In vitro evaluation of bronchodilator drug delivery by jet nebulization during pediatric mechanical ventilation

To determine the influence of jet nebulizer brands and nebulization mode on albuterol delivery in a mechanically ventilated pediatric lung model.

In vitro, laboratory study.

Research laboratory of a university hospital.

Using albuterol as a marker, six jet nebulizers (Microneb NA420, Sidestream, Acorn II, Cirrus, Upmist, Micro Mist) were tested in four nebulization modes in a bench model mimicking the ventilatory pattern of a 10-kg infant (Galileo ventilator, Hamilton Medical). The amounts of albuterol deposited on the inspiratory filters at the end of the endotracheal tube were determined, as well as the pressure, flow profiles, and particle size distribution of the jet nebulizers.

Pooling the data of the six jet nebulizer brands (n = 30) indicated that intermittent nebulization during the expiratory phase was more efficient (6.5 +/- 2.5% of the initial dose, p < .001) than intermittent nebulization during the inspiratory phase (1.9 +/- 1.2%) and continuous nebulization with air from the ventilator (4.0 +/- 1.5%) or from an external source (4.2 +/- 1.4%). The particle size distribution at 6 L x min(-1) was between 2.81 and 3.30 microm.

In our in vitro pediatric lung model, the quantity of inhaled drug was low. Jet nebulizer brands and nebulization modes significantly affected drug delivery, and in vitro models designed for adults cannot be extrapolated to infants.