Small bowel obstruction is a common surgical condition where the small intestine becomes blocked. The most frequent cause is adhesions from prior abdominal surgery, accounting for up to 75% of cases. Symptoms include abdominal pain, nausea, vomiting and constipation. Diagnosis involves imaging like abdominal x-rays showing dilated bowel loops or CT scans identifying transition points. Treatment depends on the severity and cause but generally involves surgery to remove blockages or adhesions and repair hernias or tumors. Outcomes are good if caught early but mortality rises with delay in surgery or if the obstruction becomes strangulated.

1. Small Bowel Obstruction
José Luis Cortés Sánchez
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

2. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Epidemiology
 Most frequently encountered surgical disorder of the
small intestine
 Anatomic relationship to intestinal wall:
 1.- Intraluminal:
 2.- Intramural
 3.- Extrinsic

3.  Intraabdominal adhesions related to
prior abdominal surgery account for
up to 75% of cases
 300,000 patients are estimated to
undergo surgery to treat them
annually
 From 1988 to 2007 there was no
decrease in this rate
 Ongoing problems with this “old”
disease
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

4. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
 Other causes:
Hernias,
malignant, Chron’s
 Few are due to
primary bowel
tumors

5.  Congenital usually become evident during childhood,
but sometimes are not
 i.e. Intestinal malrotation, mid-gut volvolus (without
history)
 Superior mesentric artery Sx. (rare etiology)
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

6. Pathophysiology
Gas and fluid acumulate
Intestinal activity increases Pain and
diarrhea
Swallowed air
and produced
Swallowed liquids
and GI secretions
Bowel distends IM/ IL pressure rises
Motility is eventually reduced
Luminal flora changes
If IM pressure high enough  perfusion is impaired  ischemia - necrosis
Strangulated bowel obstruction
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

7. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Partial
 Allows passage of some fluid
and gas
 Event progression occur more
slowly
 Less likely to become
strangulated
Closed-loop
 Particularly dangerous
 E.g. volvolus
 Rapid rise in luminal pressure
 Rapid progression to
strangulation

8. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Clinical presentation
 Colicky abdominal pain, nausea, vomiting, obstipation
 More vomiting w/proximal than distal
 Feculent?  bacterial overgrowth (more established)
 Continuos passage of flattus/stool >6-12 hours=
Partial

9. Signs
 Abdominal distention (more if distal)
 Initially hyperactive bowel sounds then minimal
 Lab:
 Intravascular volume depletion
 Hemoconcentration
 Electrolyte abnormalities
 Mild leukocytosis
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

10. Strangulated
 Abd. pain disproportionate to degree of abd findings
 -suggestive of intestinal ischemia
 Tachycardia,
 Localized abd tenderness
 Fever
 Marked leukocytosis
 Acidosis
Alert!
Prompt early surgical
intervention!
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

11. Diagnosis
 1.-Distinguishing mechanical obstruction from ileus
 2.-Determine the etiology
 3.-Discriminate partial from complete
 4.-Discriminate simple from strangulated
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

12. History
 Prior abd operations
 Abd disorders (cancer, IBD)
 Meticulous search for hernias(inguinal, femoral)
 Dx.- confirmed by radiographic exams
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

13. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Abdominal series
 Rx of the abdomen patient in supine
 Abdomen w/patient upright
 Rx of the chest w/patient in upright
Most specific triad:
-Dilated small bowel loops (>3 cm in diameter)
-Air-fluid levels on upright
-Paucity of air in colon
S= 70-80%
E= lowDDX.-
Ileus, colonic obstruction
FN= proximal; fluid but no gas Closed-loop
Despite these limitations, abdominal radiographs
remain an important study in patients with
suspected small bowel obstruction because of
their wide- spread availability and low cost

14. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
CT scan
 Discrete transition zonew/dilation of proximal
 Decompression of distally
 Contrast that doesn’t pass beyond transition
 Colon with little gas or fluid
S= 80-90%
E= 70-90%
-CT may also provide
evidence of closed-
loop/strangulation
-
-Closed-loop U-/C-
shaped bowel+ radial
messenteric vessels in torsion
point
-Strangulation
Thickening of bowel wall,
pneumatosis intestinalis,
portal venous gas, mesenteric
haziness
Poor uptake of IV contrast
CT also reveals the etiology

15. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
 Appearance of contrast
in colon w(24hrs) is
predictive of non-
surgical resolution
 Reduce overall length
of hospitalization
 S= 50% , for low-grade
or partial
 Small bowel series/
Enteroclysis can be
helpful

16. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Therapy
 Marked depletion of IV volume –> fluid resuscitation is integral to
treatment
 Central venous o pulmonary artery catheter assist fluid
management (CVS or severe)
 Antibiotics? No data to support it
Isotonic fluid IV + Bladder catheter
 NG tube to evacuate
stomach. Not jejunum nor
ileum
 Decreases nausea, vomiting,
distention, aspiration

17. “the sun should never rise
and set on a complete bowel
obstruction.”
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

18. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
nonoperative
aproaches
 R/O closed-loop ;
neither intestinal
ischemia
 Observe closely and
undergo serial exams
Early surgical
intervention
 Minimize the risk for
strangulation
 Morbimortality
 Signs and lab tests and imaging don’t distinct between
them
Goal?  operate before onset of ischemia
A period of observation and NG decompression, provided no
tachycardia, tenderness or WBC increases

19. Conservative therapy
 1. Partial small bowel obstruction
 2. Obstruction occurring in the early postoperative
 3. Intestinal obstruction due to Crohn’s disease
 4. Carcinomatosis
Strangulation is unlikely to occur.
Succesful in 65-81%
Of these 5-15% don’t improve at 48 hrs
Patients with partial obstruction thath do not improve at
48h should undergo surgery!0
-Occur in 0.7% patients undergoing laparotomy.
-Pelvic surgery, especially colorectal procedures, have the greatest
risk.
-Should be considered if
-symptoms of intestinal obstruction occur after the initial
return -Function fails to return within the expected 3 to 5 days after
-25-33% of patients with
-Even in cases in which the obstruction is related to recurrent malignancy,
palliative resection or bypass can be performed.
-Patients with obvious carcinomatosis pose a difficult challenge, given their
limited prognosis.
May be best achieved by a bypass procedure
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

20. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
 Adhesions  lysed
 Tumors  resected
 Hernias  reduced and repaired.
 The affected intestine should be examined, and nonviable bowel
resected.
 If the patient is hemodynamically stable, short lengths of bowel of
questionable viability should be resected
 Bowel of uncertain viability should be left intact and the patient
re-explored in 24 to 48 hours in a “second- look” operation.
Criteria suggesting viability:
-normal color,
-peristalsis,
-marginal arterial pulsation
Operative procedure varies according to the
etiology
Laparascopic procedure have a
quicker recovery, less
complications, and lower costs.
Distended loops of bowel can
interfere with adequate
visualization, early cases likely
due to a single adhesion
Conversion rate to open surgery
is between 17% and 33%

21. Outcomes
 Prognosis is related to the etiology
 Less than 20% of conservative patients will have a
readmission over the subsequent 5 years
 The perioperative mortality rate associated with
surgery for nonstrangulating small bowel obstruction is
less than 5%,
 Mortality rates associated with surgery for
strangulating obstruction range from 8% to 25%.
Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed

22. Brunicardi, F. C. (2015). Schwartz's Principles of Surgery. 10 Ed. McGrawHill Ed
Prevention
 Good surgical technique, careful handling
of tissue, and minimal use and exposure
of peritoneum to foreign bodies form the
cornerstone of adhesion prevention.
 Colorectal or pelvic surgery, hospital
readmission rates of greater than 30%
over the subsequent 10 years
 .
Seprafilm

25. fistula
 abnormal communication between two
epithelialized surfaces.
 internal fistula .- between two parts of the GI
tract or adjacent organs
 external fistula involves the skin or another
external surface epithelium.
 Over 80% of enterocutaneous fistulas represent
iatrogenic complications that occur as the result
of enterotomies or intestinal anastomotic
dehiscences.
 Spontaneously without antecedent iatrogenic
injury are  Crohn’s disease or cancer.
low-output fistulas
Entero- cutaneous fistulas that drain
less than 200 mL of fluid per day
high-output fistulas.
those that drain more than 500 mL of
fluid per day

26. Pathophysiology
 Low-resistance enteroenteric  bypass 
malabsorption
 Enterovesicular  Recurrent UTI’s
 Drainage from enterocutaneous  irritates skin
excoriation
 Loss of enteric luminal contents (high-output) 
dehydration, electrolyte abnormalities, malnutrition

27.  Fistulas have the potential to close spontaneously,
but:

28. Clinical
Presentation
 Fever
 Leukocytosis
 prolonged ileus
 abdominal tenderness,
 wound infection
evident between the 5th-10th
postoperative days.
initialsigns.
Iatrogenic enterocutaneous fistulas
The diagnosis is obvious
when drainage of enteric material
occurs.
These fistulas are often associated with

29. Diagnosis
 CT scanning following the
administration of enteral
contrast
Most useful initial test?
Leakage of contrast material from the
intestinal lumen can be observed.
Intraabdominal abscesses should be
sought and drained percutaneously.
-Small bowel series or enteroclysis
examination can be obtained to
demonstrate the fistula’s site of origin
in the bowel.
-Useful to R/O the presence of intestinal obstruction distal to the site of origin.
If the anatomy of the fistula
is not clear on CT
scanning?
A fistulogram,

30. Therapy
 1. Stabilization.
 Fluid and electrolyte resuscitation is begun.
 Nutrition is provided, usually through the parenteral route initially.
Sepsis is controlled with antibiotics and drainage of abscesses.
 The skin is protected from the fistula effluent with ostomy appliances or
fistula drains.
 2. Investigation. The anatomy of the fistula is defined
 3. Decision. Tx options considered, and timeline for conservative
 4. Definitive management. surgical procedure
 5. Rehabilitation.

31.  Objective is to increase the probability of
spotaneous closure.
 Nutrition and time are the key components
of this approach.
 Most patients will require TPN
however, a trial of oral
enteral nutrition should
attempted in patients w
low-output fistulas
originating from the dis
intestine.Octreotide is a useful adjunct, particularly
in patients with high-output fistulas;
-reduces the volume of fistula output
thereby
facilitating fluid and electrolyte management.

32. Timing of Surgical
Intervention.
 2 to 3 months of conservative therapy before
considering surgical intervention.
 surgical intervention after this time period is
associated with better outcomes and lower
morbidity
90% of fistulas that are
going to close do so
within 5 weeks
fails to resolve during this period ?
fistula tract, together with the segment of
intestine from which it originates, should be
resected.
Simple closure of the opening in the intestine from which the fistula
originates is associated with high recurrence rates.

33. Outcomes
“FRIEND”
 Foreign body within the fistula tract
 Radiation enteritis
 Infection/Inflammation at the fistula origin
 Epithelialization of the fistula tract
 Neoplasm at the fistula origin
 Distal obstruction of the intestine
Over 50% of intestinal fistulas close spontaneously.

34. 153 cases of
enterocutaneous fistulas
 Majority were found to originate from the small bowel
 Patients having undergone 5 or + previous surgeries.
 30-day mortality of approximately 4%
 1-year mortality of 15%.
 Morbidity was over 80%.
 First surgical repair attempt was successful 70% of
cases
Some patients
requiring up to
three attempts at
surgical repair.
Owen RM, Love TP, Perez SD, et al. Definitive surgical treatment of enterocutaneous fistula: outcomes of a 23-year experi- ence.
Arch Surg. 2012;15:1.

35.  A 43-year-old woman comes to the emergency department with a
3-day history of abdominal distention, nausea, and vomiting. She
also reports decreased urine output over the last 24 hours. She
has a history of total abdominal hysterectomy 5 years ago for
benign disease. She does not take any medications. Her pulse is
110 beats/minute. Her abdomen is distended and there is mild
diffuse tenderness. Bowel sounds are hyperactive. The rest of
her exam is normal. Serum electrolytes are sodium—140,
chloride—90, bicarbonate—32, and potassium—4.0. Which of
the following is the most appropriate initial intravenous fluid to
administer to this patient?
A.-D5 1⁄2 normal saline with 40 mEq KCl/L
B. Lactated Ringer’s solution
C. Normal saline
D. Colloidal starch solution
E. 5% albumin in normal saline