Sabiston SBO

Question 1

Which Primary colonic cancers Present Like SBO

Answer 1

Tumors arising from the cecum and ascending colon

Question 2

MC Cause of SBO

Answer 2

Adhesions 60%
Malignant 20%
Hernia 10%
Crohns 5%

Question 3

Early in the course of an obstruction

Answer 3

intestinal motility and contractile activity increase > diarrhea

Question 4

Later in the course of obstruction

Answer 4

intestine becomes fatigued and dilates > water and electrolytes accumulate intraluminally and in the bowel wall itself > massive third-space fluid loss > dehydration and hypovolemia

Question 5

proximal obstruction vs Distal obstruction

Answer 5

Proximal > dehydration, hypochloremia, hypokalemia, and metabolic alkalosis

Distal > large quantities of intestinal fluid into the bowel; however, abnormalities in serum electrolyte levels are usually less dramatic.

Question 6

Sepsis in SBO

Answer 6

-the jejunum and proximal ileum Normally have only 103 to 105 (CFU/mL) of bacteria.

-With obstruction (most commonly Escherichia coli, Streptococcus faecalis, and Klebsiella spp.) > reaching concentrations of 109 to 1010 CFU/mL.

increase in the number of indigenous bacteria translocating to mesenteric lymph nodes and even systemic organs

> amplifies the local inflammatory response leading to intestinal leakage and subsequent increase in systemic inflammation.

Question 7

higher obstruction vs Distal

Answer 7

Higher > Nausea and vomiting , hyperactive bowel sounds

distally > less emesis;
initial and most prominent symptom is cramping abdominal pain, minimal or no bowel sounds are noted

As the obstruction becomes more complete with bacterial overgrowth, the vomitus becomes more feculent, indicating a late and established intestinal obstruction.

Question 8

Plain abdominal film signs of SBO

Answer 8

Supine :
-Dilated gas or fluid filled small bowel >3 cm
-Dilated stomach
-Small bowel dilated out of proportion to colon
-Stretch sign
-Absence of rectal gas
-Gasless abdomen
-Pseudotumor sign

Question 9

Plain abdominal film signs of SBO

Answer 9

Upright or Left Lateral Decubitus :
-Multiple air fluid levels
-Air fluid levels longer than 2.5 cm
-Air fluid levels in same loop of small bowel of unequal lengths
-String of beads sign

Question 10

why put NGT in SBO

Answer 10

-empties the stomach
-reducing the hazard of pulmonary aspiration of vomitus
-minimizing further intestinal distention from swallowed air

Question 11

Radiation enteropathy causing SBO Tx

Answer 11

can be treated nonoperatively with tube decompression and the potential addition of corticosteroids, particularly during the acute setting.

In the chronic setting, laparotomy will be required with possible resection of the irradiated bowel or bypass of the affected area.

Question 12

If intestinal viability is questionable

Answer 12

the bowel segment should be completely released and placed in a warm, saline-moistened sponge for 15 to 20 minutes and then reexamined.

If normal color has returned and peristalsis is evident, it is safe to retain the bowel

Another options : Doppler probe, administration of fluorescein and Intraoperative near-infrared angiography or second-look laparotomy 18 to 24 hours after the initial procedure.

Question 13

consideration of laparoscopic management in SBO

Answer 13

-mild abdominal distention
-proximal or partial obstruction;
-anticipated single-band obstruction
-and those with low risk of strangulation or perforation

laparoscopic found to be of greatest benefit in
-patients with fewer than three previous operations
-were seen early after the onset of symptoms
-and were thought to have adhesive bands as the cause.

Question 14

the most effective means of limiting the number of adhesions

Answer 14

is a good surgical technique :
-gentle handling of the bowel to reduce serosal trauma
-avoidance of unnecessary dissection
-exclusion of foreign material from the peritoneal cavity
-the use of absorbable suture material when possible,
-avoidance of excessive gauze sponge use,
-the removal of starch from gloves
-adequate irrigation and removal of infectious and ischemic debris
-preservation and use of the omentum around the site of surgery or in the denuded pelvis

Question 15

Causes of ileus.

Answer 15

• After laparotomy
• Metabolic and electrolyte derangements (e.g., hypokalemia, hyponatremia, hypomagnesemia, uremia, diabetic coma)
• Drugs (e.g., opiates, psychotropic agents, anticholinergic agents)
• Intraabdominal inflammation
• Retroperitoneal hemorrhage or inflammation
• Intestinal ischemia
• Systemic sepsis

Question 16

Ileus vs SBO

Answer 16

-Plain abdominal radiographs may reveal distended small bowel as well as large bowel loops.

-In cases that are difficult to differentiate from obstruction, barium studies may be beneficial