P292 Pilot study to assess bronchodilator response during an acute exacerbation of copd using a vibrating mesh nebuliser versus jet nebuliser for bronchodilator delivery

[Can mesh nebulizers improve prehospital aerosol therapy? An in vitro study on simulated prehospital emergency patients suffering from respiratory distress]

BACKGROUND

Nebulizers used to treat prehospital emergency patients should provide a high output efficiency to achieve a fast onset of therapeutic drug effects while remaining unaffected by the presence of supplementary oxygen flow or the patient's breathing pattern. On the other hand, nebulizer performance is directly influenced by differences in device design, gas flow and patients' breathing patterns. Several studies from emergency departments were able to demonstrate an improvement in patient outcome when using a mesh nebulizer instead of a jet nebulizer. Data or bench studies regarding prehospital care are non-existent.

OBJECTIVE

The aim of the present in vitro study was to evaluate which type of aerosol generator would best address the requirements of a prehospital adult emergency patient suffering from respiratory distress.

MATERIAL AND METHODS

We evaluated the performance of a jet nebulizer (Cirrus™ 2, Intersurgical®) and two mesh nebulizers (Aerogen Solo® with USB controller, Aerogen Limited and M‑Neb® mobile, NEBU-TEC International med. Produkte Eike Kern GmbH) with the possibility of portable operation in an in vitro model of a spontaneously breathing adult emergency patient. One physiological and three pathological breathing patterns (distressed breathing pattern as well as stable and acute exacerbated chronic obstructive pulmonary disease) were simulated. Nebulizer output and salbutamol lung deposition were measured at different oxygen flow rates using a face mask as the delivery interface.

RESULTS

The mesh nebulizers produced a significantly higher aerosol output when compared to the jet nebulizer. The M‑Neb® mobile was able to significantly exceed the output of the Aerogen Solo®. Oxygen flow had the largest influence on the output of the jet nebulizer but hardly affected the mesh nebulizers. After a nebulization time of 10 min the M‑Neb® mobile also achieved the highest total salbutamol lung deposition (P < 0.001). Aerosol drug deposition was therefore mainly determined by the nebulizer's drug output per unit time. The deposition could not be improved using a spacer but was strongly influenced by the simulated emergency patients' breathing pattern.

CONCLUSION

The use of mesh nebulizers might have the potential to improve the aerosol therapy of prehospital emergency patients. In general, mesh nebulizers seem to be superior to jet nebulizers regarding aerosol output per unit time and total lung deposition. The present data suggest that aerosol output and drug deposition to the collection filter in this simulated setting are closely connected and crucial for total salbutamol deposition, as the deposition could not be improved by adding a spacer. Aerosol drug deposition in simulated emergency patients' lungs is therefore mainly determined by the nebulizer's drug output per unit time. The level of oxygen flow used had the largest influence on the output of the jet nebulizer but hardly affected the output of the tested mesh nebulizers. Mesh nebulizers could therefore enable a demand-adapted oxygen therapy due to their consistent performance despite the presence of oxygen flow. A high respiratory rate was associated with a high drug deposition, which is clinically desirable in the treatment of patients in respiratory distress; however, drug underdosing must also be expected in the treatment of bradypneic patients. Further clinical studies must prove whether our findings also apply to the treatment of real prehospital emergency patients.

[Nebulization of emergency medications in the south German rescue service]

BACKGROUND

In German emergency rescue services, inhalation treatment is routinely carried out by qualified health personnel. Standard operating procedures (SOP) for nebulization are neither uniform throughout Germany nor available in all federal states. Standardized recommendations with respect to which nebulizer type should be used are missing. The aerosol output as well as the drug deposition rates of jet and mesh nebulizers, however, differ considerably. Mesh devices can achieve a threefold higher lung deposition. Their use in emergency departments has also been shown to be associated with a better patient outcome when compared to jet nebulizers.

OBJECTIVE

This survey was designed to evaluate the type of nebulizer used in the south German rescue services. Special attention was paid to the influence of existing SOP on the decision to perform nebulization during emergency treatment.

MATERIAL AND METHODS

A total of 4800 emergency paramedics working in Baden-Württemberg, Bavaria and Rhineland-Palatinate received a questionnaire with a total of 17 questions on the implementation of drug nebulization in the daily practice.

RESULTS

Despite the existence of more efficient nebulizer types, the jet nebulizer was by far the most frequently used nebulizer in the south German rescue services. The deposition rates of both the jet and mesh nebulizers were considerably overestimated by most respondents; however, 77.5% of all respondents could not give any information about the deposition rates of the mesh nebulizer. Only two thirds of all respondents carried out nebulization treatment on the basis of SOP. The implementation of SOP, however, was pivotal to the application of nebulization during emergencies. If SOP were in place,76.9% of the responders used aerosol treatment compared to 23.1% when there were none. The perceived safety when using nebulization during emergencies was also significantly higher (p = 0.013) when SOP were implemented.

CONCLUSION

The exclusive use of mesh nebulizers could standardize the treatment of emergency patients in the south German rescue services. The use of mesh devices might possibly improve patient outcomes, even if clinical studies are still lacking. Nebulizer treatment differs between the federal states. A comprehensive implementation of SOP for nebulization treatment might support this process and could increase the application frequency and the perceived safety of nebulization during emergencies. A better training of paramedic personnel could improve the knowledge of aerosols as a treatment option for emergency patients and help to classify the advantages and disadvantages of the different aerosol generators available.

In Vitro Evaluation of Aerosol Delivery by Hand-Held Mesh Nebulizers in an Adult Spontaneous Breathing Lung Model

Background: Drug inhalation is common mode of treatment for chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the efficiency of aerosol devices in a simulated COPD adult lung model using five commercially available hand-held mesh nebulizers. Materials and Methods: Five nebulizers (PARI VELOX^®, Omron NE-U22, Aeroneb^® Go, APEX PY001, and Pocket Air^®) were tested with a unit dose of 5.0 mg/2.5 mL salbutamol. An in vitro lung model (compliance: 0.06 L/cm H₂O, resistance: 20 cm H₂O/L/sec) was constructed to simulate parameters (tidal volume of 500 mL, respiratory rate of 15 breaths/min, inspiratory time of 1 second) of an adult patient with COPD. A bacterial filter was attached at the bronchi level for drug collection, referring as inhaled mass. After nebulization, the inhaled mass (%), dose remaining on each component (%), particle size characteristics, and nebulizer performances were analyzed. Particle size characteristics were analyzed using an 8-stage Anderson Cascade Impactor. The salbutamol particles deposited were eluted and analyzed using a spectrophotometer at 276 nm. The inhaled mass (%), dose remaining on each component (%), particle size distribution, and nebulizer performance were statistically analyzed using analysis of variance (ANOVA) with Sheffee post hoc tests. Results: Pocket Air and APEX PY001 showed the greatest inhaled mass and the lowest dose in the mouthpiece connection. The largest and smallest mass median aerodynamic diameters were found with Omron NE-U22 and PARI VELOX, respectively. In addition, the output rate and inhaled aerosol rate (IAR) of PARI VELOX were higher than those of other nebulizers. Conclusions: This study showed that the performance of commercially available mesh nebulizers varied. Aerosol particles deposited on different auxiliary equipment directly influenced the output rate and IAR of the mesh nebulizer. Clinical validation of the drug IAR is necessary to avoid overdose and reduce drug wastage.

Comparison of Vibrating Mesh and Jet Nebulizers During Noninvasive Ventilation in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background: Advances in aerosol technology have improved drug delivery efficiency during noninvasive ventilation (NIV). Clinical evaluation of the efficacy of aerosol therapy during NIV in the treatment of acute exacerbation of chronic obstructive pulmonary disease (COPD) is very limited. The aim of our study was to compare the efficacy of bronchodilators administered through a vibrating mesh nebulizer (VMN) and jet nebulizer (JN) during NIV in patients with acute exacerbation of COPD. Methods: Prospective randomized cross-over study included 30 patients treated with NIV for acute exacerbation of COPD in an acute care hospital. Patients were consented and enrolled after stabilization of acute exacerbation (3-5 days after admission). Subjects were randomly assigned into two treatment arms receiving salbutamol (2.5 mg): with VMN (Aerogen Solo) and JN (Sidestream) positioned between the leak port and the nonvented oronasal mask during bilevel ventilation with a single-limb circuit. Measurements (clinical data, pulmonary function tests [PFTs], and arterial blood gases) were performed at baseline, 1, and 2 hours after treatment. Results: All measured PFT parameters significantly increased in both groups, but numerically results were better after inhalation with VMN than with JN: for forced expiratory volume in 1 second (FEV₁) (mean increase from baseline to 120 minutes-165 ± 64 mL vs. 116 ± 46 mL, p = 0.001) and for forced vital capacity (FVC) (mean increase-394 ± 154 mL vs. 123 ± 57 mL, p < 0.001). There was also a statistically significant reduction in respiratory rate and in Borg dyspnea score after therapy with VMN in comparison with the conventional JN. In both groups, there were improvements in PaCO₂, but with VMN these changes were significantly higher. Conclusion: Bronchodilator administration in patients with acute exacerbation of COPD during NIV with VMN resulted in clinically significant improvements in FVC and in Borg dyspnea score. Additional studies required to determine the impact on clinical outcomes.

Short-acting bronchodilators for the management of acute exacerbations of chronic obstructive pulmonary disease in the hospital setting: systematic review

BACKGROUND

Currently, there is a lack of guidelines for the use of short-acting bronchodilators (SABD) in people admitted to hospital for acute exacerbation of chronic obstructive pulmonary disease (AECOPD), despite routine use in practice and risk of cardiac adverse events.

AIM

To review the evidence that underpins use and optimal dose, in terms of risk versus benefit, of SABD for inpatient management of AECOPD and collate the results for future guidelines.

METHODS

Medline, Embase, the Cochrane Central Register of Controlled Trials, clinicaltrials.gov and International Clinical Trials Registry Platform were searched (inception to November 2017) for published and ongoing studies. Included studies were randomised controlled trials or controlled clinical trials investigating the effect of SABD (β2-agonist and/or ipratropium) on inpatients with a diagnosis of AECOPD. This review was undertaken in accordance with PRISMA guidelines and a pre-defined protocol. Due to heterogeneous methodologies, meta-analysis was not possible so the results were synthesised qualitatively.

RESULTS

Of 1378 studies identified, 10 met inclusion criteria. Narrative synthesis of 10 studies revealed no significant differences in most outcomes of interest relative to dose, delivery via inhaler or nebuliser, and type of β2-agonist used. However, some evidence demonstrated significantly increased cardiac side effects with increased dosage of β2-agonist (45% versus 24%), P<0.05).

CONCLUSION

This review identified a paucity of methodologically rigorous evidence evaluating use of SABD among AECOPD. The available evidence did not identify any additional benefits for participants receiving higher doses of short-acting β2-agonists compared to lower doses, or based on type of delivery method or β2-agonists used. However, there was a small increase in some adverse events for participants using higher doses of β2-agonists.

Vibrating Mesh Nebulisers – Can Greater Drug Delivery to the Airways and Lungs Improve Respiratory Outcomes?

Aerosols are an increasingly important mode of delivery of drugs, particularly bronchodilators, for the treatment of respiratory diseases, notably asthma and chronic obstructive pulmonary disease. The most common type of nebuliser is the jet nebuliser (JN); they have been in use for more than a century but these devices can be cumbersome to use and may sometimes deliver insufficient amounts of drug. A more recent development in aerosol therapy is the vibrating mesh nebuliser (VMN) which is very user friendly and is more efficient than the JNs due to an extremely low residual volume. Scintigraphy images from studies of volunteer subjects using radio-labelled aerosol treatment show that VMN-generated aerosols deliver more drug to patients in a shorter period of time than JN-generated aerosols. Various bench, animal model and small clinical studies have shown that VMNs are more efficient than JNs in drug delivery, potentially improving clinical outcomes. These studies have included various breathing circuits used in mechanical ventilation (MV), non-invasive ventilation, high-flow nasal cannula systems and devices for spontaneously breathing patients. The efficiency of drug delivery was affected by factors including the position of the nebuliser in the circuit and humidity. Some studies have shown potential substantial savings by hospitals in the cost of MV treatments after switching from metered dose inhalers to VMNs. VMNs have also been shown to be effective for the administration of inhaled antibiotics, corticosteroids and other drugs. Larger studies of the effects of VMNs on patient outcomes are needed but they are likely to be an increasingly important means of administering therapies to a burgeoning population with respiratory disease.