Bowel Obstruction, Large Intestinal obstruction (mechanical or functional) occurs when blockage prevents the flow of contents through the intestinal tract. Large bowel obstruction results in an accumulation of intestinal contents, fluid, and gas proximal to the obstruction. Obstruction in the colon can lead to severe distention and perforation unless gas and fluid can flow back through the ileal valve. Dehydration occurs more slowly than in small bowel obstruction. If the blood supply is cut off, intestinal strangulation and necrosis occur; this condition is life threatening. Clinical Manifestations Symptoms develop and progress relatively slowly. • Constipation may be the only symptom for months (obstruction in sigmoid colon or rectum). • Blood loss in the stool, which may result in iron-deficiency anemia. • The patient may experience weakness, weight loss, and anorexia. • Abdomen eventually becomes markedly distended, loops of large bowel become visibly outlined through the abdominal wall, and patient has crampy lower abdominal pain. • Fecal vomiting develops; symptoms of shock may occur. Assessment and Diagnostic Methods Symptoms plus imaging studies (abdominal x-ray and abdominal CT scan or MRI; barium studies are contraindicated) Medical Management • Restoration of intravascular volume, correction of electrolyte abnormalities, and nasogastric aspiration and decompression are instituted immediately. • Colonoscopy to untwist and decompress the bowel, if obstruction is high in the colon. • Cecostomy may be performed for patients who are poor surgical risks and urgently need relief from the obstruction. • Rectal tube to decompress an area that is lower in the bowel. • Usual treatment is surgical resection to remove the obstructing lesion; a temporary or permanent colostomy may be Nursing Management • Monitor symptoms indicating worsening intestinal obstruction. • Provide emotional support and comfort. • Administer IV fluids and electrolyte replacement. • Prepare patient for surgery if no response to medical treatment. • Provide preoperative teaching as patient’s condition indicates. • After surgery, provide general abdominal wound care and routine postoperative nursing care. For more information, see Chapter 38 in Smeltzer, S. C., Bare, B. G., Hinkle, J. L., & Cheever, K. H. (2010). Brunner and Suddarth’s textbook of medical-surgical nursing (12th ed.). Philadelphia: Lippincott Williams & Wilkins. Bowel Obstruction, Small Most bowel obstructions occur in the small intestine. Intestinal contents, fluid, and gas accumulate above the intestinal obstruction. The abdominal distention and retention of fluid reduce the absorption of fluids and stimulate more gastric secretion. With increasing distention, pressure within the intestinal lumen increases, causing a decrease in venous and arteriolar capillary pressure. This causes edema, congestion, necrosis, and eventual rupture or perforation of the intestinal wall, with resultant peritonitis. Reflux vomiting may be caused by abdominal distention. Vomiting results in loss of hydrogen ions and potassium from the stomach, leading to reduction of chlorides and potassium in the blood and to metabolic alkalosis. Dehydration and acidosis develop from loss of water and sodium. With acute fluid losses, hypovolemic shock may occur. Clinical Manifestations • Initial symptom is usually crampy pain that is wavelike and colicky. Patient may pass blood and mucus but no fecal matter or flatus. Vomiting occurs. • If the obstruction is complete, peristaltic waves become extremely vigorous and assume a reverse direction, propelling intestinal contents toward the mouth. • If the obstruction is in the ileum, fecal vomiting takes place. • Dehydration results in intense thirst, drowsiness, generalized malaise, aching, and a parched tongue and mucous membranes. • Abdomen becomes distended (the lower the obstruction in the gastrointestinal tract, the more marked the distention). • If uncorrected, hypovolemic shock occurs due to dehydration and loss of plasma volume. Assessment and Diagnostic Findings Symptoms plus imaging studies (abnormal quantities of gas and/or fluid in intestines) and laboratory studies (electrolytes and complete blood count show dehydration and possibly infection) Medical Management Decompression of the bowel may be achieved through a nasogastric or small bowel tube. However, when the bowel is completely obstructed, the possibility of strangulation warrants surgical intervention. Surgical treatment depends on the cause of obstruction (eg, hernia repair). Before surgery, IV therapy is instituted to replace water, sodium, chloride, and potassium. Nursing Management • For the nonsurgical patient, maintain the function of the nasogastric tube, assess and measure nasogastric output, assess for fluid and electrolyte imbalance, monitor nutritional status, and assess improvement (eg, return of normal bowel sounds, decreased abdominal distention, subjective improvement in abdominal pain and tenderness, passage of flatus or stool). • Report discrepancies in intake and output, worsening of pain or abdominal distention, and increased nasogastric output. • If patient’s condition does not improve, prepare him or her for surgery.
Posted on: Mon, 01 Sep 2014 10:04:33 +0000
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