Technical Evaluation of Soft Mist Inhaler Use in Patients with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study.

Background: Proper inhaler technique is highly relevant to the effective management of chronic obstructive pulmonary disease (COPD). The tiotropium bromide spray (TBS) (Spiriva Respimat) is a soft mist inhaler (SMI) preferred by patients to pressurized metered-dose inhalers (pMDIs) and dry powder inhalers (DPIs) because of its convenience in use. However, the technique of using TBS inhaler in the real world is unclear.

Objective: To evaluate techniques in using TBS inhaler and investigate the association between the patient characteristics and the correct use of TBS inhaler.

Methods: This cross-sectional study enrolled 74 COPD patients who used TBS inhaler device for more than 3 months. The sociodemographic and clinical characteristics of the patients were recorded. The technique of using TBS inhaler was evaluated step by step. Incorrect use was defined as the patient's inability to complete the key steps in the inhalation manoeuvre. The percentage of incorrect use was compared between the groups. Risk factors related to incorrect use were analyzed by logistic regression analysis.

Results: Of the 74 participants, only 2 (2.7%) patients completed all the steps correctly, and 48 (64.9%) patients misused the key steps in the inhalation manoeuvre. Incorrect preparation of the TBS inhaler for the first use was the most frequently misused step, accounting for 77.0%. Factors associated with misuse of TBS inhaler included the educational background (p=0.010), living state (p=0.031) and COPD assessment test (CAT) score (p=0.005) of the patients. Additionally, logistic regression analysis showed that the COPD duration was significantly associated with the incorrect use (p=0.019). Compared with patients with a higher educational background, patients with an elementary school background [OR 11652.99, CI: 22.72-5975697.72], junior high school background [OR 7187.78, CI: 16.41-3146787] and high school background [OR 1563, CI: 4.27-572329.67] were more likely to misuse TBS inhaler. Patients living with their spouses alone were also more likely to commit errors in using TBS inhaler as compared with those living with their children [OR 12.29, CI of 1.14-1.96]. Clinical factors like the COPD symptoms were relative to the technical use of the device. Better technique was accompanied by a lower CAT score [OR 1.49, CI of 1.14-1.96].

Conclusion: The incorrect use of TBS inhaler was common in COPD patients. Healthcare providers should not only teach the patients about the drug preparation but help them use the inhaler correctly. Special attention should be paid to patients with a short COPD duration and a low educational background and those who live without the company of their children. Proper use of TBS inhaler can significantly improve the symptom control of COPD patients.