Inspiratory flow rates at different levels of resistance in elderly COPD patients

Dry powder inhaler design and particle technology in enhancing Pulmonary drug deposition: challenges and future strategies

OBJECTIVES

The efficient delivery of drugs from dry powder inhaler (DPI) formulations is associated with the complex interaction between the device design, drug formulations, and patient's inspiratory forces. Several challenges such as limited emitted dose of drugs from the formulation, low and variable deposition of drugs into the deep lungs, are to be resolved for obtaining the efficiency in drug delivery from DPI formulations. The objective of this study is to review the current challenges of inhaled drug delivery technology and find a way to enhance the efficiency of drug delivery from DPIs.

METHODS/EVIDENCE ACQUISITION

Using appropriate keywords and phrases as search terms, evidence was collected from the published articles following SciFinder, Web of Science, PubMed and Google Scholar databases.

RESULTS

Successful lung drug delivery from DPIs is very challenging due to the complex anatomy of the lungs and requires an integrated strategy for particle technology, formulation design, device design, and patient inhalation force. New DPIs are still being developed with limited performance and future device design employs computer simulation and engineering technology to overcome the ongoing challenges. Many issues of drug formulation challenges and particle technology are concerning factors associated with drug dispersion from the DPIs into deep lungs.

CONCLUSION

This review article addressed the appropriate design of DPI devices and drug formulations aligned with the patient's inhalation maneuver for efficient delivery of drugs from DPI formulations.

Suboptimal peak inspiratory flow rate in dry-powder inhaler users for chronic obstructive pulmonary disease in Korea

BACKGROUND

A suboptimal peak inspiratory flow rate (PIFR) in dry-powder inhaler (DPI) users can lead to insufficient therapeutic effects in the treatment of chronic obstructive pulmonary disease (COPD). However, few data on the prevalence of and factors associated with suboptimal PIFR in Korean patients with COPD are available.

METHODS

We conducted a cross-sectional study of patients with COPD who had been using DPIs for more than three months. PIFR was measured using an In-Check DIAL G16 device. Suboptimal PIFR was defined as below the resistance-matched threshold. Multivariable logistic regression analysis was used to determine factors associated with suboptimal PIFR.

RESULTS

Of 444 DPI users with COPD, the rate of suboptimal PIFR was 22.0 % (98/444). In a multivariable analysis, significant factors associated with suboptimal PIFR were age (adjusted odds ratio [aOR] = 1.06 by 1-year increase; 95 % confidence interval [CI] = 1.02-1.09), male sex (aOR = 0.28; 95 % CI = 0.11-0.73), body mass index (BMI) (aOR = 0.91 by 1 kg/m2 increase; 95 % CI = 0.85-0.99), post-bronchodilator forced vital capacity (FVC) %pred (aOR = 0.97 by 1%pred increase; 95 % CI = 0.95-0.99), and In-Check DIAL R2-type inhaler [medium-low resistance] use (aOR = 3.70 compared with R1-type inhalers [low resistance]; 95 % CI = 2.03-7.03).

CONCLUSIONS

In Korea, more than one-fifth of DPI users with COPD had a suboptimal PIFR. The factors associated with suboptimal PIFR were age, female gender, low BMI, low FVC, and R2-type inhaler use. Therefore, clinicians should carefully evaluate the possibility of suboptimal PIFR when prescribing DPIs.

Changes in Peak Inspiratory Flow After Acute Bronchodilation: An Observational Study of Patients with Stable Chronic Obstructive Pulmonary Disease

Introduction: Identifying factors influencing peak inspiratory flow (PIF) is essential for aerosol drug delivery in stable patients with chronic obstructive pulmonary disease. While a minimum PIF for dry powder inhalers (DPIs) is established, acute bronchodilator (BD) effects on PIF remain unknown. Materials and Methods: An inspiratory flow meter (In-Check™ DIAL) was used to measure PIF in stable patients during a 24-week observational cross-sectional study. Additionally, bronchodilator responsiveness (BDR) was determined using the In-Check DIAL device and spirometry. Patients received four puffs of albuterol, and pre- and post-BD PIF, forced expiratory volume in one second (FEV1), and forced vital capacity were measured. Sixty-three patients completed acute BDR data collection from July 31, 2019, to November 9, 2021. Primary endpoints were pre- and post-BD spirometry and PIF. Statistical analyses included PIF correlations with FEV1. BD change was assessed according to inhaler resistance and sex (subgroup analysis). Results: Median patient age was 64.8 years, 85.7% were non-Hispanic White, and 57.1% were female. The median increase in absolute PIF (In-Check DIAL) was 5.0 L/min, and the % PIF change was 8.9%. With albuterol, 57.1% experienced a PIF BD change >5.0%, whereas 49.2% experienced a change >10.0%. Similarly, 55.6% experienced an FEV1 BD change >5.0% and 28.6% had a >10.0% FEV1 BD change with albuterol. PIF was weakly correlated with FEV1 BD change (absolute; % PIF; r = 0.28 [p = 0.02]; r = 0.21 [p = 0.11]). Pre- and post-BD median PIF were 75.5 and 83.5 L/min for low-to-medium-resistance DPI and 45.0 and 52.0 L/min for high-resistance, respectively. The median increases in pre- and post-BD PIF were 9.0 L/min in males and 4.5 L/min in females. In contrast to when using the In-Check DIAL device, we observed no consistent bronchodilatory effects on PIF measured by spirometry. Conclusions: Using the In-Check DIAL device, ∼50% of patients experienced >10% PIF increase after acute BD, potentially enhancing medication lung deposition. Further research is required to understand PIF's impact on medication delivery. ClinicalTrials.gov Identifier: NCT04168775.

Real-Time Particle Emission Monitoring for the Non-Invasive Prediction of Lung Deposition via a Dry Powder Inhaler

Although inhalation therapy represents a promising drug delivery route for the treatment of respiratory diseases, the real-time evaluation of lung drug deposition remains an area yet to be fully explored. To evaluate the utility of the photo reflection method (PRM) as a real-time non-invasive monitoring of pulmonary drug delivery, the relationship between particle emission signals measured by the PRM and in vitro inhalation performance was evaluated in this study. Symbicort® Turbuhaler® was used as a model dry powder inhaler. In vitro aerodynamic particle deposition was evaluated using a twin-stage liquid impinger (TSLI). Four different inhalation patterns were defined based on the slope of increased flow rate (4.9-9.8 L/s2) and peak flow rate (30 L/min and 60 L/min). The inhalation flow rate and particle emission profile were measured using an inhalation flow meter and a PRM drug release detector, respectively. The inhalation performance was characterized by output efficiency (OE, %) and stage 2 deposition of TSLI (an index of the deagglomerating efficiency, St2, %). The OE × St2 is defined as the amount delivered to the lungs. The particle emissions generated by four different inhalation patterns were completed within 0.4 s after the start of inhalation, and were observed as a sharper and larger peak under conditions of a higher flow increase rate. These were significantly correlated between the OE or OE × St2 and the photo reflection signal (p < 0.001). The particle emission signal by PRM could be a useful non-invasive real-time monitoring tool for dry powder inhalers.

Suboptimal peak inspiratory flow rate: a noticeable risk factor for inhaler concordance in patients with chronic airway diseases

BACKGROUND

Inhaler concordance and the peak inspiratory flow rate (PIFR) are important determinants of treatment effects in patients with chronic airway diseases. Adequate PIFR is required for driving aerosol medication into the lower respiratory tract. However, the relationship between them has not been discussed previously. This study aimed to describe the characteristics of inhaler concordance and PIFR in Chinese patients with chronic airway diseases and discuss the associated variables and the relationship between them.

METHODS

In this single-centre, observational study, a total of 680 patients with chronic airway diseases were enrolled from July 2021 to April 2023. We collected data on the socio-demographic and clinical variables of inhaler concordance using the test of adherence to inhalers (TAI) and PIFR. Multivariate logistic regression was conducted to examine variables related to inhaler concordance and PIFR.

RESULTS

A total of 49.4% of patients had low concordance. Patients with chronic obstructive pulmonary disease (COPD) were more concordant than patients with asthma (mean TAI score: 43.60 vs 41.20; p<0.01), while there was no difference in concordance between the asthma-COPD overlap group and the asthma or COPD group. Suboptimal PIFR (adjusted OR, 1.61; 95% CI 1.04 to 2.51) increased the risk of poor concordance among all patients, while triple therapy (adjusted OR, 0.60; 95% CI 0.35 to 0.86) reduced the risk. A total of 54.9% of patients had suboptimal PIFR. Older age, lower educational level, use of dry powder inhalers and lower forced expiratory volume in 1 s % predicted were significantly correlated with insufficient PIFR. Subgroup analysis revealed a greater proportion of patients with insufficient PIFR during exacerbation than during the stable phase (61.7% vs 43.5%, p<0.001).

CONCLUSION

Inhaler concordance was low, and suboptimal PIFR was a risk factor for poor concordance among Chinese patients with chronic airway diseases. In addition, current inhalation devices may not be suitable, and PIFR reassessment should be considered for patients with COPD during exacerbation.

TRIAL REGISTRATION NUMBER

The study was registered in chictr.org.cn (ChiCTR2100052527) on 31 October 2021.

Comparative study of the inhalation parameters of COPD patients through NEXThaler® and Ellipta® dry powder inhalers

The deposition of dry powder aerosol drugs depends on the inhalation parameters of the patients through the inhaler. These data are not directly measured in clinical practice. Their prediction based on the routinely measured spirometric data could help in choosing the appropriate device and optimizing the therapy. The aim of this study was to perform inhalation experiments to find correlations between inhalation parameters of COPD patients through two DPI devices and their native spirometric data, gender, age and disease severity. Another goal was to establish relationships between peak inspiratory flows through NEXThaler® and Ellipta® inhalers and their statistical determinants. Breathing parameters of 113 COPD patients were measured by normal spirometry and while inhaling through the two DPIs. Statistical analysis of the measured data was performed. The average values of peak inspiratory flow through the devices (PIFdev) were 68.4 L/min and 78.0 L/min for NEXThaler® and Ellipta®, respectively. PIFdev values were significantly higher for males than for females, but differences upon age, BMI and disease severity group were not significant. PIFdev values correlated best with their native spirometric counterparts (PIF) and linear relationships between them were revealed. Current results may be used in the future to predict the success of inhalation of COPD patients through DPI devices, which may help in the inhaler choice. By choosing the appropriate device-drug pair for each patient the lung dose can be increased and the efficiency of the therapy improved. Further results of the clinical study will be the subject of a next publication.

Clinical Burden of Chronic Obstructive Pulmonary Disease in Patients with Suboptimal Peak Inspiratory Flow

Introduction

Many patients with chronic obstructive pulmonary disease (COPD) may derive inadequate benefit from dry powder inhalers (DPIs) because of suboptimal peak inspiratory flow (sPIF).

Objectives

To assess the clinical burden of COPD by characterizing the clinical characteristics of participants with sPIF against medium-low resistance DPIs versus those with optimal PIF (oPIF) from two phase 3 clinical trials.

Methods

Baseline data were collected from two randomized, controlled, phase 3 trials (NCT03095456; NCT02518139) in participants with moderate-to-severe COPD. oPIF (60 L/min) against the medium-low resistance DPIs was used as the threshold for defining the PIF subgroups (<60 L/min (sPIF) vs ≥60 L/min (oPIF)).

Results

Most participants included in this analysis were White (92%) and male (63%); the mean (range) age was 65 (43-87) years. Participants with sPIF had significantly greater dyspnea than those with oPIF as measured using the modified Medical Research Council scoring (mean (95% CI): 2.1 (2.0-2.2) vs 1.6 (1.4-1.7); P  < 0.001) and baseline dyspnea index (mean (95% CI): 5.1 (4.9-5.4) vs 6.1 (5.8-6.3); P  < 0.001). Based on COPD Assessment Test scores, participants with sPIF had a higher COPD symptom burden than those with oPIF (mean (95% CI): 21.5 (19.7-23.3) vs 19.5 (18.6-20.4); P = 0.05).

Conclusion

In these trials, participants with COPD who had sPIF against the medium-low resistance DPIs had more dyspnea and worse health status than those with oPIF. These results demonstrate that sPIF is associated with a higher clinical burden as measured by patient-reported outcomes.

How can we identify subglottic stenosis in patients with suspected obstructive disease?

PURPOSE

Subglottic stenosis, a rare condition of the upper airway, is frequently misdiagnosed as obstructive lung disease. The aim of this study was to investigate whether subglottic stenosis could be identified and distinguished from asthma and chronic obstructive pulmonary disease (COPD) using spirometry or the dyspnea index (DI).

METHODS

The study population included 43 patients with asthma, 31 patients with COPD and 50 patients with subglottic stenosis planned to undergo endoscopic intervention. All patients completed the DI and underwent dynamic spirometry registering both inspiratory and expiratory volumes and flows, including the expiratory disproportion index (EDI), the ratio of forced expiratory volume in 1 s to peak expiratory flow. One-way analysis of variance assessed the discrepancy of the variables among the study groups, and receiver operating curve (ROC) analysis determined the measurement with the best discriminatory power providing a cutoff value, maximizing both sensitivity and specificity.

RESULTS

The only statistically significant variables differing between all three groups were the EDI and the DI. The EDI showed an excellent area under the ROC curve (0.99, p < 0.001) with a cutoff value of 0.39 (98% sensitivity, 96% specificity), followed by DI (0.87, p < 0.001) with a cutoff score of > 25 (83% sensitivity and 78% specificity).

CONCLUSION

In patients with dyspnea of unknown cause, an increase in EDI should arouse a suspicion of extrathoracic airway obstruction, advocating for further evaluation with laryngotracheoscopy.

Evaluating dry powder inhalers: From in vitro studies to mobile health technologies

Dry powder inhalers (DPIs) are essential in treating patients with pulmonary diseases. Since DPIs were introduced in the 1960s, a remarkable improvement has been made in their technology, dose delivery, efficiency, reproducibility, stability, and performance based on safety and efficacy. While there are many DPIs on the market and several more under development, it is vital to evaluate the performance of DPIs for effective aerosol drug delivery to patients with respiratory disorders. Their performance evaluation includes particle size, metering system, device design, dose preparation, inhalation technique, and patient-device integration. The purpose of this paper is to review current literature evaluating DPIs through in vitro studies, computational fluid models, and in vivo/clinical studies. We will also explain how mobile health applications are used to monitor and evaluate patients' adherence to prescribed medications.

Dry Powder Inhaler with the technical and practical obstacles, and forthcoming platform strategies

A Dry Powder Inhaler (DPI) is a technique as well as a device used to inhale formulation which is in the form of dry powder, and is inhaled through the nose or mouth. It was developed for the purpose of treating conditions like chronic obstructive pulmonary disease (COPD), Asthma, and even cystic fibrosis etc. The aim of the review is to discuss the different methods of preparation of dry powders along with the characterization of DPI. Here we present the outline of different methods like supercritical fluid extraction (SCF), spray drying, and milling. The review focussed on various devices including single and multi-dose devices used in the DPI. It also highlights on recent advances in the DPI including nano particulate system, siRNA-based medication, liposomes, and pro-liposomes based delivery. In COVID-19 silver nanoparticles-based DPIs provide very prominent results in the infected lungs. Moreover, this review states that the AI-based DPI development provides and improvement in the bioavailability and effectiveness of the drug along with the role of artificial neural networks (ANN). The study also showed that nasally administered drugs (nose to brain) can easily cross the blood-brain barrier (BBB) and enter the central nervous system (CNS) through the olfactory and trigeminal pathway which provides effective CNS concentrations at lower dosage. It is suggested that DPIs not only target respiratory complications but also treat CNS complications too. This review provides support and guides the researcher in the recent development and evaluation of DPI.

Can patients achieve sufficient peak inspiratory flow rate (PIFR) with Turbuhaler® during acute exacerbation of asthma?

INTRODUCTION

Anti-inflammatory reliever (AIR) with or without regular maintenance delivered through Turbuhaler® has been widely recommended in the GINA strategy document. These patients are not prescribed with additional reliever inhalers, but dependent on Turbuhaler^® during acute asthma episodes. The peak inspiratory flow rate (PIFR) is crucial in drug delivery from a dry powder inhaler (DPI) such as Turbuhaler^®. Despite its increasing usage, there are some concerns that patients on Turbuhaler^® are not able to achieve adequate PIFR during acute exacerbation of asthma.

OBJECTIVE

This study aimed to assess the PIFR at resistance settings that matched Turbuhaler^® in patients with acute exacerbation of asthma.

METHODOLOGY

A six-month cross-sectional study was conducted at the Emergency Department (ED) of Hospital Sultanah Bahiyah and Hospital Kulim, Kedah, Malaysia. Adult patients diagnosed with mild to moderate acute exacerbations of asthma were recruited. The PIFRs were measured using the In-Check DIAL G16 that was set to simulate the resistance of Turbuhaler^® (R3). The PIFRs were assessed before (pre) and after (post) the initial bronchodilator (BD) treatment at the ED. The minimal required PIFR was defined as flow rates ≥ 30 L/min while a PIFR of 60 L/min was considered as optimal.

RESULTS

A total of 151 patients (81 females and 70 males) were recruited. The mean age was 37.5 years old with a range between 18 and 79 years old. The results showed that 98% (n = 148) of patients managed to achieve the minimal PIFR required for pre-BD. The mean PIFR pre-BD was 60 ± 18.5 L/min and post-BD was 70 ± 18.5 L/min. Furthermore, more than half (54%, n = 82) of the patients recorded PIFR ≥ 60 L/min during pre-BD, and about three-quarters (71%, n = 92) achieved PIFR ≥ 60 L/min post-BD. The PIFR showed a moderate correlation with peak expiratory flow rate (PEFR) (r = 0.55, 95% CI: 0.43-0.65, p < 0.001).

CONCLUSION

The majority of patients with asthma in the present study were able to achieve sufficient PIFR from Turbuhaler^® during mild to moderate acute exacerbations.

Breath-actuated INhalation TheRapy: survey of phySicians' PErCepTion (INTROSPECT) in Nepal

OBJECTIVE

Breath-actuated inhalers (BAIs) are gaining attention in the management of obstructive airway diseases (OADs). In Nepal, a BAI containing fluticasone propionate/salmeterol (FPS) has been available for a year. This survey is aimed at determining the perception and experience of physicians in Nepal concerning BAIs.

METHODS

A cross-sectional, questionnaire-based survey was conducted. A total of 141 physicians participated and filled the survey.

RESULTS

Most physicians felt that the right device should be easy to teach, learn and remember. They considered coordination and multiple steps as the primary challenges with pressurized metered-dose inhalers and dry powder inhalers, respectively. Most of them agreed that BAIs could address these challenges. BAIs were not only preferred by most of the physicians for asthma and chronic obstructive pulmonary disease but were also the preferred choice in newly diagnosed patients. Physicians believed that if current patients were shifted to BAIs, it could improve inhalation technique (88%) and compliance/adherence (81%). Almost all of them (92-97%) agreed that teaching the breathing technique and the cleaning process was easier and faster in BAIs. BAIs were considered easy and simple to use. Also, BAI's dose-counter helps patients to increase adherence to inhalation therapy.

CONCLUSIONS

In this INTROSPECT survey, physicians in Nepal believed that BAIs could address the key challenges faced with using pMDIs and DPIs in asthma and COPD patients.

An Investigation into the Factors Associated with Incorrect Use of a Pressurized Metered-Dose Inhaler in Japanese Patients

Rationale: Inhalation of the correct dose of a short-acting beta 2 agonist (SABA) from a pressurized metered-dose inhaler (pMDI) is essential for the relief of symptoms in patients with asthma and/or chronic obstructive pulmonary disease. The aim of this study was to evaluate the prevalence and factors associated with the incorrect use of a pMDI. Methods: This study retrospectively assessed the electronic medical records of 161 patients with various respiratory diseases. The patients had never used a pMDI and underwent training by pharmacists educated in the use of a pMDI followed by bronchodilator reversibility testing at our hospital. The patients' characteristics and various lung capacity parameters were evaluated for association with the incorrect use of a pMDI. Results: Thirty-nine of the 161 (24.2%) patients, including 46% of 28 patients older than 80 years, used the pMDI incorrectly, mainly because of incoordination between activation of the device and inhalation (n = 11), inadequate strength to manipulate the device (n = 9), too short duration of inhalation (n = 6), and difficulty in breath holding (n = 3). Advanced age; lower height; and decreased lung volumes, including vital capacity (VC), inspiratory capacity, inspiratory reserve volume (IRV), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow rate, were associated with the incorrect use of a pMDI. Neither the body weight, tidal volume, expiratory reserve volume, %FVC predicted, %FEV1 predicted, nor FEV1% was associated with the incorrect use of a pMDI. Multivariate binomial logistic regression analysis identified decreased IRV as the only independent predictor associated with the incorrect use of a pMDI. Conclusions: Physicians should be aware that elderly patients or patients with decreased IRV might be unable to obtain the correct SABA dose from a pMDI. A large-scale prospective study is required to confirm these findings from our retrospective study with a small group of patients.

Temporal and geographical variation in low carbon inhaler dispensing in England, 2016 to 2021: an ecological study

OBJECTIVES

In 2019-2020, four national recommendations were published in the United Kingdom to encourage use of low carbon inhalers. This study aimed to investigate whether these were associated with a change in primary care dispensing in England and to explore associations between geographical variation and clinical commissioning group (CCG) characteristics.

DESIGN

Ecological study using aggregated publicly available data.

SETTING

All CCGs in England (March 2016 to February 2021).

PARTICIPANTS

not applicable.

MAIN OUTCOME MEASURES

Percentage of low carbon inhalers dispensed.

RESULTS

The percentage of low carbon inhalers dispensed was 26.3% in 2020-2021 (of 8.8 million inhalers). This decreased over the study period for short-acting beta-agonist (SABA), inhaled corticosteroid (ICS) and ICS+long-acting beta-agonist (LABA) inhalers. The same trend was seen for LABA and ICS+LABA+long-acting muscarinic antagonist inhalers from 2019. The SABA and ICS classes were less often dispensed as low carbon inhalers (⁓6% versus 35-45%). Interrupted time series analyses found slight increases in low carbon inhaler percentage in the SABA, LABA and ICS classes after April 2019, which were soon erased by the long-term trend. There was also geographical variation, with the north-west, Birmingham and London consistently dispensing more low carbon inhalers. The presence of advice on climate change in CCG formularies/guidelines, the prevalence of asthma and population age profile were associated with significant variation in low carbon inhaler percentage for some classes.

CONCLUSIONS

The percentage of low carbon inhalers dispensed in England remains low and continues to decrease. Greater use of low carbon inhalers is achievable, but is more likely with locally implemented initiatives.

[Reducing the environmental impact of inhalers dispensed in France. From diagnosis to sustainable action]

OBJECTIVES

While inhaled drugs are mainly used to treat chronic respiratory diseases, they are also responsible for greenhouse gas (GHG) emission. To highlight this issue, a dispensed analysis and a carbon footprint evaluation of inhalers in France have been conducted.

METHODS

A national qualitative and quantitative analysis of dispensed inhalers in community pharmacies (CP) and hospitals (H) was conducted in France for 2019. A data review from the literature led to the determination of the inhalers carbon footprint, expressed in carbon dioxide equivalent (CO₂e) during the inhaler life cycle.

RESULTS

Close to 40 million inhalers were dispensed by community pharmacies and one million by hospitals in 2019. It concerned three types of inhalers: metered-dose inhalers (MDI) [CP: 49%; H: 45%], dry powder inhalers (DPI) [CP: 47%; H: 51%], and soft mist inhalers (SMI) [CP: 4%; H: 4%]. According to the literature, MDI have the highest carbon footprint, ranging from 11 to 28 kgCO2e versus less than 1 kgCO2e for DPI/SMI. In 2019, the national carbon footprint of salbutamol (MDI), the most dispensed inhaler, was estimated to be over 310 million kgCO2e (CP+H) corresponding to more than 310,000 round-trip Paris-New York.

CONCLUSIONS

This study shows the involvement of MDI in GHG emissions. Taking actions as part of a global and coordinated approach to limit their environmental impact is possible and thus is a priority.

Solid state of inhalable high dose powders

High dose inhaled powders have received increased attention for treating lung infections. These powders can be prepared using techniques such as spray drying, spray-freeze drying, crystallization, and milling. The selected preparation technique is known to influence the solid state of the powders, which in turn can potentially modulate aerosolization and aerosolization stability. This review focuses on how and to what extent the change in solid state of high dose powders can influence aerosolization. It also discusses the commonly used solid state characterization techniques and the application of potential strategies to improve the physical and chemical stability of the amorphous powders for high dose delivery.

An expert opinion on respiratory delivery of high dose powders for lung infections

INTRODUCTION

High dose powder inhalation is evolving as an important approach to to treat lung infections. It is important to its identify applications, consider the factors affecting high dose powder delivery, and assess the effect of high dose drugs in patients.

AREA COVERED

Both current and pipeline high dose inhalers and their applications have been summarized. Challenges and opportunities to high dose delivery have been highlighted after reviewing formulation techniques in the context of factors affecting aerosolization, devices, and patient factors.

EXPERT OPINION

High dose inhaled delivery of antimicrobials is an innovative way to increase treatment efficacy of respiratory infections, tackle drug resistance, and the scarcity of new antimicrobials. The high dose inhaled technology also has potential for systemic action; however, innovations in formulation strategies and devices are required to realize its full potential. Advances in formulation strategies include the use of excipients or the engineering of particles to decrease the cohesive property of microparticles and their packing density. Similarly, selection of a synergistic drug instead of an excipient can be considered to increase aerosolization and stability. Device development focused on improving dispersion and loading capacity is also important, and modification of existing devices for high dose delivery can also be considered.

Lung Function Can Predict the Expected Inspiratory Airflow Rate through Dry Powder Inhalers in Asthmatic Adolescents

Several factors affect drug delivery from dry powder inhalers (DPIs). Some are related to patient’s physiological characteristics, while others depend on DPIs’ technical aspects. The patient’s inspiratory airflow rate (IAR) affects the pressure drop and the turbulence needed to disaggregate the powder inside a DPI. The present study investigated whether lung function limitations occurring in asthmatic adolescents affect their IAR when inhaling through a DPI simulator. Eighteen consecutive adolescents with asthma were recruited, and IAR was randomly assessed at low-, mid-, and high-resistance regimens. A multiple logistic model was developed to evaluate the association of patients’ lung function characteristics and devices’ resistance with the probability to achieve the expected IAR (E-IAR). The mean value of E-IAR achieved seemed to be sex- and age-independent. Low- and high-resistance regimens were less likely to consent the E-IAR level (odds ratio [OR] = 0.035 and OR = 0.004, respectively). Only the basal residual volume and the inspiratory resistance, but not the Forced Expiratory Volume in 1 s (FEV1), seemed to affect the extent of IAR in asthmatic adolescents (OR = 1.131 and OR = 0.290, respectively). The results suggest that the assessment of current lung function is crucial for choosing the proper DPI for asthmatic adolescents.

How to Choose the Right Inhaler Using a Patient-Centric Approach?

There are many different inhaler devices and medications on the market for the treatment of asthma and chronic obstructive pulmonary disease, with over 230 drug-delivery system combinations available. However, despite the abundance of effective treatment options, the achieved disease control in clinical practice often remains unsatisfactory. In this context, a key determining factor is the match or mismatch of an inhalation device with the characteristics or needs of an individual patient. Indeed, to date, no ideal device exists that fits all patients, and a personalized approach needs to be considered. Several useful choice-guiding algorithms have been developed in the recent years to improve inhaler–patient matching, but a comprehensive tool that translates the multifactorial complexity of inhalation therapy into a user-friendly algorithm is still lacking. To address this, a multidisciplinary expert panel has developed an evidence-based practical treatment tool that allows a straightforward way of choosing the right inhaler for each patient.

Relationship between Peak Inspiratory Flow and Patient and Disease Characteristics in Individuals with COPD—A Systematic Scoping Review

Optimal delivery of medication via dry powder inhalers, the most commonly prescribed inhaler type, is dependent on a patient achieving a minimum level of inspiratory flow during inhalation. However, measurement of peak inspiratory flow (PIF) against the simulated resistance of a dry powder inhaler is not frequently performed in clinical practice due to time or equipment limitations. Therefore, defining which patient characteristics are associated with lower PIF is critically important to help clinicians optimize their inhaler choice through a more personalized approach to prescribing. The objective of this scoping review was to systematically evaluate patient and disease characteristics determining PIF in patients with chronic obstructive pulmonary disease (COPD). Medline, Cochrane and Embase databases were systematically searched for relevant studies on PIF in patients with COPD published in English between January 2000 and May 2021. The quality of evidence was assessed using a modified Grading of Recommendations Assessment, Development and Evaluation checklist. Of 3382 citations retrieved, 35 publications were included in the review (nine scored as high quality, 13 as moderate, nine as low, and four as very low). Factors correlating with PIF in >70% of papers included both patient characteristics (lower PIF correlated with increased age, female gender, shorter height, decreased handgrip and inspiratory muscle strength, and certain comorbidities) and disease characteristics (lower PIF correlated with markers of lung hyperinflation, lower peak expiratory flow [PEF] and increased disease severity). Other factors correlating with adequate/optimal or improved PIF included education/counseling and exercise/inspiratory muscle training; impaired physical function and errors in inhalation technique/non-adherence were associated with low/suboptimal PIF. In conclusion, clinicians should measure PIF against the simulated resistance of a particular device wherever possible. However, as this often cannot be done due to lack of resources or time, the patient and disease characteristics that influence PIF, as identified in this review, can help clinicians to choose the most appropriate inhaler type for their patients.

Measuring Peak Inspiratory Flow in Patients with Chronic Obstructive Pulmonary Disease

Dry powder inhalers (DPIs) are breath actuated, and patients using DPIs need to generate an optimal inspiratory flow during the inhalation maneuver for effective drug delivery to the lungs. However, practical and standardized recommendations for measuring peak inspiratory flow (PIF)—a potential indicator for effective DPI use in chronic obstructive pulmonary disease (COPD)—are lacking. To evaluate recommended PIF assessment approaches, we reviewed the Instructions for Use of the In-Check™ DIAL and the prescribing information for eight DPIs approved for use in the treatment of COPD in the United States. To evaluate applied PIF assessment approaches, we conducted a PubMed search from inception to August 31, 2021, for reports of clinical and real-life studies where PIF was measured using the In-Check™ DIAL or through a DPI in patients with COPD. Evaluation of collective sources, including 47 applicable studies, showed that instructions related to the positioning of the patient with their DPI, instructions for exhalation before the inhalation maneuver, the inhalation maneuver itself, and post-inhalation breath-hold times varied, and in many instances, appeared vague and/or incomplete. We observed considerable variation in how PIF was measured in clinical and real-life studies, underscoring the need for a standardized method of PIF measurement. Standardization of technique will facilitate comparisons among studies. Based on these findings and our clinical and research experience, we propose specific recommendations for PIF measurement to standardize the process and better ensure accurate and reliable PIF values in clinical trials and in daily clinical practice.

Managing hospitalized patients with a COPD exacerbation: the role of hospitalists and the multidisciplinary team

Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with high rates of hospitalizations, costs, and morbidity. Therefore, hospitalists and the multidisciplinary team (hospital team) need to take a proactive approach to ensure patients are effectively managed from hospital admission to postdischarge. Comprehensive screening and diagnostic testing of patients at admission will enable an accurate diagnosis of COPD exacerbations, and severity, as well as other factors that may impact the length of hospital stay. Depending on the exacerbation severity and cause, pharmacotherapies may include short-acting bronchodilators, systemic corticosteroids, and antibiotics. Oxygen and/or ventilatory support may benefit patients with demonstrable hypoxemia. In preparation for discharge, the hospital team should ensure that patients receive the appropriate maintenance therapy, are counseled on their medications including inhalation devices, and proactively discuss smoking cessation and vaccinations. For follow-up, effective communication can be achieved by transferring discharge summaries to the primary care physician via an inpatient case manager. An inpatient case manager can support both the hospitalist and the patient in scheduling follow-up appointments, sending patient reminders, and confirming that a first outpatient visit has occurred. A PubMed search (prior to 26 January 2021) was conducted using terms such as: COPD, exacerbation, hospitalization. This narrative review focuses on the challenges the hospital team encounters in achieving optimal outcomes in the management of patients with COPD exacerbations. Additionally, we propose a novel simplified algorithm that may help the hospital team to be more proactive in the diagnosis and management of patients with COPD exacerbations.

Aerosol drug-delivery and short-term clinical outcomes of suboptimal peak inspiratory flow rate in chronic obstructive pulmonary disease

AIM OF WORK

Suboptimal peak inspiratory flow rate (PIFR) is highly prevalent in chronic obstructive pulmonary disease (COPD) patients owing to the mismatch of their own PIFR with the corresponding inhaler-device resistance. This study aimed to evaluate aerosol drug-delivery and short-term clinical outcomes of suboptimal PIFR in COPD subjects.

METHODS

Twenty optimal and suboptimal COPD subjects were crossed over in this prospective, randomised, controlled, open-label study. They were tested for urinary salbutamol amount (USAL30) and spirometric response 30 min poststudy dose (200 µg salbutamol) through Aerolizer^® and Handihaler^® after assessment of their own PIFR through In-Check™ Dial G16. Urine samples were extracted through solid-phase extraction and assayed through a high performance liquid chromatography (HPLC) method.

RESULTS

Mean USAL30 was significantly higher in the optimal group than in the suboptimal group (P = .001). There was no significant difference in ΔFEV1% predicted and ΔFVC% predicted between optimal and suboptimal groups, with higher values in optimal Aerolizer^® and Handihaler^® than in suboptimal groups.

CONCLUSION

Suboptimal PIFR was associated with a significantly lower drug delivery in COPD subjects at hospital discharge, and a slightly lower pulmonary function response 30 min postbronchodilation if compared with optimal PIFR.

Understanding the Importance of Capsules in Dry Powder Inhalers

Pulmonary drug delivery is currently the focus of research and development because of its potential to produce maximum therapeutic benefit to patients by directing the drug straight to the lung disease site. Among all the available delivery options, one popular, proven and convenient inhaler device is the capsule-based dry powder inhaler (cDPI) for the treatment of an increasingly diverse range of diseases. cDPIs use a hard capsule that contains a powder formulation which consists of a mixture of a micronized drug and a carrier usually the lactose, known for its good lung tolerance. The capsule is either inserted into the device during manufacturer or by the patient prior to use. After perforating, opening or cut the capsule in the device, patients take a deep and rapid breath to inhale the powder, using air as the vector of drug displacement. The system is simple, relatively cheap and characterized by a lower carbon footprint than that of pressurized metered dose inhalers. This article reviews cDPI technology, focusing particularly on the importance of capsule characteristics and their function as a drug reservoir in cDPIs.

Optimizing inhalation therapy in the aspect of peak inhalation flow rate in patients with chronic obstructive pulmonary disease or asthma

Background

Pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) are commonly used drug-delivering devices for patients with chronic airway diseases. Appropriate peak inhalation flow rate (PIFR) and inhaler technique is essential for effective therapy. We aimed at optimizing inhalation therapy through the analysis of PIFRs in patients with chronic obstructive pulmonary disease (COPD) or asthma as well as the effect of technique training using In-Check DIAL® to help patients to achieve their optimal inspiratory flow rates.

Methods

The study continuously enrolled patients who were diagnosed as COPD or asthma from respiratory clinics. PIFRs were described and analyzed between the newly-diagnosed and follow-up patients, and the stable and acute exacerbation patients, respectively. Every participant was trained inhaler technique using In-Check DIAL®. PIFRs before and after training was compared by self-control analysis.

Results

Among a total of 209 patients, the average age was 56.9 years. For DPIs users, 10.8% patients had a PIFR < 30 L/min and 44.1% patients had a PIFR ≥ 60 L/min before technique training. After technique training, scarcely patient (1.5%) had a PIFR < 30 L/min, and 60.5% patients had a PIFR ≥ 60 L/min. The patient’s average PIFR increased by 5.6L/min after training. The increase in PIFR before and after training was significant (p < 0.001) for most patients, but no significant variation was found in patients with acute exacerbation (p = 0.822).

Conclusions

A considerable number of patients with COPD or asthma were not able to achieve the minimum or optimal PIFR for DPIs. Inhaler training can increase patients’ PIFRs and improve their ability to use DPIs.

Trail registration The study has registered in chictr.org.cn (ChiCTR1900024707) and been approved by the Ethics Committee of Zhongshan Hospital of Fudan University (B2019-142).

TRONARTO: A Randomized, Placebo-Controlled Study of Tiotropium/Olodaterol Delivered via Soft Mist Inhaler in COPD Patients Stratified by Peak Inspiratory Flow

Background

Inhaled bronchodilator therapy is currently the mainstay of treatment for patients with chronic obstructive pulmonary disease (COPD). Some inhalers require patients to achieve certain inhalation efforts either to activate the device or to deliver medication to the site of action. For dry powder inhalers, low peak inspiratory flow (PIF) can result in poor medication delivery but the clinical significance of this is not well understood.

Methods

TRONARTO was a 4-week, randomized, double-blind, placebo-controlled, multicenter, parallel-group study which stratified patients with moderate-to-severe COPD according to their PIF against medium-low resistance at screening. Patients were randomized to receive tiotropium/olodaterol (5 μg/5 μg) or matched placebo delivered via the Respimat^® Soft Mist™ inhaler (SMI). After 4 weeks of treatment, we assessed change from baseline in forced expiratory volume in 1 second (FEV₁) area under the curve 0–3 hours (FEV₁ AUC_0–3h) and trough FEV₁.

Results

Overall, 213 patients were randomized, of whom 106 received tiotropium/olodaterol (PIF <60 L/min, 55; PIF ≥60 L/min, 51) and 107 received placebo (PIF <60 L/min, 55; PIF ≥60 L/min, 52). For FEV₁ AUC_0–3h, the adjusted mean change from baseline versus placebo was 336 mL (95% confidence interval [CI] 246–425 mL; P<0.0001) in the PIF <60 L/min group and 321 mL (95% CI 233–409 mL; P<0.0001) in the PIF ≥60 L/min group. For trough FEV₁, the adjusted mean change from baseline versus placebo was 201 mL (95% CI 117–286 mL; P<0.0001) in the PIF <60 L/min group and 217 mL (95% CI 135–299 mL; P<0.0001) in the PIF ≥60 L/min group.

Conclusion

In the TRONARTO study, which included patients with moderate-to-severe COPD and varying inspiratory flow abilities, treatment with tiotropium/olodaterol resulted in significant lung function improvements versus placebo. This SMI can be used irrespective of the PIF that a patient can generate.

Peak-Inspiratory-Flow-Rate Guided Inhalation Therapy Reduce Severe Exacerbation of COPD

Optimal peak inspiratory flow rate (PIFR) is crucial for inhalation therapy in patients with chronic obstructive pulmonary disease (COPD). However, little is known about the impact of PIFR-guided inhalation therapy on the clinical outcomes among patients with varying severities of COPD. A PIFR-guided inhalation therapy, including PIFR assessment and PIFR-guided inhaler education, was introduced in a pay-for-performance COPD management program in National Taiwan University Hospital. Among 383 COPD patients, there was significant reduction in incidence of severe acute exacerbation in the PIFR-guided inhalation therapy (PIFR group) than conventional inhaler education (control group) (11.9 vs. 21.1%, p = 0.019) during one-year follow-up. A multivariable Cox’s proportional-hazards analysis revealed that the PIFR-guided inhalation therapy was a significant, independent factor associated with the reduced risk of severe exacerbation (adjusted hazard ratio = 0.49, 95% confidence interval, 0.28–0.84, p = 0.011). Subgroup analysis found PIFR-guided inhalation therapy was more beneficial to patients with older age, short body stature, COPD stage 1&2, group C&D (frequent exacerbation phenotype), and using multiple inhalers. This study showed the PIFR-guided inhalation therapy significantly reduced the incidence of severe acute exacerbation than conventional inhaler education in patients with COPD. Careful PIFR-assessment and education would be crucial in the management of COPD.

Peak inspiratory flow in children and adolescents with asthma using dry powder inhalers: a cross-sectional study

Objective:

To measure peak inspiratory flow (PIF) and assess dynamic lung function in children and adolescents with asthma, as well as to determine the association of PIF with dynamic lung function and clinical variables.

Methods:

This was a cross-sectional study of children and adolescents with asthma using dry powder inhalers (DPIs) regularly. The control group included sex-, age-, weight-, and height-matched individuals without lung disease. Socioeconomic and clinical variables were collected. PIF and dynamic lung function variables were obtained with a specific device. Between-group comparisons were made with the Student’s t-test and ANOVA. Multiple linear regression analysis was performed, and Pearson’s correlation coefficients were calculated to assess associations between PIF and the other variables.

Results:

A total of 88 individuals (44 asthma patients and 44 controls) participated in the study. PIF and respiratory muscle strength (S-index) values were lower in the asthma patients than in the controls. PIF correlated positively with age, weight, height, and S-index in the asthma group. After controlling for height, we found an increase of 0.05 units in PIF associated with an increase of 1 unit in the S-index in the asthma group.

Conclusions:

PIF appears to be lower in children and adolescents with asthma than in those without asthma, correlating positively with age, height, weight, and respiratory muscle strength.

Prevalence and Associated Factors of Suboptimal Daily Peak Inspiratory Flow and Technique Misuse of Dry Powder Inhalers in Outpatients with Stable Chronic Airway Diseases

Purpose

The present study aimed to investigate the prevalence and associated factors of suboptimal daily peak inspiratory flow (PIF) and technical misuse of three commonly used dry powder inhalers (DPIs) in outpatients with stable chronic airway diseases.

Patients and Methods

Included in this study were 85 outpatients with stable asthma, chronic obstructive pulmonary disease (COPD), or asthma-COPD Overlap (ACO) and had previously used any of Turbuhaler^® (TUR), Diskus^® (DIS), HandiHaler^® (HAN) between December 2018 and September 2019. The patient’s daily PIF against the resistance of a specific DPI and operation technique was investigated by two pharmacists by using In-Check DIAL G16 and a checklist.

Results

Of the 85 patients, the proportion of patients with a suboptimal daily PIF and technical misuse was 38.8% and 65.9%, respectively. In logistic regression, we observed that the factors that increase the risk for suboptimal daily PIF were age (OR=1.06) and combination with respiratory diseases (OR = 6.59). The factor that decreases the risk for misuse was the higher education level (OR =0.63).

Conclusion

Even if patients have received training at the time of initial prescription, the standardization of the use of DPIs by patients in our center was still unoptimistic. Age and combined with respiratory diseases were associated with suboptimal PIF. Higher education level decreased the incidence of technique misuse.

Inspiratory flow patterns with dry powder inhalers of low and medium flow resistance in patients with pulmonary arterial hypertension

Inhalation profiles to support use of dry powder inhalers for drug delivery in patients with pulmonary arterial hypertension have not been reported. We aimed to evaluate the inspiratory flow pattern associated with low and medium flow resistance dry powder inhaler devices (RS01-L and RS01-M, respectively) in patients with pulmonary arterial hypertension. This single-center study enrolled patients with pulmonary arterial hypertension associated with connective tissue disease (n = 10) and idiopathic pulmonary arterial hypertension (n = 10) to measure the following inhalation parameters: inspiratory effort (kPa), peak inspiratory flow rate (L/min), inhaled volume (L), and flow increase rate (L/s²) using the two devices. We identified a trend toward higher mean pulmonary artery pressure in the idiopathic pulmonary arterial hypertension group (50 ± 13 mmHg vs. 40 ± 11 mmHg in pulmonary arterial hypertension associated with connective tissue disease; p = 0.077). On average, peak inspiratory flow rate was higher with RS01-L vs. RS01-M (84 ± 19.7 L/min vs. 70.4 ± 13.2 L/min; p = 0.015). In the overall group, no differences between RS01-L and RS01-M were observed for inhaled volume, inspiratory effort, or flow increase rate. Inhaled volume with RS01-L was higher in pulmonary arterial hypertension associated with connective tissue disease vs. idiopathic pulmonary arterial hypertension patients: 1.6 ± 0.4 L vs. 1.3 ± 0.2 L; p = 0.042. For the RS01-L, inhaled volume correlated with forced expiratory volume in one second (r = 0.460, p = 0.030) and forced vital capacity (r = 0.507, p = 0.015). In patients with pulmonary arterial hypertension associated with connective tissue disease using RS01-L, both inspiratory effort and flow increase rate were highly correlated with pulmonary vascular compliance (r = 0.903, p = 0.0001 and r = 0.906, p = 0.0001; respectively); while with RS01-M, inspiratory effort was highly correlated with pulmonary vascular compliance (r = 0.8, p = 0.001). Our data suggest that the use of RS01-L and RS01-M dry powder inhaler devices allowed adequate inspiratory flow in pulmonary arterial hypertension patients. The correlation between flow increase rate and pulmonary vascular compliance in pulmonary arterial hypertension associated with connective tissue disease deserves further investigation.

Clinical Characterization of Nursing Facility Residents With Chronic Obstructive Pulmonary Disease

OBJECTIVE AND DESIGN

To describe clinical characteristics, medication use, and low peak inspiratory flow rate (PIFR) (< 60 L/min) prevalence in nursing facility residents with chronic obstructive pulmonary disease (COPD).

PATIENTS AND SETTING

Residents 60 years of age and older with a COPD diagnosis and≥ 6 months' nursing facility residence, were enrolled between December 2017 and February 2019 from 26 geographically varied United States nursing facilities.

OUTCOME MEASURES

Data, extracted from residents' charts, included demographic/clinical characteristics, COPD-related medications, exacerbations and hospitalizations within the past 6 months, and functional status from the most recent Minimum Data Set. At enrollment, residents completed the modified Medical Research Council (mMRC) Dyspnea Scale and COPD Assessment Test (CAT™). Spirometry and PIFR were also assessed.

RESULTS

Residents' (N = 179) mean age was 78.0 ± 10.6 years, 63.7% were female, and 57.0% had low PIFR. Most prevalent comorbidities were hypertension (79.9%), depression (49.2%), and heart failure (41.9%). The average forced expiratory volume in 1 second (FEV1₁) % predicted was 45.9% ± 20.9%. On the CAT, 78.2% scored≥ 10 and on the mMRC Dyspnea Scale, 74.1% scored≥ 2, indicating most residents had high COPD symptom burden. Only 49.2% were receiving a scheduled long-acting bronchodilator (LABD). Among those with low PIFR prescribed a LABD, > 80% used dry powder inhalers for medication delivery.

CONCLUSION

This study highlights underutilization of scheduled LABD therapy in nursing facility residents with COPD. Low PIFR was prevalent in residents while the majority used suboptimal medication delivery devices. The findings highlight opportunities for improving management and outcomes for nursing facility residents with COPD.

Inhalation Profiles Through a Dry Powder Inhaler: Relation Between Inhalation Technique and Spirometric Measures

Background: The understanding of the real flow profiles through a dry powder inhaler (DPI), generated by asthma patients, is a prerequisite for satisfactory drug delivery to the lungs. The aims of the study were to assess the relationship between spirometric measures and inhalation profiles through a low-resistance DPI, and to compare parameters of those profiles between optimal and suboptimal inhalation technique type. Methods: Both healthy adult volunteers and patients with asthma were included in the study. Spirometry was conducted along with modified flow-volume test to detect expiratory levels (maximum "100%" exhalation to residual volume [RV] and halfway "50%" to RV). These were the reference levels of the depth of exhalation for each patient to simulate the effect of incomplete exhalation. Individual inhalation profiles were recorded using spirometry in-house software as the volumetric airflow through the inhaler versus time. Inspiratory flow parameters were extracted: time to peak inspiratory flow through inhaler (PIF_inh), time at which peak inspiratory flow occurs (tPIF_inh), total inhalation time (T), and inhaled volume during maneuver (V). Results and Conclusions: There are significant relationships between spirometric indices and parameters of inhalation through a low-resistance, cyclohaler-type DPI (assessed by single-factor analysis of Spearman's rank correlation coefficient). Multiple regression models were constructed, predicting inspiratory flow parameters (including spirometric indices, demographic parameters, and inhaler's usage history as determinants). The exhalation halfway to RV before inhalation did not affect significantly PIF_inh and tPIF_inh (and, thus, initial flow dynamics) in asthma patients. T and V parameters were then significantly decreased, but seemed sufficient for successful DPI performance. Both exhalation to RV and incomplete exhalation halfway to RV preceding inhalation allow for effective usage of low-resistance DPI.

Lung Deposition and Inspiratory Flow Rate in Patients with Chronic Obstructive Pulmonary Disease Using Different Inhalation Devices: A Systematic Literature Review and Expert Opinion

BACKGROUND

Our aim was to describe: 1) lung deposition and inspiratory flow rate; 2) main characteristics of inhaler devices in chronic obstructive pulmonary disease (COPD).

METHODS

A systematic literature review (SLR) was conducted to analyze the features and results of inhaler devices in COPD patients. These devices included pressurized metered-dose inhalers (pMDIs), dry powder inhalers (DPIs), and a soft mist inhaler (SMI). Inclusion and exclusion criteria were established, as well as search strategies (Medline, Embase, and the Cochrane Library up to April 2019). In vitro and in vivo studies were included. Two reviewers selected articles, collected and analyzed data independently. Narrative searches complemented the SLR. We discussed the results of the reviews in a nominal group meeting and agreed on various general principles and recommendations.

RESULTS

The SLR included 71 articles, some were of low-moderate quality, and there was great variability regarding populations and outcomes. Lung deposition rates varied across devices: 8%-53% for pMDIs, 7%-69% for DPIs, and 39%-67% for the SMI. The aerosol exit velocity was high with pMDIs (more than 3 m/s), while it is much slower (0.84-0.72 m/s) with the SMI. In general, pMDIs produce large-sized particles (1.22-8 μm), DPIs produce medium-sized particles (1.8-4.8 µm), and 60% of the particles reach an aerodynamic diameter <5 μm with the SMI. All inhalation devices reach central and peripheral lung regions, but the SMI distribution pattern might be better compared with pMDIs. DPIs' intrinsic resistance is higher than that of pMDIs and SMI, which are relatively similar and low. Depending on the DPI, the minimum flow inspiratory rate required was 30 L/min. pMDIs and SMI did not require a high inspiratory flow rate.

CONCLUSION

Lung deposition and inspiratory flow rate are key factors when selecting an inhalation device in COPD patients.

The contribution of patients' lung function to the inspiratory airflow rate achievable through a DPIs' simulator reproducing different intrinsic resistance rates

Background

The performance of DPIs depends on several physiological (patient-dependent) and technological (device-dependent) factors. The inspiratory airflow rate is the only active force generated and operating in the system for inducing the required pressure drop and eliciting the resistance-induced turbulence needed to disaggregate the powder through the device. The present study aimed to investigate in the most prevalent respiratory disorders whether and at what extent the inspiratory airflow rate achievable when inhaling through a DPIs’ simulator reproducing different intrinsic resistance regimens (low, mid, and high resistance) is affected by peculiar changes in lung function and/or can be predicted by any specific lung function parameter.

Methods

The inspiratory airflow rate was assessed in randomized order by the In-Check DIAL G16 at low, mid, and high resistance regimens in a sample of consecutive subjects at recruitment. Independent predictors of the probability to achieve the expected inhalation airflow rate were investigated by means of a multivariate logistic regression model, specific to the disease.

Results

A total of 114 subjects were recruited (asthmatics n=30; COPD n=50, restrictive patients n=16, and normal subjects n=18). The mean values of the expected inspiratory airflow rate achieved proved significantly different within the groups (p<0.0001), independently of sex and age. In asthmatics and in COPD patients, the mid-resistance regimen proved highly associated with the highest mean values of airflow rates obtained. Low- and high-resistance regimens were significantly less likely to consent to achieve the expected level of inspiratory airflow rate (OR<1 in all comparisons). Restrictive patients performed the lowest airflow rates at the low-resistance regimen (p<0.01). Unlike FEV¹, RV in asthmatics (OR=1.008); RV and I_Raw in COPD (OR=0.587 and OR=0.901, respectively), and FIF and TLC in restrictive patients (OR=1.041, and OR=0.962, respectively) proved the only sensitive predictors of the inspiratory airflow rate achievable at the different resistive regimens.

Conclusions

The intrinsic resistive regimen of DPIs can play a critical role. The patients’ lung function profile also affects the extent of their inhalation airflow rate. Some specific lung function parameters (such as: FIF; RV; I_Raw; TLC, but not FEV₁) may be regarded as specific predictors in real-life. In order to optimize the DPI choice, further to the device’s technology, also the current patients’ lung function should be properly investigated and carefully assessed.

Peak Inspiratory Flow Rate in COPD: An Analysis of Clinical Trial and Real-World Data

Background

The influence of peak inspiratory flow (PIF) on dose delivery from dry powder inhalers (DPIs) and association with treatment efficacy in patients with chronic obstructive pulmonary disease (COPD) has not been fully determined. In vitro studies have demonstrated adequate dose delivery through ELLIPTA DPI at PIF ≥30 L/min. This analysis of two clinical trials and a real-world population of COPD patients determined spirometric PIF distribution, and explored the relationship between PIF and outcomes in the trials.

Methods

The replicate Phase IV, 12-week, randomized, double-blind 207608/207609 (NCT03478683/NCT03478696) trials evaluated fluticasone furoate/umeclidinium/vilanterol via ELLIPTA DPI versus budesonide/formoterol+tiotropium in COPD patients. This post hoc analysis assessed spirometric PIF distribution at screening and relationship between PIF and lung function outcomes in the pooled 207608/207609 population. Spirometric PIF distributions in a real-world population of COPD patients were evaluated by retrospective analysis of the Kaiser Permanente Northwest (KPNW) database to assess similarities between clinical trial and real-world populations.

Results

A total of 1460 (207608/207609) and 3282 (KPNW) patients were included. There was considerable overlap between spirometric PIF distributions for both populations. Overall, 99.7% and 99.8% of the 207608/207609 and KPNW populations, respectively, reported spirometric PIF ≥50 L/min, estimated as equivalent to ELLIPTA PIFR ≥30 L/min. In the 207608/207609 combined analysis, there was no significant interaction between spirometric PIF and treatment for lung function endpoints, indicating treatment effect is independent of PIF.

Conclusion

Nearly all COPD patients in the 207608/207609 and KPNW populations achieved spirometric PIF values estimated as equivalent to PIFR of ≥30 L/min through the ELLIPTA DPI. Lack of correlation between spirometric PIF at screening and treatment efficacy aligns with consistent dose performance from the ELLIPTA DPI across a wide range of PIFs, achieved by patients with COPD of all severities.

Peak Inspiratory Flow as a Predictive Therapeutic Biomarker in COPD

Biomarkers in COPD may be clinical (prior exacerbation history), physiologic (FEV₁), or blood based (eosinophil count or fibrinogen level). Recent interest in using biomarkers to predict response to therapy in clinical practice has emerged. The benefits of inhaled therapy depend on the correct use of the inhaler, including an appropriate inspiratory flow. Of the available delivery systems, dry powder inhalers are unique because they have an internal resistance, are breath actuated, and are flow dependent. Ideally, the user inhales "forcefully" to generate turbulent energy (determined by an individual's inspiratory flow and the resistance of the device) within the device that disaggregates the powder so that the individual inhales the medication particles into the lower respiratory tract. Because of specific features of dry powder inhalers and the required optimal inspiratory flow, an unmet need exists to identify individuals who are likely or unlikely to benefit from dry powder medications. Peak inspiratory flow, defined as the maximum airflow generated during inhalation against the simulated resistance of a dry powder inhaler, is a physiologic measure that has biological plausibility, has good test characteristics (repeatability and reliability), and is generalizable. Current evidence supports peak inspiratory flow as a predictive therapeutic biomarker to optimize therapy in both outpatients with COPD as well as those hospitalized for an exacerbation before discharge. This approach is consistent with the precepts of precision medicine, which considers differences in a person's biological features, exposure, and lifestyle to prevent and treat disease.

A Practice Redesign Collaborative for Reducing Hospital Readmission for Chronic Obstructive Pulmonary Disease in an Affiliated Network of Health Care Organizations

BACKGROUND

Patients discharged following admissions for acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) frequently require unplanned readmissions, increasing costs and morbidity for thousands of patients suffering from COPD. The Hospital Readmissions Reduction Program provided financial incentives to reduce 30-day readmissions for AE-COPD, but although risk factors for readmission are known, few evidence-based interventions achieve this goal. Members of the Mayo Clinic Care Network (MCCN) formed a collaborative to seek ways to reduce 30-day readmission for patients admitted with AE-COPD.

METHODS

Seventeen MCCN organizations participated in an improvement collaborative in 2016 and 2017. Mayo Clinic subject matter experts shared improvement webinars, protocols, and educational materials related to AE-COPD and delivered individualized coaching to facilitate improvement at each site over a six-month engagement. Among other recommended interventions, organizations worked to increase the proportion of COPD patients who had a standardized disease severity staging during admission, inhaler appropriateness evaluations, a COPD treatment action plan, and clinical contact at < 48 hours and 10 ± 4 days postdischarge.

RESULTS

Same-hospital readmission rates improved from 17.7% ± 3.6 to 14.5% ± 4.0 (weighted difference -4.38, p = 0.008, paired t-test). In addition, participating teams stated that the collaborative framework helped them develop strategies that improved patient care and organizational capacity for improvement in other domains.

CONCLUSION

The collaborative framework, beginning with education delivered in person and via webinars, combined with telephonically delivered coaching and knowledge sharing, assisted most members to improve care. Fourteen of 17 participating sites experienced a reduced AE-COPD readmission rate.

Performance Characteristics of Breezhaler® and Aerolizer® in the Real-World Setting

The evaluation of errors in use with different inhaler devices is challenging to quantify as there are a number of definitions of critical and non-critical errors with respect to inhaler use; in addition, performance characteristics of the device, such as airflow resistance, can also influence effective use in the real-world setting. Repeated observations and checking/correcting inhaler use are essential to optimise clinical effectiveness of inhaled therapy in patients. Breezhaler^® is a single unit-dose dry powder inhaler used in chronic obstructive pulmonary disease and in asthma (budesonide) that has low airflow resistance, making it easier for patients of varying disease severities to achieve the inhalation flow rate required for lung deposition of treatment. Similar to Breezhaler^®, the Aerolizer^® is a single unit-dose dry powder inhaler used in asthma management with low airflow resistance. Studies have shown relatively low rates of critical errors with Breezhaler^® and Aerolizer^®, with similarities in the critical errors reported; these data on critical errors together with similarities in the usability of Breezhaler^® and Aerolizer^® further support the functional similarity between the two devices in both asthma and chronic obstructive pulmonary disease. Breezhaler^® also has patient-feedback features, including use of a transparent drug capsule that can be checked after inhalation to see it is empty. The low resistance of the dose-confirming Breezhaler^® results in less inspiratory effort being required by patients for its effective use, which allows the device to be used effectively across a wide age range of patients and disease severities.

The emerging role of nebulization for maintenance treatment of chronic obstructive pulmonary disease at home

Inhalation therapy is the cornerstone of chronic obstructive pulmonary disease (COPD) management. However, for many COPD patients who are managed at home, nebulization therapy offers an effective alternative treatment and fulfills the gap of catering to the specific population of patients who are unable to use handheld inhaler devices appropriately. The present review highlights key aspects, namely selection of the right beneficiaries for home nebulization, available drugs in nebulized formulations for the treatment of COPD, and the importance of care, cleaning, and maintenance, which are prerequisites for ensuring successful nebulization therapy.

Patients with asthma or chronic obstructive pulmonary disease (COPD) can generate sufficient inspiratory flows via Easyhaler® dry powder inhaler: a pooled analysis of two randomized controlled trials

Background

To evaluate whether patients of varying ages and lung function with asthma or those with chronic obstructive pulmonary disease (COPD) can achieve sufficient inspiratory flows for effective use of the fixed-dose combination of salmeterol-fluticasone propionate and budesonide-formoterol dispensed with the Easyhaler^® (EH) device-metered, multi-dose dry powder inhaler (DPI).

Methods

A pooled analysis of two randomized, multicenter, crossover, open-label studies (NCT01424137; NCT009849061) was conducted to characterize inspiratory flow parameters across the EH, Seretide Diskus (DI) and Symbicort Turbuhaler (TH) inhalers in patients with asthma and/or COPD of varying severity. The primary endpoint was peak inspiratory flow (PIF) rate through the EH.

Results

The intent-to-treat population comprised 397 patients; 383 patients were included in the per-protocol (PP) population. The mean PIF (standard deviation) values through the EH in patients <18 and ≥18 years of age with asthma and in those with COPD, were similar: 61.4 (11.5), 69.7 (13.5), and 61.9 (13.2) L/min, respectively. These flow rates correspond to pressure drops of 5.05 (1.80), 6.52 (2.34) and 5.19 (2.07) kPa, respectively. In total, 380 (99.2%) of patients in the PP population were able to generate a PIF rate through the EH of ≥30 L/min, which is required to enable consistent dose delivery from the DPI; there was a moderate direct association between age and PIF in younger patients with asthma, but this was inverse and less apparent in adult patients with asthma and/or those with COPD. Height and weight were also moderately correlated with PIF. Stronger associations with PIF were observed for some lung function parameters, particularly native PIF and forced inspiratory vital capacity.

Conclusions

Over 99% of patients with asthma and/or COPD were able to inhale through the EH with an adequate PIF rate, irrespective of age, or severity of airway obstruction. This confirms that patients with asthma and/or COPD can achieve inspiratory flows via the EH DPI that are sufficient for its effective use.

Consistent Pulmonary Drug Delivery with Whole Lung Deposition Using the Aerosphere Inhaler: A Review of the Evidence

Metered dose inhalers (MDIs) are one of the most common device types for delivering inhaled therapies. However, there are several technical challenges in development and drug delivery of these medications. In particular, suspension-based MDIs are susceptible to suspension heterogeneity, in vitro drug–drug interactions, and patient handling errors, which may all affect drug delivery. To overcome these challenges, new formulation approaches are required. The Aerosphere^TM inhaler, formulated using co-suspension delivery technology, combines drug crystals with porous phospholipid particles to create stable, homogenous suspensions that dissolve once they reach the airways. Two combination therapies using this technology have been developed for the treatment of COPD: glycopyrrolate/formoterol fumarate (GFF MDI; dual combination) and budesonide/glycopyrrolate/formoterol fumarate (BGF MDI; triple combination). Here, we review the evidence with a focus on studies assessing dose delivery, lung deposition, and effects on airway geometry. In vitro assessments have demonstrated that the Aerosphere inhaler provides consistent dose delivery, even in the presence of simulated patient handling errors. Combination therapies delivered with this technology also show a consistent fine particle fraction (FPF) and an optimal particle size distribution for delivery to the central and peripheral airways even when multiple drugs are delivered via the same inhaler. Studies using gamma scintigraphy and functional respiratory imaging have demonstrated that GFF MDI is effectively deposited in the central and peripheral airways, and provides clinically meaningful benefits on airway volume and resistance throughout the lung. Overall, studies suggest that the Aerosphere inhaler, formulated using co-suspension delivery technology, may offer advantages over traditional formulations, including consistent delivery of multiple components across patient handling conditions, optimal particle size and FPF, and effective delivery to the central and peripheral airways. Future studies may provide additional evidence to further characterize the clinical benefits of these technical improvements in MDI drug delivery.

Peak In- and Expiratory Flow Revisited: Reliability and Reference Values in Adults

BACKGROUND

While peak in- and expiratory flow rates offer valuable information for diagnosis and monitoring in respiratory disease, these indices are usually considered too variable to be routinely used for quantification in clinical practice.

OBJECTIVES

The aim of the study was to obtain reproducible measurements of maximal inspiratory flow rates and to construct reference equations for peak in- and expiratory flows (PIF and PEF).

METHOD

With coaching for maximal effort, 187 healthy Caucasian subjects (20-80 years) performed at least 3 combined forced inspiratory and expiratory manoeuvres, until at least 2 peak inspiratory flow measurements were within 10% of each other. The effect on PIF preceded by a slow expiration instead of a forced expiration and PIF repeatability over 3 different days was also investigated in subgroups. Reference values and limits of normal for PIF, mid-inspiratory flow, and PEF were obtained according to the Lambda-Mu-Sigma statistical method.

RESULTS

A valid PIF could be obtained within 3.3 ± 0.6(SD) attempts, resulting in an overall within-test PIF variability of 4.6 ± 3.2(SD)%. A slow instead of a forced expiration prior to forced inspiration resulted in a significant (p < 0.001) but small PIF increase (2.5% on average). Intraclass correlation coefficient for between-day PIF was 0.981 (95% CI: 0.960-0.992). Over the entire age range, inter-subject PIF variability was smaller than in previous reports, and PIF could be predicted based on its determinants gender, age, and height (r2 = 0.53).

CONCLUSIONS

When adhering to similar criteria for the measurement of effort-dependent portions of inspiratory and expiratory flow-volume curves, performed according to current ATS/ERS standards, it is possible to obtain reproducible PIF and PEF values for use in routine clinical practice.

Evaluation of Suboptimal Peak Inspiratory Flow in Patients with Stable COPD

Objective: Although the importance of assessing inspiratory flow in the selection of treatments for chronic obstructive pulmonary disease (COPD) is understood, evaluation of this factor is not yet widespread or standardized. The objective of the present work was to evaluate the peak inspiratory flow (PIF) of patients with COPD and to explore the variables associated with a suboptimal PIF. Methods: An observational, cross-sectional study was carried out at specialized nursing consultations over a period of 6 months. We collected clinical data as well as data on symptoms, treatment adherence, and patient satisfaction with their inhalers via questionnaires. PIF was determined using the In-Check Dial G16^® device (Clement Clarke International, Ltd., Harlow, UK). In each case, the PIF was considered suboptimal when it was off-target for any of the prescribed inhalers. The association with suboptimal PIF was evaluated using multivariate logistic regression and the results were expressed as the odds ratio (OR) with 95% confidence interval (CI). Results: A total of 122 COPD patients were included in this study, of whom 34 (27.9%) had suboptimal PIF. A total of 229 inhalers were tested, of which 186 (81.2%) were dry powder devices. The multivariate analysis found an association between suboptimal PIF and age (OR = 1.072; 95% CI (1.019, 1.128); p = 0.007) and forced vital capacity (OR = 0.961; 95% CI (0.933, 0.989); p = 0.006). Conclusions: About a third of patients in complex specialized COPD care have suboptimal PIFs, which is related to age and forced vital capacity.

Climate change in healthcare: Exploring the potential role of inhaler prescribing

Climate change has been described as the biggest global health threat of the 21st century. As a result, governments around the world are committing to legislative change in order to reduce greenhouse gas emissions (GHGEs). The healthcare sector makes a significant contribution to GHGEs and in line with national legislation in the UK, the NHS has recently committed to achieving net zero emissions by 2050. The management of asthma and COPD largely depends on the prescribing of medications that are delivered through inhalers. In the UK, the use of pressurized metered dose inhalers (pMDIs), which rely on hydrofluorocarbon (HFC) propellants accounts for 3.5% of the NHS's total carbon footprint. In contrast, dry powder inhalers (DPIs) have a much lower carbon footprint due to the absence of a HFC propellant. Here we review evidence of the impact of inhaler choices across four domains: environmental impact, clinical effectiveness, cost effectiveness and patient preferences. We find that as well as a lower global-warming potential, DPIs have additional benefits over pMDIs in other domains and should be considered first line where clinically appropriate.

Clinically Important Deterioration Among Patients with Chronic Obstructive Pulmonary Disease (COPD) Treated with Nebulized Glycopyrrolate: A Post Hoc Analysis of Pooled Data from Two Randomized, Double-Blind, Placebo-Controlled Studies

Purpose

Using a composite endpoint, pooled data from two 12-week Phase III placebo-controlled trials (GOLDEN 3, NCT02347761; GOLDEN 4, NCT02347774) were analyzed to determine whether glycopyrrolate inhalation solution (25 mcg and 50 mcg) administered twice daily (BID) via the eFlow^® Closed System nebulizer (GLY) reduced the risk of clinically important deterioration (CID) in patients with moderate-to-very-severe COPD.

Methods

CID was defined as ≥100-mL decrease from baseline in post-bronchodilator trough forced expiratory volume in one second (FEV₁), or ≥4-unit increase in baseline St. George’s Respiratory Questionnaire (SGRQ) total score, or moderate/severe exacerbation. The relative treatment effect of GLY versus placebo on the odds of CID (any and by component endpoints) was expressed as the odds ratio (OR) and 95% confidence interval (CI). Subgroups categorized by age (<65/≥65 years), sex, smoking status (current/former), long-acting beta agonist (LABA) use, FEV₁ (<50%/≥50%), and peak inspiratory flow rate (PIFR) (<60 L/min/≥60 L/min) were analyzed.

Results

Compared to placebo, GLY 25 mcg and 50 mcg BID over 12 weeks significantly reduced the risk of CID by 50% (OR: 0.50 [0.37–0.68]) and 40% (OR: 0.60 [0.44–0.80]), respectively. Subjects treated with GLY 25 mcg BID were 59% less likely to experience CID in FEV₁ (OR: 0.41 [0.27–0.62]) and 48% less likely to perceive CID in health status (OR: 0.52 [0.37–0.73]). Statistically significant reductions were also observed at the higher dose. The incidence of moderate/severe exacerbations was low and comparable among the cohorts. GLY 25 mcg BID was significantly more effective than placebo (p<0.05) in preventing CID irrespective of age, smoking status, LABA use, COPD severity, or PIFR. Subjects <65 years (OR 0.45 [0.29–0.68]) and those with PIFR <60 L/min (OR 0.36 [0.20–0.67]) exhibited the largest benefit.

Conclusion

Nebulized GLY over 12 weeks significantly reduced the risk of CID and provided greater short-term stability in patients with moderate-to-very-severe COPD.

Nebulized Therapies in COPD: Past, Present, and the Future

Current guidelines recommend inhalation therapy as the preferred route of drug administration for treating patients with chronic obstructive pulmonary disease (COPD). Inhalation devices consist of nebulizers and handheld inhalers, such as dry-powder inhalers (DPIs), pressurized metered-dose inhalers (pMDIs), and soft mist inhalers (SMIs). Although pMDIs, DPIs and SMIs may be appropriate for most patients with COPD, certain patient populations may have challenges with these devices. Patients who have cognitive, neuromuscular, or ventilatory impairments (and receive limited assistance from caregivers), as well as those with suboptimal peak inspiratory flow may not derive the full benefit from handheld inhalers. A considerable number of patients are not capable of producing a peak inspiratory flow rate to overcome the internal resistance of DPIs. Furthermore, patients may have difficulty coordinating inhalation with device actuation, which is required for pMDIs and SMIs. However, inhalation devices such as spacers and valved holding chambers can be used with pMDIs to increase the efficiency of aerosol delivery. Nebulized treatment provides patients with COPD an alternative administration route that avoids the need for inspiratory flow, manual dexterity, or complex hand-breath coordination. The recent approval of two nebulized long-acting muscarinic antagonists has added to the extensive range of nebulized therapies in COPD. Furthermore, with the availability of quieter and more portable nebulizer devices, nebulization may be a useful treatment option in the management of certain patient populations with COPD. The aim of this narrative review was to highlight recent updates and the treatment landscape in nebulized therapy and COPD. We first discuss the pathophysiology of patients with COPD and inhalation device considerations. Second, we review the updates on recently approved and newly marketed nebulized treatments, nebulized treatments currently in development, and technological advances in nebulizer devices. Finally, we discuss the current applications of nebulized therapy in patients with COPD.

Wixela Inhub: Dosing Performance In Vitro and Inhaled Flow Rates in Healthy Subjects and Patients Compared with Advair Diskus

Background: Wixela™ Inhub™ is a fluticasone propionate/salmeterol dry powder inhaler developed as a generic equivalent of Advair Diskus^® for the treatment of asthma and chronic obstructive pulmonary disease (COPD). Wixela Inhub and Advair Diskus are comparable in terms of functionality, user interface, and device resistance. The primary objectives of the studies were to evaluate in vitro dose delivery with Wixela Inhub compared with Advair Diskus at relevant flow rates and to explore inhalation profiles generated by patients with asthma or COPD. Methods: In vitro studies: Emitted dose (ED) and individual dose aerodynamic particle size distribution (APSD) were measured at flow rates ranging from 30 to 90 L min^-1. Patient inhalation study: Inhalation profile recording was conducted three times in each patient (40 children with asthma, 14 adults with asthma, and 14 adults with severe-to-very-severe COPD) with an empty Inhub in an open-label study. The primary endpoint was peak inhaled flow rate (PIFR). An additional endpoint was peak pressure drop. Results: In vitro studies: ED and APSD delivered from Wixela Inhub showed low flow dependency across the patient-relevant flow-rate range. Wixela Inhub gave in vitro performance comparable with Advair Diskus for all strengths and flow rates. Patient inhalation study: For Inhub, mean PIFR was lowest for children with asthma ages 4 to 7 years (50.6 L min^-1) and highest for adults with asthma (74.8 L min^-1). For adults with severe-to-very-severe COPD, mean PIFR was 69.5 L min^-1 with Inhub. The PIFRs observed with Diskus were higher than those with Inhub, consistent with slightly higher resistance measured in vitro. The difference in resistance did not impact demonstration of bioequivalence and does not impact substitutability of the product. Peak pressure drop values were comparable between Diskus and Inhub. Conclusions: Comparable in vitro performance of Wixela Inhub to Advair Diskus confirmed that Wixela Inhub is a generic equivalent to Advair Diskus across all patient groups.

Inappropriate Peak Inspiratory Flow Rate with Dry Powder Inhaler in Chronic Obstructive Pulmonary Disease

Optimal peak inspiratory flow rate (PIFR) is crucial for optimizing dry powder inhaler (DPI) effectiveness for chronic obstructive pulmonary disease (COPD). This study provide an insight that there was a substantial proportion of improper PIFRs (not only insufficient but also excessive) among COPD patients using DPIs. We enrolled 138 COPD patients from a medical center in Taiwan and measured PIFRs against different internal resistances of DPIs. Proportion of excessive, optimal, suboptimal, and insufficient PIFRs were 2%, 54%, 41%, 3%, respectively, against medium-high resistance; 2%, 77%, 20%, 1%, respectively, against medium resistance; 27%, 63%, 9%, 1%, respectively, against medium-low resistance; and 42%, 57%, 1%, 0%, respectively, against low resistance (p < 0.01). Although most PIFRs against medium-high (54%), medium (77%), medium-low (63%) and low (57%) resistance were optimal, a substantial proportion of PIFRs against low resistance were excessive (42%, p < 0.01), irrespective of age, body-mass index, dyspnea severity score, and COPD severity. Insufficient PIFRs were infrequent, but suboptimal/insufficient PIFRs were most prevalent in patients older than 75 years than in younger patients (36% vs. 56%, p = 0.036) against medium-high resistance. Regularly monitoring PIFRs against the specific resistance of the DPIs and instructing patients to employ a proper inspiration effort may help to optimize the effects of DPIs.