Intraperitoneal Pressure is associated with the complications of increased intra-abdominal pressure in peritoneal dialysis patients. Due to the complicated operations, routine measurement of hydrostatic intraperitoneal pressure is not used routinely in adult peritoneal dialysis patients. There ars some limitions in equations from previous studies, such as the sample size was small , and the study population was limited. In the study, we aim to develop and validate an equation for estimating intraperitoneal pressure in peritoneal patients.

Inclusion Criteria:

• Peritoneal dialysis patients
• Dialysis length >1 month
• Aged 18-80 years
• Injection volume of peritoneal dialysis solution>1500ml

Exclusion Criteria:

• Acute complications （ peritonities, cardiovascular and cerebrovascular diseases) to hospitalization 1 month prior to the study
• History of abdominal surgery and trauma 1 month prior to the study
• Previous history of hernia, leakage, or thoracoabdominal fistula
• Can't come for a follow-up visit

All peritoneal dialysis patients meet the inclusion and exclusion criteria in a single center