Hypotension Complicating Hemodialysis

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Marked decrease (> 30 mm Hg systolic) in blood pressure or a systolic blood pressure of < 90 mm Hg during dialysis

• Symptoms of decreased cerebral perfusion

GENERAL CONSIDERATIONS

• More common in those with diabetes, atherosclerosis, and hypertension

• Usually occurs in the setting of aggressive ultrafiltration to reduce intradialytic weight gain

• Hypotension limits the achievement of diuresis during dialysis

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Symptoms of decreased cerebral perfusion:

  • – Somnolence

  • – Dizziness

  • – Syncope

PHYSICAL EXAM FINDINGS

• Systolic blood pressure drop of > 30 mm Hg or systolic blood pressure < 90 mm Hg

• Cool clammy skin

DIFFERENTIAL DIAGNOSIS

• Pericardial effusion due to uremia or other causes

• Left ventricular diastolic dysfunction due to hypertrophy

• Autonomic dysfunction, often due to diabetes

• Myocardial ischemia or infarction (may be produced by hypotension also)

• Overzealous use of antihypertensive agents

• Cardiac arrhythmias

• Severe left ventricular systolic dysfunction

• Low dry weight of patient

• Decreased plasma osmolarity

• Splanchnic vasodilation due to a large meal

• Characteristics of the dialysate (eg, acetate)

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• CBC: anemia frequently a contributing factor

ELECTROCARDIOGRAPHY

• Left chamber enlargement signs

• Cardiac arrhythmias

IMAGING STUDIES

• Echocardiography:

  • – Usually shows left ventricular hypertrophy and left atrial enlargement

  • – Reduced systolic left ventricular function may be present

TREATMENT

CARDIOLOGY REFERRAL

• When simple measures do not correct the problem

• Suspected cardiac disease

HOSPITALIZATION CRITERIA

• Inability to safely dialyze

MEDICATIONS

• Identify and treat myocardial ischemia

• Carefully adjust antihypertensive medications

• Prevent cardiac arrhythmias

• Treat heart failure

• Administer vasoconstrictors in refractory cases

THERAPEUTIC PROCEDURES

• Myocardial revascularization when appropriate

• Identify and remove pericardial fluid if present

MONITORING

• Blood pressure during dialysis

• ECG as appropriate

DIET AND ACTIVITY

• Renal disease diet

• Low-fat diet

• Activity as tolerated

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

• Resolution of problem

FOLLOW-UP

• According to dialysis routine

• As appropriate for underlying diseases

COMPLICATIONS

• Myocardial infarction

• Stroke

• Cardiac arrhythmias

• Death

PROGNOSIS

• In general, hypotension during dialysis is a poor prognostic sign

PREVENTION

• Decrease fluid removal in patients with low dry weight

• Adjust sodium in dialysate to > 135 mmol/L to prevent hypo-osmolarity

• Use cooled bicarbonate dialysate

• Frequent shorter dialysis sessions with less aggressive ultrafiltration

• Nocturnal dialysis

RESOURCES