Mechanisms of early decrease in systemic vascular resistance after total paracentesis: Influence of flow rate of ascites extraction

Background: An early decrease in systemic vascular resistance (SVR) after total paracentesis has been observed in ascitic patients who developed paracentesis- induced circulatory dysfunction. Aims: To investigate the mechanisms of early changes in SVR after total paracentesis and the influence of intra- abdominal pressure and the flow rate of ascites extraction on the development of an early decrease in SVR. Methods: Twenty-two cirrhotic patients with tense ascites were treated by total paracentesis (7 ± 0.4 l). Measurements of intra-abdominal pressure and the volume of ascites removed were recorded every 10 min. Hormonal and haemodynamic measurements were performed at baseline and 3 h after total paracentesis. Results: SVR decreased 3 h after paracentesis in 17 patients and remained stable in five patients. Patients with a decrease in SVR showed a significant increase in nitrite/ nitrate serum values (4.4 ± 0.9 to 7.4 ± 1 nmol/ml; P < 0.05). A significant correlation was observed between the decrease in SVR and nitrite/nitrate serum values (r = 0.566; P < 0.05). The volume of ascites removed was similar in patients with and without a decrease in SVR. Patients with a decrease in SVR showed higher baseline intra-abdominal pressure, shorter duration of paracentesis (60 ± 4.9 vs 88 ± 0.4 min; P < 0.01) and higher flow rate of ascites extraction (1.18 ± 0.08 vs 0.81 ± 0.12 l/ min; P < 0.05). Conclusions: Our results confirm that an early decrease in SVR after total paracentesis is due to an increase in arterial vasodilation that may be related to an abrupt decrease in intra-abdominal pressure after fast paracentesis. Haemodynamic disturbances after total paracentesis could be prevented by reducing the flow rate of ascites extraction. © 2004 Lippincott Williams & Wilkins.