The post market surveillance study will employ a prospective, multi-center, single-arm, observational design to capture data on children who undergo CRRT using the Carpediem™ system. Participating clinicians will manage subjects in accordance to their local standard of care practices and decisions on initiating, modifying or discontinuing CRRT are up to the local investigative team's prescription.

A minimum of 10 centers in the United States, that have been trained on the use of the Carpediem™ system, will be invited to participate in the study. After obtaining institutional review board approval and written informed consent from a parent or legally authorized representative (LAR), data from all subjects treated with the Carpediem™ system will be included in the study. A minimum of 35 subjects will be enrolled and sites may be asked to screen and enroll patients for the study for up to 36 months.

Status of subjects discharged from hospital will be collected at 30- and-90 days following hospital discharge by phone interviews in accordance to local standard of care practices, review of in-hospital records or in-clinic visit, as available.

The post market surveillance study is designed to capture data in the real-world clinical setting on the use of the Carpediem™ system and will evaluate the safety and performance in children requiring CRRT in the US. Data on survival and the effectiveness of the Carpediem™ system on renal function recovery will be evaluated. A comprehensive evaluation of subjects being treated with Carpediem™ will include, but is not limited to, acuity at hospital/ICU admission and prior to CRRT initiation, Carpediem™ treatment parameters, laboratory data, and requirement for mechanical ventilation and/or inotropic support. Subject status and requirement for renal replacement therapy post hospital discharge will be evaluated at 30- and 90-days.

Inclusion Criteria:

• Parent or LAR has signed information consent
• Subject weighs between 2.5-10 kg (or 5.5-22 lbs)
• Subject is receiving medical care in an intensive care unit
• Parental or LAR consent to receive full supportive care through aggressive management utilizing all available therapies for a minimum of 96 hours
• Subject has a clinical diagnosis of acute kidney injury per Kidney Disease Improving Global Outcomes (KDIGO) criteria or fluid overload requiring CRRT

Exclusion Criteria:

• Subject is not expected to survive 72 hours due to an irreversible medical condition, in the opinion of the investigator
• Subject has irreversible brain damage, in the opinion of the investigator
• Subject is intolerant to anticoagulation, as documented in the medical record
• Subject has a Do Not Attempt Resuscitate (DNAR), Allow Natural Death (AND), withdrawal of care or similar order, or anticipated change in status, in the opinion of the investigator, within the next 7 days
• Subject has pre-existing end-stage renal disease or pre-existing, advanced chronic kidney disease, defined as an estimated Glomerular Filtration Rate (eGRF) < 30 ml/min/1.73m2
• Subject is currently or has chronically been treated with a circulatory support device (i.e., left ventricular assist device (LVAD)) other than ECMO
• Subject has had prior CRRT treatments using the Carpediem™ system
• Subject is enrolled in clinical trials or being treated with other investigational therapeutic devices or products for acute kidney injury or fluid overload
• Subject has any other medical condition that may confound the study objectives, in the opinion of the investigator

Patients who have acute kidney injury or fluid overload requiring hemodialysis or hemofiltration who weigh between 2.5 and 10 kilograms (5.5 to 22 pounds).