What is it about?
Heliox is a helium-oxygen mixture at either 80:20 or 70:30 mixtures. It is known to be much lighter than normal air and has no known poisonous side effects. It was first test in the 1930’s in patients experiencing asthma and compared with patients receiving normal air. Some early medicines were given alongside the helium-oxygen mixtures and this showed benefits over standard air treatment. However, the advent of more modern medicines after World War II resulted in helium-oxygen being cast aside. The rebirth of helium-oxygen mixture use in asthma began in 1976 with case study reports of its use up until 1987, where it became known as Heliox. Despite case study reports of its efficiency, Heliox therapy continues to be viewed as experimental due a limited number of randomised controlled trials across Emergency Department and Intensive Care Units worldwide. There have been no trials within the pre-hospital setting to determine whether the administration of Heliox in tandem with current drug therapy in moderate-severe asthma offers further benefit to patients.
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Why is it important?
The studies have identified that Heliox offered benefit to patient within the Emergency Department setting who were experiencing a peak expiratory flow rate (PEFR) of <50% of their predicted range in tandem with agreed drug therapy (i.e. bronchodilator and corticosteroid) in the management of asthma exacerbations. Similar findings were identified in the Intensive Care Unit (ICU) setting, with some patients showing a clinically significant improvement in oxygenation and shorter treatement time compared with standard oxygen-nitrogen mixture use. There is a paucity of evidence surrounding Ambulance use of Heliox primarily because the delivery module is not suitable for Ambulance transportation and the Heliox cylinders are non-portable. Consent to Heliox treatment requires some consideration as patients who would benefit from this therapy are likely to be hypoxic and may not understand the side effects of the treatment e.g. high pitched voice. The cost of Heliox, at the time of publication, is reported to be four times that of standard oxygen-nitrogen therapy and is likely to have an impact on the funding of trials and use within hospitals. Further controlled trials are needed within the hospital setting and potentially a trial within pre-hospital care.
Perspectives
Early initiation of treatment in severe asthma presentations is likely to offer significant benefits to the patient and wider healthcare systems. Ambulance Practitioners have the ability to deliver critical care interventions in the pre-hospital setting to facilitate on-going patient treatment within the receiving hospital unit. The ability to utilise a helium-oxygen mixture that supports quicker drug delivery in the lungs, a perceived patient reduction in dyspnoea and shorter patient treatment times is likely to be welcomed by clinical practitioners. However, the limited number of Heliox studies is currently insufficient to inform a decision on wider use. This is only compounded by the costs associated with its use and a lack of portability of the equipment. Further research and innovation is needed in this area to determine if this is a potential future treatement for severe asthma presentations within UK practice.
Mr Steven Scholes
North West Ambulance Service NHS Trust
Read the Original
This page is a summary of: Heliox in acute severe asthma in the A&E setting: a review, Journal of Paramedic Practice, March 2009, Mark Allen Group,
DOI: 10.12968/jpar.2009.1.6.42047.
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