Intra-Abdominal Pressure Changes During Continuous Renal Replacement Therapy in Critically Ill Patients

Intra-abdominal hypertension may occur in critically ill patients and can contribute to impaired organ perfusion and organ dysfunction. Patients receiving continuous renal replacement therapy may experience substantial changes in fluid status, which may be associated with changes in intra-abdominal pressure.

This is a single-center, prospective, observational cohort study conducted in critically ill adult patients receiving continuous renal replacement therapy in the intensive care unit. Patients who meet the study eligibility criteria will be enrolled consecutively. No additional therapeutic intervention will be performed as part of the study.

Intra-abdominal pressure will be measured using the intravesical technique through an indwelling urinary catheter. Measurements will be obtained at baseline before initiation of continuous renal replacement therapy and at 6, 12, 24, 48, and 72 hours after initiation.

Clinical and laboratory variables will be recorded, including demographic characteristics, comorbidities, indication and modality of continuous renal replacement therapy, Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, fluid balance, mean arterial pressure, vasopressor requirement, urine output, lactate level, respiratory parameters, and related clinical findings.

The primary objective is to characterize the temporal change in intra-abdominal pressure during continuous renal replacement therapy. Secondary analyses will evaluate associations between intra-abdominal pressure and clinical outcomes, including the presence of intra-abdominal hypertension, duration of continuous renal replacement therapy, intensive care unit length of stay, hospital length of stay, and 30-day survival.

The planned sample size is 95 participants.

Inclusion criteria

• Age 18 years or older
• Admission to the intensive care unit
• Receiving continuous renal replacement therapy (CRRT)
• Presence of an indwelling urinary (Foley) catheter for intra-abdominal pressure measurement

Exclusion criteria

• Pregnancy
• Open abdominal wound or open abdomen
• Neurogenic bladder
• History of bladder surgery
• Pelvic hematoma
• Pelvic fracture
• Presence of an intra-abdominal mass or other anatomical/technical condition that may compromise the reliability of intravesical pressure measurement