Spacer devices for inhaled therapy: why use them, and how?

Abstract

We present an extensive review of the literature to date pertaining to the rationale for using a spacer/valved holding chamber (VHC) to deliver inhaled therapy from a pressurised, metered-dose inhaler, a discussion of how the properties of individual devices may vary according to their physical characteristics and materials of manufacture, the potential risks and benefits of ancillaries such as valves, and the evidence that they contribute tangibly to the delivery of therapy.We also reiterate practical recommendations for the correct usage and maintenance of spacers/VHCs, which we trust offer practical help and advice to patients and healthcare professionals alike.

Engineering of Nebulized Metal–Phenolic Capsules for Controlled Pulmonary Deposition

“…To enable control of capsule deposition, a spacer was added between the nebulizer and the NGI (Figure S17, see section Aerodynamic Behavior Analysis, Supporting Information). A spacer is commonly used in practice together with inhalation devices to produce fine aerosols by slowing down the aerosol cloud and promoting evaporation and filtration of larger aerosol particles . With the spacer in place, only the finer droplets entered the NGI, which appeared dry on the collection cups after 20 min of nebulization (Figure S15b, Supporting Information).…”

In vitro drug delivery performance of five valved holding chambers with and without facemasks

“…On the other hand, Vortex (194 mL) performed significantly better than A2A without masks, despite having a similar volume. It has been speculated that the aerosol concentration and particle impaction in a larger volume VHC are less than those in a smaller volume VHC, which results in lower inhaled doses at a small V T but higher doses when the VHC can be emptied faster with a larger V T . However, chamber volume is not the only factor that affects drug delivery .…”

“…V T but higher doses when the VHC can be emptied faster with a larger V T . 17,29 However, chamber volume is not the only factor that affects drug delivery. 11,24 For example, Vortex, and A2A have comparable chamber volumes but differed in almost every other aspect (eg, shape, material, and valve design), any of which could be responsible for the recovered drug mass on the filter.…”

“…Studies evaluating drug delivery by VHCs have mainly been performed with inspiratory flow rates of 20 to 60 L/minute, and only a few have used rates below 10 L/minute . Nevertheless, drug delivery is dependent on the patient population since the breathing pattern, V T , peak inspiratory flow rate (PIFR), and resting RR all change with growth and development . Tidal volume is approximately 7 to 10 mL/kg of ideal body weight in the first few years of life.…”

“…[14][15][16] Nevertheless, drug delivery is dependent on the patient population since the breathing pattern, V T , peak inspiratory flow rate (PIFR), and resting RR all change with growth and development. 13,[17][18][19] Tidal volume is approximately 7 to 10 mL/kg of ideal body weight 19 in the first few years of life. With age, RR decreases while V T increases.…”