Predicting progression in acute kidney injury

Last month the final study from my time at NIH was published. This study explored a promising, and relatively new, biomarker for acute kidney injury during critical illness. Although the biomarker had been previously tested in humans we were able to develop a potential refinement in a preclinical model.

During critical illness, such as sepsis, organ failure is a major complication increasing the risk of death. For the kidneys, treatment is limited to more focused management. This means avoiding further harm and keeping the patient alive long enough for kidney function to return.

The sooner kidney injury is detected the better the likely outcome but this can be surprisingly difficult. Some significantly improved options have been developed but further, even better, options are still desired. A new approach is giving the kidney something to do and measuring how well it performs. This idea is similar to the treadmill stress test commonly used to detect cardiovascular disease such as angina.

The test that was developed gave a dose of a drug called furosemide that is actively excreted by the kidneys and stimulates urine production. If the kidneys are healthy, the furosemide will be excreted and the amount of urine produced will increase. In a human clinical study this approach performed very well and there have been several subsequent studies in different settings.

Urine volume is altered by a variety of factors and we decided to investigate whether further improvements in performance would be possible by measuring furosemide excretion directly. When used in ideal conditions results were comparable. However, when we gave a drug called vasopressin that is commonly used to manage blood pressure during critical illness measuring urine volume gave erroneous results while furosemide excretion remained reliable.

The study is published in Critical Care Explorations and is freely available.