone ghrelin is removed. Technically simple, shorter surgery time, and can be used as a bridge to a bypass procedure. However, non-reversible, may worsen reflux, has less impact on weight loss, and higher risk for a leak from staple site. Done laparoscopically. Patients go home 1-2 days after surgery.
Malabsorptive Procedures
Biliopancreatic diversion with Duodenal switch: Following creation of the sleeve-like stomach, the first portion of the small intestine is separated from the stomach. A part of the small intestine is then brought up and connected to the outlet of the newly created stomach, so that when the patient eats, the food goes through the sleeve pouch and into the latter part of the small intestine. Even more than gastric bypass and sleeve gastrectomy, it affects intestinal hormones in a manner that reduces hunger, increases fullness and improves blood sugar control. Very effective for the treatment of type 2 diabetes.
Combination Procedures
Roux-en-Y Gastric bypass: First, the stomach is divided into a smaller top portion (pouch) which is about the size of an egg. The larger part of the stomach is bypassed and no longer stores or digests food.
The small intestine is also divided and connected to the new stomach pouch to allow food to pass. The small bowel segment which empties the bypassed or larger stomach is connected into the small bowel approximately 3-4 feet downstream, resulting in a bowel connection resembling the shape of the letter Y.
Eventually the stomach acids and digestive enzymes from the bypassed stomach and first portion of the small intestine will mix with food that is eaten. Pros: Reliable and long-lasting weight loss. Cons: more complex surgery, higher incidence of deficiencies, higher incidence of ulcers (especially with NSAIDS) and may result in dumping syndrome. Patients stay 1-2 days post op.