Tobramycin Serum Concentrations in Tracheostomy-Dependent Children Receiving Inhaled Tobramycin.

Introduction: In recent years, administration of inhaled aminoglycosides has gained popularity in tracheostomy-dependent pediatric patients because of medication delivery to the target site of action while minimizing systemic absorption and adverse effects. A recent report of detectable serum tobramycin concentrations in critically ill children receiving inhaled tobramycin 300 mg every 12 h prompted our investigation in tracheostomy-dependent pediatric patients receiving inhaled tobramycin 80 mg every 8 h. Methods: Serum tobramycin trough concentrations were obtained from tracheostomy-dependent pediatric patients receiving treatment with inhaled tobramycin 80 mg every 8 h for the treatment of tracheitis. Patient data, including demographic data, medical history, renal function, and serum concentrations, were collected. Results: Twelve patients with a median age of 0.5 (0.3-6.1) years had serum tobramycin concentrations evaluated. Eleven of the 12 patients had undetectable trough concentrations (<0.6 mcg/mL). All of these patients had normal blood urea nitrogen (BUN) and serum creatinine (SCr) for age and no history of kidney disease. One patient had a detectable trough concentration of 2.1 mcg/mL. This patient was 11 months old and had polycystic kidney disease with an elevated BUN and SCr for age. Conclusions: Detectable serum concentration from systemic absorption of inhaled tobramycin 80 mg every 8 h is unlikely in tracheostomy-dependent pediatric patients with normal renal function. However, in tracheostomy-dependent pediatric patients with a history of renal dysfunction or elevations in BUN or SCr, inhaled tobramycin should be used with caution. Monitoring serum concentrations to guide dose modification should be considered in these patients.