Spark Study: Do low doses of Lasix provide renal protection in AKI? Interview with: Sean Bagshaw MD Master, Director of Research for the Division of Critical Care Medicine School of Public Health, University of Alberta, Canada What is the origin of this study? What are the main findings?

Answer: The justification for SPARK was derived from two general observations.

First, experimental and preclinical data have suggested that the timely use of loop diuretics in early ARF could provide a “kidney protection” mediated to a large extent through reduced demand for medullary oxygen. However, this is an apparent paradox with clinical data (largely derived from older observational studies with some risk of bias), suggesting that the use of loop diuretics in ARF may be associated with an increased risk of Death and / or failure of renal function.

Second, in IRA, loop diuretics are used very often. Surveys of health professionals and observational data suggest that more than two-thirds to three-quarters of patients are exposed to diuretics at some point during their course. This represents a significant misalignment between evidence and clinical practice. This would suggest the need to generate new evidence and knowledge that would ideally help inform best practices in the management of AKI.

SPARK was designed as a pilot trial largely with the aim of assessing the feasibility of approaching the use of loop diuretics in early AKI. Although SPARK did not find significant differences in the risk of worsening ARF, the use of SRT or mortality, we recognize that the trial did not have sufficient power to report on these and other patient-centered outcomes. We have seen differences in secondary endpoints (ie, fluid balance); However, the use of loop diuretics in this context was also associated with a higher incidence of electrolyte abnormalities. What should readers get out of your report?

Answer: Our trial at best suggests that there was no evidence of improvement in clinical criteria associated with low dose furosemide in early infusion of AKI (although there was no tendency to suggest worse clinical outcomes); However, the protocol was challenging and resulted in major adverse effects largely driven by minor electrolyte abnormalities. What recommendations do you have for future research as a result of this study?

Answer: SPARK had a protocol that was very difficult to implement. As a consequence, we currently have no plans to conduct a more comprehensive final study with this approach. However, we strongly believe, given the apparent misalignment in evidence and practice, that additional studies should focus on the optional population, adjustments, and conditions for loop diuretic use in ARF. Is there anything else you would like to add?

Answer: The trial was funded by a grant from Alberta Innovates – Health Solutions and a seed grant provided by members of the Department of Critical Care Medicine at the University of Alberta School of Medicine and Dentistry. The authors do not have any relevant disclosures regarding the SPARK study to declare. Thank you for your contribution to our community.