Ability of patients with asthma to achieve correct inspiratory flow rates for different inhalers — insights from Dr Omar Usmani

Consultant physician Doctor Omar Usmani, from Imperial College London and Royal Brompton Hospital, gave his expert insights on the correct inhalation technique for dry powder inhalers and metered dose inhalers, and shared the results of his recently published study¹ in a video interview:

• Inhaling with the optimal peak inspiratory flow rate (PIFR) is important for efficient drug delivery from an inhaler.
• Patients with asthma were more often able to achieve a PIFR in the optimal range for a high-resistance dry powder inhaler than for a metered dose inhaler.
• It is important for healthcare professionals to ensure that each respiratory patient has the inhaler that is right for them and is able to use it correctly.

In the management of asthma it is important that each patient has an inhaler device they are able to use efficiently. One key factor in successful inhaler use is the patient’s ability to inhale with the optimal peak inspiratory flow rate (PIFR). Since metered dose inhalers (MDIs) and dry powder inhalers (DPIs) require different PIFRs and inhalation techniques, it is important that healthcare professionals know how to instruct the patients accordingly.

Dr. Omar Usmani talked about these topics in a video. “It is important that our patients use the correct inhalation technique and have the correct inhalation flow for the device they are using. But it is also important that we as healthcare professionals instruct our patients properly,” Dr Usmani highlighted.

Dr. Usmani also presented a study he recently published together with his colleagues.¹ The aim of the study was to estimate the ability of patients with asthma to generate a PIFR in the optimal range for MDIs and DPIs. The PIFRs of 994 patients were measured with the In-Check DIAL device using various resistance settings, from R0 (MDI equivalent) to R5 (high-resistance DPI equivalent).

They found that nearly all patients (94%) were able to achieve the optimal PIFR with the high resistance setting (R5). A total of 71% of patients were able to achieve the optimal PIFR with an R0 resistance setting. The patients tended to have too strong inhalation for this setting: “The biggest problem for these patients was that they inhaled too fast, over 60 L/min”, Usmani explained.

Dr Usmani also talked about the results on patients’ ability to inhale optimally from the device they were currently using. Only 1% of current DPI users failed to achieve an optimal inhalation flow for the resistance of their inhaler device. In contrast, one in five MDI users inhaled too fast for their own device.

Doctor Omar Usmani talks about peak inspiratory flow rates. The video can be seen here.

As his first take-home message, Dr Usmani highlighted that the inhaler resistance and patient’s inspiratory flow effort work together to allow the drug to be efficiently deposited into the lungs. His second take-home message was a reminder that every healthcare professional should instruct the patients correctly for their inhaler use. He emphasized that, “Every time we see any respiratory patient using an inhaler device, we need to make sure that they have the correct device for them to be able to achieve the best in terms of managing their condition”.