Jacob Counts
The Wexner Medical Center at The Ohio State University
Columbus, Ohio
Disclosure information not submitted.
Jessica Elefritz, PharmD, BCCCP
PGY2 Critical Care Residency Program Director Critical Care Pharmacist
The Ohio State University Medical Center
Blacklick, Ohio
Disclosure information not submitted.
Erica Reed, PharmD, BCPS, BCIDP
Pharmacy Specialist
The Ohio State University Wexner Medical Center, United States
Disclosure information not submitted.
Connor Aossey, BS
Pharmacy Intern
The Ohio State University College of Pharmacy, United States
Disclosure information not submitted.
Marilly Palettas, MPH
Biostatistician
The Ohio State University Wexner Medical Center, United States
Disclosure information not submitted.
Julia Beatty, PharmD, BCCCP
Pharmacy Specialist
The Ohio State University Wexner Medical Center, United States
Disclosure information not submitted.
Title: Risk Factors Associated with Suboptimal Tobramycin Levels in The Medical Intensive Care Unit
Introduction/Hypothesis: Optimal aminoglycoside (AG) dosing in critically ill patients represents a challenge in the medical intensive care unit (MICU). MICU patients exhibit altered pharmacokinetics (PK) due to pathophysiological changes the body undergoes during critical illness. The literature surrounding optimal dosing and therapeutic drug monitoring strategies of AGs in MICU patients is scarce and conflicting, and only a few studies have investigated risk factors for suboptimal PK targets. Currently, no definitive risk factors have been identified to predict suboptimal AG target obtainment in MICU patients.
Methods: This retrospective cohort study included MICU patients who received at least one 7 mg/kg tobramycin dose with two detectable post-dose tobramycin concentrations. The primary outcome was to determine the incidence of optimal PK target obtainment, defined as a Cmax ≥10 mcg/ml, and to identify the risk factors for suboptimal PK target obtainment. Secondary outcomes were compared in a subgroup analysis between suboptimal and optimal target obtainment in patients with culture confirmed gram-negative infection susceptible to tobramycin. These included all-cause in-hospital mortality, ICU length of stay (LOS), hospital LOS, and vasopressor duration in those with shock.
Results: A total of 230 patients were included. 187 (81.3%) patients achieved optimal PK target obtainment. Through multivariate logistic regression, female sex and serum albumin < 2.5 mg/dL were identified as independent risk factors for suboptimal target obtainment; [OR= 2.14; 95% CI (1.05- 4.37), p=0.037], [OR= 2.50; 95% CI (1.21- 5.19), p=0.014], respectively. Fifty-four (23%) patients had culture-confirmed gram-negative infections susceptible to tobramycin and were included in the subgroup analysis. Of these 54 patients, 43 (79.6%) achieved a Cmax ≥10 mcg/ml. There were no differences between subgroups in ICU LOS, hospital LOS, all-cause mortality, or vasopressor duration in those with shock.
Conclusions: Among patients receiving their first dose of tobramycin in the MICU, 81.3% achieved optimal PK target obtainment. Female sex and serum albumin < 2.5 mg/dL were identified as independent risk factors for suboptimal target obtainment in critically ill MICU patients.