1. RESEARCH
Practical Solutions
Acute Bariatric Surgery Complications: Managing
Parenteral Nutrition in the Morbidly Obese
YIMIN CHEN, MS, RD
A
fter years of failure achieving and/or maintaining sium, and zinc should be supplemented because the du-
weight loss with diet and exercise alone, many indi- odenum is bypassed. Use of high-potency multivitamins
viduals with obesity turn to surgical treatment. In can help individuals meet the needs of most micronutri-
1991, the National Institutes of Health established guide- ents. An additional 18 to 27 mg elemental iron and 1,500
lines for selecting individuals considered appropriate for to 2,000 mg elemental calcium have been recommended
bariatric surgery in the treatment of morbid obesity as to avoid deficiencies (3). B vitamins can become depleted
those with a body mass index (BMI; calculated as kg/m2) as normal absorption of these vitamins takes place in the
40 or a BMI 35 with substantial comorbidities who have proximal jejunum, which is also bypassed. The following
failed supervised diet and exercise programs. The most com- case highlights the importance and challenges of special-
mon bariatric surgery procedures include the Roux-en-Y ized nutrition support in a critically ill individual with
gastric bypass (RYGB), gastric banding (adjustable and complications after the RYGB procedure.
nonadjustable bands), vertical banded gastroplasty, and
biliopancreatic diversion (duodenal switch). RYGB ac-
counts for the majority of bariatric surgery performed in PATIENT PROFILE
the United States and includes both restrictive and mal- RT is a 59-year-old African-American female with a med-
absorptive techniques (1). In RYGB, a small (1 to 2 oz) ical history of asthma, hypertension, type 2 diabetes,
gastric pouch is created as the new gastric reservoir and congestive heart failure, arthritis, obstructive dyspnea,
is directly connected to a distal portion of the small bowel, and a surgical history of cholecystectomy. RT is 64 inches
bypassing the remainder of the stomach as well as the and weighs 273 kg, with a BMI of 103. After failing
proximal portion of the small bowel. Weight loss after multiple attempts at supervised weight loss and after a
RYGB has been reported to reach up to 28.6% after 1 comprehensive multidisciplinary workup, RT was cleared
year, with some individuals showing maintenance of for an elective RYGB surgery for weight loss.
long-term weight loss for 10 to 15 years (1).
As with any surgical procedures, bariatric surgery is CLINICAL COURSE
not without known complications. During the immediate
postoperative period, the most commonly observed com- The elective procedure started initially as a laparoscopic
plications include anastomotic leak and anastomotic RYGB surgery, which was converted to an open proce-
stricture. These have obvious nutritional implications be- dure because of difficulties with manipulation of the lap-
cause the surgical reconnections of the gastrointestinal aroscope secondary to an enlarged fatty liver. The re-
tract make it difficult to place conventional temporary mainder of the surgical procedure was noted to be
enteral feeding access and often require use of specialized unremarkable. RT was extubated on postoperative day 2,
nutrition support (2). Anastomotic leak has a reported but was emergently reintubated within 24 hours after
prevalence of 5% with the RYGB procedure and often extubation secondary to respiratory failure. She was un-
requires the use of parenteral nutrition (PN) if the leak able to be weaned from mechanical ventilation for the
cannot be surgically corrected (3). Because of the malab- next 5 days because of poor respiratory efforts. In addi-
sorptive nature of RYGB, risk of micronutrient deficien- tion, RT developed hypotension on postoperative day 6
cies requires close monitoring and observation as well. and responded minimally to fluid resuscitation. She re-
Vitamin B-12 deficiency can develop because of the lack of quired the initiation of norepinephrine administration for
intrinsic factor from the stomach. Nutrients typically ab- blood pressure support. During the next 24 hours, RT’s
abdomen became distended and she developed acute re-
sorbed in the duodenum such as iron, calcium, magne-
nal failure with minimal urine output (320 mL during 24
hours). RT was taken back to the operating room on
postoperative day 8 when she had increased serosanguin-
Y. Chen is an advanced level dietitian, Rush University eous drainage from her abdominal wound. In the opera-
Medical Center, Chicago, IL. tive room, RT was found to have a strangulated, necrotic
Address correspondence to: Yimin Chen, MS, RD, Rush bowel with a small anastomotic leak at the distal anas-
University Medical Center, 1700 W. Van Buren, Suite 425, tomosis connecting the Y limb of the jejunum to the
Chicago, IL 60612. E-mail: yimin_chen@rush.edu remaining small bowel. The necrotic bowel was resected,
Manuscript accepted: April 7, 2010. the wound was debrided, a gastrostomy tube was placed
Copyright © 2010 by the American Dietetic for gastric decompression, and the anastomotic leak was
Association. repaired. Because the entirety of the small intestine
0002-8223/$36.00 was extremely edematous, a polyglycolic acid mesh was
doi: 10.1016/j.jada.2010.08.010 placed over RT’s open abdomen and sutured in place to
1734 Journal of the AMERICAN DIETETIC ASSOCIATION © 2010 by the American Dietetic Association

2. Table. Nutrition prescriptions, laboratory results, resting energy expenditure, and clinical status of a patient with morbid obesity after
complications after Roux-en-Y gastric bypass
PNa day 1 PN day 5 PN day 11 PN day 16 PN day 18 PN day 25 PN day 41
Weight (kg) 279 NAb NA 293 NA NA 295
kcal/day 2,050 2,050 2,050 2,050 2,050 2,050 2,050
kcal/kg actual 7.5 7.5 7.5 7.5 7.5 7.5 7.5
body weight
Protein (g/day) 155 155 105 155 155 125 125
IBWc (g/kg) 2.8 2.8 1.9 2.8 2.8 2.3 2.3
Albumin (g/dL) 1.6 1.8 1.5 1.5 1.7 2
Prealbumin (g/dL) 15 7 9
N-balanced Unsuccessful; continuous Positive 0.6 g
furosemide infusion
initiated
Indirect calorimetry 3,480
(kcal)
e f
Clinical course POD 10 initial surgery Tracheostomy Increased BUN Substantial improvement Oxygen requirement Increasing BUN Stable clinical
POD 1 wound placed and in renal function with on ventilator and status,
dehiscence, bowel creatinine decreased BUN and decreased below creatinine. granulating
resection, creatinine 60% Suspected tissues
anastomotic leak sepsis
repair, open
abdomen
a
PN parenteral nutrition.
b
NA not available.
c
IBW ideal body weight.
d
N-balance nitrogen balance.
e
POD postoperative day.
f
BUN blood urea nitrogen.
the fascia. RT returned to the surgical intensive care unit tomotic leak and compromised gastrointestinal tract
for postoperative care and remained on mechanical ven- function, as evidenced by multiple draining fistulas.
tilation.
NUTRITION INTERVENTION
NUTRITION ASSESSMENT Although guidelines are available to facilitate clinical
On postoperative day 9, PN was initiated by the physi- decisions on feeding morbidly obese individuals, actual
cian and the nutrition support service was consulted to clinical situations might not always fit within the frame-
evaluate RT for management of PN. Upon initial nutri- work provided by these guidelines. Because of RT’s class
tion assessment, it was noted that RT had been consum- III obesity, it was difficult to use traditional predictive
ing a very-low-calorie liquid diet for 2 weeks in prepara- equations to determine caloric and protein requirements.
tion for surgery (approximately 800 calories per day). In However, indirect calorimetry, the “gold standard,” was
addition, she had received only maintenance intravenous unable to be performed at this time because of her high
fluid support for 10 days since surgery secondary to her oxygen requirements through mechanical ventilation
clinical status. Based on the nutritional history collected, (fraction of inspired oxygen 60%). The nutrition support
it was determined that vitamin/mineral intake had also service decided to adjust RT’s PN prescription to provide
been suboptimal. It was evident that RT had inadequate hypocaloric feeding with additional amino acids to pro-
oral food/beverage intake (Nutrition Diagnostic Term In- mote wound healing and preservation of lean body mass
take Domain 2.1) related to preoperative liquid diet con- (Table) (4). PN was initiated on postoperative day 10 and
sumption, as evidenced by reported insufficient intake of provided 7.5 kcal/kg of actual body weight obtained before
energy (approximately 800 calories per day). On physical hospitalization, and 2.8 g/kg protein of ideal body weight.
examination, RT was found to have low muscle tone in Although RT was in acute renal failure, she started to
both upper and lower extremities secondary to her pre- produce urine and it was determined that the benefits of
surgical physical inactivity, and her family reported that meeting her increased protein needs for healing out-
she had not been able to walk for many years because of weighed the need for protein restriction for her acute
her morbid obesity and worsening arthritis. Applying renal failure at this time. RT received a tracheostomy on
Subjective Global Assessment, RT’s nutritional status postoperative day 15 because of prolonged intubation.
was categorized as normal at admission; however, she After 11 days of PN, RT’s renal function continued to
was deemed at high nutrition risk because of the com- decline and she became azotemic; her blood urea nitrogen
plexities of providing adequate nutrients, her increased increased to 105 mg/dL (37.5 mmol/L). As a result, the
postoperative energy and protein needs, and her altered amount of protein in her PN prescription was decreased
gastrointestinal anatomy (4). It was evident that RT had to 1.9 g/kg of ideal body weight.
altered gastrointestinal function (Nutrition Diagnostic On postoperative day 23, RT returned to the operating
Term Clinical Domain 1.4) related to postoperative anas- room because of increased output that appeared to be
November 2010 ● Journal of the AMERICAN DIETETIC ASSOCIATION 1735

3. succus from her abdominal wound. In the operating room, charge, no plans for enteral nutrition were in place be-
she was found to have multiple small bowel fistulae and cause she had evidence of multiple small bowel and co-
one colonic fistula. Because of the friable nature of the lonic fistulae. Upon discharge, it was determined that the
bowel walls at the time, repairs of the fistulae were not surgeon would continue to care for RT at the long-term
performed. Instead, small surgical drains were placed acute care facility for continuity of care; the clinician
near the fistulae for decompression and monitoring pur- communicated with the surgeon to ensure that RT would
poses. On postoperative day 26, in light of an improve- transition to enteral nutrition as soon as medically feasi-
ment in RT’s renal function, with blood urea nitrogen of ble pending closure of the multiple small bowel and co-
39 mg/dL (13.9 mmol/L) and serum creatinine down to 1.7 lonic fistulae. The clinician also communicated with the
mg/dL (150.3 mol/L), the protein content of her PN nutrition support clinician at the long-term acute care
prescription was increased back to 2.8 g/kg to facilitate facility to continue monitoring for weight loss of 1 to 2 lb
healing of her multiple intestinal fistulas. On postopera- per week with routine nitrogen balance studies to assure
tive day 28, indirect calorimetry was conducted, revealing adequate protein provision to promote wound healing.
her resting energy expenditure to be 3,480 kcal/day, with
a respiratory quotient of 0.81 and a coefficient of variance
of 10%, indicating a good measurement. Because the DISCUSSION
PN was providing only 2,050 kcal/day with 155 g protein Nutrition support in the critically ill patient can be chal-
per day, this created a 1,430 caloric deficit per day. On lenging; however, nutrition support in the critically ill
postoperative day 29, a 24-hour urine collection for urine patient who is morbidly obese is even more difficult. This
urea nitrogen was initiated; however, because of changes case report highlights the complexities in determining
in her intravenous medications, erroneous nitrogen bal- appropriate nutrition support for an individual with class
ance results were obtained, which were deemed unusable III obesity (BMI of 103 at admission) who developed mul-
for clinical application. On postoperative day 35, RT’s tiple surgical complications of the gastrointestinal tract,
blood urea nitrogen level again had been rising; therefore, with a prolonged intensive care unit stay for respiratory
the protein in her PN was decreased to 2.3 g/kg to prevent failure, sepsis, and acute renal failure. It has been shown
azotemia. Her prealbumin level had also decreased from that positive nitrogen can be achieved in the obese during
15 to 7 mg/dL (150 to 70 mg/L), which was thought to be critical illness when fed hypocalorically (13 to 21 kcal/kg
caused by a new infection secondary to her low-grade of actual body weight) with adequate provision of protein
temperatures, slowly increasing white blood cell count, (1.9 to 2.1 g/kg of ideal body weight) (5-7). Although the
and intermittent hypotension. Blood cultures and abdom- existing literature provides some level of guidance for
inal wound cultures were obtained on the same day with caloric and protein provision in the morbidly obese, there
positive infectious bacterial growth from both blood and is a paucity of research on how to optimally feed the
wound cultures. In patients undergoing hemodialysis, ni- critically ill obese. The existing literature is limited by
trogen balance can be assessed by collecting and analyz- small sample sizes and the combination of different
ing nitrogen losses through dialysate to calculate total classes of obesity (BMI range 33 to 51). Collectively, this
nitrogen appearance. However, during RT’s acute renal makes extrapolation to patient care difficult, especially in
failure, dialysis was not initiated; therefore, total nitro- individuals who have a higher BMI than those included
gen appearance could not be assessed. During the next 2 in these studies (5-7). A clinical decision was made to
weeks, RT’s clinical condition stabilized, infections were provide a lower-caloric prescription than used in the stud-
treated with antibiotics, her abdominal wound started to ies (7.5 kcal/kg) because RT’s BMI was essentially twice
develop granulating tissue, and her renal function con- that of the highest BMI included in these studies; addi-
tinued to improve. A second 24-hour urine for urine urea tional protein was also prescribed (2.8 g/kg) as a higher
nitrogen was successfully completed to assess nitrogen caloric deficit was created for RT.
balance. RT was found to be in even nitrogen balance, When providing nutrition support to the morbidly
with net balance of positive 0.6 g; it was decided at that obese individual in the intensive care unit with caloric
time that the current PN prescription was appropriate deficit and additional protein, it is often difficult to bal-
and no changes were necessary. Serum levels of trace ance the increased protein needs for the promotion of
elements were also studied as RT had been on PN for wound healing and decreased protein tolerance second-
more than 1 month with additional succus output, and all ary to acute renal failure. It is also difficult to determine
values were found to be within normal limits. Plasma the appropriate amount of caloric deficit without increas-
zinc was found to be 1,030 g/L (157.6 mol/L) (normal ing the likelihood of protein catabolism and resultant
range 600 to 1,300 g/L [91.8 to 198.9 mol/L]); whole lean body wasting. In this case report, RT did not have
blood selenium was 131 g/L (1.66 mol/L) (normal excessive gastrointestinal output causing additional pro-
range 120 to 200 g/L [1.52 to 2.54 mol/L]); whole tein losses; however, an astute clinician should always
blood manganese was 13 g/L (237 nmol/L) (normal monitor for all possible excessive body fluid losses that
range 7 to 16 g/L [127 to 291 nmol/L]). Throughout can lead to additional protein depletion. These losses
RT’s hospitalization, blood glucose was controlled with a must be accounted for in the total nitrogen balance cal-
continuous insulin infusion to maintain glucose levels at culation and the nutrition support prescription. It has
the institution’s goal glucose levels (80 to 120 mg/dL [4.44 been found by Cheatham and colleagues that a substan-
to 6.66 mmol/L]). tial amount of protein (2 g/L) can be lost through abdom-
On postoperative day 56, RT was discharged to a long- inal fluids, which further validates the need to quantify
term acute care facility for continued ventilator support, additional protein losses of body fluids (8). However, no
potential weaning, and rehabilitation. At the time of dis- other studies have been conducted to further validate
1736 November 2010 Volume 110 Number 11

4. and/or evaluate protein losses of body fluids, especially in References
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November 2010 ● Journal of the AMERICAN DIETETIC ASSOCIATION 1737