Blocked and Bloated: Bowel Obstructions in the ED

Small bowel obstruction is common ED pathology, but the dangerous misses are ischemia, perforation, and closed-loop or colonic obstruction. Plain films still matter for free air and interval progression, while CT and selective oral contrast help define anatomy and guide operative planning.

Small Bowel Obstruction Workup

• Plain film first pass: Acute abdominal radiographs can be enough in the ill-appearing patient with perforation, and serial KUBs remain useful for trending bowel dilation or interval improvement.
• CT with contrast nuance: CT is the main anatomic study for suspected SBO, but oral contrast still has a role by improving bowel visualization and sometimes helping a partial obstruction move along.
• Routine surgical involvement: Every ED patient with suspected SBO should have a surgical consult in the workup, even when the patient looks well and immediate operative intervention is unlikely.
• Partial obstruction priorities: Partial SBO is usually not a surgical emergency; initial management centers on symptom control, IV fluids, electrolyte correction, and searching for causes like Crohn disease or malignancy. We get into the disposition nuances in the episode.
• Emergency operative red flags: Peritonitis, free air, large abscess, bowel ischemia, perforation, and closed-loop obstruction are the findings that should push bowel obstruction toward urgent operative management.

NG Tubes and Surgical Urgency

• Challenged NGT routine: Recent retrospective studies and a limited systematic review found no clear reduction in surgery, bowel resection, or mortality with routine nasogastric decompression for SBO.
• Why NGT still matters: Despite weaker outcome data, NG decompression reduces recurrent vomiting and decompresses the bowel before surgery, which may improve the chance of a laparoscopic approach.
• NGT contraindication groups: Nasogastric tubes deserve extra caution or avoidance in Roux-en-Y gastric bypass, closed-loop obstruction, and colonic obstruction, where anatomy or pathophysiology changes the risk.
• Colonic obstruction urgency: High-grade colonic obstruction behaves as a closed-loop obstruction and should be treated as a surgical emergency rather than a wait-and-see admission problem.
• Well-appearing high grade SBO: A high-grade SBO in a stable, well-appearing patient may still start with conservative care such as decompression and fluids, but the operative boundary lines are worth hearing in the chapter.

References:

1. Fonseca AL, Schuster KM, Maung AA, Kaplan LJ, Davis KA. Routine nasogastric decompression in small bowel obstruction: is it really necessary? Am Surg. 2013 Apr;79(4):422-8. PMID: 23574854.
2. Berman DJ, Ijaz H, Alkhunaizi M, Kulie PE, Vaziri K, Richards LM, Meltzer AC. Nasogastric decompression not associated with a reduction in surgery or bowel ischemia for acute small bowel obstruction. Am J Emerg Med. 2017 Dec;35(12):1919-1921.  Epub 2017 Aug 15. PMID: 28912083.
3. Klingbeil KD, Wu JX, Osuna-Garcia A, Livingston EH. Management of small bowel obstruction and systematic review of treatment without nasogastric tube decompression. Surg Open Sci. 2022 Nov 7;12:62-67. PMID: 36992798.