Treatment For Severe Respiratory Failure From Conditions Like Swine Flu Is Better When ECMO Is Part Of Treatment Than With Conventional Ventilation

Main Category: Respiratory / Asthma
Also Included In: Swine Flu;  Flu / Cold / SARS
Article Date: 23 Sep 2009 - 0:00 PDT

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Patients with severe acute respiratory failure (ARF) should be referred for treatment using extracorporeal membrane `oxygenation (ECMO), rather than using conventional ventilator management, to improve their chances of survival without disability. ECMO would be cost-effective in the UK and other countries with similar health care costs. These are the conclusions of an Article published Online First and in a forthcoming edition of The Lancet, written by 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. ECMO 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.

Severe ARF causes high mortality in adults despite improvements in ventilation techniques and other treatments (eg, steroids, inhaled nitric oxide). Conventional management 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 on top of the underlying lung disease, delaying or preventing recovery. ECMO is an alternative which uses heart-lung bypass technology to provide gas exchange outside the body, allowing 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 specialised ECMO team with care from specialist intensive care unit teams using conventional ventilation, and also assessed the cost-effectiveness of referral for ECMO care. In this UK-based randomised controlled trial, 180 adults were randomly assigned to receive continued conventional management (90) or ECMO (90). Eligible patients were aged 18-65 years and had severe but potentially reversible respiratory failure. The primary outcome was death or severe disability at 6 months after randomisation. Data about resource use and economic outcomes (quality-adjusted life-years [QALYs]) were collected.

The researchers found that 68 of the 90 patients (75%) assigned to consideration of ECMO actually received it. Of those referred for consideration of ECMO, 63% survived to 6 months without disability compared to 47% of those who were assigned to conventional management. This is equivalent to 1 extra survivor without disability for every 6 patients treated. Consideration of ECMO treatment led to a gain of 0.03 QALYs at 6-month follow-up. Use of modelling, making assumptions about life expectancy, costs and quality of life after 6 months, predicted that the cost per QALY of ECMO referral as ÂŁ19,252. The cost per case was twice that for conventional treatment, but the cost-effectiveness was still well within the range regarded as cost-effective by health technology assessment organisations such as the UK's National Institute for Health and Clinical Excellence (NICE).

The authors say: "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 conclude: "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 adds*: "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 accompanying Comment, Dr Joseph B Zwischenberger, University of Kentucky College of Medicine, Lexington, KY, USA, and James E Lynch, ECMO programme 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."

Source
The Lancet

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