Blood Culture Collection in Patients with Acute Kidney Injury Receiving Renal Replacement Therapy: An Observational Study

Abstract

Critically ill patients receiving renal replacement therapy (RRT) for acute kidney injury (AKI) have high reported intensive care unit (ICU) mortality. Blood culture (BC) collection practices in this population have to date been poorly characterised, specifically in regards to the influence of RRT on the clinical triggers for such an investigation. Utilising our electronic clinical information system, we conducted a retrospective observational study of patients admitted to a 30-bed tertiary level ICU and requiring RRT over a four-year period. Patients with a history of chronic kidney disease, prior RRT or ICU length-of-stay (LOS) <48 hours were excluded. Two hundred and thirty-one patients treated with RRT for AKI were identified. The observed median [interquartile range] BC collection rate in those having them drawn was 18 [11-32] per 100 patient days, although 42% of the cohort had no BC drawn during their ICU stay. Application of RRT in the 24 hours prior to initial BC collection was associated with lower body temperatures, higher white cell counts and greater use of vasopressor therapy. Bloodstream infection (identified from the first BC) was associated with greater ICU and in-hospital mortality. We also observed a predominance of candidaemia in this cohort, despite the absence of neutropenia. This study provides unique data describing BC collection rates in a cohort of critically ill patients receiving RRT for AKI and at high risk of dying. Further study of temperature alteration, detection of bloodstream infection and outcome in patients receiving RRT is now warranted.