Aerosol delivery with two ventilation modes during mechanical ventilation: a randomized study

Abstract

BackgroundVolume-controlled ventilation has been suggested to optimize lung deposition during nebulization although promoting spontaneous ventilation is targeted to avoid ventilator-induced diaphragmatic dysfunction. Comparing topographic aerosol lung deposition during volume-controlled ventilation and spontaneous ventilation in pressure support has never been performed. The aim of this study was to compare lung deposition of a radiolabeled aerosol generated with a vibrating-mesh nebulizer during invasive mechanical ventilation, with two modes: pressure support ventilation and volume-controlled ventilation.MethodsSeventeen postoperative neurosurgery patients without pulmonary disease were randomly ventilated in pressure support or volume-controlled ventilation. Diethylenetriaminepentaacetic acid labeled with technetium-99m (2 mCi/3 mL) was administrated using a vibrating-mesh nebulizer (Aerogen Solo®, provided by Aerogen Ltd, Galway, Ireland) connected to the endotracheal tube. Pulmonary and extrapulmonary particles deposition was analyzed using planar scintigraphy.ResultsLung deposition was 10.5 ± 3.0 and 15.1 ± 5.0 % of the nominal dose during pressure support and volume-controlled ventilation, respectively (p < 0.05). Higher endotracheal tube and tracheal deposition was observed during pressure support ventilation (27.4 ± 6.6 vs. 20.7 ± 6.0 %, p < 0.05). A similar penetration index was observed for the right (p = 0.210) and the left lung (p = 0.211) with both ventilation modes. A high intersubject variability of lung deposition was observed with both modes regarding lung doses, aerosol penetration and distribution between the right and the left lung.ConclusionsIn the specific conditions of the study, volume-controlled ventilation was associated with higher lung deposition of nebulized particles as compared to pressure support ventilation. The clinical benefit of this effect warrants further studies.Clinical trial registration NCT01879488Electronic supplementary materialThe online version of this article (doi:10.1186/s13613-016-0169-x) contains supplementary material, which is available to authorized users.

Nebulized antibiotics in mechanically ventilated patients: a challenge for translational research from technology to clinical care

“…A nebulizer operating continuously during both insufflation and expiration should be placed in the inspiratory limb, 15–40 cm upstream of the Y -piece [ 11 , 17 ]. The optimal distance from the Y -piece depends on bias flow and the circuit section.…”

“…Ventilator settings that enhance nebulization efficacy include a low respiratory frequency, low inspiratory flow and increased inspiratory time [ 14 , 26 ]. Volume-controlled ventilation with constant low inspiratory flow increases efficacy compared to pressure-controlled ventilation (high peak flow followed by deceleration) [ 17 , 27 ]. An end inspiratory pause may facilitate the settling of aerosol particles in the lung [ 26 ].…”

Aerosolized Amikacin as Adjunctive Therapy of Ventilator-associated Pneumonia Caused by Multidrug-resistant Gram-negative Bacteria

“…[16] Third, to optimize the drug delivery and to improve the deposition of amikacin particles in the deep lung tissue, a nebulization procedure protocol including operational specification, nebulizer type, drug formulation, and ventilator settings were optimized and standardized before the beginning of this study and carefully followed up during the study. [1718192021] We believed that these three improvements make our results to be a better evaluation of the therapeutic effects of AA on VAP caused by MDR-GNB.…”

Study of the disposition of nebulized tobramycin

“…The in vitro particle sizing study showed that 99% particles were in the 1-5 µm size range. This could be one of the reasons for better penetration compared to that reported for DTPA and 99m Tc labelled human serum albumin (0.32 to 0.75) [280,285]. The correlation with actual drug concentrations will need to be investigated with further studies using other techniques.…”

“…For the aerosol deposition, this right-left lung asymmetry is in keeping with the findings in experimental settings [286,287] and is likely due to airway geometry and the interaction between aerosol particles and airflow, called the Stokes number. Other studies have reported a right preponderance for lung deposition of DTPA with a wide variability in deposition between the lungs [285]. One reason for the variations in the distribution could be the effect of formulation and physicochemical properties of the aerosol on the deposition preference [182].…”