Types of enemas
Administering an enema involves instilling a solution into the rectum and the sigmoid colon to stimulate peristalsis and promote defecation. The most common reason for administering an enema is to relieve constipation. An enema can also be administered to expel flatus, to empty the bowels before a diagnostic procedure or surgery, to instill a medication, or to initiate a bowel training program.
Before administering an enema, position the patient on his left side in Sims’ position with the right knee flexed. This position allows the solution to flow downward by gravity along the curve of the sigmoid colon and rectum, thus improving the effectiveness of the enema.
If you feel resistance or the patient reports pain when you are inserting the tube or the tip of the container, stop and try asking the patient to take a deep breath and then instilling a small amount of fluid. This will often relax the sphincter or soften the stool enough so that the tube or tip can be inserted and the enema can be administered.
Four types of enemas are commonly administered: cleansing, return-flow, medicated, and oil-retention. The type of enema prescribed depends on the indication.
|Fluid amounts for large-volume enemas|
||50 to 150 mL|
||250 to 350 mL|
||300 to 500 mL|
||500 to 750 mL|
||750 to 1,000 mL|
A cleansing enema can be either large- or small-volume. It acts by stimulating peristalsis by instilling a solution or irritating the mucosa of the colon. Solutions used for cleansing enemas are tap water, normal saline, and a soapsuds solution. The amount of solution instilled varies with the patient’s age.
Because infants and children are at risk for fluid and electrolyte imbalances, they should only receive normal saline enemas. Normal saline (0.9% sodium chloride) is an isotonic solution, so it does not pull electrolytes from the body. Using this solution reduces the risk of electrolyte imbalance.
When administering a cleansing enema, be cautious about instilling tap water. It is a hypotonic solution, thus it pulls electrolytes from the body into the fluid. This increases the risk of electrolyte imbalance.
Soapsuds enemas act by stimulating peristalsis through intestinal irritation. As long as pure castile soap is used, it is considered a safe procedure. Other harsher soap products are contraindicated, as they can cause bowel inflammation.
Some patients having a procedure or surgery involving the bowel have an order for an enema to be administered “until clear.” This directs you to repeat the enema until the patient passes fluid that is clear of fecal matter. To reduce the risk of fluid or electrolyte imbalances, do not administer more than three enemas.
Return-flow enemas are usually administered to expel flatus. They involve instilling a large volume of fluid in small increments, usually 100 to 200 mL at a time, into the rectum and the sigmoid colon to stimulate peristalsis. After instilling the solution, lower the container to allow the solution to flow back into the container. Repeat the process several times until the patient expels flatus and abdominal distention is relieved.
An oil-retention enema is administered to lubricate the rectum and the colon. The oil is absorbed by the feces, making them softer and easier to pass. For this type of enema to have optimal results, instruct patients to retain the enema for as long as possible, usually 30 to 60 minutes if possible. For adults, the usual amount of solution instilled is 150 to 200 mL; for children, it is 75 to 100 mL.
Medicated enemas may be given for the local effect they exert on the rectal mucosa. A common example is one containing the antibiotic neomycin, which is used to reduce bacteria in the colon before bowel surgery. Medicated enemas can also be given to produce a systemic effect. An example is one containing sodium polystyrene sulfonate (Kayexalate), which is administered to treat patients who have dangerously high serum potassium levels.
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