a. Intestinal obstruction is defined as any hindrance to the passage of intestinal contents through the small and/or large bowel.
Obstruction may be partial or complete. Severity depends upon the area of bowel affected, the degree of blockage, and the degree of vascular impairment.
b. Intestinal obstruction is divided into two basic categories: mechanical and non-mechanical.
(1) Mechanical obstruction results from obstruction within the lumen of the intestine or mural obstruction from pressure on the walls of the intestines. Causes include:
(a) Foreign bodies such as fruit pits, parasitic worms, or gallstones.
(b) Volvulus.
(c) Intussusception.
(d) Hernia.
(e) Cancer.
(f) Adhesions.
(g) Strictures.
(2) Non-mechanical obstruction is the result of physiological disturbances. Causes include:
(a) Electrolyte imbalances.
(b) Neurogenic disorders (such as spinal cord lesions).
(c) Paralytic (adynamic) ileus, developing as a result of abdominal surgery, trauma, or infection.
c. Signs and symptoms of small bowel obstruction.
(1) Small bowel obstruction is characterized by colicky pain, constipation, nausea, and vomiting.
(2) If the small bowel obstruction is complete, the peristaltic waves become quite vigorous, assuming reverse direction and propelling intestinal contents toward the mouth rather than the rectum. The patient vomits stomach contents first, then the bilious contents of the duodenum, and finally the fecal contents of the ileum.
(3) In later stages, dehydration and plasma loss result in hypovolemic shock. (As much as 10 liters of fluid can collect in the small bowel, causing a drastic reduction in plasma volume.)
d. Signs and symptoms of large bowel obstruction.
(1) Symptoms of large bowel obstruction differ from those of small bowel obstruction because the colon is able to absorb its fluid contents and distend well beyond normal size.
(2) Constipation may be the only symptom for several days.
(3) Eventually, the distended colon loops will be visible on the abdomen.
(4) Nausea and cramps, abdominal pain will occur.
(5) Vomiting is absent at first, but when obstruction becomes complete, fecal vomiting will occur.
(6) If the obstruction is only a partial one, any of the above symptoms may occur in a less severe form. Additionally, liquid stool may leak around the obstruction.
e. Nursing implication for intestinal obstruction.
(1) Abdominal girths should be measured daily. For accuracy of comparison, follow these suggested guidelines:
(a) Use the same measuring tape each time.
(b) Place the patient in the same position each time.
(c) Ensure that the tape measure is placed in the same position each time. This can be done by drawing small tic marks on the patient’s abdomen to indicate position for the tape.
(d) Measure the patient at the same time each day.
(2) Note the color and character of all vomitus. Test for the presence of occult blood.
(3) Any stool passed should be tested for the presence of occult blood.
(4) Monitor vital signs closely. Elevations of temperature and pulse may indicate infection or necrosis.
(5) Monitor I&O closely. Fluid and electrolyte losses must be replaced.