CMO better for severe respiratory failure

Patients with severe acute respiratory failure from conditions such as swine flue should be treated with extracorporeal membrane reoxygenation (ECMO) rather than conventional ventilation to improve their chances of survival without disability.

These are the conclusions of an article published in the Lancet today by Dr Giles Peek of Glenfield Hospital in Leicester, Prof Miranda Mugford of the University of East Anglia (pictured), and Prof Diana Elbourne of the London School of Hygiene and Tropical Medicine. ECMO is cost-effective and has already been a vital tool for battling swine flu. It will be essential during the northern hemisphere winter when cases could rise dramatically again.Severe acute respiratory failure (ARF) causes high mortality in adults despite improvements in ventilation techniques and other treatments such as steroids and 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 the Lancet 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. IIn a UK-based randomised controlled trial, 180 adults were randomly assigned to receive either 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 before hospital discharge or death severe disability by six 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 one extra survivor without disability for every six patients treated. Consideration of ECMO treatment led to a gain of 0.03 QALYs at six-month follow-up. Use of modelling, making assumptions about life expectancy, costs and quality of life after six months, predicted that the cost per QALY of ECMO referral as £19,252. 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 report concluded: “This study shows a significant improvement in survival without severe disability at six months in patients transferred to a specialist centre for consideration for ECMO treatment compared with continued conventional ventilation.“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 said: “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.”

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