Characteristics of Antimicrobial Administration in Patients Receiving CRRT

Background: Antimicrobials are given frequently to patients requiring renal replacement therapy (RRT) in the intensive care unit (ICU). Antibiotic overuse is associated with increasing antimicrobial resistance, which comes with individual, public health, and socioeconomic consequences. While early antimicrobial therapy crucial for surviving sepsis, there are no studies that characterize the incidence of confirmed infection and antimicrobial resistance in patients receiving continuous RRT (CRRT). Methods: A retrospective chart review identified 954 ICU patients admitted to University of Chicago Medicine between May 2016 and April 2020 who received an antimicrobial of interest and continuous veno-venous hemodialysis (CVVHD). Antimicrobial administration, specimen cultures and sensitivities were recorded. Patients were grouped according to the antimicrobial received, culture type, microbe present and sensitivities. Results: In 954 patients receiving antimicrobials on CVVHD, vancomycin was the most administered (941, 99%), followed by cefepime (824, 86%). Of the patients receiving antibiotics, 175 (18.3%) had a confirmed infection identified with culture data. A total of 13,960 cultures were sent, with 4022 (28.8%) returned positive. The most common infections were respiratory (36.7%), blood stream (31.3%) and skin and soft tissue infections (12.8%). The most common bacteria were Pseudomonas aeruginosa identified in 10.3% of positive cultures (Table 1). In patients with positive cultures 132 (75.4%) died compared to 557 (71.1%) in culture negative patients (p = 0.24). Conclusion: The incidence of positive cultures in ICU patients receiving CVVHD was low, but when present was most often a respiratory or blood stream infection. Vancomycin is administered in nearly every patient despite the high incidence of vancomycin resistant pathogens. Additionally, positive cultures are not associated with increased mortality. - Antimicrobial n (% total patients) Culture n (% positive cultures) Pathogen n (% positive cultures) Sensitivities Percentage of Resistant Isolates (%) Cefepime 824 (86) Respiratory 1140 (36.7) Candida sp. 910 (22.6) Vancomycin resistance 76.6 Meropenem 124 (13) Blood stream 972 (31.3) P. aeruginosa 428 (10.6) Carbapenem resistance 17.8 Piperacillin-Tazobactam 223 (23) Urine 365 (11.3) E. coli 193 (4.8) Cefepime resistance 34.1 Vancomycin 941 (99) Skin and soft 398 (12.8) S. aureus 310 (7.6) Table 1 – Summary of most administered antibiotics confirmed source of infection and causative pathogens in ICU patients on CVVHD.