What is dry weight?
Dry weight is your weight when your body doesn’t have any excess fluid. Dry weight determines how much fluid your dialysis treatment should remove. If your body has too much fluid, it can lead to health risks such as high blood pressure, swelling, and complicate your dialysis treatment.
Does your dry weight change?
Yes, your dry weight isn’t a constant. In fact, it may change as you begin dialysis treatment. For example, most patients feel better after starting dialysis treatment. If you feel well enough to resume light exercise, you may lose weight. If you then use the same dry weight, you could have too much fluid removed, leading to hypovolemia, or fluid loss.
So, it’s essential to speak with your care providers regularly to ensure your dialysis treatment changes as your health changes.
How is dry weight calculated?
Dry weight refers to your body’s weight without excess fluids. But how do you know if your body has excess fluids? Nephrologists and researchers have studied dry weight to determine the best way to determine patients’ dry weights.
A lack of swelling (edema) in your extremities may be a good indicator of your dry weight. Likewise, a lack of symptoms like dizziness after dialysis treatment indicates that you are at your dry weight. But, the absence of swelling doesn’t guarantee that you are at your dry weight.
Some research suggests that you're at your dry weight when your blood pressure is normal (neither high nor low) without taking medication. This is because if you have too much fluid in your body, it will increase your blood pressure. So, normal blood pressure may indicate dry weight.
Another measurement that has been shown to measure dry weight is the cardiothoracic ratio (CTR). This refers to the width of your heart in comparison to the width of your ribcage, and is measured with an X-ray. A CTR greater than .48 may indicate fluid overload or hypervolemia. A CTR between .42 and .48 may indicate regular fluid levels or dry weight. Together, a normal blood pressure and CTR between .42 and .48 may be the most accurate measure of dry weight.
Clearly, finding your dry weight is a complicated matter. Plus, as we mentioned earlier, your dry weight can change over time. It’s important to communicate with your care team if you notice any negative or uncommon symptoms during, following, or between your dialysis treatments.
What is fluid gain?
Dialysis treatments remove excess fluids to help you stay near your dry weight. However, you naturally gain some weight from fluid between your treatments. This is fluid gain. While some fluid gain is to be expected, too much can lead to additional health risks and complications. Some of the most common side effects of fluid gain include high blood pressure, swelling in your extremities, pulmonary edema, and difficulties with your dialysis treatment.
High blood pressure
The most common side effect of excess fluid gain (hypervolemia) is high blood pressure. Your kidneys are responsible for regulating fluid volumes in your body. But, if your kidneys aren’t functioning properly, they can’t do it as effectively.
The fluid your kidneys can't remove remains in your bloodstream. That increases the volume of fluid in your blood and raises your blood pressure.
Swelling in your arms, hands, legs, or feet
Your kidneys can't manage your sodium levels effectively when they don't function properly. This causes your body to retain more fluid, leading to both high blood pressure and swelling. Swelling, or edema, is most likely to occur in your arms, hands, legs, feet, or around your eyes.
When you have too much fluid in your body, it increases your blood pressure and can lead to congestive heart failure. When the heart can’t pump blood to meet your body’s needs, blood backs up in the blood vessels of your lungs like a bottleneck effect.
This pushes fluid into your lungs’ air sacs, creating what’s called pulmonary edema. This can make breathing extremely difficult and is a medical emergency. If you are struggling to breathe, seek medical care immediately.
Difficulties with dialysis treatments
It’s vital to control your fluid gain between dialysis treatments. While dialysis removes fluid from your body, each treatment can only remove so much. Removing too much fluid too rapidly can lead to drastic drops in blood pressure. These drops in blood pressure prevent your blood from carrying nutrients and oxygen to organs like your brain and heart.
Tips for maintaining your fluid intake between dialysis treatments
At this point, the importance of dry weight and its implications for your health are clear. But understanding dry weight and maintaining yours are two different stories. Many new dialysis patients find it challenging to limit their fluid intake. How can you limit your fluid intake while managing your thirst and comfort? Let’s take a look at some common strategies:
Follow a dialysis diet
Dialysis is an effective treatment, but it’s not a replacement for healthy kidneys. As you begin dialysis, you’ll need to ensure that the nutrients you consume aren’t adding toxins to your blood unnecessarily.
A hemodialysis diet typically includes an increase in protein, calcium, and fibers. At the same time, it will limit sodium, phosphorus, and potassium.
Drink kidney-healthy fluids
As a dialysis patient, you’ll need to limit your fluid intake. Additionally, the fluids you drink must be kidney-friendly. The best drinks for kidney health include water and sparkling water, black coffee, unsweetened herbal teas, and some vegetable juices.
Common drinks that will only damage your kidney health include sodas, sugary juices, and alcohol. Consult with your care team to determine what fluids you should avoid.
Finally, make sure you follow your care team’s directions when it comes to limiting your fluid intake. Most dialysis patients are limited to around 32 ounces of fluid a day.
Manage your thirst
Given the challenge of limiting your fluid intake to just a few glasses each day, many new dialysis patients struggle with thirst. Some good ways to satisfy the craving for water without consuming too much liquid include sucking on low-sugar candies or frozen grapes, limiting your salt intake, and using smaller drinkware.
Milwaukee Nephrologists is Southeastern Wisconsin’s Leader in Kidney Health
From dry weight to dietary concerns, Milwaukee Nephrologists are your go-to resource for kidney health. To learn more, check out some of our other educational articles, or get in touch with our staff of nephrologists, transplant specialists, and dietitians to schedule an appointment.