Ascites, paracentesis & PCD (post-paracentesis circulatory disfunction)

Pearls of the week:

Ascites basics: DDX

Paracentesis basics: SAAG & SBP criteria

PCD risk & prevention

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On Tuesday Drs. Khan & Liang presented a 55 yo woman with a history of NASH who was admitted with worsening ascites & underwent large volume paracentesis of 11 L in the ED with rapid re-accumulation of ascitic fluid.

R.C. Oey, H.R. van Buuren, R.A. de Man. Review: The diagnostic work-up in patients with ascites: current guidelines and future prospects. The Netherlands Journal of Medicine. October 2016.

When to perform a paracentesis:

1. New onset ascites
2. ANY admitted patient with ascites
3. Other: Concern for infection, confusion, painful abdomen, AKI

So you have fluid, now you need to answer two questions:

1. What is the SAAG? 

Serum albumin minus ascitic fluid albumin: Albuminserum - Albuminascites

• > 1.1 : likely 2/2 portal hypertension
• < 1.1 : consider other causes (pancreatic, infectious, malignant)

NEXT: The ascitic fluid protein concentration can help to differentiate further.

2. Does the fluid meet SBP criteria?

• Calculate the number of PMNs in the ascitic fluid (Neutrophil % x WBCs)
• If PMNs > 250, this MEETS SBP criteria & the patient should receive empiric treatment for SBP with a third generation cephalosporin. 

How much is too much?

For patient comfort (especially in diuretic resistant patients) or for rapid reduction of ascites: paracentesis with removal of < 5 L is a considered to be a safe & effective option.

With removal of more than 5L of ascites (called large volume paracentesis), there is a theoretical risk of post-paracentesis circulatory dysfunction also called paracentesis induced circulatory dysfunction.

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What is PCD? 

Post Paracentesis Circulatory Dysfunction

When the removal of large volumes of fluid leads to decreased SVR subsequently activating the RAAS system leading to rapid re-accumulation of fluid & increased mortality.

Albumin infusion after large volume paracentesis (> 5 L) is used to prevent PCD & reduce mortality:

Bernardi M1, Caraceni P, Navickis RJ, Wilkes MM. Albumin infusion in patients undergoing large-volume paracentesis: a meta-analysis of randomized trials. Hepatology. 2012 Apr;55(4):1172-81. doi: 10.1002/hep.24786

This figure summarizes the trials comparing albumin with other treatments post large volume paracentesis with regard to the endpoint of mortality. 

Many of the trials reviewed also demonstrated benefit with albumin for other secondary endpoints including decreased: ascites recurrence, renal impairment, hepatic encephalopathy, portal hypertensive bleeding, & hospital readmission.

In summary, patient's who undergo paracentesis of more than 5L should be given albumin (6-8 g per L removed) which has been shown to reduce mortality. 

Thanks for reading, Emma