Diversifying Aquapheresis Applications in Critical Care: Nephrology-Led Institutional Experience

Background: Aquapheresis(AQ) is a procedure that uses a semipermeable membrane for the extracorporeal removal of plasma water driven by a transmembrane pressure gradient. Primarily employed in the management of diuretic-resistant congestive heart failure(CHF). AQ distinguishes itself through a more compact and intuitive device compared to conventional dialysis systems. This report outlines our institution’s experience with AQ, demonstrating its utility in clinical scenarios extending beyond CHF. Methods: This retrospective analysis was conducted to elucidate the clinical indications for the utilization of AQ at Lenox Hill Hospital from January 2018 to July 2024. The use of AQ was at the discretion of the Nephrology overseen the case. COVID-19 cases were excluded from the study. The study population was categorized according to hospital unit and specific indications for AQ therapy. Results: A total of 69 patients that underwent AQ had complete data. The hospital unit where AQ was performed and the number of patients per unit follows this order: 23 located in the Cardiothoracic ICU, 21 in the Cardiac Care Unit, 21 in the Medical ICU and 4 in the Surgical ICU. All patients had a component of kidney dysfunction and volume overload: Oliguric Acute Kidney Injury(39); Non-Oliguric AKI in CHF(10); Non-Oliguric AKI post-cardiac surgery(10); Optimization pre cardiac surgery in End Stage Renal Disease(7); Non-Oliguric AKI in septic shock(2); Transfusion-Associated Circulatory Overload(1). All patients underwent AQ via a central venous catheter. The average ultrafiltration(UF) volume was 6.4L per patient, with an UF rate of 82 ml/hr. The mean AQ duration was 78hr per patient. A 64% (n=44), were receiving vasopressor support during AQ due to cardiac or septic shock. Circuit clotting occurred in 10% of patients, the majority of whom were not receiving anticoagulation due to coexisting comorbidities. Conclusion: Volume optimization remains a fundamental component of management in critically ill patients. AQ can be employed as an additional resource to accelerate fluid removal in diverse clinical settings. This retrospective analysis underscores the versatility of AQ as an effective treatment and demonstrated its capacity to effectively and predictably remove significant volumes of fluid highlighting its utility in managing fluid overload across diverse patient populations.