From the Guidelines
Yes, fluid overload can cause acute kidney injury (AKI). According to the most recent evidence from 1, both intravascular hypovolaemia and fluid overload are harmful and associated with organ dysfunction, including AKI. Excessive fluid accumulation in the body can increase renal venous pressure and intra-abdominal pressure, which reduces renal blood flow and glomerular filtration rate, leading to kidney damage.
Key Points to Consider
- Fluid overload causes kidney compression from edema, further impairing function, and creates a dangerous cycle where fluid retention worsens kidney function, which then leads to more fluid retention 1.
- Patients with heart failure, sepsis, or existing kidney disease are particularly vulnerable to fluid overload-induced AKI, as they have lower fluid tolerance and are at higher risk of fluid accumulation 1.
- Management typically involves careful fluid balance monitoring, diuretics like furosemide, and sometimes renal replacement therapy in severe cases, as suggested by 1 and 1.
- Prevention strategies include judicious fluid administration, especially in high-risk patients, and regular monitoring of kidney function markers such as creatinine, urine output, and fluid balance, as emphasized by 1 and 1.
Clinical Implications
- Early recognition and intervention are essential to prevent progression to more severe kidney injury, highlighting the importance of close monitoring and timely management of fluid balance in high-risk patients 1.
- The goal of fluid therapy should be to keep the individual fluid status in the ‘green zone’, that is, in a state of intravascular euvolaemia, to minimize the risk of AKI and other organ dysfunctions 1.
From the Research
Association between Fluid Overload and Acute Kidney Injury
- Fluid overload has been associated with an increased risk of acute kidney injury (AKI) and mortality, as shown in a study by Wang and colleagues 2.
- The exact cause-effect relationship between fluid overload and AKI remains unclear, but there is evidence to suggest that fluid accumulation can contribute to the development of AKI 2, 3, 4.
Pathophysiological Link between Fluid Overload and AKI
- Fluid overload can lead to interstitial edema, which can further delay renal recovery and contribute to ongoing organ dysfunction 3, 4.
- The use of diuretics may help to prevent or treat fluid overload, but their efficacy in critically ill AKI patients needs to be confirmed with randomized controlled trials 5, 6.
Management of Fluid Overload in AKI
- A conservative strategy of fluid management, aiming for a neutral or negative fluid balance, may be beneficial in patients with AKI 3, 4, 5.
- Early guided resuscitation, followed by careful assessment of fluid status, and early initiation of renal replacement therapy may be necessary to manage fluid overload in critically ill patients with AKI 4, 5.
- The use of isotonic crystalloids instead of colloids for initial expansion of intravascular volume may be recommended in patients at risk for AKI or with AKI 6.