DENVER – Antibiotics were dosed too low about 20% of the time in ICU patients on continuous venovenous hemodialysis at the Cleveland Clinic.
Continuous venovenous hemodialysis (CVVHD) artificially improves creatinine clearance; the clinic’s guidelines call for increasing antibiotic doses to compensate.
That didn’t always happen in the 42 Cleveland Clinic patients, and doesn’t always happen elsewhere, said lead investigator Marianna Fedorenko, Pharm.D., a Cleveland Clinic pharmacy resident when the study was done but currently at Barnes-Jewish Hospital in St. Louis.
Dr. Marianna Fedorenko
The clinic has since added an alert to the electronic medical record system to notify prescribers that patients are on CVVHD.
Poor communication was probably to blame. Amid the stress of ICU care, residents, nephrologists, internists, and others may not have known when ordering or adjusting antibiotic doses that patients were on CVVHD. "This is an [issue] that people need to look at it. There are a lot of points during dialysis that are critical for communication. These patients need a closer eye than some other intensive care unit patients," Dr. Fedorenko said.
Most of the patients had failing kidneys and were on pressors and mechanical ventilation; the majority were probably septic. The investigators assessed them at 24 hours for appropriate antibiotic dose. Vancomycin and aminoglycosides – both dosed according to blood levels – were excluded from the analysis.
The 42 patients had a total of 209 antimicrobial days; some were on more than one antibiotic. The median CVVHD flow rate was 26 mL/kg per hour; about half of the patients died during the study period. Overall, "78% [163] of our 209 study days met" CVVHD Cleveland Clinic antibiotic dosing guidelines. The rest were underdosed, Dr. Fedorenko said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
That seemed to be a particular problem with ciprofloxacin, ampicillin/sulbactam, and meropenem. There were fewer problems with Zosyn (piperacillin/tazobactam). "We are more familiar with it," Dr. Fedorenko said.
It took a median of about 20 hours to catch and fix the problems, but some patients remained underdosed throughout CVVHD.
Mistakes were more common on weekdays. "Patients are more likely to be started on CVVHD then, so there’s more room for errors – that’s my hypothesis," she said.
Dr. Fedorenko and the other investigators said they had no financial conflicts of interest.