Albuterol Delivery During Invasive Mechanical Ventilation via In-Line Intrapulmonary Percussive Ventilation in a Pediatric Lung Model

Background:

Aerosol and airway clearance are simultaneously delivered with intrapulmonary percussive ventilation (Percussionaire, IPV). The device can be used during mechanical ventilation with an in-line adapter with adjustable pressure relief port that remains in the ventilator circuit, reducing the need for disconnection. Previous evaluations of in-line albuterol via IPV using a cone adapter reported low aerosol delivery. We hypothesized that opening the adapter will decrease aerosol delivery.

Methods:

The aim was to evaluate albuterol delivery via IPV using an in-line adjustable adapter during invasive mechanical ventilation with a pediatric lung model. A ventilator (Maquet, Servo-i) was connected in series to a dual limb circuit, 5.5 pediatric endotracheal tube with cuff inflated, filter (lung dose), and test lung set as ARDS (resistance Rp20, compliance 10 mL/mbar) or normal (Rp20, 30 mL/mbar). The adapter was placed in the inspiratory limb of the circuit at the wye. Pressure control ventilation was set to obtain V_T 100 with RR 20, PEEP 10, and I-time 0.8. Variables were IPV pressure (25 or 40), percussion (easy or hard), and adapter opening (closed, 25% or 50% open). Three different IPV nebulizers were loaded with albuterol 7.5 mg/9 mL and operated 15 min. Albuterol mass was measured via spectrophotometer and reported as percentage of loading dose. Bivariate analysis was performed to evaluate the different variables. Non-parametric tests Kruskal-Wallis (adapter opening) and Mann Whitney (IPV settings) were used.

Results:

Aerosol delivery ranged between 0.3 and 1.2% of the loading dose. The adapter setting had a significant effect on aerosol deposition in the ARDS model (P = .006). Opening the adapter 50% reduced aerosol delivery in both lung models but more on ARDS (P = .02). No statistical differences were found between pressures or percussion settings. This could be due in part to large variance of the measurements.

Conclusions:

In a pediatric model of mechanical ventilation, IPV with an in-line adapter results in very low deposition of albuterol. Opening the IPV adapter results in decreased lung deposition in an ARDS model. IPV settings (pressure and percussion) do not seem to affect lung deposition.

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