Fluid Balance in Continuous Renal Replacement Therapy: Prescribing, Delivering, and Review

Abstract

Background. Historically IV and enteral fluids given during acute kidney injury (AKI) were restricted before the introduction of continuous renal replacement therapies (CRRT) when more liberal fluids improved nutrition for the critically ill. However fluid accumulation can occur when higher volumes each day are not considered in the fluid balance prescribing and daily review for the NET ultrafiltration (NUF) volume target. Key messages: The delivered hours of CRRT each day are vital for achievement of fluid balance and time off therapy makes the task more challenging. Clinicians inexperienced with CRRT makes this aspect of AKI management a focus of rounding with senior oversight, clear communication, and ‘precision’ a clinical target. Sepsis associated AKI can be a complex patient where resuscitation and admission days are with a positive fluid load and replacement mind set. Subsequent days in ICU requires fluid regulation, removal, with a comprehensive multilayered assessment before prescribing the daily fluid balance target and the required hourly NET plasma water removal rate (NUF rate) to achieve this . Forecasting and prediction is necessary. The future : Future machines may include advanced software, new alarms – display metrics, messages and association with machine learning and ‘AKI models’ for setting, monitoring, and guaranteeing fluid removal. This could also link to current hardware such as on-line blood volume assessment with continuous haematocrit measurement.