11.13 Bowel Obstruction

A bowel obstruction is a blockage of the intestines caused by a mechanical or nonmechanical condition. A mechanical blockage is when something is physically blocking the inside of the bowel and  inhibiting the passage of bowel contents. Potential causes of a mechanical bowel obstruction are adhesions or scar tissue that occurs after surgery, tumors, incarcerated hernias, strictures, or the ingestion of a foreign object. A mechanical bowel obstruction can also be caused by a volvulus (twisting of the intestines) or intussusception (part of the bowel telescopes into itself).^{[1],[2],[3],[4]} See Figures 11.34^[5] and 11.35^[6] for illustrations of a volvulus and an intussusception.

A nonmechanical blockage means that nothing is physically blocking the lumen of the bowel, but peristalsis is not occurring, and bowel contents are not moving forward through the intestines normally. An example of a nonmechanical bowel obstruction is an ileus. An ileus is commonly caused by manipulation of the bowels during abdominal surgeries.^{[7],[8],[9],[10]}

Bowel obstructions can cause either a partial or complete blockage. Furthermore, a bowel obstruction can occur in the small or large intestine, but they occur more commonly in the small bowel.^{[11],[12],[13],[14]}

Risk factors for a bowel obstruction include the following^{[15],[16],[17],[18]}:

• Abdominal surgery
• Cancer of the gastrointestinal tract
• Chronic inflammatory disorders affecting the GI tract, such as Crohn’s disease
• Presence of hernias (abdominal or inguinal)
• Prior radiation
• Opioid medications
• Severe constipation/impacted stool
• GLP-1RA medications used to treat type 2 diabetes and nondiabetes obesity^[19]

Pathophysiology

The purpose of the small intestine is to break down ingested food and absorb the resulting nutrients. The goal of the large intestine is to continue digestive processes and absorb water. When an obstruction occurs, the intestine cannot move digested food and fluid through the gastrointestinal tract, resulting in the accumulation of intestinal contents above the level of the obstruction and visible abdominal distension. The body tries to compensate by increasing secretions to help move the contents through, which leads to further obstruction. As the obstruction continues, the bowel becomes edematous, and increased capillary permeability causes plasma to leak into the peritoneal cavity, trapping fluid in the intestinal lumen and reducing the absorption of fluid and electrolytes into the bloodstream. As a result, blood flow is compromised, leading to hypovolemia and electrolyte imbalances, as well as bowel necrosis, perforation, and peritonitis.^{[20],[21],[22],[23]}

Assessment

Physical Exam

Signs and symptoms of a bowel obstruction may differ based on the location and cause of the obstruction. Common signs and symptoms of a bowel obstruction are as follows^{[24],[25],[26],[27]}:

• Abdominal pain
• Nausea
• Vomiting (Vomit may contain or smell like stool.)
• Abdominal distention/bloating
• Changes in bowel movements (Inability to pass stool or diarrhea as only liquid stool can pass obstruction.)
• Inability to pass gas
• Changes in bowel sounds (May have increased bowel sounds in early stages of obstruction and decreased or absent bowel sounds in later stages. Bowel sounds may also be increased above the obstruction and decreased or absent below the obstruction.)

Common Laboratory and Diagnostic Tests

Bowel obstructions can be confirmed by an abdominal CT scan with the use of contrast. Test results allow the provider to locate the site of the obstruction and any potential complications to determine if surgical intervention is required. An abdominal X-ray may be completed prior to a CT scan, but it may not give enough detail to determine the type of obstruction present.^[28],[29]

A number of labs may also be done to evaluate for the presence of complications^[30],[31]:

• Complete blood count (CBC) results may show elevated white blood cell count in cases of bowel necrosis.
• Electrolytes (particularly potassium) may be decreased due to vomiting.
• Lactic acid can be elevated in cases of sepsis or bowel perforation.

Review normal reference ranges for common diagnostic tests in “Appendix A – Normal Reference Ranges.”

Nursing Diagnosis

Nursing priorities for those suffering from bowel obstruction include symptom management, promoting nutrition, and preventing complications from occurring.

Nursing diagnoses for clients with bowel obstruction are created based on the specific needs of the client, their signs and symptoms, and the etiology of the disorder. These nursing diagnoses guide the creation of client specific care plans that encompass client outcomes and nursing interventions, as well the evaluation of those outcomes. These individualized care plans then serve as a guide for client treatment. Possible nursing diagnoses for those with a bowel obstruction are as follows^[32],[33]:

• Acute Pain
• Constipation
• Imbalanced Nutrition: Less than Body requirements
• Fluid Volume Deficit

Outcome Identification

Outcome identification encompasses the creation of short- and long-term goals for the client. These goals are used to create expected outcome statements that are based on the specific needs of the client. Expected outcomes should be specific, measurable, and realistic. These outcomes should be achievable within a set time frame based on the application of appropriate nursing interventions.

Sample expected outcomes for some of the above nursing diagnoses are listed below:

• The client will rate their pain at 3 or less on a scale of 0 to 10 within four hours.
• The client will pass bowel movements without straining within 48 hours.
• The client will maintain a weight within a healthy range that is appropriate for their height until their follow-up appointment.
• The client will exhibit blood pressure and heart rate within normal limits for age, moist mucous membranes, and urine output appropriate for age during their hospitalization stay.

Interventions

Medical Interventions

A bowel obstruction is medically managed based on the type of bowel obstruction and its severity. A mainstay of bowel obstruction treatment is the insertion of a nasogastric (NG) tube. The nasogastric tube serves a variety of purposes. Primarily, an NG tube allows for decompression of the bowel to prevent vomiting, and it also allows for measurement of output. If a volvulus occurs in the sigmoid portion of the colon, a rectal tube may be inserted for decompression.^{[34],[35],[36],[37]}

Some clients may only require nasogastric tube insertion and supportive care as needed. Supportive care measures include nothing by mouth (NPO) diet order, administration of intravenous fluids, electrolyte replacement, and encouragement of ambulation. If the client is unable to take food by mouth for an extended period of time, total parenteral nutrition may be needed. Limiting opioid use is also warranted, and antibiotics may also be prescribed in some instances.^{[38],[39],[40],[41]}

Some clients may require surgical intervention to treat the blockage. The surgical procedure needed will depend on the degree and type of obstruction, but may include removing the affected portion of the bowel and creating a stoma.^{[42],[43],[44],[45]}

Nursing Interventions

When providing nursing care for a client with a bowel obstruction, nursing interventions can be divided into nursing assessments, nursing actions, and client teaching^[46]:

Nursing Assessments

• Assess the contour of the client’s abdomen and the presence of bowel sounds and flatus. The return of bowel sounds and flatus could indicate an improvement in the obstruction.
• Assess intake and output. Due to their NPO status and vomiting, the client is at risk for dehydration. The amount/color/consistency of NG tube drainage should also be monitored.
• Monitor the client’s vital signs. Vital signs may be altered due to dehydration, pain, or complications such as perforation/peritonitis.
• Monitor lab results, including WBCs, for signs of infection and electrolyte levels, particularly sodium, potassium, and magnesium, as these may be altered due to vomiting and NG suctioning.
• Assess skin around NG tube and output of NG tube.

Nursing Actions

• Employ nonpharmacological methods to reduce pain such as distraction, deep breathing techniques, meditation, or the use of hot or cold.
• Insert a nasogastric tube per provider order and assess the tube every shift and as needed. Provide frequent oral care.
• Encourage ambulation, as this can help increase peristalsis.
• When the client is able to resume intake, encourage small, frequent meals and advance the client’s diet as tolerated/ordered by the provider.
• Administer intravenous fluids and electrolyte replacements as ordered by the provider.
• Provide oral care as needed while the nasogastric tube is in place.
• Consult with a dietician as indicated to review potential nutritional causes of bowel obstruction and create a diet plan.

Client Teaching

• Teach about the effects of opioid use on the bowel, as indicated.
• Teach the purpose of the nasogastric tube.
• Reinforce teaching about planned surgical procedures and what to expect postoperatively.

Evaluation

Evaluation of client outcomes refers to the process of determining whether or not client outcomes were met by the indicated time frame. This is done by reevaluating the client as a whole and determining if their outcomes have been met, partially met, or not met. If the client outcomes were not met in their entirety, the care plan should be revised and reimplemented. Evaluation of outcomes should occur each time the nurse assesses the client, examines new laboratory or diagnostic data, or interacts with another member of the client’s interdisciplinary team.