Why should diuretics (e.g. furosemide, spironolactone) be held before paracentesis?

Why Diuretics Should Be Held Before Paracentesis

Diuretics do not need to be routinely held before paracentesis, but should be restarted immediately after the procedure to prevent rapid ascites reaccumulation. The evidence shows that diuretics can be safely reintroduced within 1-2 days post-paracentesis without increasing the risk of post-paracentesis circulatory dysfunction 1.

The Core Rationale

The question reflects a common clinical misconception. The actual concern is not about holding diuretics before paracentesis, but rather understanding their role after the procedure:

Post-Paracentesis Management

• Diuretics should be restarted promptly after paracentesis (typically within 1-2 days) to prevent ascites reaccumulation, which occurs in 93% of patients not receiving diuretic therapy versus only 18% in those treated with spironolactone 1.

• Early reinstitution of diuretics does not increase post-paracentesis circulatory dysfunction risk 1. A randomized trial demonstrated that patients receiving spironolactone 225 mg/day immediately after paracentesis had significantly lower ascites recurrence (18%) compared to placebo (93%), with no increase in circulatory complications 2.

When Diuretics Should Actually Be Held

The guidelines specify clear situations where diuretics must be discontinued, but these are based on clinical status, not the paracentesis procedure itself:

Mandatory discontinuation criteria 1:

• Severe hyponatremia (serum sodium <120-125 mmol/L)
• Progressive renal failure or acute kidney injury
• Worsening hepatic encephalopathy
• Severe hypokalemia (<3 mmol/L for furosemide)
• Severe hyperkalemia (>6 mmol/L for aldosterone antagonists)
• Incapacitating muscle cramps

Post-Paracentesis Circulatory Dysfunction

The primary concern with large-volume paracentesis is post-paracentesis circulatory dysfunction (PPCD), not diuretic use 1:

• PPCD occurs due to reduction of effective blood volume after ascites removal 1.
• This leads to activation of vasoconstrictor systems, rapid ascites reaccumulation, potential hepatorenal syndrome (20% of cases), and shortened survival 1.
• Albumin infusion (8 g/L of ascites removed for >5L) is the most effective prevention, superior to other plasma expanders 1.

Volume Considerations

The risk of hemodynamic complications relates to volume removed, not diuretic therapy 3:

• Severe clinical hypotension occurs in 31% of patients within 72 hours of large-volume paracentesis 3.
• Risk factors include: withdrawn ascitic fluid >7.5 liters and absence of peripheral edema 3.
• Volume expanders should be introduced before the 4th hour from paracentesis start 3.

Practical Clinical Algorithm

For patients undergoing large-volume paracentesis:

1. Continue baseline diuretics unless contraindications exist (severe hyponatremia, renal impairment, encephalopathy) 1.

2. Perform paracentesis with albumin replacement (8 g/L for volumes >5L) 1.

3. Restart or continue diuretics within 1-2 days post-procedure 1, 2:

   • Non-azotemic patients: spironolactone 225 mg/day is effective empirically 2
   • Adjust based on pre-paracentesis renin/aldosterone levels if available 2

4. Monitor for PPCD indicators (increased renin >50% over baseline to >4 ng/ml/h at day 3) 2.

Common Pitfalls to Avoid

• Do not withhold diuretics unnecessarily before paracentesis - this is not supported by guidelines and leads to faster ascites reaccumulation 1, 2.

• Do not confuse the timing of albumin administration with diuretic management - albumin prevents PPCD, while diuretics prevent reaccumulation 1.

• Do not delay diuretic reinstitution after paracentesis - ascites recurs within the first 2 weeks in >50% of patients without diuretics 2.

• Excessive diuresis is the actual concern, not the paracentesis procedure itself - this causes dehydration, circulatory collapse, and electrolyte depletion 4.

1, 2