Kashani, Kianoush

Background: Medication use in the intensive care unit (ICU) depends on creatinine-based glomerular filtration rate (GFR) estimates. Urine output deterioration may precede the creatinine rise resulting in delayed recognition of GFR reductions. Our objective was to quantify the disparity between estimated GFR (eGFR) and true GFR in ICU patients with hospital-acquired oligoanuric acute kidney injury (hAKI). Methods: This single-center cohort study examined adults who met the Acute Kidney Injury Network stage III urine output criterion ≥48 hours after ICU admission. True GFR was ≤15 mL/min/1.73 m 2 , and eGFR was described by 6 different creatinine-based equations. True GFR and eGFR were compared on the day of hAKI diagnosis and followed for 4 days using multivariable linear regression with generalized estimating equations, adjusting for day and method. Results: Of the 691 patients screened, we enrolled 61 patients. After adjustment for multiple comparisons and day, there were significant differences in eGFR between the estimation methods and true GFR ( P < .001). After day adjustment, eGFR overestimated true GFR by 17 to 50 mL/min/1.73 m 2 and overestimation persisted through the fourth day of hAKI ( P ≤ .001). Conclusion: Creatinine-based equations overestimated GFR in ICU patients with hAKI. This study highlights a population at risk of medication misadventures in whom systems optimization should be considered.

ABSTRACT The vancomycin dose necessary for the achievement of target serum trough concentrations during continuous venovenous hemofiltration (CVVH) remains to be elucidated. This was a retrospective cohort study of critically ill adults at a tertiary medical center on concurrent CVVH and vancomycin between 2006 and 2010 with a steady-state vancomycin trough concentration. The 87 included patients were grouped according to low (≤30 ml/kg/h; n = 10) or high (>30 ml/kg/h; n = 77) CVVH hemofiltration rate (HFR) for analysis. Vancomycin goal trough achievement occurred in only 32 (37%) patients. The primary endpoint of trough attainment significantly differed between HFR subgroups: 90% versus 30% in low- and high-HFR individuals, respectively ( P < 0.001). Patients with subtherapeutic trough concentrations had a median (interquartile range) HFR of 40 ml/kg/h (range, 37 to 47 ml/kg/h) compared to 36 ml/kg/h (range, 30 to 39 ml/kg/h) in those who achieved the trough goal. Irrespective of goal trough, an inverse correlation existed between HFR and serum vancomycin concentration ( r = −0.423; P < 0.001). In the subgroup of 14 methicillin-resistant Staphylococcus aureus (MRSA) patients, trough achievement was similar to the aggregate cohort (36%). Mortality at 28 days was unrelated to trough achievement in both the overall sample ( P = 0.516) and in culture-positive MRSA patients ( P = 0.396). Critically ill patients undergoing CVVH therapy may experience clinically significant reductions in goal vancomycin troughs. The results of the present study justify prospective evaluations in this population to determine the optimal vancomycin dosing strategy for attainment of goal trough concentrations.