42
Obesity and Bariatric Surgery

Thomas A. O’Hara, DO¹ and Gregory S. Peirce, MD²

¹ Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA, USA

² Womack Army Medical Center, Fort Bragg, NC, USA

Which of the following statements regarding obesity and COVID‐19 is true?
1. Obese patients who contract COVID‐19 have a decreased rate of severe infection compared to nonobese patients who contract COVID‐19.
2. The mortality rate of COVID‐19 is comparable between obese and nonobese patient populations.
3. Obesity is only a risk factor for severe COVID‐19 infection in patients older than 60 years of age.
4. Obese patients are twice as likely to develop a severe COVID‐19 infection as nonobese patients.
5. All overweight patients have similar COVID‐19 outcomes regardless of BMI.
Answer: D

Multiple studies have shown that obesity significantly increases the risk of severe COVID‐19 infection, with odds ratios ranging from 1.84 to 3.6. The mortality rate also significantly increased in obese patients, with an odds ratio up to 8.43. Also, obesity is an independent risk factor for hospital and ICU admission in COVID‐19 patients less than 60 years of age. Furthermore, the severity of the COVID infection appears to worsen within the overweight population with increasing BMI. As seen in Table 42.1 below, there exists a significant difference in rates of ICU admission between patients with BMI 30–34 and BMI > 35.

Cai Q, Chen F, Wang T, Luo F, Liu X, Wu Q, He Q, Wang Z, Liu Y, Liu L, Chen J, Xu L. Obesity and COVID‐19 severity in a designated hospital in shenzhen. China Diabetes Care. 2020; 43(7):1392–1398. doi: 10.2337/dc20‐0576. Epub 2020 May 14. PMID: 32409502.

Lighter J, Phillips M, Hochman S, Sterling S, Johnson D, Francois F, Stachel A. Obesity in patients younger than 60 years is a risk factor for COVID‐19 hospital admission. Clin Infect Dis. 2020; 71(15):896–897. doi: 10.1093/cid/ciaa415. PMID: 32271368; PMCID: PMC7184372.

Peng Y, Meng K, He M, Zhu R, Guan H, Ke Z, Leng L, Wang X, Liu B, Hu C, Ji Q, Keerman M, Cheng L, Wu T, Huang K, Zeng Q. Clinical characteristics and prognosis of 244 cardiovascular patients suffering from coronavirus disease in Wuhan. China J Am Heart Assoc. 2020; 9(19):e016796. doi: 10.1161/JAHA.120.016796. Epub 2020 Aug 14. PMID: 32794415.

A 55‐year‐old man status‐post gastric bypass 8 weeks ago presents to the emergency department with confusion and numbness in the hands and feet. She has had prolonged vomiting and poor oral hydration for 3 weeks. Which of the following will best treat her symptoms?

Normal saline bolus
Broad‐spectrum antibiotics
“Banana bag” of fluids
Bolus of D5 half normal saline
Endoscopic dilation

Answer: C

Peripheral neuropathy and confusion are consistent with thiamine or vitamin B₁ deficiency. Thiamine has a half‐life of 18 days and is an essential vitamin. Its deficiency can result in Wernicke’s encephalopathy (WE) and beriberi. This patient needs thiamine—the standard content of a “banana bag,” which typically contains 100 mg thiamine, 1 mg folate, 3 g magnesium, and other daily vitamins. Afterward, the patient may need additional thiamine. For WE, patients should receive 500 mg IV thiamine three times a day until symptoms abate. In most cases, symptoms improve within 24 hours of administration.

Table 42.1 Adult patients who tested positive for COVID‐19 during 3 March–4 April 2020 (N = 3615).

BMI, kg/m²	No. (%)	Admission to acute (vs discharge From ED), OR (95% CI)	P value	No. (%)	ICU admission (vs discharge from ED), OR (95% CI)	P value
Age ≥ 60 years
BMI 30–34	141 (19)	0.9 (0.6–1.2)	0.39	57 (22)	1.1 (0.8–1.7)	0.57
BMI ≥ 35	99 (14)	0.9 (0.6–1.3)	0.59	50 (19)	1.5 (0.9–2.3)	0.10
Age < 60 years
BMI 30–34	173 (29)	2.0 (1.6–2.6)	<0.0001	39 (23)	1.8 (1.2–2.7)	0.006
BMI ≥ 35	134 (22)	2.2 (1.7–2.9)	<0.0001	56 (33)	3.6 (2.5–5.3)	<0.0001

Abbreviations: BMI, body mass index; CI, confidence interval; COVID‐19, coronavirus disease 2019; ED, emergency department; ICU, intensive care unit; OR, odds ratio.

Patients who undergo malabsorptive procedures are particularly at risk of thiamine deficiency, as it is mostly absorbed in the duodenum and proximal jejunum. All bariatric patients should take a daily multivitamin (which contains thiamine) and have regular thiamine level checks. Most importantly, any bariatric patient with prolonged vomiting and poor intake should be treated empirically with thiamine supplementation to prevent irreversible neurologic complications.

The patient is dehydrated and would benefit from normal saline, but this will not reverse her neurologic symptoms. As with alcoholics, thiamine should be given prior to any glucose‐containing fluids. Broad‐spectrum antibiotics would be important if an infection, leak, or perforated marginal ulcer was suspected. The patient may soon need endoscopic dilation, as she could have a stricture at the gastro‐jejunal anastomosis, but her encephalopathy must be addressed first.

Oudman E, Wijnia JW, van Dam M, Biter LU, Postma A. Preventing wernicke encephalopathy after bariatric surgery. Obes Surg. 2018; 28(7):2060–2068.

Raziel A Thiamine deficiency after bariatric surgery may lead to Wernicke encephalopathy. Isr Med Assoc J. 2012; 14:692–694.

A 50‐year‐old woman presents to the emergency department with severe abdominal pain and PO intolerance. She had a laparoscopic Roux‐en‐Y gastric bypass (RYGB) 2 years ago and now weighs 100 pounds less than her preoperative weight. Contrast‐enhanced CT abdomen reveals portions of the small bowel to be dilated with vascular rotation at the mesenteric root. Which of the following is true regarding her condition?
1. This is more likely to occur with an antecolic Roux limb.
2. An appropriate management option is nasogastric decompression and observation.
3. Definitive diagnosis of this condition can only be achieved through surgical exploration.
4. Due to the high sensitivity of CT scans, a lack of dilated small bowel and mesenteric rotation almost always rules this condition out.
5. Closure of the mesenteric defects at her index surgery does not decrease the possibility of this condition.
Answer: C

This patient has an internal hernia. Internal hernias may occur following any procedure in which the mesentery is divided—such as a RYGB or duodenal switch with biliopancreatic diversion. The small bowel may herniate through mesenteric defects created by the procedure. For an antecolic‐oriented RYGB, the two possible sites of herniation are at the jejunojejunostomy or between the Roux limb mesentery and the transverse mesocolon (Peterson’s defect). For a retrocolic RYGB, an additional site of herniation is at the mesocolic defect. Patients with internal hernias typically present with intermittent nonspecific abdominal pain and PO intolerance, but symptoms may worsen if the hernia incarcerates. CT imaging will often show a circular rotation of the vasculature (i.e. a “swirl sign”), as well as dilated small bowel. However, these findings are neither sensitive or specific and their absence does not rule out internal hernia.

Internal hernias more commonly occur with a retrocolic Roux limb. The lowest incidence of internal hernia occurs with an antecolic approach with closure of the mesenteric defects. Observation and decompression is not a viable option in bariatric patients with an internal hernia. If concerned for an internal hernia, exploration must be performed to diagnose the condition, assess the viability of the intestines, reduce the hernia, and close the defect.

Geubbels N, Lijftogt N, Fiocco M, van Leersum NJ, Wouters MW, de Brauw LM. Meta‐analysis of internal herniation after gastric bypass surgery. Br J Surg. 2015; 102(5):451–460. doi: 10.1002/bjs.9738. Epub 2015 Feb 24. PMID: 25708572.

Santos EPRD, Santa Cruz F, Hinrichsen EA, Ferraz ÁAB, Campos JM. Internal hernia following laparoscopic Roux‐en‐Y gastric by‐pass: indicative factors for early repair. Arq Gastroenterol. 2019; 56(2):160–164. doi: 10.1590/S0004‐2803.201900000‐32. PMID: 31460580.

Lockhart ME, Tessler FN, Canon CL, Smith JK, Larrison MC, Fineberg NS, Roy BP, Clements RH. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. AJR Am J Roentgenol. 2007; 188(3):745–750. doi: 10.2214/AJR.06.0541. PMID: 17312063.

Altinoz A, Maasher A, Jouhar F, Babikir A, Ibrahim M, Al Shaban T, Nimeri A. Diagnostic laparoscopy is more accurate than computerized tomography for internal hernia after Roux‐en‐Y gastric bypass. Am J Surg. 2020; 220(1):214–216. doi: 10.1016/j.amjsurg.2019.10.034. Epub 2019 Oct 19. PMID: 31668708.

Blockhuys M, Gypen B, Heyman S, Valk J, van Sprundel F, Hendrickx L. Internal hernia after laparoscopic gastric bypass: effect of closure of the petersen defect ‐ single‐center study. Obes Surg. 2019; 29(1):70–75. doi: 10.1007/s11695‐018‐3472‐9. PMID: 30167987.
For the above patient, you perform a laparoscopic exploration. You reduce the hernia by running the small bowel from the ileocolic valve toward the jejunojejunostomy. You find 40 cm of the common channel to be of questionable viability. This starts about 20 distal to the jejunojejunostomy. During the case, the patient was started on norepinephrine for hypotension and a blood gas showed her pH to be 7.15. Which of the following is most appropriate in the management of this patient?
1. Convert to a laparotomy, resect the questionable portion, and perform a small bowel anastomosis to place the common channel back in continuity
2. Resect the concerning portion, perform a small bowel anastomosis to place the common channel in continuity, and reverse the gastric bypass to prevent short gut syndrome
3. Plan for a “second look” procedure to assess bowel viability
4. Leave bowel intact, terminate the procedure, administer antibiotics, and follow the patient clinically to assess the need for future intervention.
5. Perform a transoral intraoperative endoscopy to assess bowel viability and visualize the mucosa
Answer: C

An internal hernia can result in small bowel ischemia and/or necrosis. The treatment principles for this are similar to managing bowel of questionable viability with damage control surgery. This patient became hypotensive and acidotic after the hernia reduction – a poor time to perform any anastomosis. A planned reoperation, or “second look” after resuscitation is the best of the choices. This could be done either laparoscopically or through a temporary abdominal closure if the procedure had been converted to open. Reversing the gastric bypass would involve the creation of an anastomosis between the gastric pouch to gastric remnant. This may be needed if the patient had necrosis of a much longer portion of her small intestine. However, the common channel averages near 400 cm and losing 40 cm will not result in short gut syndrome. During reoperation for a previous malabsorptive procedure, one should measure the separate small intestinal limbs (i.e. Roux limb, biliopancreatic limb, and the common channel) and document the lengths. Leaving the bowel intact and following clinically is wrong without a planned reassessment of the bowel. Performing an intraoperative endoscopy to assess the small bowel distal to the jejunojejunostomy has no utility in this context.

Bradley JF 3rd, Ross SW, Christmas AB, Fischer PE, Sachdev G, Heniford BT, Sing RF. Complications of bariatric surgery: the acute care surgeon’s experience. Am J Surg. 2015; 210(3):456–461. doi: 10.1016/j.amjsurg.2015.03.004. Epub 2015 May 8. PMID: 26070377.
A 45‐year‐old woman presents to the emergent department complaining of severe abdominal pain and nausea. The patient had a Roux‐en‐Y gastric bypass 5 days prior. Her heart rate remains in the 120s, and her systolic blood pressure is in the 80s. What is the most appropriate next step in management for this patient?
1. Operative washout and drainage
2. Barium swallow
3. CT scan with oral contrast
4. Broad spectrum antibiotics only
5. Nasogastric tube decompression
Answer: A

This patient is presenting with an anastomotic leak. A leak occurs in 1–3% of patients following a Roux‐en‐Y gastric bypass. Leaks can occur at any of the staple lines (gastric pouch, remnant stomach, gastrojejunostomy and jejunojejunostomy) but most commonly occur at the gastrojejunostomy. Leaks typically present within 5 days of surgery, as postoperative edema subsides. Patients most commonly present with tachycardia, fevers, and abdominal pain. Patients may also present with nausea, emesis, purulent drainage from incision sites, hypotension, oliguria, or tachypnea.

Because this patient is presenting with signs of sepsis, the most appropriate for this patient is operative intervention. The tenets of operative management of anastomotic leaks include washout and wide drainage. The leak site may also be primarily oversewn or an omental patch may be placed. Placement of enteral feeding access with jejunostomy tube or gastric tube in the remnant stomach should also be considered for postoperative nutrition. Barium swallow and CT scan with oral contrast are appropriate diagnostic studies to diagnose anastomotic leak in hemodynamically stable patients but are inappropriate in an unstable patient. Broad‐spectrum antibiotics and nasogastric decompression are also appropriate, but source control must be obtained for definitive management.

Wernick B, Jansen M, Noria S, Stawicki SP, El Chaar M. Essential bariatric emergencies for the acute care surgeon. Eur J Trauma Emerg Surg. 2016; 42(5):571–584. doi: 10.1007/s00068‐015‐0621‐x. Epub 2015 Dec 15. PMID: 26669688.

Contival N, Menahem B, Gautier T, Le Roux Y, Alves A. Guiding the non‐bariatric surgeon through complications of bariatric surgery. J Visc Surg. 2018; 155(1):27–40. doi: 10.1016/j.jviscsurg.2017.10.012. Epub 2017 Dec 23. PMID: 29277390.
A 65‐year‐old man presents to the emergency room complaining of worsening abdominal pain. The patient had a sleeve gastrectomy 6 days ago. The patient has a sustained heart rate in the low 100s and is normotensive. The patient’s abdomen is tender in the left upper quadrant, without guarding or rebound. CT scan with oral contrast shows a fluid collection posterior to the stomach, with a small amount of contrast extravasation from the proximal staple line. Which of the following is true regarding this patient’s condition?
1. This patient’s condition is likely due to a technical error.
2. CT scan has a sensitivity of > 95% for diagnosing this condition.
3. The most appropriate management for this patient is emergent surgical exploration.
4. Endoluminal stenting eliminates the need for drainage of the fluid collection.
5. Endoscopy with fluoroscopy and contrast injection is the most accurate diagnostic method.
Answer: E

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