Ch 39: Bowel Elimination

Anatomy and Physiology of the Gastrointestinal Tract

Bowel elimination is a vital function involving the removal of waste products from the digestive tract. Understanding the anatomy and physiology of the gastrointestinal (GI) system is essential for effective clinical care.

• Stomach: Stores food, secretes digestive fluids, and churns food to aid in digestion.

• Small Intestine: Secretes enzymes that digest proteins and carbohydrates; responsible for digestion and absorption of nutrients into the bloodstream.

• Large Intestine: The primary organ of bowel elimination, extending from the ileocecal valve to the anus. Functions include absorption of water, formation of feces, and expulsion of feces from the body.

Functions of the Large Intestine

• Absorption of Water: The large intestine reabsorbs water from indigestible food residues.

• Formation of Feces: Compacts waste into fecal matter.

• Expulsion of Feces: Eliminates waste from the body through the anus.

Peristalsis

Peristalsis refers to the involuntary, rhythmic contractions of the GI tract that propel contents forward. It is regulated by the nervous system.

• Contractions occur every 3 to 12 minutes.

• Mass peristalsis sweeps occur 1–4 times per 24 hours.

• Approximately one third to one half of food waste is excreted in stool within 24 hours.

Variables Influencing Bowel Elimination

Developmental Considerations

• Infants: Stool characteristics and frequency depend on feeding type (formula or breast milk).

• Toddlers: Physiologic maturity is necessary before bowel training.

• Children, Adolescents, Adults: Defecation patterns vary in quantity, frequency, and rhythmicity.

• Older Adults: Constipation is common; diarrhea and fecal incontinence may result from physiologic or lifestyle changes.

Other Influencing Factors

• Daily patterns

• Food and fluid intake

• Activity and muscle tone

• Lifestyle and psychological variables

• Pathologic conditions

• Medications

• Diagnostic studies, surgery, and anesthesia

Foods Affecting Bowel Elimination

• Constipating foods: Cheese, lean meat, eggs, pasta

• Laxative effect: Fruits, vegetables, bran, chocolate, alcohol, coffee

• Gas-producing foods: Onions, cabbage, beans, cauliflower

Effect of Medications on Stool

• Opioids: Cause constipation

• Antacids: Decrease GI motility

• Antibiotics, magnesium, metformin: Can cause diarrhea

Assessment of Bowel Elimination

Nursing History

• Usual patterns of bowel elimination

• Aids to elimination

• Recent changes in bowel habits

• Problems with elimination

• Presence of bowel diversion

Physical Assessment

• Abdomen: Sequence: inspection, auscultation, percussion, palpation

• Inspection: Observe contour, masses, scars, distention

• Auscultation: Listen for bowel sounds in all quadrants; note frequency and character (hypoactive, hyperactive, absent, infrequent)

• Percussion and palpation: Performed by advanced practitioners

Assessment of Anus and Rectum

• Inspect and palpate for lesions, ulcers, fissures, inflammation, external hemorrhoids

• Ask patient to bear down to assess for internal hemorrhoids, fissures, fecal masses

• Inspect perineal area for skin irritation from diarrhea or incontinence

Stool Collection and Characteristics

• Use medical aseptic technique; hand hygiene and gloves are essential

• Do not contaminate outside of container

• Label and transport according to policy

• Stool characteristics: Volume, color, odor, consistency, shape, constituents

Diagnostic Studies

Direct Visualization (Endoscopy)

• Esophagogastroduodenoscopy (EGD): Examines esophagus, stomach, upper duodenum

• Colonoscopy: Visualizes rectum, colon, and distal small bowel with a flexible, fiberoptic-lighted scope

• Sigmoidoscopy: Examines distal sigmoid colon, rectum, anal canal

• Wireless video capsule endoscopy: Swallowed capsule transmits images

Indirect Visualization

• Upper GI series

• Small bowel series

• Barium enema

• Abdominal ultrasound

• Magnetic resonance imaging (MRI)

• Abdominal CT scan

Promoting and Maintaining Normal Bowel Elimination

Patient Outcomes

• Soft, formed bowel movement without discomfort

• Understanding the relationship between elimination, diet, fluid, and exercise

• Seeking medical evaluation for persistent changes in stool

• Maintaining skin integrity

Promoting Regular Bowel Habits

• Timing

• Positioning

• Privacy

• Hygiene

• Nutrition

• Exercise (abdominal settings, thigh strengthening)

Individuals at High Risk for Constipation

• Bedrest or decreased mobility

• Use of constipating medications

• Reduced fluid or dietary bulk

• Depression

• CNS disease or painful local lesions

Nursing Measures for Diarrhea

• Respond to call bells promptly

• Remove cause of diarrhea if possible

• Withhold antidiarrheal medications if impaction is suspected

• Provide special care to perianal region

Preventing Food Poisoning

• Refrigerate perishable items promptly

• Wash hands and surfaces often

• Use separate cutting boards for different foods

• Wash fruits and vegetables thoroughly

• Do not wash meat, poultry, or eggs

• Avoid raw eggs and undercooked seafood

• Use a food thermometer; keep food hot (≥140°F)

• Give only pasteurized juices to children

Methods of Emptying the Colon

• Enemas

• Rectal suppositories

• Oral intestinal lavage

• Digital removal of stool

Types of Enemas

• Cleansing

• Retention

• Oil

• Carminative

• Medicated

• Hypotonic (large volume)

• Hypertonic (small volume)

• Anthelmintic: Used to destroy intestinal parasites

Managing Bowel Incontinence and Training

Bowel Incontinence

• Assist patient to bathroom at likely times

• Maintain skin cleanliness and dryness

• Change linens and clothing as needed

• Implement bowel-training programs

• Consider indwelling rectal tube or external anal pouch

Bowel-Training Programs

• Manipulate food, fluid, exercise, and timing to promote regular, soft stools without laxatives

• Plan with patient and caregivers

• Set regular time for bowel movements

• Monitor and stimulate as needed

• Ensure privacy and encourage adequate fluid and diet

Nasogastric Tubes

• Inserted to decompress or drain the stomach

• Used pre- or post-abdominal surgery to promote GI rest

• Monitor for GI bleeding

Ostomies and Colostomy Care

Types of Ostomies

• Sigmoid colostomy

• Descending colostomy

• Transverse colostomy

• Ascending colostomy

• Ileostomy

Colostomy Care

• Prevent odors; empty appliance frequently

• Inspect stoma regularly

• Keep skin around stoma clean and dry

• Monitor fluid intake and output

• Educate and support patient in self-care and body image

Patient Teaching for Colostomies

• Explain reason and rationale for bowel diversion

• Demonstrate self-care and management

• Describe follow-up care and resources

• Address fears and concerns

• Promote positive body image

Colostomy Diet

• Low-fiber foods for first 6–8 weeks

• At least 2.5 quarts of fluids daily (preferably water)

• Avoid foods that cause blockage: nuts, corn, popcorn, coconuts, mushrooms, stringy vegetables, foods with skins/casings

• Avoid foods that cause gas or odor

• Add foods to thicken stool: bananas, cheese, pasta, rice, yogurt, applesauce, potatoes

Sample Table: Foods Affecting Bowel Elimination

Sample Table: Types of Enemas

Key Definitions

• Peristalsis: Involuntary, rhythmic contractions of the GI tract that move contents forward.

• Colostomy: Surgical creation of an opening from the colon to the abdominal surface for fecal elimination.

• Ileostomy: Surgical opening from the ileum to the abdominal surface.

• Enema: Introduction of fluid into the rectum to promote evacuation of feces.

• Bowel training: Program to promote regular, controlled bowel movements.

Example: Clinical Application

• Case: An older adult with chronic constipation is advised to increase fruit and vegetable intake, maintain adequate hydration, and engage in regular physical activity to promote bowel regularity.

Additional info: This summary expands on the original notes by providing definitions, clinical context, and structured tables for clarity and exam preparation.