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After completing this case study, the reader should be able to:
Evaluate clinical and laboratory findings in a patient with acute kidney injury (AKI).
Select pharmacotherapy for treatment of complications associated with AKI.
Assess appropriateness of aminoglycoside serum concentrations in relation to efficacy and toxicity.
Develop strategies to prevent drug-induced AKI, including the selection of pharmacologic alternatives that do not adversely affect kidney function.
Adjust drug dosages based on kidney function to maximize efficacy and minimize adverse events.
Wilbur Elliott is a 79-year-old man who originally presented to the hospital 1 month ago with symptoms of heart failure that required open heart surgery for mitral valve replacement. His surgery was complicated by a 1-hour hypotensive episode, with BP of 70/50 mm Hg during surgery. Three days postoperation, purulent drainage was noted from the surgical site, and he was subsequently diagnosed with mediastinitis. At that time, he was in septic shock with severe hypotension. He was found to have Serratia bacteremia (blood cultures × 4 positive for Serratia marcescens, sensitive to gentamicin, piperacillin, cefepime, ceftriaxone, and ciprofloxacin; resistance was noted to ampicillin). Therapy was initiated with gentamicin and cefepime. Thus far, he has completed day 21 of a 6-week course of antibiotics. A gradual increase in his BUN and serum creatinine concentrations from baseline has been noted (Table 53-1), and signs of volume overload are present.
TABLE 53-1SCr, BUN, and Serum Gentamicin Concentrations During Hospitalization ||Download (.pdf) TABLE 53-1 SCr, BUN, and Serum Gentamicin Concentrations During Hospitalization
|Postoperative Day ||SCr (mg/dL) ||BUN (mg/dL) ||Gentamicin (mcg/mL) ||Gentamicin Dosages |
|Peaka ||Troughb |
|3 ||1.5 ||19 || || ||140 mg × 1, and then 120 mg Q 12 H |
|5 ||1.5 ||21 ||6.3 ||1.1 ||Continue current regimen |
|7 ||1.8 ||25 || || || |
|10 ||2.1 ||31 ||6.9 ||1.8 ||Continue current regimen |
|14 ||2.7 ||38 ||8.3 ||2.5 ||Decrease to 120 mg Q 24 H |
|17 ||3.1 ||46 || || || |
|21 ||3.2 ||50 ||9.4 ||2.7 ||Gentamicin on hold |
Mechanical mitral valve replacement surgery 28 days ago