Hoda Rabea

Modelling of in-vitro and in-vivo performance of aerosol emitted from different vibrating mesh nebulisers in non-invasive ventilation circuit

&NA; Substituting nebulisers by another in non‐invasive ventilation circuit (NIV) involves many process variables which must be adjusted to ensure patient optimum therapy. However, there is a doubt when nebulisers use the same technology. Data mining technology based on artificial neural networks and genetic algorithms were used here to model in‐vitro inhalation process and predict bioavailability from inhaled doses delivered by three different vibrating mesh nebulisers (VMNs) in NIV. Modelling of data indicated that in‐vitro performance of VMNs was dependent mainly on fine particle fraction, mass median aerodynamic diameter (MMAD), total emitted dose (TED) and to lesser extent on nebuliser type. Ex‐vivo model indicated that amount of salbutamol collected on facemask filter was directly affected by TED. In‐vivo model showed that amount of salbutamol deposited into the lung (0.5 hQ) and amount absorbed systemically (24 hQ) were dependent directly on MMAD and TED. Female patients showed higher 24 hQ values than males. Nebuliser type affected TED, 0.5 hQ but not 24 hQ values. Results indicate suitability of VMNs in achieving appropriate in‐vitro inhalation performance model. The results also, indicate that the three VMNs are comparable and can be interchanged with no fear of any additional toxicity. Graphical abstract Figure. No caption available.

In vitro aerodynamic characteristics of aerosol delivered from different inhalation methods in mechanical ventilation

Abstract Aerodynamic characteristics of aerosol delivery during invasive mechanical ventilation (IMV) are mostly determined by inserting cascade impactor in the circuit. Impactor might have some effect on airflow within IMV. Hence, the aim of the present study was to develop and evaluate new in vitro aerodynamic characterization methodology without affecting airflow in IMV. Breathing simulator was set in standard adult IMV circuit with inspiratory and expiratory pressures of 20 and 5 cm H2O, 1:3 inspiratory–expiratory ratio, 15 breaths min−1, and tidal volume of 500 ml. Two ml of salbutamol solution containing 10,000 μg was nebulized using three different vibrating mesh nebulizers (VMNs) and Sidestream jet nebulizer (JET). Sixteen-metered doses, containing 100 μg salbutamol each, were delivered using three different spacers. Each device was placed in inspiration limb of Y-piece of ventilator tubing. Aerodynamic characteristics of aerosol delivered were measured using cooled Andersen cascade impactor, with mixing inlet connected to it. VMNs used had significantly more total mass in the impactor (p < .001) and fine particle dose (p < .001) compared to JET. Spacers used had higher total mass in the impactor percent (p < .001) and fine particle fraction compared to nebulizers. The in vitro IMV methodology setting suggested here showed encouraging results in comparison of different aerosol delivery systems in intubated patient.

Lung deposition and systemic bioavailability of different aerosol devices with and without humidification in mechanically ventilated patients

Background: During mechanical ventilation medical aerosol delivery has been reported to be upto two fold greater with dry inhaled gas than with heated humidity. Urine levels at 0.5 h post dose (URSAL0.5%) has been confirmed as an index of lung deposition and 24 h (URSAL24%) as index of systemic absorption. Our aim was to determine the effect of humidification and aerosol device type on drug delivery to ventilated patients using urine levels. Methods: In a randomized crossover design, 36 (18female) mechanically ventilated patients were assigned to one of three groups. Groups 1 and 2 received 5000 &mgr;g salbutamol using vibrating mesh (VM) and jet nebulizers (JN), respectively, while group 3 received 1600 &mgr;g (16 puffs) of salbutamol via metered dose inhaler with AeroChamber Vent (MDI‐AV). All devices were placed in the inspiratory limb of ventilator downstream from the humidifier. Each subject received aerosol with and without humidity at >24 h intervals with >12 h washout periods between salbutamol doses. Patients voided urine 15 min before each study dose and urine samples were collected at 0.5 h post dosing and pooled for the next 24 h. Results: The MDI‐AV and VM resulted in a higher percentage of urinary salbutamol levels compared to the JN (p < 0.05). Urine levels were similar between humidity and dry conditions. Conclusions: Our findings suggest that in‐vitro reports overestimate the impact of dry vs. heated humidified conditions on the delivery of aerosol during invasive mechanical ventilation.

Effect of a Nebulizer Holding Chamber on Aerosol Delivery

BACKGROUND: A new holding chamber was designed to be used with the Aerogen Solo nebulizer to increase the aerosol emitted that reach the patient. The aim of this study was to evaluate the efficacy of this holding chamber with the nebulizer and determine its usability with other nebulizers. METHODS: The study was divided into 2 parts. In the first part, aerosol emitted of 1 mL respirable solution (nominal dose of 5000 μg salbutamol), delivered by using the mesh nebulizer, Pro nebulizer, and jet nebulizer, connected to a T-piece or a holding chamber, was determined by using a breathing simulator set to provide a tidal volume of 500 mL, frequency of 15 breaths/min, and the inspiratory-expiratory ratio of 1:1 for adults as the quiet breathing pattern. Aerodynamic particle size characterizations were determined by using a cooled cascade impactor at an inhalation flow of 15 L/min. In the second part of the study, 12 healthy nonsmoking subjects (6 females) >18 y, with an FEV1 > 90% were enrolled. Inhaled aerosol of 1 mL respirable solution (5,000 μg salbutamol) was delivered through the mesh nebulizer–holding chamber and an mesh nebulizer–T-piece using normal tidal breathing. The subjects provided urine samples 30 min after dosing and cumulatively collected their urine for 24 h. The samples were analyzed for salbutamol content. RESULTS: The holding chamber significantly increased aerosol emitted by the 3 nebulizers compared with the T-piece (P < .01) and relatively decreased the mass median aerodynamic diameter but with no significant difference. The mesh nebulizer–holding chamber resulted in significantly higher aerosol emitted compared with any other delivery method tested (P < .01). The mesh nebulizer–holding chamber resulted in higher urine samples 30 min after dosing (as an index of lung deposition) and cumulatively collected urine for 24 h (as an index of systemic absorption) compared with the nebulizer–T-piece (P < .05). CONCLUSIONS: The use of the holding chamber with a jet nebulizer, Pro nebulizer, and the Solo nebulizer significantly increased the aerosol delivery. The Solo nebulizer–holding chamber had the highest aerosol emitted compared with all nebulizer-adapter combinations and higher urine samples 30 min after dosing and cumulatively collected urine for 24 h compared with the nebulizer–T-piece.

Modeling and optimization of nebulizers' performance in non-invasive ventilation using different fill volumes: Comparative study between vibrating mesh and jet nebulizers

BACKGROUNDS Substituting nebulisers by another, especially in non-invasive ventilation (NIV), involves many process-variables, e.g. nebulizer-type and fill-volume of respirable-dose, which might affect patient optimum-therapy. The aim of the present work was to use neural-networks and genetic-algorithms to develop performance-models for two different nebulizers. METHODS In-vitro, ex-vivo and in-vivo models were developed using input-variables including nebulizer-type [jet nebulizer (JN) and vibrating mesh nebulizer (VMN)] fill-volumes of respirable dose placed in the nebulization chamber with an output-variable e.g. average amount reaching NIV patient. Produced models were tested and validated to ensure effective predictivity and validity in further optimization of nebulization process. RESULTS Data-mining produced models showed excellent training, testing and validation correlation-coefficients. VMN showed high nebulization efficacy than JN. JN was affected more by increasing the fill-volume. The optimization process and contour-lines obtained for in-vivo model showed increase in pulmonary-bioavailability and systemic-absorption with VMN and 2 mL fill-volumes. CONCLUSIONS Modeling of aerosol-delivery by JN and VMN using different fill-volumes in NIV circuit was successful in demonstrating the effect of different variable on dose-delivery to NIV patient. Artificial neural networks model showed that VMN increased pulmonary-bioavailability and systemic-absorption compared to JN. VMN was less affected by fill-volume change compared to JN which should be diluted to increase delivery.

Effects of Fill Volume and Humidification on Aerosol Delivery During Single-Limb Noninvasive Ventilation

BACKGROUND: The aim of this work was to determine the effect of fill volume and humidification change on aerosol delivery during single-limb noninvasive ventilation (NIV). METHODS: Four groups were recruited, each consisting of 12 subjects (6 females) with COPD receiving NIV. Groups 1 and 3 received inhaled salbutamol with a vibrating mesh nebulizer, and Groups 2 and 4 received inhaled salbutamol with a jet nebulizer. The in vivo study was carried out on days 1 and 3. In groups 1 and 2, 2 fill-volumes were delivered to each subject; 1 mL 5,000 μg/mL salbutamol respirable solution used as it is or diluted to a total of 2 mL using normal saline. In groups 3 and 4, 1 mL 5,000 μg/mL salbutamol respirable solution diluted to 2 mL total volume using normal saline was delivered to each subject with and without humidification. Unchanged salbutamol in urine at 30 min (USAL0.5) and in pooled urine at 24 h (USAL24) was determined. On day 2, the ex vivo study was carried out on subjects using the same experimental setting with a filter placed proximal to their face mask for collection of total inhaled dose of salbutamol (aerosol emitted). RESULTS: The vibrating mesh nebulizer delivered higher USAL0.5, USAL24, and aerosol emitted compared to the jet nebulizer at all fill volumes and humidification conditions (P < .001). Increasing fill volume from 1 mL to 2 mL resulted in a significant increase in USAL0.5, USAL24, and aerosol emitted from the jet nebulizer (P < .05) with an insignificant effect on the vibrating mesh nebulizer. A 2-mL fill volume with the jet nebulizer delivered USAL24 and aerosol emitted comparable to those of 1 mL with the vibrating mesh nebulizer with significantly longer nebulization times (P < .001). Humidification had an insignificant effect on aerosol delivery. CONCLUSIONS: Increasing the fill volume of a jet nebulizer is essential to increase the amount of inhaled medication reaching a subject. In contrast, there is no need to increase fill volumes when using a vibrating mesh nebulizer. There is no need to switch off the humidifier while delivering aerosol through a single-limb NIV circuit.

Performance of Large Spacer Versus Nebulizer T-Piece in Single-Limb Noninvasive Ventilation

BACKGROUND: Predosing patients with COPD with salbutamol by using a pressurized metered-dose-inhaler (pMDI) as a bronchodilator was hypothesized to improve the distribution of the subsequent nebulized dose. This study determined the effect of a pMDI preliminary bronchodilator dose on the aerosol delivered by a mesh nebulizer during single-limb noninvasive ventilation. METHODS: Twelve subjects with COPD who received noninvasive ventilation were enrolled in a randomized, open-label, urinary pharmacokinetic study. A bi-level ventilator with a dry single-limb circuit and the fixed expiratory port was set in the spontaneous mode, with initial inspiratory and expiratory pressures of 20 and 5 cm H2O respectively, a 1:3 inspiratory-expiratory ratio, and 15 breaths/min. Salbutamol was administered via a mesh nebulizer with a large spacer or T-piece placed between the fixed-orifice expiratory valve and the oronasal mask. In vivo dosing methods were randomized for days 1, 3, and 5 of the study. On each day, a 1-mL respirable solution that contained 5,000 μg salbutamol was nebulized by using a mesh nebulizer with 3 setting: (1) T-piece, (2) large spacer, and (3) large spacer plus pMDI. Only with the large spacer plus pMDI setting, 2 pMDI doses, which contained 100 μg salbutamol each, were actuated before nebulization. Urine samples were collected at 0.5 h (as an index of pulmonary bioavailability) and pooled up to 24 h after dosing (as an index of systemic absorption). On day 2, ex vivo studies were performed for the 3 setting with salbutamol collected onto filters placed before the mask. The drug was eluted from the filters and analyzed to determine the inhaled dose. RESULTS: A large spacer plus pMDI showed a trend to deliver a higher fraction (percentage of nominal dose) of both ex vivo filters and 0.5-h urinary salbutamol. The 0.5-h urinary salbutamol excreted with a large spacer plus pMDI (1.99%) was larger than with the T-piece (1.73%) and large spacer (1.78%). This trend did not extend to the 24-h levels, in which bioavailability with the large spacer plus pMDI (49.9%) was lower than with the T-piece (52.8%) and with the large spacer (54.3%). However, no differences were significant. CONCLUSIONS: The T-piece and large spacer were equally efficient for salbutamol delivery from the mesh nebulizer in patients with COPD and on single-limb noninvasive ventilation. Adding a preliminary bronchodilator dose by pMDI prenebulization showed a trend toward greater pulmonary bioavailability of nebulized salbutamol and may be worth considering to maximize delivery of salbutamol to patients who are severely ill.

Total emitted dose of salbutamol sulphate at different inhalation flows and inhalation volumes through different types of dry powder inhalers

Abstract The aim of the present study was to compare the performance of two different dry powder inhalers (DPIs) at different inhalations volumes and inhalation flows. Ventolin Diskus contain blisters of 200µg salbutamol. To test the TED from Aerolizer, salbutamol in Diskus blister was emptied and placed in size 3 capsules suitable for use with Aerolizer. Total emitted dose (TED) delivered by Diskus and Aerolizer was determined using DPI sampling apparatus after one and two inhalations from the same dose. 10-60L/min inhalation flows at 2 and 4L inhalation volume were used in the determination. At inhalation flow ≤30L/min, two inhalations resulted in higher TED than one inhalation (p < 0.05) and Diskus resulted in higher TED than Aerolizer (p < 0.05). The highest TED was at inhalation flow 40L/min above which the effect of the second inhalation and formula device relation were negligible. Device formula relation is present at low inhalation flow but at flow >30L/min Diskus drug formula can be delivered by Aerolizer with no significant difference in TED produced. For the best TED patients are required to inhale as fast as possible (a minimum of 40L/min). At lower inhalation flow two inhalations results in better emitted dose than one inhalation for both DPIs. So, we recommend patients with poor inspiratory efforts to inhale twice and as hard and deep as possible from each dose as they may not receive much benefit from one inhalation even when using DPI with low resistance (Aerolizer) or medium resistance (Diskus). However, further in-vivo study are required to validate this recommendtation.

Transradial artery approach in STEMI patients reperfused early and late by either primary PCI or pharmaco-invasive approach☆☆☆

Highlights • There was a non-significant difference regarding LVEF and TIMI flow between both PPCI and PI.• Myocardium wall preservation was significant in early PI (P = 0.023)• Mean procedural and fluoroscopic time were 35.1 ± 6.1 and 6.3 ± 0.9 min.• No reported entry site complications also no difference in primary end point (P = 0.326).• It is safe and effective to use TRA in STEMI patients who reperfused by either early or late PPCI or PI.