The zero balance approach to fluid administration is a strategy employed during surgical procedures to manage the volume of fluids administered to a patient. Its primary aim is to achieve equilibrium between the fluids introduced into the body and those lost, thereby preventing fluid overload and its consequential complications such as edema, respiratory difficulties, and cardiovascular stress.
To implement this approach effectively, it necessitates the accurate quantification of a patient's fluid losses—including blood, insensible losses (like respiration and evaporation from surgical sites), and urine output. Fluid replacement is then tailored specifically to these measurements and the patient's clinical status, using a combination of monitoring tools to guide the administration of fluids. The choice of fluids, whether crystalloids, colloids, or blood products, is made based on the patient's individual needs and the nature of their fluid loss.
The advantages of this approach are significant, offering a reduction in postoperative complications such as pulmonary edema, heart failure, and delayed wound healing, which in turn can lead to quicker patient recoveries and shorter hospital stays. However, this method requires complex, continuous monitoring and a high level of skill from anesthesia providers, alongside a deep understanding of the patient's unique health profile.
In contrast to the points made above, the 2018 RELIEF clinical trial, which compared liberal versus restrictive intravenous fluid therapy in patients undergoing major abdominal surgery, found that those on a restrictive fluid regimen had a significantly higher risk of developing acute prerenal kidney injury compared to those on a liberal fluid regimen. Specifically, the restrictive group received a median of 1.7 liters of fluid intraoperatively, in contrast to 3 liters in the liberal group. This outcome suggests that, although the over administration of intravenous fluids is not advisable, a modestly liberal approach to fluid administration may be safer than a restrictive one. The findings indicate that a zero-balance approach, aimed at minimizing fluid administration, might be overly restrictive and potentially increase the risk of adverse events, particularly acute kidney injury.
