Intestinal obstruction is any condition that prevents the normal forward movement of intestinal contents.

Types

• Mechanical obstruction — a physical blockage
  • Small bowel: adhesions from previous abdominal or pelvic surgery (most common cause), hernias, tumors, Crohn strictures, volvulus, intussusception, gallstone ileus
  • Large bowel: colorectal cancer (most common), sigmoid or cecal volvulus, diverticular stricture, fecal impaction
• Functional (nonmechanical) obstruction — the bowel does not move contents
  • Paralytic (adynamic) ileus: after abdominal surgery, hypokalemia, opioids and anticholinergics, peritonitis, sepsis, spinal injury, pancreatitis
  • Acute colonic pseudo-obstruction (Ogilvie syndrome): massive colonic dilation without a blockage, often in older, critically ill clients

Sequence of events

1. Gas and fluid collect above the obstruction → distension
2. The bowel wall secretes more fluid and absorbs less; fluid moves into the lumen and peritoneum ("third spacing"), and vomiting adds loss → hypovolemia and electrolyte imbalance
3. Rising pressure in the wall reduces blood flow → strangulation, ischemia, necrosis, perforation, peritonitis, sepsis
4. Bacteria multiply and may translocate across the damaged wall

Simple vs strangulated: a strangulated obstruction has compromised blood supply and is a surgical emergency. A closed-loop obstruction (e.g., volvulus) is especially dangerous.

Bowel sounds

• Early mechanical obstruction: high-pitched, "tinkling" or rushing sounds with pain waves
• Late obstruction or paralytic ileus: hypoactive or absent

Signs of strangulation — report immediately

• Pain that becomes constant, severe, and localized, or pain out of proportion to examination
• Fever, tachycardia, hypotension
• Peritoneal signs: rebound tenderness, guarding, rigidity
• Leukocytosis, rising lactate, metabolic acidosis

Also assess: surgical history, hernia sites (a tender, irreducible groin lump), last bowel movement and flatus, medications (opioids), and hydration (skin turgor, mucous membranes, urine output).

Fluid, electrolyte, and acid–base changes by level

Older adults may have less pain, a lower fever response, and confusion as the first sign; fecal impaction is a common and preventable cause in immobile clients and those taking opioids or anticholinergics. Paradoxical liquid stool leaking around an impaction can be mistaken for diarrhea.

Initial management for most obstructions

• NPO
• Nasogastric (NG) tube to low suction as ordered (low intermittent for a single-lumen tube; low continuous for a double-lumen sump tube) for decompression — relieves vomiting and distension and lowers aspiration risk
• IV isotonic fluids (normal saline or lactated Ringer's) and electrolyte replacement; potassium replacement once urine output is adequate
• Analgesia (opioids used cautiously; they are not withheld) and antiemetics
• Urinary catheter in severe cases for hourly output

Nonoperative trial — many adhesive small bowel obstructions resolve with decompression and fluids within about 48–72 hours; water-soluble contrast may speed resolution.

Surgery — urgent laparotomy or laparoscopy for strangulation, perforation, closed-loop obstruction, or failure of nonoperative care: adhesiolysis, hernia repair, bowel resection, or colostomy/ileostomy for obstructing colorectal cancer. Colonic stents can relieve malignant large-bowel obstruction as a bridge or palliation.

Sigmoid volvulus — endoscopic detorsion, then elective resection (high recurrence).

Paralytic ileus

• Treat the cause: correct potassium and magnesium, reduce opioids (multimodal analgesia), treat infection
• Bowel rest and NG decompression if vomiting or distension
• Enhanced recovery after surgery (ERAS) measures prevent postoperative ileus: early ambulation, early feeding, opioid-sparing analgesia, chewing gum (sham feeding stimulates motility)
• Alvimopan (peripheral opioid antagonist) after bowel resection: short-term hospital use only (maximum 15 doses) under a restricted program because long-term use was linked to myocardial infarction; contraindicated after more than 7 consecutive days of therapeutic opioid use

Ogilvie syndrome — decompression, correct electrolytes, stop offending drugs; neostigmine if no improvement: give with cardiac monitoring and atropine at the bedside (bradycardia), avoid in mechanical obstruction. A cecal diameter above about 12 cm raises perforation risk — report increasing distension.

Listed in priority order.

1. Airway and aspiration — head of bed elevated (semi-Fowler's); suction available; keep NG tube patent
2. Circulation and fluid balance
   • Vital signs frequently; watch for tachycardia and hypotension (hypovolemia, sepsis)
   • Strict intake and output, including NG drainage; urine output at least 0.5 mL/kg/h
   • Monitor electrolytes; give IV fluids and potassium as ordered; daily weight
3. Detect deterioration — reassess pain character, abdominal girth, bowel sounds, and peritoneal signs; report sudden constant pain, fever, rigidity, or rising lactate (strangulation or perforation)
4. NG tube care
   • Initial placement is confirmed by X-ray; before each use, check the external length mark and aspirate pH per policy; check patency and suction settings each shift
   • For a double-lumen sump tube, keep the vent (air) lumen open and above the level of the stomach; never clamp the vent or use it for irrigation — flush it with air only
   • Record amount, color, and character of drainage (bilious, feculent, bloody)
   • Irrigate only as ordered; secure the tube and inspect the nares for pressure injury
5. Comfort and oral care — frequent mouth care and lubrication of lips (NPO and mouth breathing cause dryness and infection risk); do not give ice chips or fluids unless ordered
6. Mobility — ambulate as tolerated to stimulate peristalsis and prevent VTE and atelectasis
7. Do not give laxatives or enemas in suspected obstruction unless ordered
8. Postoperative care — incision, stoma care if created, return of bowel function (flatus, bowel sounds, stool), gradual diet advancement

• Explain the purpose of the NG tube and NPO status; teach not to pull the tube
• After abdominal surgery: walk early and often; chewing gum may help bowel function return if the surgeon approves
• Report nausea, vomiting, abdominal swelling, cramping pain, or no gas or stool — especially after previous abdominal surgery (adhesions can cause later obstruction)
• Prevent constipation (fluids, fiber if no stricture, activity); use opioids only as prescribed with a bowel regimen
• Clients with strictures (e.g., Crohn disease) may need a low-residue diet and to chew food thoroughly
• After resolution of an obstruction managed without surgery, return to eating gradually — start with liquids or soft low-residue foods and advance as tolerated
• Keep follow-up appointments; a large-bowel obstruction in an adult needs evaluation for colorectal cancer if not already done
• Know hernia warning signs: a painful, hard bulge that will not go back in, with vomiting — seek emergency care

• Most common cause of small bowel obstruction: postoperative adhesions; large bowel: colorectal cancer
• SBO: early profuse vomiting, colicky pain; LBO: marked distension, late vomiting
• Bowel sounds: high-pitched early, absent late or in paralytic ileus
• X-ray: air-fluid levels; CT is the preferred test
• First steps: NPO, NG decompression, IV fluids and electrolytes
• Monitor NG tube position and drainage amount and character; include NG output in I&O
• Constant localized pain, fever, tachycardia, peritoneal signs = strangulation → surgery
• Paralytic ileus causes: surgery, hypokalemia, opioids, peritonitis
• Postoperative ileus prevention: early ambulation, opioid-sparing analgesia, chewing gum
• Frequent oral care during NG decompression