Can all patients with COPD use the correct inhalation flow with all inhalers and does training help?

Abstract

The inhalation rate is important when patients use an inhaler. Dry powder inhalers (DPIs) require an inhalation rate >30 L min(-1) whereas metered dose inhalers (MDIs) should be used at <90 L min(-1). Within the setting of a routine clinic, we have measured peak inhalation flows (PIF) of COPD patients when they used a Diskus (SDSK), Turbuhaler (STBH), Handihaler (SHAND) and MDI. Subjects were then randomised into trained (VT) and non-trained (NT) groups. One hundred and sixty-three patients with a mean (S.D.) age and % predicted FEV(1) of 72.5 (9.9) years and 47.8 (22.2)% completed the study. Of the patients, 4.9%, 14.2% and 57.0% inhaled <30 L min(-1) through SDSK, STHB and SHAND, respectively and 59.5% inhaled >90 L min(-1) with the MDI. Generally, the more severe the COPD, the slower was their PIF with all inhalers. The MDI PIF values in the VT group (n=84) post-training were significantly (p<0.001) slower but there was no change for the DPIs. Of the 55 VT patients inhaling >90 L min(-1) through the MDI only 7 (p<0.001) inhaled too fast post-training. Pre-training 3, 15 and 46 VT subjects inhaled <30 L min(-1) through the SDSK, STBH and SHAND and after training none, 5 and 26 did not inhale faster than this minimum required rate. Some COPD patients have problems achieving required PIFs through DPIs but training is useful to help some exceed the minimum required rate despite only small improvements. The patients found it easier to slow their PIF through the MDI.

Inhaler technique: does age matter? A systematic review

“…This may be difficult to rectify in practice, with changes subsequent to counselling considered too minor to be cost-effective [39]. The effectiveness of training also appears to be superior with the MDI relative to the DPI [40], demanding a greater consideration of PIF rate in elderly patients prior to device selection.…”

Inhaler technique and training in people with chronic obstructive pulmonary disease and asthma

“…Many of the difficulties with pMDIs are related to the need to coordinate activation of the device while inhaling slowly and deeply. Al-Showair et al demonstrated that approximately 60 and 92% of patients with COPD and asthma, respectively, were inhaling too fast from a pMDI [20,21].…”

“…In one study determining whole lung deposition using the charcoal block method, deposition of radiolabeled terbutaline was reduced by a third by increasing the airflow through the MDI device from 30 to 180 l/min (mean ± standard deviation: 11.2 ± 4.0 vs 7.2 ± 2.2; p < 0.05) [50]. A significant proportion of patients with asthma and COPD have been shown to have an inspiratory flow too high for an MDI, which could potentially reduce the clinical effectiveness of inhaled drugs [20,21].…”

“…The ability to generate appropriate inspiratory flow is particularly important for patients with severe airflow obstruction, young children and the elderly [40]. Peak inspiratory flow through a Accuhaler, Turbohaler and HandiHaler device have been shown to be too slow among 4.9, 14.2 and 57.0% of patients with COPD, respectively [20].…”

“…The effect of increased airflow resistance on inhalation flow has been demonstrated [20], and it can be seen that lower inhalation flows can be achieved through the devices with the highest airflow resistance (the Easyhaler ® [Orion Pharma, UK]and HandiHaler) than through devices with lower resistance, such as the Accuhaler (TaBle 1). Consequently, using the same amount of effort of inhalation, patients can achieve faster inspiratory flows through the Accuhaler, than through a Turbohaler, HandiHaler or Easyhaler device.…”