[chapter 47] bowel elimination

Effect of aging on bowel elimination

Reduced peristalsis, decreased muscle tone, reduced thirst sensation, polypharmacy — all increase constipation risk

How does fiber promote elimination?

It adds bulk that stretches the intestinal wall and stimulates peristalsis

Why does immobility cause constipation?

Movement stimulates peristalsis and maintains abdominal and pelvic muscle tone

Effect of stress and anxiety on the bowel

Can increase motility, causing diarrhea or IBS flares

Normal position for defecation

Sitting or squatting

Why does pain cause constipation?

The patient suppresses the urge to avoid pain, stool hardens, and defecation becomes more painful

Why does pregnancy cause constipation?

Uterine compression of the colon, progesterone slowing motility, and iron supplements hardening stool

Effect of general anesthesia on the bowel

Temporarily stops peristalsis, causing paralytic ileus for about 24 to 48 hours

Signs that peristalsis has returned after surgery

Return of bowel sounds and passage of flatus

Medications causing constipation

Opioids, anticholinergics, iron, aluminum-containing antacids, calcium channel blockers

Medications causing diarrhea

Antibiotics, laxative overuse, magnesium-containing antacids

Constipation

Infrequent stools and/or hard, dry, difficult-to-pass stool

Signs of constipation

Straining, hard stool, distention and bloating, cramping, decreased appetite, sensation of incomplete evacuation, firm left lower quadrant

Why do opioids cause constipation?

Opioid receptors in the gut slow peristalsis, so stool sits longer and more water is reabsorbed

Fecal impaction

A hardened mass of stool in the rectum too large to pass voluntarily

Hallmark sign of fecal impaction

Continuous oozing of liquid stool with no passage of normal stool

Why is liquid stool seen with impaction?

Liquid stool seeps around the hardened obstructing mass

Why is an antidiarrheal harmful in impaction?

It slows motility further and worsens the obstruction; the correct action is to assess bowel history and perform a digital rectal exam

Patients at highest risk for impaction

Debilitated, confused, dehydrated, immobile, and older adult patients

Diarrhea

Increased frequency of loose liquid stool from decreased transit time and less water absorption

Main dangers of diarrhea

Fluid and electrolyte loss (dehydration, hypokalemia, metabolic acidosis)

Why does liquid stool destroy skin quickly?

It contains active digestive enzymes that break down proteins including skin

C. difficile

Infectious diarrhea following antibiotic use that wipes out normal flora; causes profuse watery foul-smelling stool

Hand hygiene for C. difficile

Soap and water

Diet during diarrhea

Low-residue foods until controlled, then return to normal diet slowly beginning with fluids

Bowel incontinence causes

Neurologic impairment, sphincter damage, severe diarrhea, impaction with overflow

Flatulence

Gas accumulating in the intestines causing distention, cramping, and fullness

Interventions for flatulence

Ambulation, positioning, avoiding straws, carbonation, and gas-forming foods; carminative enema if severe

Hemorrhoids

Dilated engorged veins in the rectal lining from repeated increased venous pressure

Causes of hemorrhoids

Straining, pregnancy, obesity, chronic constipation, prolonged sitting

Hemorrhoid bleeding appearance

Bright red on the tissue or coating the stool

Melena

Black tarry stool indicating upper GI bleeding, where blood has been digested

Crohn disease

Chronic transmural inflammation affecting any part of the GI tract in patchy skip lesions; may require ileostomy

Ulcerative colitis vs Crohn disease

UC is continuous and limited to colon mucosa and can be cured by removing the colon; Crohn is patchy and transmural and cannot

Order of abdominal assessment

Inspect, auscultate, percuss, palpate

Why auscultate before palpating the abdomen?

Palpation stimulates the bowel and produces false bowel sounds

Bristol Stool Scale

Types 1-2 indicate constipation, 3-4 are normal, 5-7 tend toward diarrhea

Normal stool color

Brown

Black tarry stool suggests

Upper GI bleeding or iron supplements

Clay or white stool suggests

Bile obstruction

Narrow pencil-thin stool suggests

Obstruction or a colorectal mass

Abnormal stool constituents

Blood, mucus, pus, parasites, foreign bodies

Associated non-bowel diagnoses

Acute Pain, Body Image Changes, Skin Breakdown

Risk reduction teaching for colorectal cancer

Regular exercise, healthy weight, no smoking, high-fiber diet low in red and processed meats, reduced sugar, limited alcohol

Colorectal cancer risk factors

Age over 50, personal history of cancer or polyps, inflammatory bowel disease, family history, familial adenomatous polyposis, Lynch syndrome, type 2 diabetes, high red and processed meat intake, obesity, inactivity, smoking, heavy alcohol

Racial and ethnic groups at highest colorectal cancer risk

American Indian, Alaska Native, and African-American people; Ashkenazi Jews have among the highest risk worldwide

Colorectal cancer warning signs

Change in bowel habits including narrowing of stool lasting more than a few days, rectal bleeding or blood in stool, sensation of incomplete evacuation, unexplained abdominal or back pain, weakness, fatigue, unintended weight loss

Age to begin average-risk colorectal screening

45

Screening after age 85

Not indicated

gFOBT and FIT frequency

Annual

Flexible sigmoidoscopy frequency

Every 5 years

DNA stool test frequency

Every 3 years

CT colonography frequency

Every 5 years

Colonoscopy frequency

Every 10 years

After a positive sigmoidoscopy or colonography

Follow up with colonoscopy

Regular bedpan

Plastic, about 5 cm (2 inches) deep, with a curved smooth upper end and a sharper-edged lower end

Fracture pan

Shallow upper end about 2.5 cm (1 inch) deep, designed for patients with lower-extremity fractures

How is a fracture pan positioned?

Shallow end under the buttocks toward the sacrum, deeper end with the handle under the upper thighs

Correct head-of-bed position on a bedpan

Elevated 30 to 45 degrees

Why not leave a patient flat on a bedpan?

It forces the patient to hyperextend the back to lift the hips onto the pan

PPE for handling a bedpan

Always wear gloves

Cathartic vs laxative

Cathartics have a stronger and more rapid effect on the intestines

Bulk-forming laxatives

Methylcellulose (Citrucel), psyllium (Metamucil), polycarbophil (FiberCon)

Bulk-forming mechanism

Fiber absorbs water and increases stool bulk, stretching the intestinal wall to stimulate peristalsis in 12 to 24 hours

Safest laxative and drug of choice for chronic constipation

Bulk-forming

Who should not take bulk-forming laxatives?

Patients for whom large fluid intake is contraindicated

Emollient laxatives (stool softeners)

Docusate sodium (Colace), docusate calcium (Surfak)

Stool softener indications

Short-term relief of straining — hemorrhoids, perianal surgery, pregnancy, recovery from MI

Stool softener limitation

Little value for treating chronic constipation

Osmotic laxatives

Magnesium citrate, magnesium hydroxide, sodium phosphate, polyethylene glycol (MiraLax), lactulose

Saline-based osmotic indications

Acute emptying only; endoscopy prep, suspected poisoning, acute constipation

Saline laxative contraindication

Kidney dysfunction; risk of toxic magnesium buildup

Phosphate salts contraindication

Patients on fluid restriction

Stimulant cathartics

Bisacodyl (Dulcolax), senna (Senokot), castor oil, docusate with senna

Stimulant laxative risks

Severe cramping, dependence on the stimulus with regular use, fluid and electrolyte imbalance with chronic use

Prescription drugs for chronic constipation and IBS

Prucalopride, linaclotide, naloxegol

Nonspecific antidiarrheal mechanism

Decreases intestinal motility so more water is absorbed, reducing stool fluidity and volume

Most effective nonspecific antidiarrheals

Opioids

Why can antidiarrheals be dangerous in infectious diarrhea?

Slowing motility traps the pathogen and its toxins in the colon and can cause toxic megacolon

Primary purpose of an enema

Promote defecation by stimulating peristalsis

Common indications for enemas

Immediate relief of constipation, emptying the bowel before tests or surgery, beginning bowel training

Position for an enema

Left lateral Sims with the right knee flexed

Normal saline enema

Isotonic — exerts the same osmotic pressure as surrounding interstitial fluid; the safest solution

Only enema solution used for infants and children

Normal saline, because of their greater risk for fluid imbalance

Tap water enema

Hypotonic — water escapes the bowel into interstitial spaces

Danger of repeated tap water enemas

Water toxicity or circulatory overload

Hypertonic enema

Pulls fluid out of interstitial spaces into the colon, causing distention that promotes defecation

Hypertonic enema contraindications

Dehydrated patients and young infants

Best enema for patients who cannot tolerate large volumes

Hypertonic

Soapsuds enema

Castile soap added to tap water or saline, causing intestinal irritation that stimulates peristalsis

Soapsuds enema cautions

Use only pure liquid castile soap; use caution in pregnancy and older adults due to electrolyte imbalance and mucosal damage

High vs low enema

High and low refer to the height and pressure of delivery; a high enema cleanses more of the colon, a low enema cleanses only the rectum and sigmoid colon

Position changes after a high enema

Turn from left lateral to dorsal recumbent to right lateral so fluid reaches the entire large intestine

Carminative enema

Provides relief from gaseous distention and improves the ability to pass flatus

MGW solution

30 mL magnesium, 60 mL glycerin, 90 mL water

Kayexalate enema

Sodium polystyrene sulfonate for dangerously high potassium; the resin exchanges sodium ions for potassium ions in the large intestine

Neomycin enema

Antibiotic used to reduce colon bacteria before bowel surgery

Steroid enema

Used for acute inflammation in the lower colon

Risks of excess rectal manipulation

Mucosal irritation, bleeding, and vagal nerve stimulation causing reflex slowing of the heart rate

Nursing action during digital stool removal

Monitor the pulse throughout and stop immediately if the heart rate drops or the rhythm changes