Aerosol delivery aspects within a high-flow therapy system in COPD patients

Performance Characterisation of the Airvo2TM Nebuliser Adapter in Combination with the Aerogen SoloTM Vibrating Mesh Nebuliser for in Line Aerosol Therapy during High Flow Nasal Oxygen Therapy

High flow oxygen (HFO) therapy is a well-established treatment in respiratory disease. Concurrent aerosol delivery can greatly expediate their recovery. The aim of this work was to complete a comprehensive characterisation of one such HFO therapy system, the Airvo2TM, used in combination with the Aerogen SoloTM vibrating mesh nebuliser. Representative adult, infant, and paediatric head models were connected to a breathing simulator via a collection filter placed at the level of the trachea. A tracheostomy interface and nasal cannulas were used to deliver the aerosol. Cannula size and gas flow rate were varied across the full operating range recommended by the manufacturer. The tracheal and emitted doses were quantified via UV-spectrophotometry. The aerosol droplet diameter at the exit of the nares and tracheal interface was measured via cascade impaction. High gas flow rates resulted in low emitted and tracheal doses (%). Nasal cannula size had no significant effect on the tracheal dose (%) available in infant and paediatric models. Higher gas flow rates resulted in smaller aerosol droplets at the exit of the nares and tracheostomy interface. Gas flow rate was found to be the primary parameter affecting aerosol delivery. Thus, gas flow rates should be kept low and where possible, delivered using larger nasal cannulas to maximise aerosol delivery.

Comparison of the Application of Vibrating Mesh Nebulizer and Jet Nebulizer in Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

Objective

To comparison of the application of Vibrating Mesh Nebulizer and Jet Nebulizer in chronic obstructive pulmonary disease (COPD).

Research Methods

This systematic review and meta-analysis was conducted following the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) statements. The primary outcome measures analyzed included: The amount of inhaler in the urine sample at 30 minutes after inhalation therapy (USAL0.5), The total amount of inhaler in urine sample within 24 hours (USAL24), Aerosol emitted, Forced expiratory volume in 1 second (FEV1), Forced vital capacity (FVC).

Results

Ten studies were included with a total of 314 study participants, including 157 subjects in the VMN group and 157 subjects in the JN group. The data analysis results of USAL0.5, MD (1.88 [95% CI, 0.95 to 2.81], P = 0.000), showed a statistically significant difference. USAL24, MD (1.61 [95% CI, 1.14 to 2.09], P = 0.000), showed a statistically significant difference. The results of aerosol emitted showed a statistically significant difference in MD (3.44 [95% CI, 2.84 to 4.04], P = 0.000). The results of FEV1 showed MD (0.05 [95% CI, -0.24 to 0.35], P=0.716), the results were not statistically significant. The results of FVC showed MD (0.11 [95% CI, -0.18 to 0.41], P=0.459), the results were not statistically significant. It suggests that VMN is better than JN and provides higher aerosols, but there is no difference in improving lung function between them.

Conclusion

VMN is significantly better than JN in terms of drug delivery and utilization in the treatment of patients with COPD. However, in the future use of nebulizers, it is important to select a matching nebulizer based on a combination of factors such as mechanism of action of the nebulizer, disease type and comorbidities, ventilation strategies and modes, drug formulations, as well as cost-effectiveness, in order to achieve the ideal treatment of COPD.

Aerosol delivery through high-flow nasal therapy: Technical issues and clinical benefits

High-flow nasal cannula (HFNC) therapy is an oxygen delivery method particularly used in patients affected by hypoxemic respiratory failure. In comparison with the conventional "low flow" oxygen delivery systems, it showed several important clinical benefits. The possibility to nebulize drugs via HFNC represents a desirable medical practice because it allows the administration of inhaled drugs, mostly bronchodilators, without the interruption or modification of the concomitant oxygen therapy. HFNC, by itself has shown to exert a small but significant bronchodilator effect and improves muco-ciliary clearance; thus, the nebulization of bronchodilators through the HFNC circuit may potentially increase their pharmacological activity. Several technical issues have been observed which include the type of the nebulizer that should be used, its position within the HFNC circuit, and the optimal gas flow rates to ensure an efficient drug delivery to the lungs both in "quiet" and "distressed" breathing patterns. The aim of this review has been to summarize the scientific evidence coming from "in vitro" studies and to discuss the results of "in vivo" studies performed in adult subjects, mainly affected by obstructive lung diseases. Most studies seem to indicate the vibrating mesh nebulizer as the most efficient type of nebulizer and suggest to place it preferentially upstream from the humidifier chamber. In a quite breathing patterns, the inhaled dose seems to increase with lower flow rates while in a "distressed" breathing pattern, the aerosol delivery is higher when gas flow was set below the patient's inspiratory flow, with a plateau effect seen when the gas flow reaches approximately 50% of the inspiratory flow. Although several studies have demonstrated that the percentage of the loaded dose nebulized via HFNC reaching the lungs is small, the bronchodilator effect of albuterol seems not to be impaired when compared to the conventional inhaled delivery methods. This is probably attributed to its pharmacological activity. Prospective and well-designed studies in different cohort of patients are needed to standardize and demonstrate the efficacy of the procedure.

Effect of oxygen flow on aerosol delivery from a vibrating mesh nebulizer with a holding chamber

Background

A holding chamber (HC) was created to work with a vibrating mesh nebulizer (VMN) to boost the total inhalable dose for patients. In addition to the optional supply of supplemental oxygen, it facilitates intermittent and continuous nebulization. Our goal was to see how well a VMN coupled to a HC with a mouthpiece or valved facemask performed at varied oxygen flows starting at 0–6 L/min. In this study, we used a breathing simulator to simulate adults' spontaneous breathing patterns with a tidal volume of 500 mL and a 1:1 inhalation–exhalation ratio. For the combination of nebulizer and HC adapter with a valved facemask or mouthpiece, five determinations were made. Salbutamol was recovered and evaluated using high-performance liquid chromatography from the inhalation filter connected to the breathing simulator, the nebulizer reservoir chamber, and the HC.

Results

The amount of salbutamol in the nebulizer reservoir chamber and within the HC did not differ significantly when using a mouthpiece or a valved facemask. However, the supplied dose to the inhalation filter was increased until oxygen flow reached 2 and 3 L/min using the mouthpiece and valved facemask as interfaces, respectively. The supplied salbutamol was much higher at this flow than at the other oxygen flows. This was followed by a progressive reduction in the supplied salbutamol until the lowest given dose was reached at 6 L/min oxygen flow, p < 0.005.

Conclusions

The supplied doses of salbutamol to the inhalation filter were variable with the VMN connected to the HC and mouthpiece or valved facemask, with significant improvements until an oxygen flow of 2 L/min with a mouthpiece and 3 L/min with a valved facemask, followed by gradual decreases to lower values at an oxygen flow of 6 L/min. An in vivo investigation is required to further validate the findings.

Effect of pressures and type of ventilation on aerosol delivery to chronic obstructive pulmonary disease patients

Background

Continuous Positive Airway Pressure (CPAP), BiPhasic Positive Airway Pressure (BiPAP), and high flow nasal cannula (HFNC) show some evidence to have efficacy in COVID-19 patients. Delivery during noninvasive mechanical ventilation (NIV) or HFNC gives faster and more enhanced clinical effects than when aerosols are given without assisted breath. The present work aimed to compare the effect of BiPhasic Positive Airway Pressure (BiPAP) mode at two different pressures; low BiPAP (Inspiratory Positive Airway Pressure (IPAP)/Expiratory Positive Airway Pressure (EPAP) of 10/5 cm water) and high BiPAP (IPAP/EPAP of 20/5 cm water), with HFNC system on pulmonary and systemic drug delivery of salbutamol. On the first day of the experiment, all patients received 2500 μg salbutamol using Aerogen Solo vibrating mesh nebulizer. Urine samples 30 min post-dose and cumulative urinary salbutamol during the next 24 h were collected on the next day. On the third day, the ex-vivo filter was inserted before the patient to collect the delivered dose to the patient of the 2500 μg salbutamol. Salbutamol was quantified using high-performance liquid chromatography (HPLC).

Results

Low-pressure BiPAP showed the highest amount delivered to the lung after 30 min followed by HFNC then high-pressure BiPAP. But the significant difference was only observed between low and high-pressure BiPAP modes (p = 0.012). Low-pressure BiPAP showed the highest delivered systemic delivery amount followed by HFNC then high-pressure BiPAP. Low-pressure BiPAP was significantly higher than HFNC (p = 0.017) and high-pressure BiPAP (p = 0.008). No significant difference was reported between HFNC and high-pressure BiPAP. The ex-vivo filter was the greatest in the case of low-pressure BiPAP followed by HFNC then high-pressure BiPAP. Low-pressure BiPAP was significantly higher than HFNC (p = 0.033) and high-pressure BiPAP (p = 0.008). Also, no significant difference was found between HFNC and high-pressure BiPAP.

Conclusions

Our results of pulmonary, systemic, and ex-vivo drug delivery were found to be consistent. The low BiPAP delivered the highest amount followed by the HFNC then the high BiPAP with the least amount. However, no significant difference was found between HFNC and high BiPAP.

Preliminary bronchodilator dose effect on aerosol-delivery through different nebulizers in noninvasively ventilated COPD patients

Objectives: This study aimed to evaluate the effect of a preliminary bronchodilator dose on the aerosol-d elivery by different nebulizers in noninvasively ventilated chronic obstructive pulmonary disease (COPD) patients. Method: COPD patients were randomized to receive study doses of 800 µg beclomethasone dipropionate (BPD) nebulized by either a vibrating mesh nebulizer (VMN) or a jet nebulizer (JN) connected to MinimHal spacer device. On a different day, the nebulized dose of beclomethasone was given to each patient by the same aerosol generator with and without preceded two puffs (100 µg each) of salbutamol delivered by a pressurized-metered dose inhaler. Urinary BPD and its metabolites in 30 min post-inhalation samples and pooled up to 24 h post-inhalation were measured. On day 2, ex-vivo studies were performed with BPD collected on filters before reaching patients which were eluted from filters and analyzed to estimate the total emitted dose.Results: The highest urinary excretion amounts of BPD and its metabolites 30 min and 24 h post-inhalation were identified with pMDI + VMN compared with other regimens(p < 0.001). The amounts of BPD and its metabolites excreted 30 min post inhalation had approximately doubled with pMDI + JN compared with JN delivery (p < 0.05). No significant effect was found in the ex-vivo study results except between VMN and JN with a significant superiority of the VMN (p < 0.001).Conclusion: Using a preliminary bronchodilator dose before drug nebulization significantly increased the effective lung dose of the nebulized drug with both VMNs and JNs. However, adding a preliminary bronchodilator dose increased the 24 hr cumulative urinary amount of the drug representing higher systemic delivery of the drug, which in turn could result in higher systemic side effects.

Real-life assessment of chronic obstructive pulmonary disease patient performance with different inhalers

PURPOSE

This study aimed to evaluate handling of six common inhalers and to determine correlations between correct inhaler technique and patient demographics/ clinical variables.

METHODS

A total of 180 chronic obstructive pulmonary disease (COPD) patients were crossed-over to handle their past-experienced inhalers among (pMDI, Aerolizer, Handihaler, Breezhaler, Turbohaler, and Diskus) randomly, without receiving verbal or demonstrative instruction (baseline assessment). Inhaler technique was assessed using previously defined checklists. The correct use of the inhaler was then demonstrated and the patient was evaluated for inhaler use again. Demonstration was repeated until a correct technique was achieved. Number of counselling attempts needed to a complete right handling, patient demographics and clinical variables were recorded.

RESULTS

The mean percentage of total correct steps showed that pMDI is significantly lower than all other inhalers (76.01 ± 12.61 vs 84.18 ± 10.87, 84.60 ± 12.10, 85.91 ± 9.82, 90.63 ± 9.29 and 91 ± 10.22 for Diskus, Turbohaler, Aerolizer, Handihaler and Breezhaler, respectively, at P < .001). Breezhaler showed the lowest percentage of participants with at least 1 critical error (20%) however, pMDI showed the highest percentage (85.19%) at P < .05. Breezhaler showed that the highest percentage of participants achieved a complete right handling after 1st counselling attempt, however, pMDI was the only inhaler included in a 3rd and 4th counselling attempts (5.93% and 0.74%, respectively). Weak and very weak correlations were found between total correct steps and demographics/clinical variables.

CONCLUSIONS

pMDI is not preferable for handling by COPD patients. DPIs vary in ease of use, so that inhaler therapy must be individualised on basis of patient handling assessment with repeated counselling.