👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Physiological Adaptation🔖 Free to read, print, and share
Also known as: blocked intestine · intestinal blockage · blocked bowel · ileus · obstructed bowel
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Use this quick-reference guide to spot, treat, and prevent Bowel Obstruction on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
📌 Types
mechanical: adhesions, hernia, tumor
functional: paralytic ileus
🩺 Signs
NO stool/flatus, distension
small bowel: ↑pitched then absent
vomiting (fecal if low), cramping
🚩 Report
fever, ↑HR, ↓BP → strangulation
metabolic alkalosis (high vomiting)
rigid abd, rebound → perforation
✅ Do
NPO, NG tube to suction
IV fluids, correct electrolytes
monitor I&O, surgery if needed
📚 Bowel Obstruction — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
A bowel obstruction is a partial or complete blockage that prevents the normal passage of intestinal contents. Mechanical causes include adhesions (most common in small bowel), hernias, tumors, and volvulus; functional causes (paralytic ileus) involve loss of peristalsis. Obstruction causes fluid and gas to accumulate, leading to distention, vomiting, and fluid/electrolyte loss. Untreated, it can progress to bowel ischemia and perforation.
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Key points
Understand these first
Small bowel obstruction causes high-pitched hyperactive bowel sounds early, then absent sounds; large bowel obstruction causes gradual onset with marked distention.
Vomiting is early and may be projectile in small bowel obstruction; vomiting (sometimes fecal-smelling) is late in large bowel obstruction.
Abdominal distention, cramping pain, and failure to pass stool or flatus (obstipation) are key signs.
Fluid and electrolyte imbalances develop from vomiting and third-spacing, risking hypovolemia and metabolic alkalosis (high) or acidosis (low).
Adhesions from prior surgery are the most common cause of small bowel obstruction.
Paralytic ileus produces absent bowel sounds without a mechanical block, often after surgery or with opioids.
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Nursing priorities
What to do, in order
Keep the patient NPO and insert an NG tube for gastric decompression as ordered.
Administer IV fluids and replace electrolytes to correct losses.
Monitor bowel sounds, abdominal girth, NG output, and intake/output.
Assess for signs of strangulation/ischemia such as fever, tachycardia, and worsening pain.
Prepare for surgery if the obstruction is complete or strangulated.
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Red flags — report now
Escalate immediately
Sudden severe constant pain, fever, and tachycardia suggest strangulation or perforation requiring emergency surgery.
Signs of peritonitis (rigid abdomen, rebound tenderness) must be reported immediately.
Marked hypovolemia or shock from fluid loss requires urgent fluid resuscitation.
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Labs & values
Numbers to know
Potassium: 3.5-5.0 mEq/L (altered with vomiting/losses)
Sodium: 135-145 mEq/L (monitor)
WBC: 5,000-10,000/mm3 (elevated with ischemia); lactate elevated with ischemia
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Patient teaching
What patients must know
Report inability to pass stool or gas, persistent vomiting, or worsening distention.
After abdominal surgery, follow guidance to promote early ambulation and prevent ileus.
Maintain adequate hydration and fiber to reduce recurrent obstruction risk where appropriate.
❓ Bowel Obstruction: NCLEX FAQs
What are the priority nursing interventions for Bowel Obstruction?
Keep the patient NPO and insert an NG tube for gastric decompression as ordered. Administer IV fluids and replace electrolytes to correct losses. Monitor bowel sounds, abdominal girth, NG output, and intake/output. Assess for signs of strangulation/ischemia such as fever, tachycardia, and worsening pain.
What are the warning signs of Bowel Obstruction a nurse must report?
Sudden severe constant pain, fever, and tachycardia suggest strangulation or perforation requiring emergency surgery. Signs of peritonitis (rigid abdomen, rebound tenderness) must be reported immediately. Marked hypovolemia or shock from fluid loss requires urgent fluid resuscitation.
What do I need to know about Bowel Obstruction for the NCLEX?
Small bowel obstruction causes high-pitched hyperactive bowel sounds early, then absent sounds; large bowel obstruction causes gradual onset with marked distention. Vomiting is early and may be projectile in small bowel obstruction; vomiting (sometimes fecal-smelling) is late in large bowel obstruction. Abdominal distention, cramping pain, and failure to pass stool or flatus (obstipation) are key signs. Fluid and electrolyte imbalances develop from vomiting and third-spacing, risking hypovolemia and metabolic alkalosis (high) or acidosis (low).
What patient teaching is important for Bowel Obstruction?
Report inability to pass stool or gas, persistent vomiting, or worsening distention. After abdominal surgery, follow guidance to promote early ambulation and prevent ileus. Maintain adequate hydration and fiber to reduce recurrent obstruction risk where appropriate.
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Quick Tip
Small bowel obstruction causes high-pitched hyperactive bowel sounds early, then absent sounds; large bowel obstruction causes gradual onset with marked distention.