Small and Large Intestines Small intestine (longest organ in the GI tract) Three major divisions: duodenum, jejunum, ileum Main function is complete digestion of food Most nutrients and water are absorbed in 6- to 8- hour passage Large intestine Segments: cecum; appendix; ascending, transverse, descending, and sigmoid colon; rectum Main functions are elimination of waste and absorption of water
Bowel Obstruction Occurs in the small (most common) or large intestine (sigmoid colon most common) Can be partial or complete Severity depends on the region of the bowel, the degree of occlusion, and the degree of vascular disruption
Bowel Obstruction In small bowel obstruction, large amounts of fluid and gases are trapped above the area of obstruction, leading to abdominal distention Dehydration can develop from loss of water and sodium Hypovolemia occurs as fluids are pulled from the vascular bed to the site of the obstruction Peristalsis below the obstruction decreases, which leads to bacterial overgrowth and may lead to peritonitis If the blood supply is cut off, it can lead to necrosis
Causative Factors Extrinsic bowel obstruction Begins outside the GI tract Adhesions, herniations, or masses Intrinsic bowel obstruction Lumen blockage Caused by acute or chronic bowel disease inflammation, congenital defects, or tumors Intraluminal bowel obstruction Caused by the inability of material to pass through the GI tract (meconium, foreign bodies, impactions)
Mechanical Causes Adhesions: Loops of intestine become adherent to areas that heal slowly or scar after abdominal surgery ( most common cause of small bowel obstruction) Herniations: The intestine protrudes through a weakened area in the abdominal muscle or wall Volvulus: Bowel twists and turns on itself; laxative use may be the cause Intussusceptions: Bowel slips into itself Tumors Diverticulitis: Pouches push out of mucosal lining of bowel
Functional Causes Intestinal muscles are unable to propel contents forward, such as in: Muscular dystrophy Endocrine disorders (such as diabetes) Neurological disorders (such as Parkinson’s disease) Electrolyte imbalances Uremia Spinal cord lesions
Signs & Symptoms: Small Bowel Obstruction Crampy abdominal pain (usually seen in small bowel obstruction) Reflux vomiting if obstruction is complete Fecal-smelling breath Dehydration signs: thirst, drowsiness, malaise, achiness, and parched tongue and mucous membranes
Signs & Symptoms: Large Bowel Obstruction Develop and progress slowly Constipation may be the only symptom for months Weakness, weight loss, and anorexia Marked abdominal distention Crampy lower abdominal pain
Assessment Past medical history and history of events leading to seeking care (pain is usually the symptom that causes patient to seek care) Assess pain characteristics (quality and intensity) Assess abdomen Auscultate bowel sounds (Bowel sounds: high- pitched, hyperactive, tinkling, and almost metallic in the area over the obstruction; quiet or absent below the obstruction)
Diagnostic Tests Lab values will determine fluid and electrolyte management Emesis causes loss of sodium, potassium, chloride, and hydrogen Sodium, blood urea nitrogen, and creatinine levels will be elevated as fluid shifts out of the vascular bed White blood cell count will be elevated as inflammation develops Hemoglobin and hematocrit will be elevated relative to fluid loss
Diagnostic Tests Liver enzymes will be elevated in response to other GI organs Metabolic acidosis may occur as perfusion decreases Frank blood is an indication of perforation (requires immediate surgical intervention) X-ray of the abdomen will show dilation of the bowel CT scan may show mechanical changes (addition of contrast may show vascular changes)
Treatment For incomplete obstructions, medical management is the treatment of choice The patient will have an NG tube inserted, which may provide resolution for many bowel obstructions Urinary catheter to monitor output I.V. therapy to replace fluids and electrolytes Administration of broad-spectrum antibiotics Conservative control of pain
NG Tube Length Measurement
Confirming NG Tube Placement To confirm placement after the initial X-ray is done, a combination of three methods is recommended: Measure the length of the exposed portion of the tube every shift and compare it with the original measurement. An increase in length of exposed tube may indicate dislodgment or a leaking or ruptured balloon if the tube has a balloon. Visually assess the color of aspirate to help distinguish between gastric and intestinal placement. Measure the pH of aspirate, which is a more accurate method of confirming tube placement than measuring the exposed tube length or assessing tube aspirate.
Surgical Treatment Depends largely on the cause In some cases, the portion of the affected bowel may be resected and anastamosed Some patients will undergo a temporary colostomy or ileostomy
Preventing Complications Monitor prothrombin time and INR Assess skin for petechiae, color, and temperature Assess body fluids for presence of blood Assess nutritional status (monitor albumin and prealbumin) Use an air mattress to prevent skin breakdown
Patient Teaching Discuss bowel regime with patient, including avoiding laxative use, increasing fluids, and increasing fiber Teach personal care to a patient who has undergone surgery with an ileostomy or colostomy (selection of the proper size of appliances, care of the site and skin near the ileostomy or colostomy, and dietary changes to help reduce gas production)
Guidelines for Changing an Ileostomy Appliance Changing an ileostomy appliance is necessary to prevent leakage (the whole appliance, including the flange or wafer, is usually changed every 5 to 7 days). Routine changes should be performed early in the morning before breakfast or 2 to 4 hours after a meal, when the bowel is least active. Have the patient assume a relaxed position, provide privacy, and explain the details of the procedure. Remove the appliance. Have the patient sit on the toilet or on a chair facing the toilet. A patient who prefers to stand should face the toilet. The appliance (pouch) can be removed by gently pushing the skin away from the adhesive.
Guidelines for Changing an Ileostomy Appliance Clean the skin. Wash the skin gently with a soft cloth moistened with tepid water and mild soap; the patient may prefer to bathe before putting on a clean appliance. Rinse and dry the skin thoroughly after cleaning. Apply an appropriate skin barrier to the peristomal skin before applying the appliance. Remove the cover from the adherent surface of the disk of the disposable plastic appliance and apply it directly to the skin. Press firmly in place for 30 seconds to ensure adherence. When skin irritation is present, clean the skin thoroughly, but gently; pat dry. Apply triamcinolone acetonide spray, blot excess moisture with a cotton pledget, and dust lightly with nystatin powder. Check the pouch bottom for closure; use the rubber band or clip provided.