The Adaptive Aerosol Delivery (AAD) technology: Past, present, and future

Abstract

Conventional aerosol delivery systems and the availability of new technologies have led to the development of "intelligent" nebulizers such as the I-neb Adaptive Aerosol Delivery (AAD) System. Based on the AAD technology, the I-neb AAD System has been designed to continuously adapt to changes in the patient's breathing pattern, and to pulse aerosol only during the inspiratory part of the breathing cycle. This eliminates waste of aerosol during exhalation, and creates a foundation for precise aerosol (dose) delivery. To facilitate the delivery of precise metered doses of aerosol to the patient, a unique metering chamber design has been developed. Through the vibrating mesh technology, the metering chamber design, and the AAD Disc function, the aerosol output rate and metered (delivered) dose can be tailored to the demands of the specific drug to be delivered. In the I-neb AAD System, aerosol delivery is guided through two algorithms, one for the Tidal Breathing Mode (TBM), and one for slow and deep inhalations, the Target Inhalation Mode (TIM). The aim of TIM is to reduce the treatment time by increasing the total inhalation time per minute, and to increase lung deposition by reducing impaction in the upper airways through slow and deep inhalations. A key feature of the AAD technology is the patient feedback mechanisms that are provided to guide the patient on delivery performance. These feedback signals, which include visual, audible, and tactile forms, are configured in a feedback cascade that leads to a high level of compliance with the use of the I-neb AAD System. The I-neb Insight and the Patient Logging System facilitate a further degree of sophistication to the feedback mechanisms, by providing information on long term adherence and compliance data. These can be assessed by patients and clinicians via a Web-based delivery of information in the form of customized graphical analyses.

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 an 8-sec inhalation (7-sec aerosol pulse) when using the I-neb AAD System in Target Inhalation Mode (TIM). The magnified area above to the left shows how the waveform is monitored every 30 msec through the AAD software, which determines the slope of the curve over three consecutive 30-msec measurements. Two consecutive increases of at least 0.65 L/min indicate that an inhalation is about to start, and when the inspiratory flow rate >1.5 L/min the pulse of aerosol is triggered. The magnified area above to the right shows the end of the inhalation during TIM. The ΔT time provides a measurement of when the patient has reached his or her instantaneous residual lung capacity, and allows the AAD algorithm to increase or decrease the length of the target inhalation time.

FIG. 3.

The vibrating mesh of the I-neb Adaptive Aerosol Delivery (AAD) System in two different magnifications.

FIG. 4.

The medication chambers designed for the I-neb Adaptive Aerosol Delivery (AAD) System are shown, including the metering chamber (left) and the nonmetering chamber (right).

FIG. 5.

The mouthpiece of the I-neb Adaptive Aerosol Delivery (AAD) System. The design with an 8 degrees slant to the base of the mouthpiece has been made to ensure that the air flow from the inhalation valve is fed in evenly around the edge of the mesh, and mixes rapidly with the aerosol plume, which is retained in the center of the air flow to minimize losses on the internal surfaces of the mouthpiece.

FIG. 6.

The software program in the I-neb Insight can be used as a feedback tool to train patients to perform the slow and deep inhalations in TIM.

FIG. 7.

Through the Patient Logging System function in the I-neb Adaptive Aerosol Delivery (AAD) System, the clinician can identify patients who are not adhering to their treatment regimen, or not complying with the correct use of the I-neb AAD System. The graph shows number of treatments per day, and the legends are (•) complete treatment, (×) incomplete treatment, and (○) no treatment.