Intraperitoneal pressure in PD patients: relationship to intraperitoneal volume, body size and PD-related complications

Background. The clinical determinants of intraperitoneal pressure (IPP) are ill defined, and the potential impact of elevated IPP on peritoneal dialysis (PD)-related complications is still a matter of debate. We measured IPP in newly started PD patients, assessed its clinical determinants and analysed the incidence of PD-related complications. Method. IPP was measured in 61 consecutive patients [46 males and 15 females, 47 automated peritoneal dialysis (APD) and 14 continuous ambulatory peritoneal dialysis (CAPD), aged: 52 +/- 17 years], an average of 2 months after PD onset, using increasing (from 0 to 3000 ml) dialysate volumes. The prescription of day and night dialysate infusion volumes was made to avoid IPP > 16 cm H2O. We assessed the relationship between baseline clinical characteristics and IPP and the putative influence of IPP on subsequent PD-related complications, such as hernias, late leakage, gastro-oesophageal reflux (GOR) and enteric peritonitis (EP). IPP at the time of the complication was computed by linear interpolation across available couples of data (volume and IPP). Correlations were assessed using Pearson's r; Kaplan-Meier survival curves with log-rank test were used for complication occurrence analysis. Results. At baseline, mean IPP was 13.5 +/- 3.3 (5-22.5) cm H2O for 2000 ml inflow; IPP rose linearly as intraperitoneal volume (IPV) increased [R-2 = 0.96, 95% CI (0.88; 1.00)]. IPP was significantly higher in patients with a higher body mass index (BMI) (P = 0.03) but age, gender, weight, height, body surface area (BSA), diabetes mellitus or a past history of abdominal surgery did not correlate with IPP. Incidence of abdominal wall complications or GOR was not correlated with IPP. Patients with a night IPP > 14 cm H2O had a higher incidence of EP (P = 0.039) and a worse survival free of EP (P = 0.03). Conclusion. This study shows a strong linear correlation between IPP and IPV, a significant impact of BMI on IPP and a higher incidence of EP in patients with higher IPP. We recommend to measure IPP in PD patients to guide the prescription of intraperitoneal volumes.