ECMO Is Better Than Conventional Ventilation For Treating Severe Respiratory Failure From Conditions Like Swine Flu (CESAR Trial)

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Main Category: Respiratory / Asthma
Also Included In: Swine Flu
Article Date: 16 Sep 2009 - 2:00 PDT

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An article published Online First and in a future edition of The Lancet reports that patients with severe acute respiratory failure (ARF) should be referred for treatment using extracorporeal membrane oxygenation (ECMO). This approach improves their chances of survival without disability compared to using conventional ventilator management. ECMO would be cost-effective in the UK and other countries with similar health care costs. It has already been a vital tool for battling swine flu and will be essential during the northern hemisphere winter when cases could rise dramatically again. The article is the work of Dr Giles Peek, Department of Cardiothoracic Surgery and Extracorporeal Membrane Oxygenation, Glenfield Hospital, Leicester, UK, Professor Miranda Mugford, University of East Anglia, UK, and Professor Diana Elbourne of the London School of Hygiene and Tropical Medicine, UK, and colleagues.

Despite improvements in ventilation techniques and other treatments, such as steroids, inhaled nitricoxide, severe ARF causes high mortality in adults. Conventional treatment is by intermittent positive-pressure ventilation where oxygen-enriched air is blown into the lungs at high pressure. This in turn causes oxygen toxicity and pressure injury to the lung tissue additional to the original lung disease, delaying or preventing recovery. ECMO is an alternative which uses heart-lung bypass technology to provide gas exchange outside the body. This allows time for the lung treatment and recovery. Heparin is also given to prevent the blood clotting when it passes through the ECMO system.

In this study, the authors compared treatment by a specialized ECMO team with care from specialist intensive care unit teams using conventional ventilation. They also assessed the cost-effectiveness of referral for ECMO care. This UK-based randomized controlled trial included 180 adults. They were randomly assigned to receive continued conventional management (90 patients) or ECMO (90 patients). Eligible patients were aged 18 to 65 years and had severe but potentially reversible respiratory failure. The primary outcome was death or severe disability at six months after randomization. Data about resource use and economic outcomes were collected and measured in quality-adjusted life-years (QALYs).

Results showed that 75 percent of the patients (68 of the 90) assigned to consideration of ECMO in fact received it. Of those referred for consideration of ECMO, 63 percent survived six months without disability compared to 47 percent of those who were assigned to conventional management. This translates to one extra survivor without disability for every six patients treated. At the six month follow-up, consideration of ECMO treatment led to a gain of 0.03 QALYs. It was estimated that the cost per QALY of ECMO referral was £19,252 by using modeling, making assumptions about life expectancy, costs and quality of life after six months. The cost per case was twice that for conventional treatment. However, the cost-effectiveness was still well within the range considered as cost-effective by health technology assessment organizations (such as the UK's National Institute for Health and Clinical Excellence (NICE)).

The authors explain: "This study shows a significant improvement in survival without severe disability at 6 months in patients transferred to a specialist centre for consideration for ECMO treatment compared with continued conventional ventilation."

They write in conclusion: "The cost-effectiveness of ECMO would be improved if costs of both transport and provision of the technique could be reduced...We are confident that ECMO is a clinically effective treatment for acute respiratory distress syndrome, which also promises to be cost effective in comparison with other techniques competing for health resources."

Dr Peek remarks: "Swine flu causes a viral pneumonia which can result in severe respiratory failure in young adults, we have already used ECMO during the first wave of the pandemic with good effect and we are expecting ECMO to prove an invaluable weapon in the fight against the winter resurgence of the infection, as has already been seen during the Australasian winter."

In an associated note, Dr Joseph B Zwischenberger, University of Kentucky College of Medicine, Lexington, KY, USA, and James E Lynch, ECMO program director, University of Texas Medical Branch, Galveston, TX, USA, conclude: "The CESAR group should be congratulated on completion of such a complex and large trial. The debate that will surround this study reflects the difficulty of this type of research in the critically ill patient. This study will likely provide ammunition for both those in favour and those against the use of ECMO in the adult population."

"Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial"
Giles J Peek, Miranda Mugford, Ravindranath Tiruvoipati, Andrew Wilson, Elizabeth Allen, Mariamma M Thalanany, Clare L Hibbert, Ann Truesdale, Felicity Clemens, Nicola Cooper, Richard K Firmin, Diana Elbourne, for the CESAR trial collaboration
DOI: 10.1016/S0140-6736(09)61069-2
The Lancet

Written by Stephanie Brunner (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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