Respiratory system mechanics in patients receiving aerosolized ribavirin during mechanical ventilation for suspected respiratory syncytial viral infection.

Respiratory syncytial virus (RSV) is an important respiratory pathogen for infants. Aerosolized ribavirin (AR) has been used in mechanically ventilated (MV) patients with RSV bronchiolitis. The purpose of this study was to measure respiratory system mechanics (RSM) in pediatric patients requiring MV and receiving AR for suspected RSV. Patients were prospectively randomized to receive AR, either at a regular dose (RD) (6 g/300 mL over 18 hr/day) or a high dose (HD) (6 g/100 mL over 2 hr, three times a day). To measure changes in RSM, a passive exhalation technique was used before and after each dose of AR; time constant (tc) in s, resistance (Rrs) in cmH(2)O/mL/kg/s, and quasistatic compliance (Crs) in mL/cmH(2)O/kg were measured. Airway pressure and flow signals were obtained and analyzed using a pneumotachograph, a differential pressure transducer, and a computer interface. Statistical analysis was done by Mann-Whitney and Wilcoxon rank tests. Thirteen patients were enrolled: 5 patients in the HD group (mean age of 52 months), and 8 patients in the RD group (mean age of 10 months). Four and 5 patients were positive for RSV by ELISA in the HD and RD groups, respectively. The RSM in the HD group were: tc, 0.58 +/- 0.15 s and 0.55 +/- 0.20 s before and after AR, respectively; Rrs, 0.03 +/- 0. 03 cmH(2)0/mL/kg/s and 0.02 +/- 0.02 cmH(2)0/mL/kg/s, respectively; and Crs, 0.63 +/- 0.21 mL/cmH(2)O/kg and 0.70 +/- 0.13 mL/cmH(2)O/kg, respectively. In the RD group, the RSM were: tc, 0.37 +/- 0.12 s and 0.31 +/- 0.10 s before and after AR, respectively; Rrs, 0.03 +/- 0.02 cmH(2)0/mL/kg/s and 0.02 +/- 0.01 cmH(2)0/mL/kg/s, respectively (P < 0.05); and Crs, 0.46 +/- 0.20 mL/cmH(2)O/kg and 0.46 +/- 0.19 mL/cmH(2)O/kg, respectively. We conclude that the use of AR for bronchiolitis in infants and young children during mechanical ventilation does not worsen RSM.