Tobramycin Serum Concentrations in Tracheostomy-Dependent Children Receiving Inhaled Tobramycin

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. 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. 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. 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.