Oxygen Versus Air-Driven Nebulisers for Exacerbations of Chronic Obstructive Pulmonary Disease

A Randomised Controlled Trial

George Bardsley; Janine Pilcher; Steven McKinstry; Philippa Shirtcliffe; James Berry; James Fingleton; Mark Weatherall; Richard Beasley


BMC Pulm Med. 2018;18(157) 

In This Article


In acute exacerbations of chronic obstructive pulmonary disease (AECOPD), administration of high concentration oxygen may cause profound hypercapnia and increase mortality, compared with oxygen titrated to achieve an oxygen saturation of between 88 to 92%.[1,2] Titrated oxygen regimens require two components: titrated supplemental oxygen to achieve a particular target arterial oxygen saturation measured by pulse oximetry (SpO2), and bronchodilators delivered by either air-driven nebulisation or metered-dose inhalers with a spacer. Oxygen-driven nebulisation inadvertently exposes patients to high concentrations of inspired oxygen, particularly with prolonged or repeated use as may occur in patients with severe exacerbations during long pre-hospital transfers or if the mask is inadvertently left in place.

We have shown that air-driven bronchodilator nebulisation prevents the increase in arterial partial pressure of carbon dioxide (PaCO2) that results from use of oxygen-driven nebulisers in patients with stable COPD.[3] However, there are only two small non-blinded randomised controlled trials of air compared to oxygen-driven nebulisation in patients admitted to hospital with AECOPD.[4,5] These trials reported that administration of a single bronchodilator dose using oxygen-driven nebulisation increases the PaCO2 in COPD patients who have baseline hypercapnia.

Robust determination of the risks of oxygen-driven nebulisation in AECOPD could identify whether widespread implementation of air-driven nebulisers, or use of metered-dose inhalers through a spacer, are required to ensure safe delivery of bronchodilators to this high-risk patient group. The objective of this study was to compare the effects on PaCO2 of air- and oxygen-driven bronchodilator nebulisation in AECOPD. Our hypothesis was that two doses of oxygen-driven bronchodilator nebulisation would increase the PaCO2 compared with air-driven nebulisation in patients hospitalised with an AECOPD.