Intradialytic Hypotension Diagnosis and Management

Definition and Pathophysiology

The American Journal of Kidney Diseases defines intradialytic hypotension (IDH) as a decrease in systolic blood pressure by 20 mm Hg or a decrease in mean arterial pressure by 10 mm Hg associated with symptoms including dizziness, fainting, nausea, muscle cramps, and restlessness in patients undergoing hemodialysis 1
The primary mechanism of IDH is hypovolemia due to an imbalance between the amount of fluid removed and the refilling capacity of the intravascular compartment, which occurs when compensatory mechanisms are overwhelmed by excessive ultrafiltration 1

Patients aged 65 years or older are at increased risk of developing IDH after excessive ultrafiltration 2
Patients with diabetic chronic kidney disease and autonomic neuropathy are at higher risk of IDH 2
Patients with pre-dialysis systolic blood pressure less than 100 mm Hg are at increased risk of IDH 2
Patients with cardiovascular disease or cardiomyopathy are at higher risk of IDH 2
Patients with poor nutritional status and hypoalbuminemia are at increased risk of IDH 2

IDH presents with symptoms including abdominal discomfort, yawning and sighing, nausea and vomiting, muscle cramps, restlessness and anxiety, and syncope or near-syncope 1
The American College of Cardiology recommends considering IDH in the differential diagnosis of patients experiencing dizziness or syncope after hemodialysis 1

Intradialytic hypotension from excessive ultrafiltration predisposes patients to serious cardiovascular events, including cardiac and cerebral ischemic events, cardiac arrhythmias, vascular access thrombosis, and mesenteric venous infarction 1 2

Recurrent IDH episodes can lead to left ventricular hypertrophy with associated increased morbidity and mortality 2
IDH can also lead to interdialytic hypertension as a compensatory response 1
Inadequate dialysis dose due to compartment effect and premature session termination can occur in patients with recurrent IDH 1