Comparison of inhalation technique with the Diskus and Autohaler in asthmatic children at home

Discussion

We found that the inhalation technique with the Autohaler was well maintained after inhalation instructions, as in 96% of the study days no critical errors were made with this device. In contrast, we observed that the quality of medication administration with the Diskus declined rapidly after receiving instructions. Worryingly, the daily technique with the Diskus was not well reflected by demonstration in the hospital, overestimating the technique at home.

To our knowledge, this is the first study to investigate the inhalation technique of asthmatic children by filming inhalations at home. Previous studies focused on inhalation technique demonstrated in a primary-care or hospital setting, where technique was assessed through video conferencing [11] or directly in front of healthcare providers and caregivers.

Studies focusing on the inhalation technique of children using dry-powder inhalers show a wide range of correct use. In a study by Sleath et al. [12], correct Diskus use was found in only 21.9% of the study population. Capanoglu et al. [5] found correct use in 34.6% of their patients, comparable with the correct use of our study population at home. In a study by Malot et al. [13], primary-care physicians assessed the inhalation technique of children with their current device using device-specific checklists. They found that 46% of the population made at least one mistake with the Diskus.

Kamps et al. [8] observed a correct inhalation technique with the Diskus in 79% of their study patients who had received instructions at a pharmacy, compared to 39% of the patients who had been trained by their general practitioner. In a control group that was trained at least twice by a research fellow during a 6-week period, 93% showed a correct technique. Similarly to Kamps et al., we provided comprehensive inhalation instructions consisting of both information and training of inhalation technique. The difference in correct inhalation technique after receiving instructions between our study and the study by Kamps et al. could be due to the fact that the most common critical error in our study group was an incorrect positioning of the device during preparation; an error that was not taken into account in the aforementioned study. Additionally, the provision of repetitive inhalation instructions is likely to have had a positive effect on the sustainability of inhalation technique, as has been shown before by the same authors [14].

The most prevalent critical error in daily life with the Diskus was an incorrect preparation of the dose before inhalation; holding the device in a vertical position after opening the inhaler or holding the counter downwards. In the home situation this error was made during 42.5% of the inhalations. However, only five (18.5%) out of 27 children showed this error in the hospital during demonstration. Another common critical error at home with the Diskus was not performing a deep inhalation (13.1%). Only one child showed this error in the hospital. Apparently children are less focused on a correct inhalation technique at home compared to a demonstration in the hospital in front of healthcare professionals. It is to be expected that the technique of children who are not participating in a clinical trial and being filmed, would be even less accurate. The risk of overestimating the inhalation technique with the Diskus should therefore be taken into account by healthcare providers.

Technology-based methods for the monitoring of inhalation technique in general are promising. Several novel methods show good feasibility [11] and efficacy when it comes to maintaining a correct inhaler use [15]. Sulaiman et al. [16] used a device that focused on both adherence and inhalation technique, monitoring most critical errors. Although efficacy on healthcare outcomes has not yet been proven [17], these novel methods could reduce the burden of hospital visits focusing on inhalation technique [15]. There is a need for controlled studies investigating these new monitoring methods, focussing on both clinical outcomes and healthcare costs.

Although the Autohaler is a commonly used device, we only found one other study focusing on the inhalation technique with this device in a paediatric population. In the aforementioned study by Malot et al. [13], 57% of the children made at least one error and 8% one critical error using the Autohaler. Similar to our study, an insufficiently deep inhalation was scored as a critical error. However, the second most frequent mistake in our population, an insufficient breath-hold, was not scored as critical by Malot et al., making comparison with our results difficult.

The two most common errors in our population were made slightly more frequent in the hospital than at home. However, due to the overall low prevalence of errors with the Autohaler, this comparison is less powerful for this device.

A recent systematic review by Usmani et al. [18] showed a large variation in how critical inhalation errors are defined for different inhalation devices. For the Autohaler as example, there is no consensus on whether to label an insufficient breath-hold as critical or noncritical, and how long this breath-hold should be. The large variation in how inhalation errors are labelled makes it difficult to compare studies and to create a clear overview of the magnitude of the problem. We agree with Usmani et al. that there is need for a consensus on defining critical and noncritical errors.

In our study, we provided comprehensive inhalation instructions for the participants, based on a checklist with seven critical errors, adapted from an inhalation checklist from the LAN [9] and based on our expert opinion. Children were only included if their technique for both devices was correct following instructions. This way, we tried to create the same correct baseline technique for both devices. The same nurse practitioner provided the inhalation technique training for all participants and scored the filmed inhalations and the hospital demonstrations.

A limitation of our study is that children used two devices simultaneously, which could have led to an increase in errors per device. Conversely, it is plausible that by filming the inhalations at home the behaviour of the participants was positively influenced. Therefore, we suspect that in real life, inhalation technique for both devices will be worse than we showed in this study. As mentioned before, our checklist with critical errors was based on expert opinion and a widely used inhalation checklist in the Netherlands [14]. Our list with critical errors was not validated, and therefore our choice of different errors may be subject to discussion.

Proper administration of inhaled medication is essential for effective asthma treatment. This includes a correct preparation of the dose before inhalation, especially with the Diskus. Healthcare professionals should be aware of device-specific critical errors and should put emphasis on these possible errors during training of technique. We recommend the development of technological solutions focussing on the monitoring of inhalation technique and the provision of feedback in daily life, thereby hopefully reducing critical errors and optimising therapy.

In summary, inhalation technique at home was markedly better with the Autohaler than with the Diskus after receiving one inhalation instruction in the hospital. Healthcare professionals should be aware that hospital-based demonstrations can overestimate daily inhalation technique in children, but probably also in adults with asthma or COPD, especially when using the Diskus.