The rate and speed of fluid removal during dialysis for patients with AKI can influence the risk of mortality, according to a study published by University of Pittsburgh School of Medicine researchers.
“We want to get this excess fluid out of our patients before it causes damage but, in removing it, we’re actually causing a controlled loss of fluid that can sometimes cause stress on the heart and lead to dangerously low blood pressure,” lead author Raghavan Murugan, MD, MS, associate professor in the department of critical care medicine and University of Pittsburgh School of Medicine (UPMC) physician, said in a press release. “So the question — how rapidly to remove fluid? — has been asked in the critical care community for many years, but there’s been no good answer.”
Previous studies that examined patients dialyzed in an outpatient setting who were not critically ill found rapid fluid removal was associated with an increased risk of death. Murugan partnered with senior author Rinaldo Bellomo, MD, PhD, a professor of intensive care medicine at the University of Melbourne, to find out if that finding extends to critically ill patients.
Their team examined data from 1,434 patients that Bellomo had previously collected for the Randomized Evaluation of Normal vs. Augmented Level of Renal Replacement Therapy trial, which was conducted between Dec. 30, 2005 and Nov. 28, 2008 in 35 intensive care units in Australia and New Zealand. The primary outcome was 90-day survival from study enrollment.
The research team found that for every 0.5-milliliter increase in fluid removed per kilogram of the patient’s weight per hour (0.5 mL/kg/hr), the patient’s risk of death increased. That translates to a 51% to 66% higher risk of death in the next 3 months for critically ill patients for whom excess fluid is removed at a rate greater than 1.75 mL/kg/hr compared to patients for whom excess fluid is removed at a rate less than 1.01 mL/kg/hr.
Murugan noted that his analysis showed association, not causation; until a clinical trial is performed to specifically test the effects of removing fluid faster vs. slower, he cannot say for sure that removing fluid slowly is better for the patient and in some cases, such as imminent heart failure, Murugan said a more rapid removal of fluid might be warranted to prevent sudden death.
“You have to balance the pros and the cons, and decide how fast to remove fluid based on your patient’s clinical condition but in a patient where I can’t find an immediate need to get fluid out quickly, I’ll be removing fluid at a slower rate until we get definitive results and guidance from a clinical trial,” Murugan said, who also is a member of the Clinical Research, Investigation, and Systems Modeling of Acute Illness Center and the Center for Critical Care Nephrology at UPMC.
Disclosures: Murugan reports receiving grants and personal fees from La Jolla Inc., Bioporto Inc., the National Institute of Diabetes and Digestive and Kidney Diseases, Beckman Coulter and AM Pharma Inc. Please see the study for all other authors’ relevant financial disclosures.