PI had difficult enrollment.

This study is an observational analysis that monitors the effect of different dialysis methods on vancomycin levels when patients are critically ill. No changes are made to therapy based on levels, but levels are checked more frequently than normal. The primary dialysis methods being studied are SLED (slow-low efficiency daily) dialysis and intermittent hemodialysis. Vancomycin is the only medication being evaluated in this study. This study will provide detailed information on how to dose vancomycin in patients that are on dialysis in the intensive care unit.

The proposed study will evaluate the pharmacokinetics of vancomycin in patients that are on being treated with various types of renal replacement therapy. The renal replacement therapies studied in this trial will be slow-low efficiency daily (SLED) dialysis and intermittent hemodialysis. This data will be collected and plotted for vancomycin for each dialysis mechanism utilized and plotted on drug concentration versus time graphs to determine drug clearance in each type of renal replacement therapy. Subjects will have blood samples drawn and sent to the laboratory according to the dialysis method studied (9 for SLED dialysis and 10 samples for intermittent hemodialysis). Serial levels will be drawn prior to the drug being administered and after the drug is infused to assess the clearance and distribution of vancomycin. Study drug levels will be drawn from blood that is already available in the laboratory when timing of such samples is appropriate, in order to limit the amount of blood that is drawn from each study subject. A total of 30 milliliters of blood will be collected from each subject for any one study arm they fit into. Blood will be collected no more than two times per week and only more than once in a particular patient if their dialysis regimen changes. A single particular subject will only be able to supply blood samples once for each dialysis regimen being studied. This study would allow for the data collection of vancomycin levels at several time points during renal replacement therapy to assess the pharmacokinetic parameters associated with vancomycin dosing in each specialized patient-dialysis combination.

Inclusion Criteria:

• > 18 years of age
• One of the following types of dialysis modalities implemented:

Slow-low efficiency daily dialysis Intermittent hemodialysis

• Use of study medication (vancomycin)

Exclusion Criteria:

• Inability to give informed consent

Patients must be admitted to the intensive care unit at Avera McKennan Hospital in Sioux Falls, SD.