Module 5 - Elimination Flashcards
Definition of bowel elimination
excretion of stool from the body
Factors impacting elimination
intake
transit
outlet
Intake
food
water
fiber
Transit
digestion & absorption
gastric motility (peristalsis & mass movements)
aerobic exercise
Outlet
coordinated muscle contraction & relaxation
neurologic function
Gastrocolic reflex
stimulates mass movements in response to stretch of stomach following food intake
Types of fiber
soluble
insoluble
How does fiber lower cholesterol
soluble fiber binds with cholesterol in the colon –> elimination
body is forced to produce new cholesterol
Soluble fiber
attracts water & forms a thick gel
adds bulk & softens stool
lowers blood cholesterol
slows sugar absorption
Insoluble fiber
indigestible fiber
increases bulk & accelerates gastric transit
Defecation reflex
diaphragm, abdomen, rectal muscles contract –> push stool forward
IAS, EAS, puborectalis relax –> allow for voiding
Normal bowel habits
x3/daily - x3/weekly
soft, brown, formed stool (bristol stool 3-4)
straining <25%
complete evacuation 250-500 mL
Definition of constipation
infrequent bowel movements (<3 week or change in individual pattern)
hardening of stools
retention of stool in rectum –> sense of incomplete evacuation
constipation is a symptom caused by an underlying condition
Fecal impaction
mechanical obstruction in the sigmoid colon/rectum
inability to pass hard collection of stool
Risk Factors for post-op constipation
low fluid intake <1500 mL/day inadequate fiber <25-30 g/daily decreased intake (NPO, N/V, <50% meal) immobility, bedrest medications (opioids, anesthesia) PSR (reduced GI motility & blood flow) electrolyte imbalances (hypokalemia) changes in routine, privacy abdominal weakness/impaired contraction comorbidties
Normal fluid intake
1500-2000 mL daily
Normal fiber intake
25-30 g daily
Opioids & GI function
bind to opioid agonists in the enteric nervous system
decrease peristalsis (increase absorption time)
increase sphincter tone
Geriatric RF for constipation
soft, processed diet low in fiber decreased food intake impaired thirst response reduced mobility & physical activity weak abdominal/pelvic muscles medications (anticholinergics, opioids, etc) depression demeentia dulled nerve impulses --> decreased urge to defecate laxative dependency
Medications causing constipation
opioids anticholinergics antihistamines aluminum antacids tricyclic antidepressants laxative abuse
GI RF for constipation
PSR ignoring urge to defecate --> overstretching of colon abdominal/perianal surgery history of chronic constipation/bowel obstruction (IBS) painful defecation (hemerrhoids)
Hemorrhoids
dilated blood vessels in the rectum
Fissures
tears in the anal canal caused by passage of hard stool
Megacolon
enlarged colon caused by non-mechanical obstruction (infection, disease, medication, surgery, idiopathic)
can cause perforation of colon
Neurologic RF of constipation
stroke
spinal cord injury (sacral)
altered cognition (dementia)
Metabolic RF of constipation
diabetes hypothyroidism pregnancy hypokalemia hypercalcemia
Consequences of constipation
discomfort/pain
N/V
impaired nutrition
straining –> wound dehiscence, vasovagal response
fecal impaction/obstruction –> perforation
complications of chronic constipation –> hemorrhoids
Location if intestinal obstruction
small bowel
large bowel
Duration of obstruction
acute
chronic
Extent of intestinal obstruction
partial
complete
Etiology of obstruction
mechanical (fecal impaction)
functional (paralytic ileus)
Causes of mechanical obstruction
mechanical = physical blockage adhesions herniations volvulus intussusception strictures tumour growth
Adhesions
scar tissue forms between adjacent bowel parts
Herniation
intestines protrude through abdominal muscle
Volvulus
twisting of bowel + mesentery around itself
Intussusception
part of intestine slides into another part of tissue (telescopic)
Strictures
narrowing of the intestinal lumen
Tumor growth
tissue mass
Causes of functional obstruction
functional = impaired motility
impaired perfusion
disrupted innervation
medications (opioids, anesthesia)
Abdominal post-op return of GI motility
small intestine = 0-24 hrs
stomach = 24-48 hrs
colon = 48-72 hrs
S/S of paralytic ileus
abdominal discomfort/distension N/V retention of stool/flatus food intolerance absent/hypoactive bowel sounds not passing gas steady pain radiographic confirmation
Prolonged post-op ileus
impairment of intestinal motility >3 days
Treatment of paralytic ileus
chewing gum
ambulation
NG suction (to decompress gastric contents)
NPO status
IV hydration & electrolytes (normovolemia if pt vomiting/ng suctioning >1-2 L)
lower/switch opioids (if risk factor)
RF for paralytic ileus
abdominal/pelvic/lower GI surgery --> surgical trauma & bowel manipulation --> inflammation open surgery opioids/anesthesia PSR electrolyte imbalances (hypokalemia) NPO/delayed enteral nutrition decreased mobility
Complications of mechanical obstruction
tissue ischemia d/t impaired blood flow through compressed blood vessels
perforation –> peritonitis/sepsis
requires surgical intervention
S/S of mechanical obstruction
abdominal distension/tenderness (gas + fluid trapped above obstruction) pain (colicky) bowel sounds (hyperactive) N/V (d/t distension/pain) constipation/obstipation compressed arteries --> ischemia bowel perforation
Where does bowel gas come from
70% swallowed air –> mostly nitrogen which body is unable to reabsorb
bacterial digestion –> fermentation in the large colon
Where do bowel fluids come from
digestive secretions (stomach, pancreas, small intestine) consumed
S/S small bowel obstruction
rapid onset vomiting colicky, cramplike, intermittent pain some bowel movement varying abdominal distension
S/S of large bowel obstruction
gradual onset vomiting = late sign low-grade, cramping, abdominal pain absolute constipation large distension/bloating
Constipation assessment
focused GI + bowel history
fluid, fiber, food intake
mobility assessment
pain + medication hx
Hypoactive bowel sounds
1-2 sounds every 2 min
Absent bowel sounds
no sounds in 3-5 minutes
Hyperactive bowel sounds
high pitched, rumbling
5-6 sounds <30 sec
Normal bowel sounds
clicks/gurgles every 5-20 seconds
Causes of hypoactive BS
paralytic ielus
late intestinal obstruction
peritonitis
Causes of hyperactive BS
diarrhea
gastroenteritis
IBD
S/S of constipation
<3 BM/week or change in pattern strains at stool hard, dry stool abdominal distension rectal pressure absence of bowel sounds unexplained N/V rectal pain/stool passing incomplete evacuation oozing/diarrhea incontinence
Alarm symptoms
fresh blood in stool
occult blood
S/S mechanical obstruction
family hx of colorectal cancer/IBD
FIT
fecal immunochemical test
FOBT
fecal occult blood test
Diagnostics
abdominal x-ray (white = stool)
colonoscopy
FIT/FOBT
colonic transit study
Non-pharm constipation mgmt
toileting routine (30 min after meals) positioning (squatting, commode) diet (limit caffeine/alcohol, increase fiber/fluid) Fruit lax gum chewing physical activity digital disimpaction
When is Fruit lax contraindicated
diabetes (high in sugar)
renal failure
hyperkalemia
Types of laxatives
stool softeners (docusate) lubricants (glycerin, mineral oil) bulk-forming (psyllium, methylcellulose) stimulant laxatives (sennosides, bisacodyl) osmotic laxative (lactulose, PEG)
Stool softeners
increases water content of stool –> softening of stool allows for easier passage
reduced straining
Lubricant
coat stool & colon allowing for easier passage
Bulk-forming
increase bulk & soften stool by adding water
stimulates stretch receptors increasing GI motility
Stimulant laxatives
irritate intestinal mucosa & stimulate enteric nerves –> increasing motility
Osmotic laxatives
osmotic fx –> rapidly draws water into bowel lumen to soften stools & increase motility
Adverse fx of laxatives
flatus,
bloating
diarrhea
abdominal cramping
nausea
F/E loss –> dizziness, headache, weakness
sympathetic fx –> sweating, palpitations
Cathartic dependence
reliance on laxatives for bowel movements
GI laxative contraindications
intestinal obstruction
ulcerative colitis
appendicitis
Cardiac laxative CI
heart block
electrolyte imbalances can affect electrical conduction
GU laxative CI
chronic kidney disease
exacerbate F/E imbalances
Pregnancy laxative CI
can induce labour
can cross placenta
can enter breast milk
Laxatives & med admin
space out by 30 min as can affect absorption
When is post-op ileus dx?
3-5 days of symptoms + mechanical obstruction ruled out via imaging
nausea/vomiting abdominal distension/bloating food intolerance absent bowel sounds no flatus
Bowel sounds & flatus
bowel sounds DO NOT mean pt is passing gas
gas/bowel movement = better indicators of bowel function
bowel sounds/flatus not + assoc w/ food tolerance
Normal-transit constipation
perceived difficulty in having a bowel movement
bowels are working properly. constipation result of external factors (fiber, fluid)
Slow-transit constiptaion
infrequent bowel movements. alterations in intestinal innervation = slowed peristalsis causing constipation
Defecation disorders
usually d/t dysfunction of pelvic floor & sphincters impairing defecation
Drugs causing constipation
opioids anticholinergics calcium-channel blockers diuretics calcium (antacids/supplements) iron supplements aluminum antacids
Simple mechanical obstruction
0 altered blood flow
Strangulated mechanical obstruction
compressed blood vessels –> ischemia progressing to infarction of the affected GI tract
weakens GI tract increasing risk of perforation –> sepsis
Factors causing GI inflammation
chemcial irritation
bacterial toxins
electrolyte imbalances (hypokalemia)
vascular insufficiency
