Excessive GI Fluid Loss

A Look at Excessive GI Fluid Loss

Normally, very little fluid is lost from the GI system. Most fluid is reabsorbed in the intestines. However, the potential for significant loss exists because large amounts of fluids—isotonic and hypotonic—pass through the GI system in the course of a day.

Isotonic fluids that may be lost from the GI tract include gastric juices, bile, pancreatic juices, and intestinal secretions. The only hypotonic fluid that may be lost is saliva, which has a lower solute concentration than other GI fluids.

How it happens

Excessive GI fluid loss may come from physical removal of secretions as a result of vomiting, suctioning, or increased or decreased GI tract motility. Excessive fluids can be excreted as waste products or secreted from the intestinal wall into the intestinal lumen, both of which lead to fluid and electrolyte imbalances. (See Imbalances caused by excessive GI fluid loss.)

Osmotic diarrhea may occur in the intestines when a high solute load in the intestinal lumen attracts water into the cavity. Both acids and bases can be lost from the GI tract.

Vomiting and suctioning

Vomiting or mechanical suctioning of stomach contents, as with a nasogastric tube, causes the loss of hydrogen ions and electrolytes, such as chloride, potassium, and sodium. Vomiting also depletes the body's fluid volume supply and causes hypovolemia. Dehydration occurs when more water than electrolytes is lost. When assessing acid-base balance, remember that the pH of the upper GI tract is low and that vomiting causes the loss of those acids and raises the risk of alkalosis. (See Characteristics and causes of vomiting.)

Bowel movements

An increase in the frequency and amount of bowel movements and a change in the stool toward a watery consistency can cause excessive fluid loss, resulting in hypovolemia and dehydration. In addition to fluid loss, diarrhea can cause a loss of potassium, magnesium, and sodium. Fluids lost from the lower GI tract carry a large amount of bicarbonate with them, which lowers the amount of bicarbonate available to counter the effects of acids in the body.

Laxatives and enemas

Laxatives and enemas may be used by patients to treat constipation, or they may be given to patients before abdominal surgery or diagnostic studies to clean the bowel. Excessive use of laxatives—such as magnesium sulfate, milk of magnesia, and Fleet Phospho-soda—can cause high magnesium (hypermagnesemia) and phosphorus (hyperphosphatemia) levels.

Excessive use of commercially prepared enemas containing sodium and phosphate, such as Fleet enemas, can cause high phosphorus and sodium (hypernatremia) levels if the enemas are absorbed before they can be eliminated. Excessive use of tap water enemas can cause a decrease in sodium levels because water absorbed by the colon can have a dilutional effect on sodium.

Factor in fluid loss

Excessive GI fluid loss can result from several other factors, too. Bacterial infections of the GI tract typically cause vomiting and diarrhea. Antibiotic administration removes the normal flora and promotes diarrhea. Age can also play a role; infants and young children are especially vulnerable to diarrhea. Pregnancy, pancreatitis, hepatitis, and, in young children, pyloric stenosis can all be accompanied by vomiting. Inflammatory bowel diseases such as ulcerative colitis and Crohn disease can be accompanied by diarrhea and thus cause fluid loss.

An abundance of imbalances

Imbalances can also result from fecal impaction, poor absorption of foods, poor digestion, anorexia nervosa, or bulimia as well as excessive intake of alcoholic substances and some illicit drugs. Such disorders as anorexia nervosa and bulimia typically involve the use of laxatives and vomiting as a means of controlling weight. This can lead to numerous fluid, electrolyte, and acid-base imbalances. (See Adolescents and excessive GI fluid loss.) Other disorders that can cause disturbances in fluid, electrolyte, or acid-base balance include the presence of fistulas involving the GI tract, GI bleeding, intestinal obstruction, and paralytic ileus.

Memory Jogger

Remember, laxatives and enemas can make a patient HYPER:

Excessive laxative use can cause hypermagnesemia and hyperphosphatemia.

Excessive use of enemas that contain sodium and phosphate can cause hypernatremia and hyperphosphatemia.

The use of enteral tube feedings and ostomies (especially ileostomies) may also lead to imbalances. Enteral tube feedings may cause diarrhea or vomiting, depending on their composition, concentration, and the patient's condition. Suctioning of gastric secretions through tubes may deplete the body of vital fluids, electrolytes, and acids. Dysphagia related to extensive head and neck cancer and other conditions that interfere with swallowing may result in saliva loss.

What to look for

With excessive GI fluid loss, the patient may show signs of hypovolemia. Look for these signs and symptoms:

Tachycardia occurs as the body tries to compensate for hypovolemia by increasing the heart rate. Blood pressure also falls as intravascular volume is lost.
The patient's skin may be cool and dry as the body shunts blood flow to major organs. Skin turgor may be decreased or the eyeballs may appear to be sunken, as occurs with dehydration. Urine output decreases as kidneys try to conserve fluid and electrolytes.
Cardiac arrhythmias may occur from electrolyte imbalances, such as those related to potassium and magnesium. The patient may become weak and confused. Mental status may deteriorate as fluid, electrolyte, and acid-base imbalances progress.

Taking a deep breath

Respirations may change according to the type of acid-base imbalance the patient develops. For instance, acidosis will cause respirations to be deeper as the patient tries to blow off acid.
The patient will also have signs and symptoms related to the underlying disorder—for instance, pancreatitis. (See Recognizing excessive GI fluid loss.)

What tests show

Diagnostic tests, such as endoscopy, ultrasound, computerized tomography, or magnetic resonance imaging, may reveal the cause and extent of the disorder. In addition, diagnostic test results related to the fluid, electrolyte, and acid-base imbalances associated with excessive GI fluid loss can help direct your nursing interventions. Such results include:

changes in arterial blood gas levels related to metabolic acidosis or metabolic alkalosis
alterations in the levels of certain electrolytes, such as potassium, magnesium, and/or sodium
hematocrit that may be falsely elevated in a volume-depleted patient
cultures of body fluid samples that may help to identify bacteria responsible for the underlying disorder.

How they're treated

Treatment is aimed at the underlying cause of the imbalance to prevent further fluid and electrolyte loss. For instance, an antiemetic and an antidiarrheal may be given for vomiting and diarrhea, respectively. In another instance, GI drainage tubes and the suction applied to them should be discontinued as soon as possible. For fluid loss caused by diet, changes in intake can often treat the underlying cause and decrease the fluid loss.

The patient should also receive IV or oral fluid replacement, depending on the patient's tolerance and the cause of the fluid loss. The patient may also need electrolytes replaced if the patient's serum levels are decreased. Long-term parenteral nutrition may be needed. If infection is the underlying cause of fluid loss, the patient may need antibiotics.

How you intervene

A patient with a condition that alters fluid and electrolyte balance through GI losses requires close monitoring. You'll need to report any increase in the amount of drainage or change in drainage characteristics from GI tubes or increase in the frequency of vomiting or diarrhea. Follow these interventions when caring for a patient with GI fluid losses:

Measure and record the amount of fluid lost through vomiting, diarrhea, or gastric or intestinal suctioning. Remember to include GI losses as part of the patient's total output. Significant increases in GI loss places the patient at increased risk for fluid and electrolyte imbalances and metabolic alkalosis or acidosis.
Assess the patient's fluid status by monitoring intake and output, daily weight, and skin turgor.
Assess vital signs and report any changes that may indicate fluid deficits, such as a decreased blood pressure or increased heart rate.
Report vomiting to keep imbalances from becoming severe and to initiate prompt treatment.
Administer oral fluids containing water and electrolytes, such as Gatorade or Pedialyte, if the patient can tolerate fluids. Remind the patient to take small sips. (See Teaching about excessive GI fluid loss.)
Perform oral care and provide lip balm because the mucous membranes and lips may be dry and cracked.
Maintain patent IV access as ordered. Administer IV replacement fluids as prescribed. Monitor the infusion rate and volume to prevent hypervolemia. (See Don't go too fast with fluids.)
If the patient is undergoing gastric suctioning, monitor GI tube placement often to prevent fluid aspiration or tube migration.
Irrigate the suction tube with isotonic normal saline solution as ordered. Remember, never use plain water for irrigation. It draws more gastric secretions into the stomach in an attempt to make the fluid isotonic for absorption. Also, the fluid is suctioned out of the stomach, causing further depletion of fluids and electrolytes.
When the patient is connected to gastric suction, restrict the amount of ice chips given by mouth and explain the reason for the restriction. Gastric suctioning of ice chips can deplete fluid and electrolytes from the stomach.
Administer medications, such as an antiemetic or antidiarrheal, as prescribed to control the patient's underlying condition.
Evaluate serum electrolyte levels and pH to detect abnormalities and to monitor the effectiveness of therapy.
Chart all instructions given and care provided. (See Documenting excessive GI fluid loss.)

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