The long-term goal is to test the clinical efficacy of senolytic therapies to reduce progression to and severity of sepsis in older patients. The central hypothesis is that a threshold burden of SnCs predisposes to a SASP mediated dysfunctional response to PAMPs, contributing to a disproportionate burden of sepsis in older patients. The study hypothesizes timely treatment with fisetin will interrupt this pathway. A multicenter, randomized, adaptive allocation clinical trial to identify the most efficacious dose of the senolytic fisetin to reduce the composite cardiovascular, respiratory, and renal sequential organ failure assessment score at 1 week, and predict the probability of success of a definitive phase III clinical trial.