Enema - Medical Usage

Medical Usage

The main medical usages of enemas are:

• As a bowel stimulant, not unlike a laxative – the main difference being that laxatives are commonly thought of as orally administered while enemas are administered directly into the rectum, and thereafter, into the colon. When the enema injection into the rectum is complete, and after a set "holding time", the patient expels feces along with the enema in the bedpan or toilet.
• Enemas may also be used to relieve constipation and fecal impaction, although in the U.S.A. and some other parts of the world, their use has been replaced in most professional health-care settings by oral laxatives and laxative suppositories. In-home use of enemas for constipation and alternative health purposes is somewhat harder to measure.
• Bowel stimulating enemas usually consist of water, which works primarily as a mechanical stimulant, or they may be made up of water with baking soda (sodium bicarbonate) or water with a mild hand soap dissolved in it. Buffered sodium phosphate solution draws additional water from the bloodstream into the colon to increase the effectiveness of the enema, but can be rather irritating to the colon, causing intense cramping or "griping." Mineral oil functions as a lubricant and stool softener, but often has the side effect of sporadic seepage from the patient's anus which can soil undergarments for up to 24 hours. Glycerol is a specific bowel mucosa irritant and when introduced in very dilute solution serves to induce peristalsis.
• Other types of enema solutions are also used, including equal parts of milk and molasses heated together to slightly above normal body temperature. In the past, castile soap was a common additive in an enema, but it has largely fallen out of use because of its irritating action in the rectum and because of the risk of chemical colitis as well as the ready availability of other enema preparations that are perhaps more effective than soap in stimulating a bowel movement. At the opposite end of the spectrum, an isotonic saline solution is least irritating to the rectum and colon, having a neutral concentration gradient. This neither draws electrolytes from the body – as can happen with plain water – nor draws water into the colon, as will occur with phosphates. Thus, a salt water solution can be used when a longer period of retention is desired, such as to soften an impaction.
• Cleansing the lower bowel prior to a surgical procedure such as sigmoidoscopy or colonoscopy. Because of speed and supposed convenience, enemas used for this purpose are commonly the more costly, sodium phosphate variety – often called a disposable enema. A more pleasant experience preparing for testing procedures can usually be obtained with gently-administered baking soda enemas; cleansing the lower bowel for colonoscopy and other bowel studies can be effectively achieved with water-based, or water with baking soda, enema administration.
• The administration of substances into the bloodstream. This may be done in situations where it is undesirable or impossible to deliver a medication by mouth, such as antiemetics given to reduce nausea (though not many antiemetics are delivered by enema). Additionally, several anti-angiogenic agents, which work better without digestion, can be safely administered via a gentle enema. Medicines for cancer, for arthritis, and for age-related macular degeneration are often given via enema in order to avoid the normally-functioning digestive tract. Interestingly, some water-based enemas are also used as a relieving agent for irritable bowel syndrome, using cayenne pepper to squelch irritation in the colon and rectal area. Finally, an enema may also be used for hydration purposes. See also route of administration.
• Emergency blood expansion. Emergency pre-hospital treatment of haemorrhage requires immediate fluid replacement therapy. In mass casualty, remote or rural settings, the lack of sterile fluids, intravenous equipment or the knowledge to use them might limit the treatment options available. In such situations proctoclysis remains an easy and effective way to provide fluid replacement. It does not require sterile fluids, special equipment or complex training, and it is useful when alternative routes are not readily available.
• The topical administration of medications into the rectum, such as corticosteroids and mesalazine used in the treatment of inflammatory bowel disease. Administration by enema avoids having the medication pass through the entire gastrointestinal tract, therefore simplifying the delivery of the medication to the affected area and limiting the amount that is absorbed into the bloodstream.
• General anesthetic agents for surgical purposes are sometimes administered by way of an enema. Occasionally, anesthetic agents are used rectally to reduce medically-induced vomiting during and after surgical procedures, in an attempt to avoid aspiration of stomach contents.
• A barium enema is used as a contrast substance in the radiological imaging of the bowel. The enema may contain barium sulfate powder, or a water-soluble contrast agent. Barium enemas are sometimes the only practical way to "view" the colon in a relatively safe manner. Following barium enema administration, patients often find that flushing the remaining barium with additional water, baking soda, or saline enemas helps restore normal colon activity without complications of constipation from the administration of the barium sulfate.
• Rectal corticosteroid enemas are sometimes used to treat mild or moderate ulcerative colitis. They also may be used along with systemic (oral or injection) corticosteroids or other medicines to treat severe disease or mild to moderate disease that has spread too far to be treated effectively by medicine inserted into the rectum alone.

In certain countries, such as the United States, customary enema usage went well into the 20th century; it was thought a good idea to cleanse the bowel in case of fever; also, pregnant women were given enemas prior to labor, supposedly to reduce the risk of feces being passed during contractions. Under some controversial discussion, pre-delivery enemas were also given to women to speed delivery by inducing contractions. This latter usage has since been largely abandoned, because obstetricians now commonly give pitocin to induce labor and because women generally found the procedure unpleasant.

Now obsolete, the tobacco smoke enema was the principal medical method for resuscitating victims of drowning during the 18th century.