Hypotension During Dialysis: Understanding the Main Causes

Hypotension, or low blood pressure, is a common complication experienced by patients undergoing dialysis. It can occur due to a variety of physiological and procedural factors. Understanding the underlying causes is essential for both medical professionals and patients to ensure safer and more effective dialysis sessions.

1. Inexperienced Patients and Vulnerable Individuals

Patients undergoing dialysis for the first time, especially elderly or physically weak individuals, may experience a sudden drop in blood pressure. This is often due to the rapid introduction of blood into the extracorporeal circuit, which can temporarily reduce circulating blood volume in the body.

2. Excessive or Rapid Ultrafiltration

During dialysis, excess fluid is removed from the blood through a process called ultrafiltration. If this process occurs too quickly or removes too much fluid, it can lead to a significant and sudden decrease in blood volume, resulting in hypotension.

3. Cardiac Arrhythmias During Treatment

Some patients may develop serious heart rhythm disturbances during dialysis. These arrhythmias can impair the heart's ability to pump blood effectively to the rest of the body, which in turn can cause a drop in blood pressure.

4. Anticoagulant Use and Its Side Effects

To prevent blood clotting during the procedure, anticoagulants such as heparin are commonly used. However, heparinization can sometimes lead to complications like acute pericardial effusion or tamponade, which can compress the heart and reduce its efficiency, ultimately causing hypotension.

5. Underlying Cardiovascular Emergencies

In rare cases, patients may experience acute cardiovascular events such as heart failure or myocardial infarction during dialysis. These conditions can severely impact cardiac output and lead to a sudden drop in blood pressure.

6. Use of Antihypertensive Medications

Blood pressure medications, especially those taken before dialysis, can contribute to hypotension during the session. Patients who are on antihypertensive therapy may be more prone to experiencing low blood pressure when fluid is removed from their system.

7. Internal or External Bleeding Events

Bleeding complications, whether internal or external, can also lead to a decrease in blood volume. This type of blood loss can significantly impact circulatory stability and cause hypotension during or after dialysis treatment.