Overcoming jet lag: optimizing aerosol delivery with and without jet nebulizers.

Early studies have shown that only a small fraction of the nominal nebulizer dose (1–12%) is available for delivery to the lungs in intubated children and adults.1-3 Since then, the characterization of forces governing aerosol delivery in ventilated patients has led to improvements in techniques, and the development of newer aerosol generators with the ability to deliver as much drug to ventilated patients as seen in the ambulatory setting.4 Optimizing aerosol nebulization in mechanically ventilated patients requires careful consideration of several factors that affect aerosol drug delivery. Major factors identified in the literature include nebulizer type and position within the circuit, timing of nebulization with respect to respiratory cycle, and humidification of the inspired gas.5 However, despite advances in the field, there is still no agreed upon or universally recommended method of aerosol delivery to ventilated patients. This may be due in part to difficulty reconciling disparities among various studies. The lack of standardization, and the introduction of numerous variables known to influence aerosol delivery, such as endotracheal tube size, tidal volumes, loading volume, inspiratory flow rates, bias flow, the external flow to jet nebulizers, and the overall volume of ventilator tubing used, create incongruences that hinder comparisons and, by extension, the development of definitive recommendations. This is especially important considering the higher cost of some of the more efficient systems described in the literature.