NEBULIZED GENTAMICIN IN CHILDREN WITH CYSTIC-FIBROSIS - ENHANCING ANTIBIOTIC LUNG DEPOSITION BY INCREASING FLOW-RATE AND FILL VOLUME

The aim of this study was to determine the influence of altering the n ebulizer flow rate and volume fill on intrapulmonary deposition of neb ulized gentamicin in adolescents with cystic fibrosis (CF). A single g roup of individuals inhaled randomly from two nebulization systems in a cross-over fashion, For System A, gentamicin 80 mg labeled with 4 mC i Tc 99m DTPA, diluted to 2 mi were placed in a jet nebulizer (JN) dri ven by an airflow of 5.5 l/min, For System B, the volume fill was 4 mi and the flow 10 l/min, The mass median diameter (MMD) of aerosol in S ystem A and B was 4.4 m and 3.1 m, respectively, The nebulizer in Syst em B released twice the volume (3.47 +/- 0.04 mi) of gentamicin soluti on compared to System A (1.71 +/- 0.03 mi) during similar nebulization time, Intrathoracic deposition was 4.0 +/- 2.7% for System A and 7.1 +/- 2.8% for System B. Lung deposition in patients inhaling from Syste m A and B was 3.2 +/- 1.8% and 6.2 +/- 2.1%, respectively (p < 0.05). This study demonstrates that operating conditions of the JN can marked ly affect the dose of antibiotic deposited in the lung, Thus, using gr eater volume fill and higher flow rate markedly increases the intra pu lmonary deposition of antibiotic in adolescents.