Eligibility criteria
This was a single center retrospective review approved by the University
of Kentucky Institutional Review Board (IRB). All patients aged one
month or older with a diagnosis of CF who received IV tobramycin for
treatment of a PsA APE during an admission to the University of Kentucky
Healthcare System between August 1, 2015 and August 31, 2019 were
evaluated for inclusion. Patients were excluded if they had no growth of
PsA on sputum culture(s) prior to or during admission, if they had
chronic kidney disease (CKD) prior to receiving the first dose of IV
tobramycin, or if two post-dose drug levels were not obtained during
admission to calculate patient-specific pharmacokinetic parameters.
Further, patients were excluded from primary outcome analysis if two
drug levels were not obtained following a dose adjustment of greater
than 20% or following adjustment of the dosing interval secondary to
fluctuating renal function.
Pharmacokinetic parameters were collected following any dose adjustment
of IV tobramycin, and only the parameters collected from the final dose
(i.e. based on clinical judgement, did not warrant further dose
adjustment) were analyzed in the primary outcome analysis. Within the
adult cohort, if a patient had >4 encounters over the
four-year study period, only the first four encounters were collected
and subsequently analyzed.