Low Blood Pressure From Hemodialysis: Signs and Prevention

A drop in blood pressure is a common complication during hemodialysis. In medical jargon, the phenomenon is called intradialytic hypotension. It happens when the body is unable to compensate properly for the loss of volume when fluid is removed from the blood during dialysis.

Your systolic blood pressure is an indicator of intradialytic hypotension. Systolic blood pressure is the top number of a blood pressure reading and refers to the amount of pressure in your arteries when your heart is beating. Normal blood pressure for most adults is greater than 90/60 mmHg and less than 120/80 mmHg.

Intradialytic hypotension is defined as a systolic reading below 90 mmHg. It can also occur when systolic blood pressure drops 20 mmHg or more during treatment.

Intradialytic hypotension can be a debilitating problem, as it often requires cutting dialysis treatments short, leading to inadequate dialysis therapy. It can also lead to organ damage, which is associated with a higher risk of death in patients receiving dialysis.

Read on to learn more about the signs and symptoms of intradialytic hypotension and the factors that put people at risk of developing this condition. You'll also learn how to treat and prevent intradialytic hypotension.

What Are the Signs and Symptoms of Intradialytic Hypotension?

Intradialytic hypotension manifests as a rapid, and obvious, drop in blood pressure, but there are other subjective symptoms. Patients will often complain of these symptoms.

• Muscle cramps
• Back, chest, or abdominal pain
• Headaches
• Nausea and vomiting
• Lightheadedness
• Yawning
• Sighing
• Fainting
• Anxiety

Risk Factors

Research and observations from medical professionals seem to indicate that some patients are more likely to experience drops in blood pressure related to dialysis treatment. In a study from 2017, researchers observed that patients with sepsis and obstructive kidney disease seemed more likely to develop hypotension.

Other possible risk factors for experiencing a drop in blood pressure while receiving dialysis include:

• Older patients
• Patients who have been on dialysis for a long time
• People with diabetes
• Female patients
• Obese patients
• Patients requiring an excessively high amount of fluid removal, or ultrafiltration, because of a high weight gain between dialysis sessions
• Patients with a dry weight that is too low
• Taking blood pressure medications just before dialysis
• Eating meals during dialysis

While the exact cause is unclear, everything from nerve disease caused by diabetes (autonomic neuropathy) to rapid fluid removal during dialysis has been proposed as an explanation for intradialytic hypotension.

There are also less common but more serious causes of hypotension associated with dialysis such as infections, abnormal heart rhythms, and even heart attacks.

How Is Intradialytic Hypotension Treated?

Intradialytic hypotension can be challenging to treat, especially in patients with multiple risk factors.

The dialysis staff will reduce or even stop fluid removal completely during this period. You might be reclined in a specific position (e.g., the Trendelenburg position which elevates the feet and legs above the heart) to increase the blood flow to the brain. However, medical professionals debate how useful the position is for treating intradialytic hypotension.

For most patients who experience a drop in blood pressure, small amounts of intravenous fluids are given (usually a common fluid, like normal saline given in a small bolus of 250 milliliters or so).

In some cases, a medication called midodrine is used as a last resort. Research has shown that while midodrine might offer short-term benefits for some patients, long-term use comes with risks and some patients don't see any benefit at all.

How Is Intradialytic Hypotension Prevented?

The underlying risk factors need to be identified and addressed in each patient who experiences a drop in blood pressure while receiving dialysis.

The recommendations will depend on an individual patient's needs and risk factors, but may include:

• Avoiding meals just before and during dialysis
• Avoiding taking blood pressure medications just before dialysis or consider switching times
• Avoiding weight gain between successive dialysis treatments, as the less fluid that needs to be removed, the easier it is for the circulatory system to maintain blood pressure
• Avoiding the use of sedatives before dialysis as this could lower blood pressure during dialysis
• Lowering the temperature of the dialysis solution to 0.5 degrees C below core body temperature

If you're complying with your prescribed fluid regimen and have no other risk factors, your healthcare provider might refer you to a cardiologist or have you get an echocardiogram, as the heart can be a cause of drops in blood pressure.

Your nephrologist might prescribe dialysis differently, such as with a higher amount of sodium. A higher amount of sodium in the dialysis solution increases weight gain and hypertension (high blood pressure) between dialysis sessions, but reduces intradialytic hypotension. Conversely, a lower amount of sodium decreases weight gain between sessions but increases intradialytic hypotension.

If nothing else works and the problem is recurrent, your healthcare provider might suggest peritoneal dialysis or home hemodialysis.

Summary

Intradialytic hypotension is the most common complication of dialysis treatment. Dialysis patients can develop this form of low blood pressure when the body does not respond adequately to the fluid loss that occurs during dialysis. Symptoms can include nausea, lightheadedness, headaches, and abdominal pain.

Treatment for intradialytic hypotension can include body positioning, fluid replacement therapy, and, possibly, medication. If you're experiencing intradialytic hypotension talk to your healthcare provider about ways you can prevent it, including avoiding meals before and during dialysis and avoiding the use of some medications.