Mode of breathing-tidal or slow and deep-through the I-neb Adaptive Aerosol Delivery (AAD) system affects lung deposition of (99m)Tc-DTPA

Abstract

Background: The I-neb AAD System was designed to deliver aerosol with two different breathing pattern algorithms: the Tidal Breathing Mode (TBM) and the Target Inhalation Mode (TIM). For the purpose of the study, the TBM breathing pattern algorithm was set to guide the subjects to inhalation during tidal breathing with aerosol pulsed during 50-80% of the time spent on inhalation, whereas the TIM breathing pattern was set to guide the subject to a slow and deep inhalation of up to approximately 9 sec with aerosol pulsed for up to 7 sec, leaving 2 sec for particle deposition in the lungs. In TIM, the inspiratory flow was guided to approximately 20 L/min through a built-in resistance in the mouthpiece.

Methods: We have, in a randomized, open-label, crossover study of 12 healthy subjects evaluated lung deposition following administration of a radiolabeled aerosol from the I-neb AAD System with the TBM and TIM breathing patterns.

Results: The results showed that mean lung deposition was significantly higher when using the I-neb AAD System with the TIM breathing pattern (73.3%) than with the TBM breathing pattern (62.8%). The mean exhaled fractions were low (<1%) for both breathing patterns. The nebulization time was significantly shorter with the TIM breathing pattern (3.0 min) than with the TBM breathing pattern (4.7 min).

Conclusions: The results of the present study showed that lung deposition with the slow and deep inhalation achieved through the I-neb AAD System in TIM was superior to the lung deposition achieved during tidal breathing in TBM. With the combination of high lung deposition, almost no loss of aerosol during exhalation, and short nebulization time the I-neb AAD System with the TIM breathing pattern should be of special value to patients who require multiple daily dosing of aerosolized medication, are using drugs that should not be wasted into the room air, or would benefit from a more efficient delivery system.

FIG. 1.

The I-neb Adaptive Aerosol Delivery (AAD) System. The main components of the device are the mouthpiece, the medication chamber assembly, and the body. The I-neb AAD System has been designed to deliver aerosol with two different breathing pattern algorithms, the Tidal Breathing Mode (TBM) and the Target Inhalation Mode (TIM). In TIM the inspiratory flow through the valve in the mouthpiece is limited to ∼20 L/min.

FIG. 2.

Graphical presentation of the two breathing patterns used with the I-neb Adaptive Aerosol Delivery (AAD) System. The first part of the graph shows the patient's tidal breathing when using the I-neb AAD System in Tidal Breathing Mode (TBM). The second, third and last parts of the graph show the process to extend the patient's slow and deep inhalations from a 3-sec inhalation (1-sec aerosol pulse) to a 9-sec inhalation (7-sec aerosol pulse) when using the I-neb AAD System in Target Inhalation Mode (TIM).

FIG. 3.

Deposition of ^99mTc-DTPA labeled saline presented in percentage of emitted dose ex-mouthpiece from the I-neb Adaptive Aerosol Delivery (AAD) System when run in Tidal Breathing Mode (TBM; black) and Target Inhalation Mode (TIM; gray) breathing patterns.

FIG. 4.

Posterior lung deposition image of ^99mTc-DTPA delivered with the I-neb Adaptive Aerosol Delivery (AAD) System when run in Tidal Breathing Mode (A) and Target Inhalation Mode (B) breathing patterns for subject 4.