What is Intradialytic hypertension?

Peng

High blood pressure after dialysis or towards the end of dialysis is a nuisance problem that just seems to keep coming up in every dialysis unit. Frequently patients are kept for observation or admitted which increases the cost of giving care. It can also be quite frustrating to treat. This phenomenon is known as intradialytic hypertension and may require more than loading more and more medication onto the patients chart.



Intradialytic hypertension can be defined as an average pre to post hemodialysis Systolic Blood Pressure elevation of >10 mmhg for more than 4/6 of the last dialysis treatment sessions according to investigators currently delving into the possible causative mechanism of this difficult area of patient care. Many patients with this problem are overhydrated and are usually above their dry weight, in my experience these are the easiest to be managed. The problem patients are those who appear to be at their dry weight and are resistant to further ultrafiltration despite still fulfilling the criteria for the diagnosis as outline above.

The cause of intradialytic hypertension in such patients may be due to excessive sympathetic nerve discharge, the body believes that there is a relative lack of fluid within the vascular compartment hence increased sympathetic discharge. This presumably results in increased stiffness of blood vessels. The result of which is decreased compliance and higher blood pressure. This theory s currently the subject of an ongoing study. Other possible causes of this condition include high blood calcium or high calcium in the dialysate being used, decreased blood potassium, subclinical fluid overload, increased dietary salt intake, inadequate salt removal on dialysis, recurrent administration of saline during dialysis.

Intradialytic hypertension is important because it is.

1. Common affecting up to 15% of hemodialysis patients.
2. Is associated with higher rates of hospitalization.
3. Is associated with decreased survival on dialysis.
4. Is commonly ignored.

Prevention & treatment.

Careful attention to dry weight

Avoidance of dialyzable antihypertensive medications

Limiting the use of high-calcium dialysate

Achieving adequate sodium solute removal during hemodialysis

Inhibit the renin-angiotensin-aldosterone system

Use medication that decrease arterial stiffness

Careful attention to dry weight is all well and good but sometimes it can be difficult to know if the patient is truly at the dry weight. This study suggests that use of a body composition monitor to determine percentage fat muscle and water may be able to assist in titrating a patient to the correct dry weight. Such a tool may be very useful in the treatment of patients with intradialytic hypertension.