Keeping Kidneys Healthy

Protective measures for individuals with ileostomies 

By Amalia Karlin, MS, RDN

It is well understood that individuals with ileostomies are at an increased risk for dehydration. Dehydration is the most common reason for hospital readmission among individuals with new ileostomies, especially during the early postoperative period when the risk for fluid and electrolyte imbalances are high. Less spoken about is the increased risk for readmission due to acute kidney injury, often secondary to both dehydration and difficulties reducing high ostomy output. Preserving kidney function and lowering the risk for subsequent kidney injury requires comprehensive patient education that begins prior to surgery.

Importance of Adequate Hydration

The kidneys are incredibly sensitive to hydration and electrolyte balance. Hydration and the metabolism of water begins with drinking. The water we drink passes through the esophagus and stomach to the small and large intestines, where it is absorbed and enters the bloodstream. In individuals with ileostomies, the small intestine adapts to absorb more water to make up for the loss in the body’s absorptive capacity that results from an absent colon. After water enters the bloodstream, it circulates to different organs where it performs various vital functions. Excess water is then excreted through sweat, stool, and urination. 

In an average person, about one liter of water leaves the body through just the skin, lungs, and stool. Individuals living with an ileostomy lose even more through their ostomy output. The rest of water excretion happens through the kidneys. This process is tightly regulated to control for the body’s volume and osmolarity of bodily fluids. Osmolarity refers to the concentration of solutes, like sodium, in a liter of bodily fluids. The kidneys are extremely sensitive to changes in osmolarity and will either excrete water or conserve water to ensure that the body’s solute to fluid balance remains in the most desirable range for optimal cell function. 

In the presence of dehydration, the kidneys do not have enough fluid to dilute the solutes that have arrived to the kidney for excretion. The build-up of solutes will have the opportunity to form into crystals and then into kidney stones. The cells of the kidneys themselves are incredibly sensitive to this solute imbalance. They will become damaged over time as a result of recurring episodes of acute dehydration and/or chronic dehydration. Individuals with ileostomies will often experience both types of dehydration, which is the reason for an increased risk of acute kidney injury and chronic kidney disease among this population. The progression of kidney injury to permanent kidney damage and ultimately kidney disease will depend on many different risk factors. Dehydration is one of many factors influencing kidney health.

Hydration Challenges with an Ileostomy

Meeting sufficient water and electrolyte needs with an ileostomy can be challenging for several reasons. Patients are generally told to just drink more water to meet hydration needs. However, drinking more water does not always translate to absorbing more water. In fact, drinking more water can increase fluid losses further, by driving more ostomy output. Patients become increasingly thirsty, drink more, and become more dehydrated. Some patients recognize this on their own and will pull back on oral fluids to reduce their ostomy output. While this technique works for managing output, it doesn’t provide the rest of the body with enough fluid to produce enough urine. This puts an added stress on the kidneys.

Another challenge in managing hydration is a reliance on hypertonic beverages to control for output consistency. Patients learn that drinks high in sugar, like juice, soda, and milk, keep their output consistency thin. The high concentration of sugar in these beverages pulls in additional water into the small intestine thinning out stool. Patients rely on these drinks to prevent a build-up of thickened stool from forming around their wafer, also known as pancaking. Individuals living with an ostomy generally want stool to fall easily to the bottom of their bag. Thinning out the stool makes it easier to empty the bag and it also helps prevent bag leaks. Patients also try to thin out their ostomy output to help move food through the intestines in efforts to prevent bowel obstructions. Unfortunately, these methods used to improve quality of life also put patients at a higher risk for dehydration and kidney injury.

Evaluating for Dehydration At Home

Few preventative measures are taken before and after ileostomy surgery to ensure patients themselves can assess if they are properly hydrated once they’ve been discharged. Patients are generally instructed to gauge hydration status by measuring their ostomy output. Patients with ileostomy output greater than 1200mls may be considered to have a “high output ileostomy”. While that increases their risk of dehydration, a patient with a high output ileostomy may not necessarily be dehydrated if they are properly replenishing fluids and electrolytes. Conversely, a patient whose ileostomy produces less than 1200ml’s of output a day and considered to have a normal amount of output, may not be adequately hydrated.

A more strategic way to assess hydration status is to measure urine output. Most patients should aim to produce at least 1200mls of urine a day, 1500ml’s if they are at high risk for producing kidney stones. A simple way to prevent readmissions due to dehydration in those early weeks post-op is by disconnecting patients from IV fluids at least two days before discharge and comparing their oral fluid intake to their urine output. Patients should be measuring their urine before leaving the hospital using the appropriate urine collection tools, like a stool hat for example. In addition, they should be given the right urine collection tools, just as they are sent home with containers to measure ostomy output.

Being able to assess hydration status through urine collection is still not enough to support adequate hydration. Patients need education about the types of fluids they should drink so that they can achieve a urine output of 1200mls. Ideally, ileostomy patients consume most of their fluid from isotonic fluids. Isotonic fluids are fluids whose concentrations are similar to that of the fluids in the body. Isotonic fluids are better absorbed by the body and more efficient at rehydrating. Oral rehydration solutions, like Liquid IV and Drip Drop, consist of a specific ratio of water, sodium, and sugar to achieve this desired isotonicity. They are great products to share with patients. Additionally, patients can be provided with an oral rehydration recipe to make at home. The one caveat here is that salt can be incredibly hard to measure accurately at home without a proper gram scale. 

In Conclusion

Maintaining adequate hydration in ileostomy patients is necessary to preventing hospital readmissions and preserving kidney function. Educating patients how to measure both ostomy output and urine output should begin perioperatively and reinforced postoperatively. Ongoing nutrition support during the months following ostomy surgery will give patients a head start in understanding their individual fluid and electrolyte needs and time to troubleshoot oral rehydration solutions. Preventing acute and chronic dehydration in efforts to support the body’s optimal function and preserve kidney function is in the best interest of individuals living with an ostomy. 

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