Detectable Concentrations With Inhaled Tobramycin in Critically Ill Infants and Children Following Implementation of Standardized Protocol

Abstract

Background: A protocol was established for ventilator-associated tracheitis or pneumonia using inhaled tobramycin 300 mg every 12 hours in mechanically ventilated children via a vibrating mesh nebulizer, 30 cm from the endotracheal tube in the inspiratory loop of the mechanical ventilator.

Objectives: The primary objective was to determine the incidence of detectable tobramycin trough concentrations >0.5 µg/mL. Secondary objectives included a comparison of clinical characteristics between those with and without detectable concentrations and identification of patients with acute kidney injury (AKI) as defined by the Kidney Diseases Improving Global Outcomes (KDIGO) criteria.

Methods: This was a single-center retrospective study of critically ill children <18 years without cystic fibrosis receiving inhaled tobramycin between July 1, 2016, and August 31, 2021. Data collection included demographics, tobramycin regimen, and renal function. Analysis was performed using SAS 9.4, with a P-value <0.05, and a multivariable regression model was performed to identify factors for detectable concentrations and AKI.

Results: Forty-four patients (66 courses) were included, with an overall age of 0.83 years. Thirty (68%) patients had detectable concentrations and 9 (20.5%) developed AKI. No significant differences in demographics, diagnosis, mechanical ventilation settings, and number of nephrotoxins were noted between those with and without detectable concentrations or AKI. Multivariable regressions did not identify factors associated with detectable concentrations or AKI.

Conclusion and relevance: Detectable concentrations occurred with the majority of courses, with AKI associated with approximately one-fourth of courses. Clinicians should consider utilizing trough monitoring for all mechanically ventilated critically ill children receiving inhaled tobramycin.

Keywords: acute kidney injury; child; inhaled tobramycin; mechanical ventilator; pharmacokinetics; tobramycin trough concentrations.