Susceptibility of hepato-splanchnic perfusion to intra-abdominal pressure in peritoneal dialysis patients.

Background: The impact of peritoneal filling on hepato-splanchnic perfusion during peritoneal dialysis has not been fully elucidated yet.

Methods: Measurements were done in 20 prevalent peritoneal dialysis patients during a peritoneal equilibration test (PET) with 2L of standard dialysate. Data were obtained in the drained state at baseline (T₀), after instillation (T₁), and after 2 h of dwell time (T₂). Intra-abdominal pressure (IAP) was measured by Durand's approach. The hepatic clearance index (KI) of indocyanine-green (ICG) was determined as an indirect measure of hepato-splanchnic blood flow. Cardiac index (CI), heart rate (HR), and total peripheral resistance index (TPRI) were derived from continuous arterial pulse analysis. Fluid volume overload (VO) was evaluated by multifrequency bioimpedance analysis. Ejection fraction (EF) was obtained from echocardiographic examination.

Results: IAP was 5.8 ± 3.5 mmHg at baseline (T₀), rose to 9.4 ± 2.8 mmHg after instillation of dialysate (T₁), and further to 9.7 ± 2.8 mmHg after 2 h of dwell time (p < 0.001). KI slightly declined from 0.60 ± 0.22 L/min/m² at T₀ to 0.53 ± 0.15 L/min/m² at T₁ (p = 0.075), and returned to 0.59 ± 0.22 L/min/m² at T₂ (p = 0.052). CI, HR, and TPRI did not change significantly. In five patients with an EF < 40% KI was significantly lower at T₁ (0.42 ± 0.12 L/min/m²; p = 0.039), and further decreased at T₂ (0.40 ± 0.04 L/min/m²; p = 0.016) compared to patients with normal EF (T₁: 0.58 ± 0.15 L/min/m² and T₂: 0.67 ± 0.22 L/min/m²).

Conclusions: Overall, hepatic clearance of ICG as a marker of hepato-splanchnic blood flow is not affected by the filling of the peritoneal cavity.