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Understanding Kidney Dialysis: How Much Fluid is Removed During Treatment?

Updated: May 21, 2023

Updated: May 21, 2023

Many people facing dialysis treatment often ask the same question: "How much fluid will be removed during dialysis?" While the answer is not straightforward, we will provide you with information to understand the fluid removal process during dialysis. But first, let's start by understanding what dialysis is and how it works.

Understanding Kidney Dialysis and Its Types

Dialysis is a process that removes waste products and excess fluid from the body when the kidneys are not functioning properly. The two most common types of dialysis are Hemodialysis and Peritoneal Dialysis.


Hemodialysis involves cleaning the patient's blood by removing it from the body, filtering it, or "dialyzing" it, and then returning it to the body. On average, a hemodialysis session lasts four hours, and patients typically undergo this treatment three times a week.

Peritoneal Dialysis

Peritoneal Dialysis involves filling the patient's peritoneal cavity with 2 liters (or 2000 ml) of dialysis fluid. This fluid stays in the patient's abdomen for about 3 hours before being removed and replaced approximately 3 to 4 times a day.

The Human Body and Fluids

Did you know that up to 60% of the human body is made up of water? Each organ in the body has its own water percentage. For example, the lungs are made up of 83% water, the heart contains 73% water, and bones carry 31% water. The kidneys, important for this discussion, contain 79% water.

Now, you might wonder, why do we need to remove so much water during dialysis. The answer lies in the fact that kidneys not working at 100% are not able to filter the water from the body and pass it as urine efficiently.

The Concept of "Dry Weight"

To determine how much fluid to remove during your dialysis treatment, your medical team will need to know your "Dry Weight". This term refers to your target weight, which is an estimate of your weight without any extra water. Dry weight measurements are done in kilograms (KG). For reference, one kilogram is equivalent to 2.2 pounds.

How Much Fluid is Removed During Dialysis?

To better understand how fluid removal works, let's consider the example of a hypothetical patient, Stephen.

Stephen is a 56-year-old male suffering from Polycystic Kidney Disease. He undergoes hemodialysis three times a week (Monday, Wednesday, and Friday). His dry weight is 160 lbs. or 72.57 kg. On a Monday pre-treatment, his weight is 165 lbs. or 75 kg, indicating the need for fluid removal.

In this scenario, Stephen's treatment would involve the removal of 2.43 kg or 5 lbs. of fluid. This is because his pre-treatment weight was over his dry weight, which is common for individuals with less than 10% of kidney function like Stephen. The dialysis machine will help remove this extra water.

Why Might You Be Over in Water Weight?

Being overweight at the start of treatment can be normal for someone just starting with dialysis. There are a few possible reasons for this:

  • Your dry weight estimate may be off.

  • Too many days have passed between treatments.

  • You may have consumed too much fluid, possibly due to a hot day, a big holiday, or simply unintentionally exceeding your maximum fluid intake.

  • You could have consumed extra water through your food. For example, vegetables are mostly made up of water, and foods high in salt can cause your body to retain more water.

The Risks of Removing Too Much Fluid Too Quickly

It's crucial to understand that removing a large amount of fluid above your dry weight too quickly can cause complications during the hemodialysis treatment, which typically lasts approximately 4 hours. Some kidney dialysis patients have shared their experiences of having a lot of fluid removed quickly during treatment, which included symptoms such as:

  • Low blood pressure, causes fainting or a feeling of faintness.

  • Cramps in the legs, feet, or hands.

  • Nausea.

  • Dizziness.

  • Difficulty breathing.

Not all people will experience these symptoms, but many have reported them. It's therefore important to try to stay close to your dry weight.

Conclusion: Personalized Fluid Removal

So, how much fluid will be removed during dialysis? The answer is dependent on you, the patient, and your dry weight. With the guidance of your medical team and knowledge about your fluid intake, you will learn how to maintain a weight close to your dry weight. Remember, the information provided here is just the beginning of the conversation. It's crucial to continue discussing your condition and treatment with your medical team. By understanding your body and actively participating in your health care, you can effectively manage your kidney disease.

Disclaimer: The information provided in this article is not medical advice. Always seek medical advice and diagnosis from your trained medical team or doctor. Kidney Conversations does not imply or give medical advice.

Did you find this article helpful? Please feel free to comment below, share with others who may benefit, or check out our other posts for more useful information. Your engagement helps us create content that is more valuable to you and others dealing with kidney disease.

Caption: A dialysis machine, a vital tool for those undergoing dialysis treatment.

Further Resources and Links For a more in-depth understanding of dialysis and kidney disease, we recommend these additional resources:

  1. Understanding Chronic Kidney Disease: A comprehensive guide to chronic Kidney disease, its stages, symptoms, and treatment.

  2. Tips for Managing Fluid Intake with Kidney Disease: Practical tips for managing fluid intake when dealing with kidney disease.

  3. Understanding Your Kidney Test Results: A helpful guide to Understanding and interpreting your kidney function test results.

Remember, staying informed and proactive is crucial in managing kidney disease effectively. We at Kidney Conversations are here to provide you with the resources you need to do just that.

If you have any more questions or need further clarification on this topic, please don't hesitate to leave a comment below. We're here to help! Also, if you found this article helpful, consider sharing it with others who might benefit from this information. Stay informed, and stay healthy!

Please note that the information provided in this article is for informational purposes only and is not intended as a substitute for advice from your physician or other healthcare professionals.


USGS.GOV Water in the body

KIDNEY.ORG Dry weight

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